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Effect of the Synchronization of the Degradation of Dietary Crude Protein and Organic Matter and Feeding Frequency on Ruminal Fermentation and Flow of Digesta in the Abomasum of Dairy Cows
Abstract
Four Holstein cows in midlactation were equipped with ruminal and abomasal cannulas and used to study the effect of synchronized degradation of crude protein (CP) and organic matter (OM) and feeding frequency on digestion and outflow of nutrients. A 4 x 4 Latin square design was used. Diets were arranged in a 2 x 2 factorial design; the four diets contained high ruminally degradable OM and high ruminally degradable CP, high ruminally degradable OM and low ruminally degradable CP, low ruminally degradable OM and high ruminally degradable CP, and low ruminally degradable OM and low ruminally degradable CP. In each period, cows were fed four times daily from d 1 to 14 and two times daily from d 15 to 28. Mean daily ruminal ammonia N concentration was reduced by high ruminally degradable OM, low ruminally degradable CP, and twice daily feeding. Fluctuation in ruminal ammonia N was lower when cows were fed four times daily than when cows were fed twice daily. Plasma urea N concentrations were lower for cows fed diets that were high in ruminally degradable CP. Higher CP flow in the abomasum was found for cows fed the diet containing high ruminally degradable OM and low ruminally degradable CP. Microbial dry matter and CP flow to the abomasum were higher for cows fed twice daily than for cows fed four times daily. Flow of OM in the abomasum was not altered by concentrations of ruminally degradable OM or CP. These results suggest that the available energy in the rumen (ruminally degradable OM) is the most limiting factor for ruminal N utilization under our experimental conditions. Use of these data may improve the prediction of plasma urea N.
... [10] Indicated that Awassi lambs increased their feed intake when fresh feed was provided to them continuously, and the frequency of feeding with fresh feed stimulates the appetite of the lambs, and thus its effect on the performance of the lambs and carcass characteristics. [11] And [12] indicated that the frequency of feeding increased weight of the lambs because of stimulation of the digestive system, salivary glands, and rumen secretions. It also affected the rumen resuscitation positively. ...
... [31] and [19] indicated that feeding frequency increased body fat deposition significantly. As for [32] and [12], they confirmed that the frequency of feeding significantly reduced the deposition of fat in the body, and as indicated by [26] that the frequency of feeding significantly reduced the internal fat of the body. ...
... Subcutaneous fat thickness: The consequences did not show any significant differences in the subcutaneous fat thickness rates between the first treatment (twice-feeding) (7.98 mm) and the second treatment (once feeding) (7.43 mm). [12] as they confirmed that feeding, frequency reduced the thickness of subcutaneous fat. Table (10), Major and minor carcass cuts: With regard to the main carcass cuts, which included (thigh, pelvis, back, six ribs and shoulder, in addition to the total number of these cuts), The consequences did not show any differences between the first and second treatments in all these cuts. ...
... It can, therefore, be suggested that the supply of Hac and Hbu, to the mammary glands of Thai and Vietnamese dairy cows is insufficient. It is well known that the aforementioned precursors of milk fat originate predominantly from organic matter that is fermented in the rumen [5]. It thus would appear that the rations typically fed in Thailand and Vietnam contain insufficient fermentable organic matter (FOM) to yield Hac and Hbu to ensure milk fat synthesis. ...
... (www.preprints.org) | NOT PEER-REVIEWED | Posted: 23 February 2024 doi:10.20944/preprints202402.1393.v15 ...
The relationship between DM yield/cutting and fermentable organic matter (FOM) content of tropical grasses was appropriately investigated to re-access optimal grass maturity to feed dairy cattle. Nine different grass species belonging to the genera: Brachiaria spp. (Mulato II, Ruzi), Panicum spp. (Guinea, Hamil, Mombasa, TD58), and Pennisetum spp. (King, Napier, VA06) were chemically analyzed and subjected to an in vitro gas production (IVGP) test. For 72 h, gas production (GP) was continuously recorded with fully automated equipment. A triphasic, nonlinear, regression procedure was applied to analyse GP profiles. Across all the grasses, it was found that the neutral detergent fiber (NDF) contents increased with increasing maturity of the grass while the CP contents decreased with increasing NDF contents. In all nine grasses, digestible organic matter (dOM) was significantly affected by the week of cutting but IVGP was similar between weeks of cutting in Ruzi, Hamil, Mombasa, and Napier grass. Except for Guinea grass, the lowest dOM values were found when the grasses were cut after ≥ 5 weeks of regrowth. Harvesting grass one or two weeks earlier than normal cutting time is a practically relevant intervention in in-creasing forage quality and productivity of dOM and fermentation potential.
... From this perspective, and in combination 57 with the genetic background of the dairy cows and low level of milk production, the low milk fat 58 content (i.e., < 4%) of Thai and Vietnamese dairy cows is unexpected. 59 It is well known that acetic acid (Hac) and ß-hydroxybutyric acid, but not propionic acid (Hpr) are 60 important precursors of fatty acid synthesis in the mammary gland of dairy cows [7]. Since the 61 aforementioned precursors of milk fat predominantly originate from rumen fermentation, The degraded OM (OMd) was determined as described by Williams et al. [13] and calculated as 128 the difference between incubated and residual OM after 72 h of fermentation. ...
... The absolute amount of these VFA is of critical importance to determine the absolute amounts 241 (g/d) of milk fat and lactose synthesized in the mammary gland of dairy cows. The total production 242 of VFA produced in the rumen is primarily determined by FOM intake [7]. In contrast to OMd, 243 the TVFA concentration after 72 h of incubation (Table 3) was not affected by genus. ...
Objective:
Determine fermentation characteristics of commonly used feedstuffs especially tropical roughages, for dairy cattle in Southeast Asia. This information is considered relevant in the context of the observed low milk fat content and milk production in Southeast Asia countries.
Methods:
A total of 29 feedstuffs commonly used for dairy cattle in Vietnam and Thailand were chemically analysed and subjected to an in vitro gas production (GP) test. For 72 h, GP was continuously recorded with fully automated equipment and methane (CH4) was measured at 0, 3, 6, 9, 12, 24, 30, 36, 48, 60, and 72 h of incubation. A triphasic, nonlinear, regression procedure was applied to analyse GP profiles while a monophasic model was used to obtain kinetics related to CH4 production.
Results:
King grass and VA06 showed a high asymptotic GP related to the soluble- and non-soluble fraction (i.e. A1 and A2, respectively) and had the highest acetate to propionate ratio in the incubation fluid. The proportion of CH4 produced (% of GP at 72 h) was found to be not different (P > 0.05) between the various grasses. Among the selected preserved roughages (n = 6) and whole crops (n = 4), sorghum was found to produce the greatest amount of gas in combination with a relatively low CH4 production.
Conclusion:
Grasses belonging to the genus Pennisetum, and whole crop sorghum can be considered as suitable ingredients to formulate dairy rations to enhance milk fat content in Vietnam/Thailand.
... Moreover, DeVries et al. (2005) reported that cows spend more time during the day eating when the diet is delivered more frequently. Also, according to Shabi et al. (1998Shabi et al. ( , 1999 and Cabrita et al. (2006), increasing frequency of diet delivery prevents extreme fluctuation of ruminal pH and metabolite concentrations (VFA, NH 3 ) in ruminal fluid, resulting into a more stable rumen environment. As a result, DMI, fiber digestion, and microbial protein synthesis increase by increasing frequency of diet delivery (Shabi et al., 1998(Shabi et al., , 1999Cabrita et al., 2006). ...
... Also, according to Shabi et al. (1998Shabi et al. ( , 1999 and Cabrita et al. (2006), increasing frequency of diet delivery prevents extreme fluctuation of ruminal pH and metabolite concentrations (VFA, NH 3 ) in ruminal fluid, resulting into a more stable rumen environment. As a result, DMI, fiber digestion, and microbial protein synthesis increase by increasing frequency of diet delivery (Shabi et al., 1998(Shabi et al., , 1999Cabrita et al., 2006). These findings indicate that increasing frequency of diet delivery may increase the amount of CH 4 emitted daily by dairy cows. ...
This study was conducted to examine the effect of method of diet delivery to dairy cows on enteric CH4 emission, milk production, rumen fermentation, nutrient digestion, N excretion, and manure CH4 production potential. Sixteen lactating cows were used in a crossover design (35-d period) and fed ad libitum twice daily a diet [52:48, forage:concentrate ratio; dry matter (DM) basis] provided as forages and concentrates separately (CF) or as a total mixed ration (TMR). For the CF treatment, concentrates were offered first followed by mixed forages 45 min afterward. Method of diet delivery had no effect on DM intake, but neutral detergent fiber (NDF) intake was greater when the diet was delivered as TMR as compared with CF. Apparent total-tract digestibility of DM, crude protein, and gross energy was slightly (1 percentage unit) lower when the diet was offered as TMR than when offered as CF. In contrast, NDF digestibility was greater when the cows were fed TMR versus CF. Although average daily ruminal pH was not affected by method of diet delivery, daily duration of ruminal pH <5.6 was less when the diet was delivered as TMR as compared with CF (0.9 h/d versus 3.7 h/d). Delivering the diet as TMR increased ruminal total volatile fatty acid and NH3 concentrations, but had no effect on acetate, propionate, or branched-chain volatile fatty acid molar proportions. Yields of milk, milk fat, or milk protein, and milk production efficiency (kg of milk/kg of DM intake or g of N milk/g of N intake) were not affected by the method of diet delivery. Daily production (g/d), yield (% gross energy intake), and emission intensity (g/kg of energy-corrected milk) of enteric CH4 averaged 420 g/d, 4.9%, and 9.6 g/kg and were not affected by diet delivery method. Fecal N output was greater when the diet was delivered as TMR versus CF, whereas urinary N excretion (g/d, % N intake) was not affected. Manure volatile solids excretion and maximal CH4 production potential were not affected by method of diet delivery. Under the conditions of this study, delivering the diet as concentrates and forages separately versus a total mixed ration had no effect on milk production, enteric CH4 energy losses, urinary N, or maximal manure CH4 emission potential. However, feeding the diet as total mixed ration compared with feeding concentrates and forages separately attenuated the extent of postprandial decrease in ruminal pH, which has contributed to improving NDF digestibility.
... Moreover, DeVries et al. (2005) reported that cows spend more time during the day eating when the diet is delivered more frequently. Also, according to Shabi et al. (1998Shabi et al. ( , 1999 and Cabrita et al. (2006), increasing frequency of diet delivery prevents extreme fluctuation of ruminal pH and metabolite concentrations (VFA, NH 3 ) in ruminal fluid, resulting into a more stable rumen environment. As a result, DMI, fiber digestion, and microbial protein synthesis increase by increasing frequency of diet delivery (Shabi et al., 1998(Shabi et al., , 1999Cabrita et al., 2006). ...
... Also, according to Shabi et al. (1998Shabi et al. ( , 1999 and Cabrita et al. (2006), increasing frequency of diet delivery prevents extreme fluctuation of ruminal pH and metabolite concentrations (VFA, NH 3 ) in ruminal fluid, resulting into a more stable rumen environment. As a result, DMI, fiber digestion, and microbial protein synthesis increase by increasing frequency of diet delivery (Shabi et al., 1998(Shabi et al., , 1999Cabrita et al., 2006). These findings indicate that increasing frequency of diet delivery may increase the amount of CH 4 emitted daily by dairy cows. ...
The objective of this study was to examine the effect of frequency of diet delivery to dairy cows on nutrient digestion, rumen fermentation, milk production, nitrogen utilization, enteric methane emission, and manure methane production potential. Twelve lactating cows were used in a replicated 3 × 3 Latin square design (35-d period) and offered a TMR ad libitum [56:44 ratio of forage to concentrate, dry matter (DM) basis] once (0930 h), twice (0930 and 2130 h), or 4 times daily (0930, 1300, 1630, and 2130 h). Frequency of diet delivery did not affect intake or apparent total-tract digestibility of DM and nutrients. Likewise, milk production, milk composition (fat, protein, and lactose), and milk production efficiency (kg of milk/kg of DM intake or g of milk N/g of N intake) were not changed by frequency of diet delivery. Although diurnal variation of ruminal pH, total VFA, and acetate molar proportion were influenced by frequency of diet delivery, daily average ruminal pH, total VFA, and acetate and propionate molar proportions were not affected by frequency of diet delivery. Daily enteric CH4 emission averaged 534 g/d and was not changed by frequency of diet delivery. Methane energy losses (on gross energy intake basis) were lower when cows received the diet once daily (5.8%) versus twice or 4 times daily (6.1%). Urinary N excretion was higher for cows receiving the diet 4 times daily compared with cows receiving the diet once or twice daily (36 vs. 34% of N intake). Frequency of diet delivery had no influence on manure volatile solids excretion or maximal CH4 production potential. Results from this study show that delivering the diet once daily reduces enteric CH4 energy losses compared with twice or 4 times daily, whereas urinary N losses increased by delivering the diet 4 times daily compared with once or twice daily. However, milk production and maximal manure CH4 emission potential were not affected by frequency of diet delivery.
... Reducing the sample size to 1.2 g reduced the differences in fermentation of the samples between the control and Conc.In, whereas no further improvement appeared when filter bags were pre-washed with acetone. Reducing the sample size may have improved the activity of microorganisms on the substrate inside the bag as suggested by Broderick and Cochran (2000) and Adesogan (2005), and may have facilitated the outflow of degradation products from the bag, allowing for a better interaction of nutrients from the concentrate and the forage portion of the substrate, with concomitant benefits on overall fermentation by promoting microbial activity (Herrera-Saldana et al., 1990;Shabi et al., 1998). ...
... The timely supply of energy and protein in a mixed diet enhances microbial activity causing a synergistic effect on a diet's degradation, a theory supported by several authors (e.g. Herrera-Saldana et al., 1990;Shabi et al., 1998). If this supply of nutrients for the rumen microbes is affected, the substrate degradability might be affected as well. ...
The current study determined the effects of using ANKOM R510 filter bags for substrate incubation during in vitro fermentations using the ANKOM RF technique on gas production (GP, ml/g DM), truly degraded dry matter (TDDM, g/100 g), and total short chain fatty acids concentration (SCFA, μmol/ml). Maize silage and grass hay tested separately in combination with a concentrate mixture (70:30 ratio, dry matter basis) were used as substrate for three experiments. In Experiment 1, 2.0 g of substrate (1.4 g of forage and 0.6 g of concentrate) were incubated during 48 h following three methodologies: Control, where the forage and concentrate were incubated freely in the incubation medium; Forage.In, where the forage was incubated inside the filter bag while the concentrate was incubated freely in the medium; Conc.In, where the concentrate was incubated inside the bag while the forage was incubated freely in the medium. In Experiment 2a only the Control and the Conc.In methodologies were considered. The sample size was reduced to 1.2 g and the incubation time was 24 h. A further modification was included in Experiment 2b by pre-washing the filter bags with acetone prior to the incubation and otherwise following the same procedures of Experiment 2a. A regression of GP, TDDM and SCFA of the control on those parameters of the Conc.In across all three experiments was performed to evaluate the correspondence between both methodologies. In Experiment 1 GP, total SCFA and TDDM decreased when utilizing the filter bag, particularly for the Forage.In methodology (P < 0.08), likely by interfering with fiber degradation. Reducing the sample size (Experiment 2a) minimized the differences between the Control and Conc.In compared with Experiment 1 (P = 0.03). No further improvement was obtained by pre-washing the bags prior to the incubation (Experiment 2b). A high correlation (R² > 0.90) between control and Conc.In was observed for all three parameters, indicating that comparable results can be expected when the concentrate is incubated inside the filter bag to those obtained when the mixed substrate is incubated freely in the incubation medium. Overall, the use of R510 filter bags to separately incubate the forage and the concentrate portion of a substrate can be used with confidence as long as the concentrate portion is incubated inside the bag and all samples studied are evaluated using the same methodology.
... From a theoretical viewpoint, it is expected that N excretion in manure decreases and milk production increases when cows are fed a diet with balanced protein and carbohydrate (CHO) fractions (Ishler, 2004;Kebreab et al., 2010;Yang et al., 2010). Nonetheless, existing reports in the literature of ruminal synchronization are confounding (Cole and Todd, 2008;Yang et al., 2010), as several studies reported that SI is not yet a certain feed test to evaluate the ruminal synchronization (Robinson and McQueen, 1994;Shabi et al., 1998;Richardson et al., 2003). A main concern arising from the SI uncertainty is that SI of a feed may not well represent the effect of the feed on animal production or microbial protein synthesis, because the in situ results are affected by numerous sources of random variations (unwanted measurement errors) among and within laboratories due to preparation of samples, characteristics of bags, procedure and locality of incubation, washing, drying, and etc. (Madsen and Hvelplund, 1994;Huhtanen, 2005;Kaswari et al., 2007). ...
... It is also reported that synchronization of dietary supplements for rapid fermentation diets (more degradable starch and protein) yielded higher microbial N flows and efficiency of microbial protein synthesis compared to slow fermentation diets such as high forage diets (Herrera-Saldana et al., 1990;Aldrich et al., 1993;Dewhurst et al., 2000). This fact could be one of the reasons for the uncertainty of SI reported in the literature ( Shabi et al., 1998;Richardson et al., 2003;Rotger et al., 2006). In contrast to Eq. (1), SI from Eq. (9) shows to be fairly insensitive to the random variations. ...
Ruminal synchronization of energy and protein supply is a strategy suggested by nutrition-ists to increase the efficiency of ruminant metabolic processes such as microbial protein synthesis and to decrease the environmental excretion of nutrients. A so-called synchronization index (SI), formulated as a function of the ratio of nitrogen to organic matter release in the rumen, is widely used to quantify and evaluate ruminal synchronization. A main concern is that SI values obtained from the in situ experimental method are influenced by many random factors and therefore SI value, calculated by the currently-used formula, may not represent actual degree of synchronization. Therefore, in this paper, we comprehensively examine sensitivity of SI to random variations (unwanted measurement errors) due to the experimental conditions variability. Evaluations were performed by means of in situ experiments on 3 ruminally fistulated Holstein lactating dairy cows, where 18 different diets were studied. The diets (g/kg DM) were formulated to a range of CP (150-190), NFC (300-400), NDF (310-410), and ADF (169-246). Based on measured data, a set of synthetic data were also generated to study a range of random variations and their effect on SI values. Our results indicated that SI values are quite sensitive to the random variations (i.e., significantly decrease as random variations increase). This fact revealed that the currently used SI depends not only on degree of synchronization, but also on degree of random variations due to the inevitable experimental conditions variability. Therefore, the original SI is not fully representative of the actual synchronization when having a high degree of variability. To resolve this problem, we propose a novel approach to calculating SI based on a regression analysis on measured data of nitrogen and organic matter release followed by an analytical derivation of SI based on the regression results. The SI values obtained from the new method showed minimal sensitivity to the random variations. The original method yielded a much lower SI than the new method (0.64 vs. 0.92) for our optimum diet (g/kg DM) (NFC = 350, Abbreviations: ADFom, acid detergent fiber expressed exclusive of residual ash; CHO, carbohydrate; CP, crude protein; DM, dry matter; MAE, mean absolute error; MN, microbial nitrogen; N, nitrogen; NEL, net energy for lactation; NDFom, neutral detergent fiber expressed exclusive of residual ash; NFC, non-fiber carbohydrate; OM, organic matter; RMSE, root mean squared error; RUP, ruminally undegradable protein; XPS, xylose protected soybean. NDF = 330, ADF = 183, and CP = 165), showing some degrees of asynchrony for this diet. Therefore, we conclude that the new method provides more reliable SI values for determining and quantifying ruminal synchronization.
... From a theoretical viewpoint, it is expected that N excretion in manure decreases and milk production increases when cows are fed a diet with balanced protein and carbohydrate (CHO) fractions (Ishler, 2004;Kebreab et al., 2010;Yang et al., 2010). Nonetheless, existing reports in the literature of ruminal synchronization are confounding (Cole and Todd, 2008;Yang et al., 2010), as several studies reported that SI is not yet a certain feed test to evaluate the ruminal synchronization (Robinson and McQueen, 1994;Shabi et al., 1998;Richardson et al., 2003). A main concern arising from the SI uncertainty is that SI of a feed may not well represent the effect of the feed on animal production or microbial protein synthesis, because the in situ results are affected by numerous sources of random variations (unwanted measurement errors) among and within laboratories due to preparation of samples, characteristics of bags, procedure and locality of incubation, washing, drying, and etc. (Madsen and Hvelplund, 1994;Huhtanen, 2005;Kaswari et al., 2007). ...
... This fact could be one of the reasons for the uncertainty of SI reported in the literature (Shabi et al., 1998;Richardson et al., 2003;Rotger et al., 2006). In contrast to Eq. (1), SI from Eq. (9) shows to be fairly insensitive to the random variations. ...
... It can, therefore, be suggested that the supply of Hac and Hbu to the mammary glands of Thai and Vietnamese dairy cows is insufficient. It is well known that the aforementioned precursors of milk fat originate predominantly from organic matter that is fermented in the rumen [7]. It thus would appear that the rations typically fed in Thailand and Vietnam contain insufficient fermentable organic matter (FOM) to yield Hac and Hbu to ensure milk fat synthesis. ...
The relationship between DM yield/cutting and the fermentable organic matter (FOM) content of tropical grasses was appropriately investigated to re-assess optimal grass maturity to feed dairy cattle. Nine different grass species belonging to the genera Brachiaria spp. (Mulato II, Ruzi), Panicum spp. (Guinea, Hamil, Mombasa, TD58), and Pennisetum spp. (King, Napier, VA06) were chemically analysed and subjected to an in vitro gas production (IVGP) test. For 72 h, gas production (GP) was continuously recorded with fully automated equipment. A triphasic, nonlinear, regression procedure was applied to analyse GP profiles. Across all the grasses, it was found that the neutral detergent fibre (NDF) contents increased with increasing maturity of the grass while the CP contents decreased with increasing NDF contents. In all nine grasses, digestible organic matter (dOM) was significantly affected by the week of cutting but IVGP was similar between the weeks of cutting in Ruzi, Hamil, Mombasa, and Napier grasses. Except for Guinea grass, the lowest dOM values were found when the grasses were cut after ≥5 weeks of regrowth. Harvesting grass one or two weeks earlier than the normal cutting time is a practically relevant intervention in increasing forage quality and productivity of dOM and fermentation potential.
... Microbiological food additives rely on selected bacterial or yeast cultures and they affect rumen fermentations and improve animal health by modifying the gastrointestinal bacteria (Tavendale et al., 2005). (Shabi et al., 1998) explained that the microbial yield in the rumen depends on many factors such as the availability of carbohydrates and nitrogen in the rumen and the pH of the rumen (Finlayson, 1986). ...
The study was conducted at the College of Agricultural Engineering Sciences / University of Baghdad for the period from 3-30-2022 to 4-10-2022 with the aim of determining the extent of improvement or change in the rumen fluid of Awassi lambs after inoculation with Iraqi buffalo rumen fluid. 5 ratios of Iraqi buffalo rumen fluid were used. Which was collected immediately after slaughter and (0.1, 0.2, 0.4, 0.6, and 0.8) represented the treatments (T1, T2, T3, T4, and T5) were added to the rumen fluid of Awassi lambs in in vitro digestion tubes to estimate the in vitro digestibility coefficient of the dry and organic matter of barley straw, pH, and total number of microorganisms in rumen fluid. The results showed a highly significant improvement (P<0.01) for the treatments (T3, T4, and T5) in the in vitro digestibility coefficient of organic matter and dry matter compared to the two treatments (T1 and T2). The results also indicated a highly significant (P<0.01) superiority in the pH value of the two treatments (T2 and T4) with buffalo rumen fluid compared to the other treatments depending on the timing during which the pH was measured. In the same context, the treatments (T3, T4, and T5) outperformed the total number of microorganisms, and the results showed highly significant differences (P<0.01) for the two treatments (T3 and T4) in the total number of microorganisms compared to the treatments (T1, T2, and T5).From the results achieved above, we conclude that the two treatments (T3 and T4) for inoculation with buffalo rumen fluid were significantly superior in improving the in vitro digestibility coefficient of dry and organic matter and improving the characteristics of the rumen fluid in light of the results achieved above. This study is one of the first studies to improve the rumen environment in Awassi lambs through inoculation with different proportions of rumen fluid taken from Iraqi buffaloes after slaughter.
... Hence, supplementing KL would decrease the aNDFom concentration in the high-fibre diets. Villalba et al. (2021) mentioned that NFC is also important in the ruminant nutrition as it can offer energy adequately for an efficient microbial protein synthesis (Shabi et al., 1998). The present study reported that supplementation of KL in the diet can increase NFC concentration in all experimental diets. ...
Katuk leaves (Sauropus androgynus (L.) Merr.; KL) are widely consumed by breast-feeding Indonesian mothers as it has been reported to increase breast milk production. It is hypothesized that supplementing KL in diets might increase crude protein (CP) concentration and fibre digestibility in the diet. KL had high CP and non-fibre carbohydrate concentrations (333 and 332 g/kg dry matter; DM, respectively), but low neutral detergent fibre assayed with heat, a stable amylase and expressed exclusive of residual ash (aNDFom; 200 g/kg DM). Fibre digestibility linearly increased with increasing of KL supplementation in low-quality hay (LQH) diets. KL did not contain a considerable amount of tannins. In LQH diets, gas production after 24 h incubation (GP24) linearly increased with increasing of KL supplementation (P < 0.001). Meanwhile, GP24 linearly decreased with increasing of KL supplementation in medium- and high-quality hays (MQH and HQH; P < 0.001). Metabolizable energy tended to linearly increase in LQH diets, but tended to linearly decrease with increasing of KL supplementation in MQH and HQH diets (P = 0.078). Therefore, this study suggested that KL can be a potential supplement in the ruminant diet due to its abundant dietary proteins but low fibre concentration in its leaves. However, further studies (e.g. in vitro or in vivo) investigating other rumen parameters after incubation should be performed
to validate how KL can be supplemented in the diet of ruminant livestock.
... Evaluation of diet components in Sacco using Ørskov et al. (1980), Widyobroto et al. (1995), and Soejono et al. (1998) developed a method. The in sacco method uses nylon/polyester bags (Shabi et al., 1998) with a porosity of 45 µm and a size of 6 × 11 cm, which are fixed on all three sides and left open on one side before, the pouches were appropriately labeled/marked for handling, incubation times and replication. The bags were then dried in an oven at 55°C for 6 h and tared. ...
The goal of this study was to ascertain the impact of soybean meal's temperature and heating duration as undegraded protein (UDP) on Bali cattle's dry matter (DM) and organic matter (OM) degradation kinetics. Soybean meal is a feed ingredient with high protein content, which is about 48%, and is rapidly degraded in the rumen. In this investigation, a factorial design was employed with the first factor being temperature (60, 80, 100, and 120°C), and the second factor being heating time (10, 20, 30, and 40 min). Protected soybean meal was tested for degradation using the in sacco technique on the rumen of fistulous Bali cattle. A sample of 5.0 g was put into a nylon bag and then for 0, 2, 4, 8, 16, 24, and 48 h in the rumen, then analyzed for feed residues for DM and OM. The results showed that soybean meal protected by the heating method could reduce the degradation of DM and OM in the rumen (p<0.05). Heating at 120°C for 40 min showed the lowest DM and OM degradations in this study.
... The synchrony between protein and dietary energy improves the nitrogen utilization in the animal (Shabi et al. 1998). The efficacy of microbial protein synthesis in forage-based diets is greater when the content of non-structural carbohydrates is increased in the diet, greater absorption in duodenum would be expected (Clark et al.1992;Salcedo 2006). ...
The objective of this study was to determine the nitrogen balance of Holstein cows grazing on an intensive silvopastoral system (ISS) with wild sunflower (Tithonia diversifolia (Hemsl.) A. Gray) and kikuyu grass (Cenchrus clandestinus (Hochst. Ex Chiov) Morrone) or on a monoculture (MONO) of kikuyu grass, and supplemented with polyunsaturated fatty acids (PUFAs), in order to compare the efficiency of animal nitrogen use in both systems, which is important for sustainable animal production. A concentrate with three different lipid combinations was used: control concentrate (D1)-3% commercial saturated fat; concentrate 2 (D2)-1% soybean oil, 0.5% fish oil, and 1.5% of bypass fat rich in n-3 fatty acids; and concentrate 3 (D3)-2.5% soybean oil and 0.5% fish oil. The variables under study were analyzed during two rotations in a randomized complete block (RCB) design. The dry matter intake was evaluated by the marker's method, using chromium oxide as an external marker and indigestible dry matter as an internal marker. The production of milk, urine, and feces was measured for 5 days to quantify nitrogen (N). The urine volume was estimated using creatinine. Nitrogen consumption (grams/day) was similar for cows in both systems (p [ 0.05). A significantly higher excretion of N in the urine (p \ 0.05) was found in the cows of the MONO group. The percent apparent nitrogen digestibility was higher (p \ 0.05) in cows of the ISS group (75.68%) than in cows of the MONO group (73.95%). The N utilization efficiency was significantly higher (p \ 0.05) in cows of the ISS group (23.24%) than in cows of the MONO group (19.39%). Therefore, the ISS with wild sunflower and unsaturated fat supplementation could be a positive strategy to improve the nitrogen balance and the productive efficiency of dairy cows in highland tropical regions, reducing the losses of nitrogen to the environment and contributing to the sustainability of the dairy production systems.
... Luc et al. (2009) suggested that organic matter and NDF digestibility for tropical grasses containing a low amount of protein increased with dietary protein level, and these digestibilities were also affected by the dietary protein source. Shabi et al. (1998) suggested that increased NDFD with higher dietary CP level could result from the improved synchronization of protein and energy availability in the rumen, which would provide an environment that was more conducive to microbial growth, and thus facilitate the utilization of dietary carbohydrates and proteins. ...
The study was designed to compare low and high levels of protein, namely 90 and 147 g/kg of dietary dry matter, and to evaluate the effect of concentrate proportions on the in situ digestion kinetics of neutral detergent fibre in buffaloes and cows fed a low protein diet at maintenance intake level. In the first experiment, heifers and lactating females were offered a high protein diet. In the second, the performances of buffaloes and cows were compared when fed diets with low and high proportions of concentrate at low dietary protein level. At higher protein supply, the heifers showed a 6% unit increase in neutral detergent fibre degradability (NDFD) compared with lactating animals. Similarly, at a higher level of concentrate proportion, an 8% unit increase was observed in NDFD. In both experiments the comparison of buffaloes and cows was non-significant for NDFD. Those data that were pooled against the stage of development of both experiments for protein levels depicted a 13% unit increase in NDFD at high protein level compared with low level. At maintenance intake level, a high dietary crude protein or concentrate supply improved the in situ NDFD of tropical forages in buffaloes and cows, owing to the enhanced intake of NDF from concentrate and better synchronization of protein and energy availability in the rumen.
... The synchrony between protein and dietary energy improves the nitrogen utilization in the animal (Shabi et al. 1998). The efficacy of microbial protein synthesis in forage-based diets is greater when the content of non-structural carbohydrates is increased in the diet, greater absorption in duodenum would be expected (Clark et al.1992;Salcedo 2006). ...
The objective of this study was to determine the nitrogen balance of Holstein cows grazing on an intensive silvopastoral system (ISS) with wild sunflower (Tithonia diversifolia (Hemsl.) A. Gray) and kikuyu grass (Cenchrus clandestinus (Hochst. Ex Chiov) Morrone) or on a monoculture (MONO) of kikuyu grass, and supplemented with polyunsaturated fatty acids (PUFAs), in order to compare the efficiency of animal nitrogen use in both systems, which is important for sustainable animal production. A concentrate with three different lipid combinations was used: control concentrate (D1)—3% commercial saturated fat; concentrate 2 (D2)—1% soybean oil, 0.5% fish oil, and 1.5% of bypass fat rich in n-3 fatty acids; and concentrate 3 (D3)—2.5% soybean oil and 0.5% fish oil. The variables under study were analyzed during two rotations in a randomized complete block (RCB) design. The dry matter intake was evaluated by the marker’s method, using chromium oxide as an external marker and indigestible dry matter as an internal marker. The production of milk, urine, and feces was measured for 5 days to quantify nitrogen (N). The urine volume was estimated using creatinine. Nitrogen consumption (grams/day) was similar for cows in both systems (p > 0.05). A significantly higher excretion of N in the urine (p < 0.05) was found in the cows of the MONO group. The percent apparent nitrogen digestibility was higher (p < 0.05) in cows of the ISS group (75.68%) than in cows of the MONO group (73.95%). The N utilization efficiency was significantly higher (p < 0.05) in cows of the ISS group (23.24%) than in cows of the MONO group (19.39%). Therefore, the ISS with wild sunflower and unsaturated fat supplementation could be a positive strategy to improve the nitrogen balance and the productive efficiency of dairy cows in highland tropical regions, reducing the losses of nitrogen to the environment and contributing to the sustainability of the dairy production systems.
... [57,60] however, reported that rangelands fail to supply energy and minerals in adequate quantity during the early to mid-wet season. The consequence is a retarded growth rate of cattle which turns out to be a main stumbling block to boosting body weight growth [61,62] and, as a result, impacting semi-arid beef production In the semiarid areas, rangeland energy and mineral supplies in the late wet and dry seasons are usually perceived as sufficient to support cattle production needs on pastoral systems [59,60]. Thus, in community rangelands in semi-arid areas, cattle production efficiency is sometimes governed by nutrient availability, which is affected primarily by temperature and seasonal rainfall distribution [54]. ...
Assisted reproductive technologies (ART) that have come to stay and are still being improved upon in developed countries are still in their infancy stage in developing countries like Nigeria. Nigeria’s cattle population is estimated to be around 18.4 million. The number is far insufficient to meet the country’s demand for meat, milk, and other cow products, let alone contribute to GDP. N’dama and Muturu are both Nigerian breeds that are resistant to trypanosomosis. They are humpless longhorn and humpless shorthorn types of beef cattle. The dairy and beef cow industries’ inadequate adoption of ART is partly to blame for Nigeria’s low cattle output. Sex determination, multiple-ovulation and embryo transfer (MOET), oestrus synchronization, artificial insemination (AI), in vitro fertilization (IVF), cloning, and genetic engineering are all examples of assisted reproductive technologies. It has been reported in humans, rodents and domestic animals, abnormal fetuses, newborns and adult offspring arise from ART. Improper matching of breeding animals mostly leads to overfat calves. This review centers on the applications and potentials of ART in the production of trypanotolerant N’dama and Muturu cattle breeds. Some unorthodox medicines which have proven effective in human reproduction can circumvent the shortfalls in the adoption of ART.
... We have found that the lower milk yield and milk protein contents in CS-fed cows compared to alfalfa-fed cows were partially due to the lower non-fiber carbohydrate (NFC) content in the CS containing diet [5]. NFCs provide sufficient energy for efficient microbial protein (MCP) synthesis [6]. Maximizing MCP synthesis increases the efficiency of N utilization and reduces N urinary excretion [7]. ...
The main objective of our current study was evaluating the effects of NFC supplementation and forage type on rumen microbiota and metabolism, by comparing microbial structures and composition among samples collected from cows fed AH (alfalfa-based diet), H-NFC (CS-based diet with high NFC) and L-NFC (CS-based diet with low NFC) diets. Our results show that microbial communities were structurally different but functionally similar among groups. When compared with L-HFC, NFC increased the population of Treponema, Ruminobacter, Selenomonas and Succinimonas that were negatively correlated with ruminal NH3-N, and urea nitrogen in blood, milk and urine, as well as significantly increasing the number of genes involved in amino acid biosynthesis. However, when compared to the AH group, H-NFC showed a higher abundance of bacteria relating to starch degradation and lactate production, but a lower abundance of bacteria utilizing pectin and other soluble fibers. This may lead to a slower proliferation of lignocellulose bacteria, such as Ruminococcus, Marvinbryantia and Syntrophococcus. Lower fibrolytic capacity in the rumen may reduce rumen rotation rate and may limit dry matter intake and milk yield in cows fed H-NFC. The enzyme activity assays further confirmed that cellulase and xylanase activity in AH were significantly higher than H-NFC. In addition, the lower cobalt content in Gramineae plants compared to legumes, might have led to the significantly down-regulated microbial genes involved in vitamin B12 biosynthesis in H-NFC compared to AH. A lower dietary supply with vitamin B12 may restrict the synthesis of milk lactose, one of the key factors influencing milk yield. In conclusion, supplementation of a CS-based diet with additional NFC was beneficial for nitrogen conversion by increasing the activity of amino acid biosynthesis in rumen microbiota in dairy cattle. However, lower levels of fibrolytic capacity may limit dry matter intake of cows fed H-NFC and may prevent increased milk yield.
... Rumen protozoa accounts for about 40 percent of the rumen microbial biomass and have a direct involvement in digestion of protein and CHO (Russell and Rychlik, 2001). Protozoa degrade fibrous and nonfibrous fibrous carbohydrates (Williams and Withers, 1991); bacteria are their main source of protein and supply about 11 per cent of the total crude protein to the small intestine (Shabi et al., 1998) due to their selective retention in rumen. Protozoa play a major role in protein degradation in vivo, in addition to regulation of bacterial nitrogen turnover in rumen and supply of soluble protein to sustain microbial growth. ...
Rice gruel is a rich source of starch but poor source of other nutrients especially nitrogen. Starch on fermentation in rumen can be effectively used in the presence of nitrogen. At the same time feeding of nitrogenous compounds without energy rich diets can lead to increase in the rumen ammonia concentration resulting in toxicity. Therefore feeding of gruel with nitrogenous compounds is a better practice. Further it would rather be economical to supplement NPN compounds viz., urea, diammonium phosphate as a source of ‘N’ to rice gruel.
... Besides providing adequate concentrations of RDP and CHO to the rumen microbes, synchronizing the supply of both RDP and rumen fermentable CHO to the rumen microbes may also be necessary to improve the efficiency of MCP synthesis. Synchronization of nutrients can be performed by (i) modifying rate and supply of CHO and N sources, by combining different fast and slow RDP and rumen degradable CHO sources, to match the release rate of CHO and RDP obtained from the individual feeds in the rumen (Herrera-Saldana et al., 1990;Shabi et al., 1998), and (ii) by changing the feeding frequency and pattern (Kolver et al., 1998;Richardson et al., 2003). ...
Feeding excess dietary crude protein (CP) beyond the requirements of dairy cattle and microbes in the rumen increases production costs for farmers, excretion of nitrogen (N) to the environment, and has negative effects on the cows health and reproductive performance. Researchers have been interested in exploring the effects that diets with negative rumen nitrogen balance (RNB) may have on the dairy cattle and their rumen function. Results so far have been inconsistent may be due to the performance level of the animal with high-yielding dairy cows being more sensitive than low performing ones. Moreover, it may be supposed that variable responses to negative RNB in different studies may at least partly be related to varying ingredient composition and the type of main carbohydrate or N sources in the animals diets. The overall objective of the thesis was to generate a comprehensive understanding on the effects of interactions between the RNB levels and carbohydrate and N sources in cattle diets on rumen fermentation, the efficiency of microbial CP synthesis, and on N use efficiency in vitro and in vivo. The results of the present thesis indicate that the effects of negative RNB levels may vary with dietary composition in dairy cows. Therefore, outlining a single minimum RNB balance threshold for dairy cattle diets may not be appropriate when optimizing N utilization in dairy cows, because several animal and dietary factors modify the requirements of rumen microbes.
... Previous studies have associated increased feeding frequency with greater feeding time, more evenly distributed meals throughout the day, and higher dry matter intake (DMI) [3,4]. Furthermore, changes in feeding frequency can modify nutrient digestibility and fermentation profiles in the rumen and lower GI tract [5,6]. In turn, diurnal fluctuations in the GI environment can impact the microbial community composition [7]. ...
This study aimed to evaluate the effects of feeding frequency on behavioral patterns and on diurnal fermentation and bacteriome profiles of the rumen and feces in Holstein and Jersey cows. Ten Holstein and 10 Jersey cows were offered a TMR (53:47 forage-to-concentrate ratio dry matter basis) for ad libitum consumption and were randomly allocated within breed to one of the following feeding frequencies: (1) TMR delivered 1×/d (at 0600 h) or (2) TMR delivered 2×/d (at 0600 and 1800 h). The experiment lasted for 28 d with the first 14 d for cow adaptation to the Calan gates and the next 14 d for data collection. On d 23 and 24, an observer manually recorded the time budget (time spent lying, eating, drinking, standing, and milking), rumination activity, and number of visits to the feeding gate from each animal. On d 28, 5 concomitant collections of rumen and fecal samples were performed at intervals of 6 h via esophageal tubing and fecal grab, respectively. The bacteriome composition from these samples was determined through sequencing of the V4 region of the 16S rRNA gene. Feeding frequency did not affect behavioral patterns; however, Holstein cows spend more time lying (15.4 vs. 13.5 ± 0.8 h) and ruminating (401 vs. 331 ± 17.5 min) than Jersey cows. Fermentation profiles were similar by feeding frequency in both breeds. While no major diurnal fluctuations were observed in the fecal bacterial community from both breeds, diurnal fluctuations were identified in the rumen bacterial community from Holstein cows which appeared to follow pH responses. Overall, the bacterial community composition was not differentiated by industry standard feeding frequencies but was differentiated by breed and sample type.
... Although the theory supports the effect of synchronized energy and protein for optimal MPS and rumen characteristics, practical results have been conflicting (Kolver et al., 1998;Shabi et al., 1998;Kaswari et al., 2007). Differences in experimental methods and animals used have made it difficult to determine the effect of energy and protein synchronization from several other factors (Cabrita et al., 2006). ...
This study investigated whether the interaction of protein level and grain type can affect milk production, nutrient digestibility, and rumen fermentation in dairy cattle. Eight primiparous Holstein cows (560 ± 65 kg of body weight; 50 ± 15 days in milk) were used in a replicated 4 × 4 Latin square design with 21-d experimental periods. Four dietary treatments contained: 1) high-protein (195 g/kg of dry matter; DM) with barley as the only grain source, HP-B; 2) high-protein (193 g/kg of DM) with an equal mix of barley and corn, HP-BC; 3) low-protein (159 g/kg of DM) with barley as the only grain source, LP-B; 4) low-protein (156 g/kg of DM) with a mix of equal amount of barley and corn, LP-BC. High-protein diets did not result in improvement of milk or protein yield compared with the low-protein diets, but barely and corn mix diets increased energy corrected milk yield and fat yield compared with the diets containing only barely. The highest total apparent digestibility of DM, organic matter and neutral detergent fiber was observed for LP-BC whereas cows fed HP-BC showed the greatest CP digestibility. The treatment had no effect on total volatile fatty acid concentrations, molar proportion of acetate and propionate, and acetate to propionate ratio. However, the lowest ruminal pH was observed for cows fed LP-B. High-protein diets (HP-B and HP-BC) resulted in greater concentrations of ammonia nitrogen, urinary N, blood and milk urea nitrogen compared with low-protein diets, whereas low-protein diets showed better nitrogen utilization efficiency. This study showed that primiparous lactating cows could not benefit from high-protein diets with different fermentation rates of grain sources, but barely and corn diets may improve milk production performance, ruminal fermentation and pH under the present dietary conditions. The results on milk production performance should be interpreted with cautious due to lower number of cows in this study.
... The supply of metabolizable protein (MP) to ruminants was positively correlated with daily gain of fattening sheep (Hao et al., 2018), which is composed of intestinally absorbable microbial CP (IAMCP) and intestinally absorbable dietary protein (IADP). The microbial CP (MCP) synthesis efficiency is affected by available nitrogen and fermentable carbohydrates in the rumen (Shabi et al., 1998). The efficiency of MCP synthesis will decrease when a low-quality forage diet is fed to sheep because of slow carbohydrate digestion, as well as the slow rate of particulate and liquid dilution turnover. ...
Some grain processing by-products rich in digestible fiber are good feed resources for ruminants. This experiment was conducted to investigate the effects of replacing a portion of corn and corn stover with the combinations of corn bran and soybean hulls in the diet of fattening lambs on nutrient digestion, rumen microbial protein synthesis, and growth performance. A total of 36 Dorper × Small Thin-Tailed crossbred ram lambs (BW = 22.2 ± 0.92 kg; mean ± SD) were randomly divided into three groups, and each group was fed 1 of 3 treatment diets: 1) 0% corn bran and soybean hulls (control); 2) 9% corn bran and 9% soybean hulls (18MIX); and 3) 17% corn bran and 17% soybean hulls (34MIX). The feeding experiment was conducted for 70 days, with the first 10 days for adaption. The DM intake was higher for 34MIX (1635.3 g/d) than for control diet (1434.7 g/d; P = 0.001). Lambs fed 18MIX and 34MIX diets (230.2 and 263.6 g/d, respectively) had higher average daily gain and feed efficiency than those fed control diet (194.8 g/d; P < 0.01). Dry matter and NDF digestibility for 34MIX group (60.9 and 49.5%) were higher than for control (55.2 and 41.3%; P < 0.01). No difference was observed in nitrogen digestibility among treatment diets (P = 0.778). The lambs fed 34MIX diet excreted more urinary purine derivatives, indicating that more microbial protein was yielded than those fed control diet (P < 0.01), while 18MIX was not different from the other two diets (P > 0.05). The metabolizable protein supplies were improved with increasing co-products inclusion rate. The results indicated that corn bran and soybean hulls in combination can effectively replace a portion of corn and corn stover in the ration of finishing lambs with positive effect on nutrient digestion and growth performance.
... There are some arguments as to whether the improvement of feed intake and growth is affected by synchronisation between energy and protein sources (Casper et al., 1999;Richardson et al., 2003;Cole and Todd, 2008) or due to some other aspects (Richardson et al., 2003). Shabi et al. (1998) reported that dietary energy supply was more influential than synchrony. ...
... The results indicate that the duodenal MCP flow of goats was reduced with the reduction of 3% in dietary CP content, whereas a reduction of 1% in the dietary CP content had no effects on the duodenal MCP flow. The rumen MCP synthesis depends largely on the availability of N and carbohydrates in the rumen (Shabi et al., 1998;Savari et al., 2018) and is primarily limited by the availability of energy in the rumen (Henke et al., 2017). Moreover, the synchronicity of ruminal degradation of carbohydrates and N plays an important role in optimizing rumen MCP synthesis (Dewhurst et al., 2000). ...
Reducing dietary CP content is an effective approach to reduce animal nitrogen excretion and save protein feed resources. However, it is not clear how reducing dietary CP content affects the nutrient digestion and absorption in the gut of ruminants, therefore it is difficult to accurately determine how much reduction in dietary CP content is appropriate. This study was conducted to investigate the effects of reduced dietary CP content on N balance, intestinal nutrient digestion and absorption, and rumen microbiota in growing goats. To determine N balance, 18 growing wether goats (25.0 ± 0.5 kg) were randomly assigned to one of three diets: 13.0% (control), 11.5% and 10.0% CP. Another 18 growing wether goats (25.0 ± 0.5 kg) were surgically fitted with ruminal, proximate duodenal, and terminal ileal fistulae and were randomly assigned to one of the three diets to investigate intestinal amino acid ( AA ) absorption and rumen microbiota. The results showed that fecal and urinary N excretion of goats fed diets containing 11.5% and 10.0% CP were lower than those of goats fed the control diet ( P < 0.05). When compared with goats fed the control diet, N retention was decreased and apparent N digestibility in the entire gastrointestinal tract was increased in goats fed the 10% CP diet ( P < 0.05). When compared with goats fed the control diet, the duodenal flow of lysine, tryptophan and phenylalanine was decreased in goats fed the 11.5% CP diet ( P < 0.05) and that of lysine, methionine, tryptophan, phenylalanine, leucine, glutamic acid, tyrosine, essential AAs ( EAA s) and total AAs ( TAA s) was decreased in goats fed the 10.0% CP diet ( P < 0.05). When compared with goats fed the control diet, the apparent absorption of TAAs in the small intestine was increased in goats fed the 11.5% CP diet ( P < 0.05) and that of isoleucine, serine, cysteine, EAAs, non-essential AAs, and TAAs in the small intestine was increased in goats fed the 10.0% CP diet ( P < 0.05). When compared with goats fed the control diet, the relative richness of Bacteroidetes and Fibrobacteres was increased and that of Proteobacteria and Synergistetes was decreased in the rumen of goats fed a diet with 10.0% CP. In conclusion, reducing dietary CP content reduced N excretion and increased nutrient utilization by improving rumen fermentation, enhancing nutrient digestion and absorption, and altering rumen microbiota in growing goats.
... Regarding FF, there were no differences except in the live sperm percentage that increased significantly in the twice rationed animals. This may be due to the increasing FF that reduced the fluctuation in ruminal environment (Shabi et al., 1998) and improve the microbial digestion and protein synthesis (Cecava et al., 1990). Therefore, it is suggested that this will enhance spermatogenesis and increase live sperm percentage. ...
Twenty Awassi male lambs aged 120 days were used in this study to evaluate the effect of grazing (GR) and feeding frequency (FF) on body weight and monthly body gain (BG), in addition to the effect of GR , FF and season (S) (autumn or summer) on semen quality. Animals were assigned to four experimental groups according to their initial weights. The 1 st and 2 nd groups (5 animals per group) were rationed once and twice ad libitum, respectively with 6 hrs grazing daily, whereas the 3 rd and 4 th groups (5 animals per group) rationed once and twice ad libitum, respectively daily without grazing. The BW and BG were recorded monthly. Semen samples from each ram were collected in October/2010 (autumn) and June /2011(summer). Semen ejaculates were evaluated for semen volume, ejaculate appearance, mass motility, individual motility %, live sperm %, abnormal sperm %, sperm concentration/ml and sperm concentration/ejaculate. The results showed a significant increase (P<0.05) in BW in the grazing group from the 4 th month to the end of treatment, and in the group that rationed once a day at the 6 th and 10 th months of treatment, while the best weight was recorded in the interaction of T 1 at the 4 th and 6 th month of treatment. There was a significant increase in BG in the grazing group at the 4 th , 8 th and 10 th months and in the group rationed twice daily at 8 th month of treatment, while BG increased significantly (P<0.05) in T 1 as interaction effect at the 4 th month, and in T 2 at 4 th and 8 th months and in T 3 in 10 th month of treatment compared with T 1.. Grazing improved most of the semen characters significantly (P<0.05), while the twice rationed group daily improved live sperm% significantly. All semen parameters were better significantly (P<0.05) in 2 nd season (summer) than in the 1 st season (autumn). It was clear that the best interaction effects were in T 2 group (summer, grazing and rationed once daily) in improving the semen quality. Results of this study indicate that grazing has positive effect on BW, BG and semen parameters, while feeding frequency had no effect on semen quality.
... Regarding FF, there were no differences except in the live sperm percentage that increased significantly in the twice rationed animals. This may be due to the increasing FF that reduced the fluctuation in ruminal environment (Shabi et al., 1998) and improve the microbial digestion and protein synthesis (Cecava et al., 1990). Therefore, it is suggested that this will enhance spermatogenesis and increase live sperm percentage. ...
Twenty Awassi male lambs aged 120 days were used in this study to evaluate the effect of grazing (GR) and feeding frequency (FF) on body weight and monthly body gain (BG), in addition to the effect of GR , FF and season (S) (autumn or summer) on semen quality. Animals were assigned to four experimental groups according to their initial weights. The 1 st and 2 nd groups (5 animals per group) were rationed once and twice ad libitum, respectively with 6 hrs grazing daily, whereas the 3 rd and 4 th groups (5 animals per group) rationed once and twice ad libitum, respectively daily without grazing. The BW and BG were recorded monthly. Semen samples from each ram were collected in October/2010 (autumn) and June /2011(summer). Semen ejaculates were evaluated for semen volume, ejaculate appearance, mass motility, individual motility %, live sperm %, abnormal sperm %, sperm concentration/ml and sperm concentration/ejaculate. The results showed a significant increase (P<0.05) in BW in the grazing group from the 4 th month to the end of treatment, and in the group that rationed once a day at the 6 th and 10 th months of treatment, while the best weight was recorded in the interaction of T 1 at the 4 th and 6 th month of treatment. There was a significant increase in BG in the grazing group at the 4 th , 8 th and 10 th months and in the group rationed twice daily at 8 th month of treatment, while BG increased significantly (P<0.05) in T 1 as interaction effect at the 4 th month, and in T 2 at 4 th and 8 th months and in T 3 in 10 th month of treatment compared with T 1.. Grazing improved most of the semen characters significantly (P<0.05), while the twice rationed group daily improved live sperm% significantly. All semen parameters were better significantly (P<0.05) in 2 nd season (summer) than in the 1 st season (autumn). It was clear that the best interaction effects were in T 2 group (summer, grazing and rationed once daily) in improving the semen quality. Results of this study indicate that grazing has positive effect on BW, BG and semen parameters, while feeding frequency had no effect on semen quality.
... Regarding FF, there were no differences except in the live sperm percentage that increased significantly in the twice rationed animals. This may be due to the increasing FF that reduced the fluctuation in ruminal environment (Shabi et al., 1998) and improve the microbial digestion and protein synthesis (Cecava et al., 1990). Therefore, it is suggested that this will enhance spermatogenesis and increase live sperm percentage. ...
Twenty Awassi male lambs aged 120 days were used in this study to evaluate the effect of grazing (GR) and feeding frequency (FF) on body weight and monthly body gain (BG), in addition to the effect of GR , FF and season (S) (autumn or summer) on semen quality. Animals were assigned to four experimental groups according to their initial weights. The 1 st and 2 nd groups (5 animals per group) were rationed once and twice ad libitum, respectively with 6 hrs grazing daily, whereas the 3 rd and 4 th groups (5 animals per group) rationed once and twice ad libitum, respectively daily without grazing. The BW and BG were recorded monthly. Semen samples from each ram were collected in October/2010 (autumn) and June /2011(summer). Semen ejaculates were evaluated for semen volume, ejaculate appearance, mass motility, individual motility %, live sperm %, abnormal sperm %, sperm concentration/ml and sperm concentration/ejaculate. The results showed a significant increase (P<0.05) in BW in the grazing group from the 4 th month to the end of treatment, and in the group that rationed once a day at the 6 th and 10 th months of treatment, while the best weight was recorded in the interaction of T 1 at the 4 th and 6 th month of treatment. There was a significant increase in BG in the grazing group at the 4 th , 8 th and 10 th months and in the group rationed twice daily at 8 th month of treatment, while BG increased significantly (P<0.05) in T 1 as interaction effect at the 4 th month, and in T 2 at 4 th and 8 th months and in T 3 in 10 th month of treatment compared with T 1.. Grazing improved most of the semen characters significantly (P<0.05), while the twice rationed group daily improved live sperm% significantly. All semen parameters were better significantly (P<0.05) in 2 nd season (summer) than in the 1 st season (autumn). It was clear that the best interaction effects were in T 2 group (summer, grazing and rationed once daily) in improving the semen quality. Results of this study indicate that grazing has positive effect on BW, BG and semen parameters, while feeding frequency had no effect on semen quality.
... In situ degradation of forage is primarily influenced by plant genotype, agronomic conditions, climate, and post-harvest processing [9] . Various animal-related factors that affect the in situ degradation of forage have been reported including intake level, forage to concentrate ratio, nutrient composition and degradation rate of the concentrate feeds, feeding frequency [10] , and animal species [11] and developmental stage [12] . Internationally, substantial research has been conducted to quantitatively evaluate the effects of these factors [13][14][15] , but information is lacking for tropical areas such as Pakistan. ...
This article probes into the weakness shown in zoological experimentlearning of biology department students and explores method in zoologicalexperiment teaching in order to adapt biology teaching in middle schools.
... Logically, if the same amount of urea is produced in cows of different sizes, the urea concentration in the blood and milk will be higher for the small cow. Shabi et al. (1998) found that feeding from two to four times a day was accompanied by a decrease in blood urea levels of 4.4 mg/dL. On the other hand, Nilsen et al. (2005) found an increase in MUN for the cows milked 3 times per day compared to cows milked twice a day. ...
The milk urea nitrogen concentration can be used as a tool management of the nutritional strategies in dairy farm and of improving proteins utilization efficiency by dairy cows. The level of dietary crude protein is the most nutritional factor that influence the milk urea nitrogen concentrations in lactating cows. Recent researches suggest that the milk urea nitrogen content depends mainly on the nitrogen/energy ratio in the diet, but other many factors may affect ureogenesis. Level and quality of protein contents, milk yield, season effects or lactation stage, parity and lactation number, weight and breed, feeding frequency and water intake are factors associated with the variation of milk urea concentration. Several studies have suggested that measuring milk urea nitrogen may serve as indicator to monitor nitrogen efficiency in dairy cows and to improve milk nitrogen production. However, the targeted milk urea nitrogen values for optimizing the nitrogen utilization efficiency are different from those required for milk protein production. Thus, an increase in milk protein production can be expected at milk urea nitrogen levels >11 mg/dL, while protein utilization efficiency is below this level (<11 mg/dL). Normal MUN values range from 10 to 14 mg/dL, but for many countries, the recommended milk urea nitrogen values for cow’s milk are ideally ranged from 10 to 16 mg/dL of milk. Finally, to ensure a balance between milk protein production and reducing urea nitrogen excretion in urine and milk, recent studies suggest to include 16.5% of crude protein supply in dairy cows diets.
Keywords: Milk urea nitrogen, crude protein, dairy cow, nitrogen efficiency, urea nitrogen excretion
... Urinary PD excretion is commonly used as indicator for rumen MCP synthesis (Henke et al., 2017); hence, the decrease in urinary PD excretion in our study suggests that RCS plus wheat reduced the MCP flow to the duodenum. The MCP synthesis depends largely on the availability of carbohydrates and N in the rumen (Shabi et al., 1998) and is primarily limited by rumen available energy (Henke et al., 2017). Moreover, the synchronicity of ruminal degradation of dietary CP and energy availability plays an important role in optimizing ruminal MCP synthesis (Hoover and Stokes, 1991;Schingoethe, 1996;Dewhurst et al., 2000). ...
The objectives of this study were to evaluate the effects of replacing maize silage plus soybean meal with red clover silage (RCS) plus wheat on feed intake, diet digestibility, N partitioning, urinary excretion of purine derivatives, and milk production in dairy cows. Forty-four lactating German Holstein cows were used in a 4 × 4 Latin square design with 21-d periods composed of a 13-d adaptation phase followed by an 8-d sampling phase. Experimental diets offered as total mixed ration consisted of a constant forage-to-concentrate ratio (75:25) with targeted proportions of RCS-to-maize silage of 15:60 (RCS15), 30:45 (RCS30), 45:30 (RCS45), and 60:15 (RCS60) on a dry matter (DM) basis. Increasing the proportion of RCS plus wheat in the diet decreased linearly the intake of DM from 22.4 to 19.8 kg/d, and of organic matter from 21.1 to 18.1 kg/d. The apparent total tract digestibility (ATTD) of DM and organic matter did not differ across diets and averaged 68.4 and 70.5%, respectively. However, ATTD of N decreased linearly from 68.5 to 63.2%, whereas ATTD of neutral detergent fiber and acid detergent fiber increased linearly from 50.4 to 59.6% and from 48.4 to 57.7%, respectively, when increasing the proportion of RCS plus wheat. Fecal N excretion increased from 31.6 (RCS15) to 37.2% (RCS60) of N intake, whereas urinary N excretion was the lowest (32.8% of N intake) with RCS45. Hence, N efficiency (milk N/N intake) decreased linearly with incremental levels of RCS plus wheat, being the lowest when feeding RCS60 (25.4%), probably due to increased nonprotein N proportion in total dietary N. Urinary excretion of purine derivatives decreased linearly from 378 to 339 mmol/d, which suggests that increasing levels of RCS plus wheat reduced the microbial crude protein flow at the duodenum. Milk yield and milk protein concentration declined linearly from 35.9 to 30.2 kg/d and from 3.20 to 3.01%, respectively, when increasing the proportion of RCS plus wheat. In conclusion, caution should be taken before introducing high levels of RCS plus wheat in diets of high-yielding dairy cows. However, RCS plus wheat can be included up to 30% of the dairy cow diet (DM basis) without a reduction in lactation performance.
... Shabi et al. [16], revealed that high concentrate and highly degradable starch using in diet may increase fluctuation of rumen pH, ruminal ammonia, volatile fatty acids and these fluctuations may be controlled and milk yield and the components may be improved by increasing feeding frequency from 2 to 4. Similarly, Devries et al. [17] reported that increasing feeding frequency from 1 to 4 times may decrease sorting and variation of consumed diet. However, some researchers [18,19], reported better results with single feeding compared to frequent feeding. ...
The aim of this study was to investigate the effects of different feeding systems on milk production
and milk composition of dairy cows. Thirty-two dairy cows having similar lactation number, Days in
Milk (DIM), live body weight and milk production was divided into four groups. First group received
Total Mixed Ration (TMR) ad libitum, second group received roughage and concentrate limited and
separately in two meals, third group fed with partial TMR which included half of the concentrate in
roughage part of the diet and remained concentrate was offered in two meals, and the last group
was fed with roughage and concentrate separately and roughage was offered limited in two meals
and concentrate was offered limited in four meals. The feeding systems affected dry matter intake
(P<0.05). Limited feeding groups were fed on roughage and concentrate separately, the roughage
intake in these groups was decreased, concentrate ratio was increased in the diet as well especially
in the group receiving concentrate in two meals (P<0.05). In TMR group, milk yield was significantly
increased due to increase in their feed intake (P<0.05, 2 kg/day higher than others). Milk total solid,
fat and urea nitrogen contents were affected by feeding systems. Restricted and separate feeding
system groups had lower total solid, fat and urea nitrogen in milk (P<0.05). In conclusion, the results
showed that restricted and separate feeding of concentrate and roughage may not be applicable in
practice as it decreased feed intake, milk yield and milk fat test.
... This reduction could be explained by a greater utilization of ammonia by the micro-organisms as a readily available energy source (Lee et al. 2003); or by reductions in the use of amino acids as an energy source by micro-organisms (Nocek and Russell, 1988). Optimization of microbial yield in the rumen depends largely on the availability of carbohydrates and nitrogen (N) in the rumen (Shabi et al. 1998). ...
This study presents the chemical composition and in vitro fermentation of five diets with different forage (alfalfa) to concentrate (faba bean) (F:C) ratios, F0:C100, F25:C75, F50:C50, F75:C25, F100:C0 on a dry matter (DM) basis. Results indicate that the chemical composition in term of organic matter (OM), ether extract (EE), crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), neutral deter-gent insoluble protein (NDIP), acid detergent insoluble protein (ADIP) and total phenols (TPh), tannin (TT) and condensed tannin (TCT) were varies among five diets (P < 0.05). After an initial gas test to evaluate 96 h gas production profiles of diets, the time to half maximal gas production was calculated and a second incu-bation was conducted with fermentation stopped at substrate specific half-time (t1/2) and 24 h for each sub-strate. In vitro true DM degradability (ivTDDM), OM degradability (ivOMD) were increased (P < 0.01) by addition proportions of concentrate in diets. Microbial mass (g/kg DM), metabolizable energy (ME) (MJ/kg DM), were greater in diets which those had been higher degradability. The efficiency of microbial produc-tion (PF) (mg/mL) were calculated for both substrate specific t1/2 and 24 h and was not shown differences between experimental diets at 24 h but F100:C0 was lesser (1.17 mg/mL) at substrate specific t1/2 (P < 0.01). Gas produced from fermentable fraction (B) and the rate of gas production (c) were (P < 0.01) greater in diets with grater concentrate ratio. Increasing the F:C ratio increased ruminal pH and N ammonia and af-fected concentrations of short-chain fatty acid (SCFA) (P < 0.01). Amount of CH4 emission from 13 to 17.16 g/kg DM and the great value was related to F100:C0.
... The synchronization of the ruminal degradation rate of carbohydrates (CHO) and crude protein (CP) has been proposed as a method of improving nitrogen use efficiency and improving animal production (Cole and Todd, 2008). A number of studies have been carried out to investigate the synchronization of CHO and CP degradation in dairy cows (Robinson and McQueen, 1994;Shabi et al., 1998;Rotger et al., 2006). It is revealed in dairy cows that dietary manipulation such as increasing the amounts of ruminally fermentable carbohydrate, or grain processing can potentially increase urea-N transfer to the rumen and enhance animal performance (Kyriazakis and Oldham, 1997). ...
... Pertinent research seems currently not to be under way, probably because important other knowledge gaps exist. For example, although yield level effects in ruminants of (a) synchronization of protein and energy supply to the host animal (Robinson et al., 1997; Shabi et al., 1998), (b) protein – energy ratio in the diet (Fattet et al., 1984; Vipond et al., 1989; Sinclair et al., 1995; Witt et al., 1999), and (c) physical form of the feed (Reynolds et al., 1991; Lachica et al., 1997) have been clearly documented, pertinent research to obtain data suitable for a prediction model currently does not seem to be fundable. Nutritional monitoring. ...
Furazolidone (Fz) is a nitrofuran member used like preventive or therapeutic drug in poultry productions.
Notwithstanding, it produces damages in reproductive variables. The purpose of this study was to determine the effects of Fz on the testicular anatomic-histopathology and ultrastructure of turkeys treated with the drug since the first day of life.Twenty two one-day old male turkey were randomly assigned to receive or not Furazolidone in the diet at 0.04% w/w during 45 weeks. Macroscopic, microscopic and ultrastructural morphology of the testis were analyzed. Localized cysts and normal testicular tissue were observed macroscopically in the treated group. Microscopically these cysts presented dilated seminiferous
tubules with only Sertoli cells, without germinal line and interstitial tissue was compressed. An important lipid degeneration and necrotic cells were saw at electronic microscope. In the macroscopically normal appearing areas, the cells of the germinal line delayed presented lipid vacuoles. An inter and intra lipidic degeneration, basal lamina increased, picnotic cells and protein fibrils bundles. It can be concluded that Furazolidone in the diet at 0.04% w/w during 45 weeks produces cystic patch with lipidic degeneration (inter and intratubular) and germinal line loss and normal testicular tissue with delayed germinal line in turkeys.
... Nocekn and Russel (1988) suggested that the efficiency of microbial growth and microbial protein production may be improved by balancing the overall daily ratio of ruminally available energy and N in the diet. Shabi et al. (1998) found that the available energy in the rumen (Ruminal degradable organic matter) is the most limiting factor for ruminal N utilization. To estimate the microbial protein yield, modern European protein systems use information, which is directly or indirectly used in estimating the energy supply to the animal. ...
Ruminants establish a symbiotic relationship with rumen microorganisms by which the animal provides nutrients and optimum environmental conditions for the fermentation of feeds, and microorganisms degrade fiber and synthesize microbial protein as an energy and protein supply for animal. Ruminal proteins degradation is affected by pH and predominant species of microbial population. A strong positive correlation was observed between dry matter intake (DMI) and microbial growth. The more carbohydrate digestion the more microbial protein synthesis occur. Fermentation energy is inversely related to microbial growth. Essential oil has domestic anti- microbial activity. Nitrogen compound or crude protein contain (CP) of many practical diets may be greater than the 11% required to support optimal microbial growth. Forage concentrate mixing preparation increase the efficiency of microbial protein synthesis than only forage preparation. The efficiency of microbial protein synthesis greater in forages containing saponin and tannins which reduce ruminal N degradability. As ruminant out flow rate increase microbial protein synthesis, it is supposed that the efficiency of microbial protein synthesis can be increased by about 20% if rumen outflow rate is increased from 0.02 to 0.08 /h. Microbial protein production will be a function of the availability of vitamins, microminerals and protein level in the diet of digestible organic matter. Microbial protein synthesis is dependent upon suitable N and carbohydrate sources. Even though trace minerals and vitamins are adequate for maximal microbial protein synthesis in many feeding conditions, inadequate trace minerals and vitamins, in some cases, could limit microbial protein synthesis.
... Sistem formulasi pakan yang sekarang populer untuk ruminansia sebagian berdasarkan atas suplai nitrogen dan energi dalam rumen (Chumpawadee et al., 2006). Shabi et al. (1998) menyatakan bahwa aktivitas mikroba akan optimal dalam memanfaatkan nitrogen pakan jika tersedia energi yang cukup dan sesuai fermentabilitasnya dengan nitrogen tersebut. ...
Products of rumen fermentation and protein microbial of dairy cattle feed with rice bran ammonization and some feedstuffs as an energy sources
ABSTRACT. This study aims to examine the energy sources of feed ingredients that can increase the production of Volatile Fatty Acids (VFA), N-NH3, microbial protein synthesis, total gas production and metabolic energy. The material used is as a source of rumen fluid inoculum from Frisian Holstein cows (FH) females, amoniasi rice straw, salt, mineral mix brand "Ultra Minerals' production Eka Farma Semarang, onggok wet and dry, corn, and rice bran. Observed variable is the concentration of (VFA), N-NH3, rumen microbial protein synthesis, and total gas production. Based on the analysis of diversity seen any significant effect (P0.05) on microbial protein synthesis. Conclusion of research is the provision of energy sources with rice bran treatment, onggok wet and dry corn flour can be used as fermentable carbohydrates on feed hay amoniasi in vitro.
... Pertinent research seems currently not to be under way, probably because important other knowledge gaps exist. For example, although yield level effects in ruminants of (a) synchronization of protein and energy supply to the host animal (Robinson et al., 1997;Shabi et al., 1998), (b) protein -energy ratio in the diet (Fattet et al., 1984;Vipond et al., 1989;Sinclair et al., 1995;Witt et al., 1999), and (c) physical form of the feed (Reynolds et al., 1991;Lachica et al., 1997) have been clearly documented, pertinent research to obtain data suitable for a prediction model currently does not seem to be fundable. ...
Furazolidone (Fz) is a nitrofuran member used like preventive or therapeutic drug in poultry productions.
Notwithstanding, it produces damages in reproductive variables. The purpose of this study was to determine the effects of Fz on the testicular anatomyc-histopathology and ultrastructure of turkeys treated with the drug since the first day of life. Twenty two one-day old male turkey were randomly assigned to receive or not Furazolidone in the diet at 0.04% w/w during 45 weeks. Macroscopic, microscopic and ultrastructural morphology of the testis were analyzed. Localized cysts and normal testicular tissue were observed macroscopically in the treated group. Microscopically these cysts presented dilated seminiferous
tubules with only Sertoli cells, without germinal line and interstitial tissue was compressed. An important lipid degeneration and necrotic cells were saw at electronic microscope. In the macroscopically normal appearing areas, the cells of the germinal line delayed presented lipid vacuoles. An inter and intra lipidic degeneration, basal lamina increased, picnotic cells and protein fibrils bundles. It can be concluded that Furazolidone in the diet at 0.04% w/w during 45 weeks produces cystic patch with lipidic degeneration (inter and intratubular) and germinal line loss and normal testicular tissue with delayed germinal line in turkeys.
Protein is an essential nutrient for dairy cattle in order for them to produce milk. Ruminant protein value can be maximized by feeding autoclave-protected soybeans, non-fiber carbohydrate (NFC) from corn, and sulfur supplementation. The purpose of this study was to see how protected soybean protein, NFC corn, and Na2SO4 supplementation affected the fermentability and digestibility of dairy cattle rations. This study used a randomized block design with five treatments: rations without corn and soybeans (R1), rations with corn but no soybeans (R2), rations with corn and soybeans (R3), rations with corn and autoclave-protected soybeans (R4), and rations with corn, autoclave-protected soybeans, and sulfur supplementation (R5) (R5). As replications, the treatments were repeated four times. The ANOVA was used to analyze the data, which was then followed by an orthogonal contrast test. The treatment had no effect on pH, protozoal number, dry matter, or organic matter digestibility. Although treatment R3 produced significantly more ammonia (P0,05) than R4 and R5, R5 produced the most VFA and total bacteria. It can be concluded that rations containing protected soybean and corn as NFC sources, as well as sulfur supplementation, increase fermentability while decreasing in vitro digestibility.
Adequate prediction of post-rumen outflow of protein fractions is the starting point for the determination of metabolizable protein supply in dairy cows. The objective of this meta-analysis was to compare the performance of 3 dairy feed programs [National Research Council (NRC, 2001), Cornell Net Protein and Carbohydrate System (CNCPS, v6.5.5), and National Academies of Sciences, Engineering and Medicine (NASEM, 2021)] to predict outflows (g/d) of NAN, microbial N (MiN), nonammonia nonmicrobial N (NANMN). Predictions of rumen degradabilities (% of nutrient) of protein (RDP), NDF and starch were also evaluated. The data set included 1,294 treatment means from 312 digesta flow studies. The 3 feed programs were compared using the concordance correlation coefficient (CCC), the ratio of root mean square prediction error (RMSPE) on standard deviation of observed values (RSR), and the slope between observed and predicted values. Mean and linear biases were deemed biologically relevant and are discussed if higher than a threshold of 5% of the mean of observed values. The comparisons were done on observed values adjusted or not for the study effect; the adjustment had a small effect on the mean bias but the linear bias reflected a response to a dietary change rather than absolute predictions. For the absolute predictions of NAN and MiN, CNCPS had the best fit statistics (8% greater CCC; 6% lower RMSPE) without any bias; NRC and NASEM under-predicted NAN and MiN, and NASEM had an additional linear bias indicating that the under-prediction of MiN increased at increased predictions. For NANMN, fit statistics were similar among the 3 feed programs with no mean bias; however, the linear bias with NRC and CNCPS indicated under-prediction at low predictions and over-prediction at elevated predictions. On average, the CCC were smaller and RSR ratios were greater for MiN vs, NAN indicating increased prediction errors for MiN. For NAN responses to a dietary change, CNCPS also had the best predictions, although the mean bias with NASEM was not biologically relevant and the 3 feed programs did not present a linear bias. However, CNCPS, but not the 2 other feed programs, presented a linear bias for MiN, with responses being over-predicted at increased predictions. For NANMN, responses were over-predicted at increased predictions for the 3 feed programs, but to a lesser extent with NASEM. The site of sampling had an effect on the mean bias of MiN and NANMN in the 3 feed programs. The mean bias of MiN was higher in omasal than duodenal studies in the 3 feed programs (from 55 to 61 g/d) and this mean bias was twice as large when 15N labeling was used as a microbial marker compared with purines. Such a difference was not observed for duodenal studies. The reasons underlying these systematic differences are not clear as the type of measurements used in the current meta-analysis does not allow to delineate if one site or one microbial marker is yielding the "true" post-rumen N outflows. Rumen degradabilities of protein (RDP) was under-predicted with CNCPS, and RDP responses to a dietary change was under-predicted by the 3 feed programs with increased RDP predictions. Rumen degradability of NDF was under-predicted and had poor fit statistics for NASEM compared with CNCPS. Fit statistics were similar between CNCPS and NASEM for rumen degradability of starch, but with an under-prediction of the response with NASEM and absolute values being over-predicted with CNCPS. Multivariate regression analyses showed that diet characteristics were correlated with prediction errors of N outflows in each feed program. Globally, compared with NAN and NANMN, residuals of MiN were correlated with several moderators in the 3 feed programs reflecting the complexity to measure and model this outflow. In addition, residuals of NANMN were correlated positively with RDP suggesting an overestimation of this parameter. In conclusion, although progress is still to be made to improve equations predicting post-rumen N outflows, the current feed programs provide sufficient precision and accuracy to predict metabolizable protein supply.
Eighty Awassi female lambs (120 day aged) used in this study to determined the effect of grazing (GR) and hormonal treatment (HT) on reproductive performance and milk gain of ewes and it ' s lambs growth. Animals were assigned to four experimental groups according to their initial weights (20 animals/group). The 1 st and 2 nd groups reared on concentrated ration and grazing for 6 hr daily, where as the 3 rd and 4 th groups reared on concentrate ration only. Estrus in female lambs (all groups) were induced and synchronized by the use of intravaginal sponges (40 mg flurogestrone acetate) twicely for 14 days each with 7 days interval between the 1 st and 2 nd intravaginal insertion. Directly after sponges removal, animals in all groups injected i.m. with eCG (600 IU). While female lambs in 2 nd and 4 th groups only were i.m treated with GnRH in a dose of 25 µg/ animal 1 day after the eCG injection. The results showed that 1 st group (GR + eCG) was the best in all reproductive parameters, as concepted ewes, fertilization rate, fertility % , litter size, and weaned lambs. Also milk gain increased significantly (P≤0.05) in GR group at the 6 th and 12 th week of lambing as compared with WGR, the better interaction was recorded in the 2 nd group (GR+eCG+GnRH) at the 6 th week of lambing. In regard of lambs growth, the GR group increased significantly (P≤0.05) in body weight (BW) at the 12 th week of lambing, the better interaction was recorded in T 2 (GR+eCG+GnRH) at 12 th week of lambing, also body gain (BG) increased significantly (P≤0.05) in GR group at 12 th week with better interaction in T 4 (WGR+eCG+GnRH) at 4 th week, T 1 (GR+eCG) at 6 th week and T 2 (GR+eCG+GnRH) at 10 th and 12 th week of lambing significantly (P≤0.05). The result of this study indicate that grazing has positive effect on reproductive parameters of Awassi female lambs and growth of lambs.
This study was conducted in Al-Rashidiya animal breeding station, using 32 Awassi ewes (3-5 yrs old) with average body weight of 66.59 kg with their single born lambs. The ewes were divided randomly into 4 groups, the first (T1) and second (T2) groups fed on rations consist of 35% barley and contained two levels of rumen degradable protein (RDP) 10 and 13 g/ MJ metabolizable energy. while barley grain raised to 62% in the ration of third and fourth groups (T3 and T4) to increase the starch ratio with observance of the same level of RDP 10 and 13 g/ MJ respectively , and all the rations were iso calorie. Results indicated that RDP and starch levels had no significant effect on milk yield which were 968 , 1067 , 1127 ,and 867 g/ day, milk composition and yield with exception milk urea concentration were decreased (p
Formulating diets conservatively for minimum crude-protein (CP) requirements and overfeeding nitrogen (N) is commonplace in grain finishing rations in USA, Canada and Australia. Overfeeding N is considered to be a low-cost and low-risk (to cattle production and health) strategy and is becoming more commonplace in the US with the use of high-N ethanol by-products in finishing diets. However, loss of N from feedlot manure in the form of volatilised ammonia and nitrous oxide, and nitrate contamination of water are of significant environmental concern. Thus, there is a need to improve N-use efficiency of beef cattle production and reduce losses of N to the environment. The most effective approach is to lower N intake of animals through precision feeding, and the application of the metabolisable protein system, including its recent updates to estimation of N supply and recycling. Precision feeding of protein needs to account for variations in the production system, e.g. grain type, liveweight, maturity, use of hormonal growth promotants and β agonists. Opportunities to reduce total N fed to finishing cattle include oscillating supply of dietary CP and reducing supply of CP to better meet cattle requirements (phase feeding).
z Kapitilizasyon, süreci, aktörleri ve uygulamaların tanımlandığı stratejik bir bilgi yönetimi anlayışı olarak kabul edilir. Bu çalışma afro-arap medya araştırmacılarının sosyal medyayı bir kapitilasyon aracı olarak kullanması ile ilgilidir. Abstract / This paper is about the use of social media by Afro-Arabic media researchers as a capitalization tool. The capitalization is conceived in a strategic conception of knowledge management process, by defining the process, actors and the practices.
Current methods of ruminant ration formulation in Pakistan use foreign-based nutrient availability values. These values may not be optimal for all geographic areas, as variation in environment, agronomic factors, animal species, and diet characteristics may not be considered. The aim of present study was to establish a database of the chemical composition and dry matter degradation parameters of tropical forage commonly fed to ruminants in Pakistan and South Asian countries using Nili-Ravi buffalo and Cholistani cattle at heifer and lactating stages. Six cereal grain and four legume species were grown in 3 locations under standard agronomic conditions and sampled at booting and at 50% flowering stage for cereal and legumes, respectively. Dried and milled feeds were analyzed for chemical composition and in situ dry matter degradation parameters using 1 g samples in bags placed in the rumen of 2 Nili-Ravi buffalo heifers, 2 lactating Nili-Ravi buffaloes, 2 Cholistani heifers, and 2 lactating Cholistani cows. The forage family (cereal vs. legumes), species, and geographic location of growth significantly influenced (P < 0.001) chemical composition and in situ degradation fractions. Animal species and developmental stage showed no effect on degradation fractions (P > 0.05). Legume-by-heifer interactions significantly increased (P < 0.05), and legume-by-lactating cow interaction tended (P = 0.065), to increase the rate of degradation (Kd). The selected forages were degraded to a similar extent independent of animal species or developmental stage, and legumes are degraded at higher rates and to a greater extent than are cereals. A moderately significant relationship between Kd and effective dry matter degradability (DMD) suggests that Kd could be the single most important predictor of forage degradability in the rumen.
In order to maximise utilisation of nutrients for ruminants, researchers directed the supply of nitrogen and organic matter synchronously to the rumen. In the current research, two experiments were conducted, one using the in situ nylon bag technique and the other using in vivo study. In Experiment 1, dynamic degradation rates of organic matter (OM) and nitrogen of each feedstuff were determined using the in situ nylon bag technique. Accordingly, three diets were formulated with the same chemical components, but differing in synchrony index (0.74, 0.85 and 0.97). Experiment 2 was subsequently carried out in vivo to evaluate the influence of diet synchrony on rumen fermentation, productive performance, immunity status and endocrine in Chinese Holstein cows. Rumen degradability of OM and neutral detergent fibre (NDF) and total tract digestibility of OM were linearly increased with the increase of synchrony index, respectively (P < 0.05). Total volatile fatty acids concentration of rumen fluid was increased linearly with the increase of synchrony index (P < 0.05). Meanwhile, rumen ammonia nitrogen concentration and blood urea nitrogen concentration were decreased in cows with the increase of synchrony index, (P < 0.05). Microbial crude protein production, the efficiency of microbial protein synthesis, and milk protein percentage, were linearly increased with the increase of synchrony index (P < 0.05). Serum concentrations of prostaglandin E2 and immunoreactive fibronectin-γ were linearly decreased with the increase of diet synchrony index (P < 0.05). The aforementioned results implicate that an increase of diet synchrony index could improve diet's nitrogen utilisation, apparent digestibility of OM, and NDF. Additionally, it could promote rumen fermentation capacity, productive performance and immunity status in dairy cows.
The increased utilization of Brassica carinata in the biofuel industry in Canada has resulted in the large scale production of coproducts that can be potentially exploited as alternative protein ingredient in dairy ration. The objectives of this study were to investigate the nutritive value of carinata presscake and meal for dairy cows in terms of (1) nutrient and anti-nutrient composition; (2) rumen degradation kinetics of organic matter (OM), crude protein (CP) and neutral detergent fiber; (3) hourly effective degradation ratio and potential N to energy synchronization; (4) intestinal digestion of rumen undegraded protein (RUP); and (5) total metabolizable protein (MP) supply to the small intestine. Samples (n=3) of carinata meal, carinata presscake and canola meal (as reference feed), collected from three consecutive batches, were evaluated. Compared to canola meal, carinata presscake and meal had greater (P < 0.05) contents of CP (39.7% vs. 48.5%, 53.5% dry matter (DM)), with a high proportion of soluble crude protein (24.0% vs. 53.0%, 72.6% CP), resulting in their extensive degradation (59.2% vs. 76.3, 89.3% CP) in the rumen. As a result, carinata presscake and meal supplied smaller (P < 0.05) quantities (92 and 136 g/kg DM) of MP as compared to canola meal (153 g/kg DM). The contents of glucosinolates was greater (P < 0.05) in carinata presscake (168.5 μmol/g) and meal (115.2 μmol/g) as compared to canola meal (3.4 μmol/g), limiting its utilization as ruminant feed. Carinata coproducts can be used as an alternative feed protein source, given their nutrient composition, rumen degradation and intestinal digestion characteristics, provided that the high glucosinolate content can be reduced.
Dietary protein intake is the most important factor determining milk production, milk composition, milk nitrogen efficiency, urinary nitrogen losses, urea content in milk and consequently, ammonia emissions from dairy cow manure. According to the nutrition requirements two main protein sources are available for cows: rumen degradable protein, provided to the animal through ruminally synthesized microbial protein, and rumen undegradable protein that escapes ruminal degradation (but is digested and absorbed in the small intestine). The presence of urea in the milk of cows is caused by metabolic changes in the gastrointestinal tract, resulting in the excess of microbially undigested ammonia in the body. Rumen degradable feed proteins are degraded by rumen microorganisms via amino acids into ammonia and branched chain fatty acids. The bacterial population uses ammonia in order to grow. The extent, to which ammonia is used to synthesize microbial protein, is largely dependent upon the availability of energy generated by the fermentation of carbohydrates. On average, 20 grams of bacterial protein are synthesized per 100 grams of organic matter fermented in the rumen. Bacterial protein synthesis may range from less than 400 g/day to about 1500 g/day, depending primarily on the digestibility of the diet. A highly toxic chemical compound generated during those processes, i.e. ammonia, is detoxified in the liver and converted to urea. The main reason for elevated levels of urea in milk is connected with excess protein contents in feed rations, and energy and protein imbalance. The increase in the percentage of total protein from 13% to 18% DM per ration is accompanied by an increase in the urea level by about 80 mg to over 150 mg in 1 liter of milk. Additional factors affecting the level of urea in milk include the following: frequency of feed administration, number of milkings and length of the interval between milkings, cow's body weight, water intake volume, the level of Na and K ration supplementation, as well as rumen pH. Recent research indicated that an addition of natural plant-origin biologically active compounds, such as tannins, saponins and essential oils, reduce ammonia production and finally urea content in milk. Information on the concentrations of milk urea and nitrogen in dairy cows allows to assess energy balance and protein rations supplied, which in turn can help to reduce both feed costs and nitrogen emission (N) to the environment.
Twenty-four multiparous ewes were used to test the hypothesis that synchronizing the hourly rate of release of energy and nitrogen in the rumen would optimize milk production. Three diets were formulated using the in situ degradability of the food ingredients, to differ in their rate of organic matter (OM) and nitrogen (N) release in the rumen. All diets contained 400 g grass silage per kg dry matter (DM) and were predicted to have a similar content of metabolizable energy (11.8 MJ/kg DM), metabolizable protein (102 g/kg DM), neutral-detergent fibre (365 g/kg DM) and daily ratio of N : OM supply to the rumen but differ in their hourly pattern of nutrient release to be either synchronous (S), asynchronous (A) or intermediate (I). The diets were offered ad libitum as a complete feed in a 3 × 3 Latin-square design consisting of three periods each of 28 days duration. Synchronizing the hourly supply of energy and N to the rumen did not significantly alter milk or milk fat yield (g/d), milk protein content (g/kg), DM intake (kg/day), total time spent eating or the number of meals per day. However, compared with ewes offered diets I or A, those offered diet S had a lower milk fat content (g/kg; P < 0.05.) whilst protein yield (g/day) tended to be increased (P = 0.05). Animals offered the synchronous diet (S) had lower plasma urea concentrations throughout the day and significantly higher beta-hydroxybutyrate concentrations at 14:00 and 18:00 h than those offered diets I or A. In conclusion, synchronizing dietary energy and N supply to the rumen did not have a major effect on milk production in ewes.
The effects of diets formulated to have two rates of organic matter (OM) release and to be either synchronous or asynchronous with respect to their hourly release of OM and nitrogen (N) in the rumen on N retention, microbial N production, growth and metabolism of ram lambs offered food at a restricted level was studied in two experiments. Four diets were formulated to differ in their rate and extent of OM and N release in the rumen based on the sum of in situ degradability data of the ingredients. All diets were formulated to have a similar metabolizable energy (10·4 MJ/kg dry matter (DM)), crude protein (140 g/kg DM) and daily ratio of N : OM released (34 g N per kg OM) and were either synchronous or asynchronous with respect to their hourly N : OM release. The four diets were slow energy, synchronous (SS), slow energy asynchronous (SA), fast energy, synchronous (FS) and fast energy asynchronous (FA). In both experiments the diets were offered at a rate of 1·75 maintenance energy requirements as two equal meals at 09:00 and 17:00 h. In experiment 1 there was no significant effect of diet on OM apparent digestibility or N retention. Lambs given diet FS had the highest daily production ofallantoin (7·82 mmol per day; P < 0·05) and microbial N (7·80 g/day; P < 0·05). Hourly plasma urea and β-hydroxy butyrate (3-OHB) concentrations exhibited a cyclical trend between meals with maximum concentrations occurring within 3 h of feeding and were higher in lambs given diet FA. In experiment 2 the four diets were offered to 32 growing ram lambs. Animals given synchronous diets (SS and FS) had a significantly higher live-weight gain than those given asynchronous diets (SA and FA; (132 g/day v. 107 g/ day respectively; P < 0·001). Food conversion efficiency (FCE; kg gain per kg DM intake) was improved proportionately by 0·23 in animals offered synchronous diets compared with asynchronous diets (P < 0·001). There was little effect of diet on carcass composition except kidney fat, which was greater in lambs offered the synchronous diets (P < 0·01). Plasma 3-OHB concentrations were higher throughout the growth period in lambs given diet FA whilst plasma urea concentrations were greater in lambs given the diet SS. In conclusion, greater attention to the formulation of diets to be synchronous for their hourly release of N : OM in the rumen can improve the growth rate and FCE of lambs. This effect may be due to an improvement in energy rather than N metabolism.
This experiment was conducted to evaluate whether a degree of rumen synchronicity with fermentable energy and nitrogen (N) supply would have an effect on the N utilization by sheep and microbial efficiency in the rumen. Two diets differing in their degrees of ruminal degradation synchronicity between N and organic matter (OM) (Synchrony index =0.3 and 0.8) were fed to four crossbred Suffolk adult rams at a maintenance level of requirement in a change-over design, and differences in microbial N (MBN) supply and N balance with both diets were investigated. The in situ rumen degradation parameters of OM and N were determined for timothy hay, rolled corn, rolled barley and sunflower meal and subsequently were used to formulate the two diets to have different ruminal degradation synchronicity. The diets were also formulated to give comparative provision levels of metabolizable energy (ME) and metabolizable protein (MP). The animals were fed asynchronous (ASYNC) and synchronous (SYNC) diet for a period of 22 days, and metabolizm trial and blood collection were carried out for the last 7 days of the period. Animals consumed their diets thoroughly. The nutrient intakes and apparent digestibility were unaffected by dietary treatments (P >0.05). There were no differences in MBN supply and microbial efficiency between the diets (P >0.05). The estimates of N retention were significantly higher for ASYNC than those for SYNC owing to the lower urinary N excretion for ASYNC compared with SYNC (P < 0.05). The concentrations of plasma urea nitrogen and glucose did not differ significantly between the diets (P >0.05), although the concentration of plasma urea nitrogen seemed to be numerically lower for ASYNC than that for SYNC (P =0.20). These results suggest that when ME and MP were provided to suffice a maintenance requirement of adult sheep, the diet being imbalanced between fermentable energy and degradable N provision could increase the N utilization efficiency by reducing their urinary N excretion or increasing urea recycling.
A reaction scheme for the spectrophotometric determination of ammonia by means of a modified Berthelot reaction is proposed, in which salicylate, dichloroisocyanurate and complex cyanides are the principal reagents. The experimental results presented are consistent with, and support, the reaction scheme proposed. It is suggested that the complex cyanides act on two stages of the reaction, firstly to stabilise monochloramine at pH values (12–13) at which it is normally unstable and hence facilitate the formation of 5-aminosalicylate from salicylate (this step is the rate determining step of the reaction), and secondly, to accelerate the oxidative coupling of 5-aminosalicylate with salicylate to form the indophenol dye [possibly via a hexacyanoferrate(III) intermediate]. It is shown that the optimum pH of reaction is a result of a complex inter-relationship of a number of equilibria and it thus remains necessary to optimise the pH value for each combination of reagents used. The implications of this study on the choice of reagents for the determination of ammonia by the Berthelot reaction are noted.
A rapid method for separation and quantitation of purines was applied to ruminal and intestinal digesta for estimating net microbial protein synthesis in the rumen. The procedure combines standard literature methods for hydrolysis of nucleotides by perchloric acid followed by precipitation of free purines with silver nitrate to separate the purines from interfering compounds. Acid resolubilized purines were quantitated spectrophotometrically at 260 nm. Microbial protein was estimated by the ratio of purines to N of isolated bacteria. The procedure is rapid, simple, precise and not costly. Duodenal passage of microbial N estimated by this procedure for steers fed semipurified and purified diets containing no protein was highly correlated (R2 = 0.98; P < 0.01) with duodenal passage of tungstic acid precipitable N. Results indicate that purines may be useful as a marker for quantitating microbial protein. Key words: Purine, RNA, DNA, microbial protein
The effects of two diets formulated to be either synchronous or asynchronous with respect to the hourly supply of energy and nitrogen on rumen fermentation and microbial protein synthesis were studied in sheep.
In Expt 1, the in situ degradation characteristics of nitrogen (N), organic matter (OM) and carbohydrate (CHO) fractions were determined in winter wheat straw, winter barley, malt distillers dark grains rapeseed meal and fishmeal. The feeds exhibited a large range in degradability characteristics of the nitrogen and energy-yielding fractions.
A computer program was developed based upon the raw material degradation characteristics obtained from the above studies. The program was used to formulate two diets with similar metabolizable energy (9·5 MJ/kg DM) and rumen degradable protein contents (96 g/kg DM) but to be either synchronous (diet A) or asynchronous (diet B) with respect to the hourly rate of release of N and energy. The program was used to predict the hourly release of N, OM and CHO and the molar production of volatile fatty acids (VFA).
In Expt 2, the two diets were fed to four cannulated sheep at the rate of 1 kg/day in four equal portions, in two periods, using a change-over design. Rumen ammonia concentrations followed the predicted rate of N degradation. A maximum concentration of 10·5 and 7 mM for diets A and B respectively was achieved within the first hour of feeding which then fell to 7 and 3 mM respectively. Rumen VFA proportions were more stable for the synchronous diet (A) than the asynchronous diet (B) and were more stable than predicted for both diets. True ruminal degradation of OM and CHO was similar for both diets and close to that predicted, although fibre degradability in diet A was 30% lower than predicted due to a reduction in both cellulose and hemicellulose digested. Microbial protein production was estimated simultaneously with L-[4,5– ³ H]leucine and a technique based on cytosine. Estimates varied with marker but mean values indicated a 27% greater production of microbial N (g N/kg DM I) with the synchronous diet (A) and an average improvement in microbial protein efficiency (g N/kg OM truly degraded or CHO apparently degraded) of 13%, although neither difference was significant. There was evidence of a greater recycling of N in the animals and a significantly lower content of rumen degradable protein when the sheep were fed the asynchronous diet (B).
The results are consistent with the view that synchronizing the rate of supply of N and energyyielding substrates to the rumen micro-organisms based upon ingredient in situ degradation data can improve microbial protein flow at the duodenum and the efficiency of microbial protein synthesis.
The effects of an asynchronous supply of fixed amounts of N and carbohydrate on bacterial growth were measured in two batch culture experiments. In Exp. 1, aqueous glucose and urea solutions were added at hourly intervals to culture flasks containing strained ruminal liquor and phosphate/bicarbonate buffer. The ratio of urea N to glucose was either constant (Synchrony, 26 mg of N/g of glucose) or increased exponentially over time (Asynchrony, .013 to 48,900 mg of N/g of glucose). After 12 h, identical quantities of glucose and urea had been added in both treatments. Bacterial population size (estimated from optical density) was greater (P less than .001) from 5 to 8 h of incubation for Synchrony than for Asynchrony, but after 12 h there was no difference (P greater than .1) between treatments. In Exp. 2, large (1 to 1.5 mm) and small (less than .5 mm) corn particles were used as slowly and rapidly degraded energy sources, with soybean meal (1 to 1.5 mm) and a papaic digest of soybean meal as sources of slowly and rapidly degraded N. At incubation times, when the ratio between total starch and N degraded was equal between treatments, bacterial population size was unaffected by the relative rate of N and OM supply. In both experiments, bacterial growth recovered quickly from transient restriction caused by deficits of N.
Seventy-six high producing Holstein cows were randomly assigned in a 2 x 2 factorial to evaluate two sources of nonstructural carbohydrates (corn and barley), which supposedly differed in degradability of starch with two sources of CP degradability (soybean meal and urea) in the concentrate mix during wk 4 through 14 postpartum. Total mixed diets, formulated to be isonitrogenous at 16% CP, contained (DM) 40% corn silage, 10% alfalfa hay, and 50% of the respective concentrate mix. Nonstructural carbohydrate degradability was similar for concentrate mixes containing corn or barley. Production of milk (32.2 and 31.8 kg/d) was similar, but production of 4% FCM (29.1 and 27.4 kg/d) and SCM (29.1 and 27.5 kg/d) was decreased for cows fed barley due to lower percentages of fat (3.39 and 3.22) and SNF (8.65 and 8.59). Percentages of protein (3.09 and 3.08) were similar for cows fed corn and barley diets. Degradability of CP did not affect production of milk (31.9 and 32.0 kg/d), 4% FCM (28.5 and 28.0 kg/d), and SCM (28.4 and 28.2 kg/d) for cows fed soybean meal and urea. Dry matter intake was lower for cows fed barley (20.7 and 19.2 kg/d), but intakes (20.1 and 19.8 kg/d) were similar for cows fed soybean meal and urea. Providing an alternative nonstructural carbohydrate source (barley versus corn) did not increase utilization of a more readily degradable CP source (urea versus soybean meal).
Four early lactation multiparous Holstein cows were used in a 4 x 4 Latin square to investigate the effects of source of protein (fish meal or soybean meal) and carbohydrate (corn or barley) on ruminal fermentation, flow of nutrients to the small intestine, and animal performance. The treatments, arranged in a 2 x 2 (protein x carbohydrate) factorial were: 1) corn plus soybean meal; 2) corn plus fish meal; 3) barley plus soybean meal; and 4) barley plus fish meal. Dry matter and starch intakes were greater when corn was fed than when barley was fed. Barley-based diets were more extensively degraded in the rumen than corn-based diets and therefore provided more energy for microbial growth. However, passage of amino acids and starch to the duodenum was greater for corn-based diets than barley-based diets, because of the greater intake and lower ruminal degradability of the corn-based diets. Microbial protein constituted a larger portion of the total N and had a greater influence on the pattern and quantity of amino acids that passed to the duodenum than did protein from fish meal or soybean meal, which escaped ruminal degradation. Feeding corn-based diets increased production of milk and milk protein compared with feeding barley-based diets.
Four lactating Holstein cows, fitted with T-type cannulas in the proximal duodenum, were used in a 4 x 4 Latin square design to determine the effect of protein supplement on production, ruminal digestion, and profile and the quantity of AA available for absorption. Supplemental protein sources were blood meal, corn gluten meal, blood meal plus corn gluten meal, and sunflower meal, which constituted 8, 10.5, 9.3, and 13% of dietary DM, respectively. The DMI and milk production were not influenced by treatment. Ruminal NH3 concentration increased with the sunflower meal diet, and molar percentage of propionate decreased with the blood meal diet. Duodenal flow of NAN was unaffected by protein source, but dietary N flow decreased, and bacterial N flow increased, when cows were fed the sunflower meal diet. Bacterial N flows were 46.0, 45.3, 46.4, and 65.8% of NAN for the respective diets. The AA profiles of isolated ruminal bacteria differed among dietary treatments but were not correlated with the respective supplementary protein sources. The essential AA profiles of duodenal digesta and duodenal flow of individual AA closely reflected AA differences in protein sources, suggesting that the composition of RUP profoundly affected the composition of protein entering the intestine when supplemental protein provided 35% of total CP intake.
ABSTRACT Thirty multiparous,Holsteins and,12 multiparous Jerseys (90 5 15 d in lacta- tion) were assigned in a 3 x 2 factorial design. Diets containing 0, 1, or 2 kg fish meal at 70 or 75% TDN were fed for 8 wk. Dry matter intake was greater on the high TDN diet. Milk and,FCM yields were not different. Percentage of milk fat, percentage of protein, and protein yield decreased with inclusion of fish meal in the diet. In Experiment 2, 30 primiparous Hol- steins (106 f 24 d in lactation) were assigned one of two diets in an incom- plete block design for two,consecutive 324 periods. Corn silage-based diets var- ied in CP and source as follows: 12% CP, soybean meal; 20% CP, soybean meal; 20% CP, fish meal; 20% CP, corn gluten meal; 20% CP, glutexsoybean; and 20% CP. fish mealsoybean.,Milk fat and milk lactose percentages,and FCM yield (kg) were higher on corn gluten meal (3.13, 5.30, 23.0) than on fish meal (2.1 1, 5.00, 20.5). Milk protein yield was affected by amount,and source of protein. Rumen ammonia,and plasma,urea were,greater on high (13.5, 16.2 mgldl) than on low soybean meal (7.3, 6.4 mgldl). Results indicatl: protein source may,affect milk composition,in cows fed corn silage diets. (Key words: protein source, milk compo-
Twenty-two Holstein cows near peak lactation were used in an 8-wk experiment to study the effects of forage fiber source and ruminal starch degradability on lactational performance. High and low digestibility forages (alfalfa hay and wheat straw) and sorghum grain processed to give low and high ruminal starch degradability (dry-rolled and steam-flaked) were factorially arranged in four treatments. Diets contained 30% total NDF and 22% forage NDF; consequently, forage to concentrate ratio decreased from 52:48 to 31:69 when straw was substituted for alfalfa hay. Source of forage fiber did not influence production characteristics. Ruminal passage rates for liquid and diet ingredients were slower when diets contained wheat straw, but chewing time and digestibility of NDF were not affected. Total tract digestibility of starch increased from 80 to 97% when grain was steam-flaked, but digestibility of NDF was not influenced. Diets containing more ruminally degradable starch resulted in higher yields of milk (+3.4 kg/d) and milk protein (+110 g/d), milk protein percentage (+.08%), and improved efficiency and persistence of milk yield. Milk fat percentage decreased from 3.6 to 3.2% when steam-flaked grain was fed, but daily yield of milk fat was not decreased. Increasing ruminal degradability of starch has the potential to improve lactational performance when the proper balance of ruminally degradable starch and forage fiber is maintained.
Fifteen multiparous, midlactation Holstein cows were used in a 5 × 5 Greco-Latin square to investigate the effects of various amounts of ruminally degradable and undegradable protein on plasma urea and milk urea N and NPN constituents. Diets were designed to provide the following percentage of degradable and undegradable protein relative to NRC requirements: diet A, 80, 80%; diet B, 100, 100%; diet C, 120, 80%; diet D, 100, 120%; and diet E, 120, 120%. All cows were fed for ad Libitum intake a TMR consisting of 47% corn silage, 18% haycrop silage, and 35% concentrate (DM basis). Concentrate consisted of various amounts of dry corn plus soybean, fish, and blood meals to alter the degradability of protein. In situ measurements were used to determine grain protein degradability. Plasma urea N was increased across diets A to E, respectively: 8.2, 14.8, 16.5, 17.8, and 20.7 mg/dl. The within-cow coefficient of correlation between plasma and milk urea N was .88. The intake of undegradable protein elevated plasma and milk urea N to a similar extent as intake of degradable protein. Multiple regression analysis across all diets revealed a negative relationship of energy intake on plasma urea N. Diet significantly influenced milk true protein yield for diets A to E, respectively: .73, 30, .73, .78, and .81 kg/d. Milk true protein yield was influenced by milk yield, undegradable protein, and energy intake. Milk NPN concentration increased across diets A to E, respectively: 28.7, 33.9, 35.6, 36.8, and 39.8 mg/dl. The increase in milk NPN concentration across diets was attributed largely to an increase in the urea component of milk NPN.
The accuracy of prediction of microbial growth in the rumen and flow of microbial protein to the small intestine is important in predicting protein and carbohydrate utilization in dairy cattle as well as the development of a protein and carbohydrate feeding system that will be an improvement over present systems. Empirical multiple and simple regression equations are presented that demonstrate the impact of body size, proportion of forage in the diet, and dry matter intake on flow of microbial protein into the small intestine from the rumen. Concepts are developed and validated for a mechanistic, dynamic approach for prediction of microbial growth and flow of microbial protein based on Michaelis-Menton equations, microbial substrate affinities, and rumen liquid flow kinetics. Emphasis is placed on the importance of quantifying dynamics of rumen function, the need for experimentation to develop a carbohydrate system that will include methods for analysis, and a factorial approach to digestion and utilization.
Thirty-six early lactation cows (51 DIM) were used in an 8-wk trial (3 × 2 factorial) to compare sorghum grain processed by dry rolling or steam flaking to .40 or .27 kg/L bulk density in TMR with or without 1% buffer (sodium sesquicarbonate). Mixed diets (16% CP) contained 42% sorghum grain with alfalfa hay as the forage source. When grain was steam flaked to .40 kg/L (31 lb/bu), milk yield was increased, and efficiency was improved, without decreasing intake or milk fat percentage. Further processing of the grain to a flake density of .27 kg/L (21 lb/bu) depressed intake and milk fat percentage, and inclusion of buffer in the diet did not alleviate these problems. Steam flaking sorghum grain increased DM, OM, starch, and CP digestibilities; lowered ruminal ammonia and acetate to propionate ratio; and increased fecal pH. The sodium sesquicarbonate buffer did not influence diet digestibility, milk fat percentage, or ruminal pH, but it increased acetate to propionate ratio in ruminal fluid. Cows fed the buffered diets consumed less feed, which resulted in increased gross efficiency. Compared with dry rolling, steam flaking the sorghum grain to .40 kg/L improved performance, but the lowest flake density was detrimental, and effects were not alleviated by inclusion of 1% buffer in the diet.
Interactions between feedstuff characteristics, animal characteristics, and quality of animal management determine potential for productive benefits to increased frequency of feeding or changes in the sequence of offer of individual feedstuffs to dairy cows. Productive benefits can be exhibited as improved milk yield, increased milk component yield, or improved maintenance of body condition. There are many reported research studies on the influence of feeding frequency that report improvement in one of these areas, particularly if infrequent feeding caused diurnal variations in rumen metabolite concentrations. However, benefits are often relatively small in relation to the importance placed upon multiple, or sequenced, daily feeding by commercial producers. The apparent dichotomy between field observations and research results is examined, and reasons for benefits under some conditions, but not others, are addressed with particular reference to the importance of rumen microbial yield, passage of particles from the rumen, as well as potential affects of end products of rumen microbial fermentation on fermentative efficiency. Design and interpretation of studies of feeding frequency, due to problems of nonsteady state conditions, continue to cause difficulties and are an obstacle to progress in this area.
A method is proposed for estimating the percentage of dietary protein that is degraded by microbial action in the rumen when protein supplement is added to a specified ration. The potential degradability, p , is measured by incubating the supplement in artificial-fibre bags in the rumen and is related to incubation time, t , by the equation p = a+b (1 – e -ct ). The rate constant k , measuring the passage of the supplement from the rumen to the abomasum, is obtained in a separate experiment in which the supplement is combined with a chromium marker which renders it completely indigestible. The effective percentage degradation, p , of the supplement, allowing for rate of passage, is shown to be p = a +[ bc/(c+k) ] (1- e -(e+k)t ) by time, t , after feeding. As t increases, this tends to the asymptotic value a+bc /( c+k ), which therefore provides an estimate of the degradability of the protein supplement under the specified feeding conditions.
The method is illustrated by results obtained with soya-bean meal fed as a supplement to a dried-grass diet for sheep. The incubation measurements showed that 89% of the soya-bean protein disappeared within 24 h and indicated that it was all ultimately degradable with this diet.
When the dried grass was given at a restricted level of feeding the allowance for time of retention in the rumen reduced the estimate of final degradability to 71% (69% within 24 h). With ad libitum feeding there was a faster rate of passage and the final degradability was estimated to be 66% (65% within 24 h).
The effects of synchronizing dietary energy and nitrogen supply in diets with a similar carbohydrate composition on microbial protein synthesis and rumen fermentation were examined in sheep. Two diets were formulated to be either synchronous (diet S) or asynchronous (diet A) for the hourly release of nitrogen (N) and energy to the rumen. Diet S contained (g/kg) 425 g wheat straw, 400 g winter barley, 150 grapeseed meal and 25 g minerals/vitamins and diet A contained 505 g wheat straw, 458.5 g winter barley, 11·5 g urea and 25 g minerals/vitamins. Both diets were fed at the rate of 1 kg/day in four equal portions, to four cannulated sheep, in two periods in a change-over design. Rumen ammonia concentrations followed the predicted hourly trend in N degradation with a peak 1 h after feeding of 10 mM for diet S and 16 mM for diet A before falling within 3 h of feeding to 4 ITIM in animals fed either diet. Rumen volatile fatty acid (VFA) concentrations followed the cyclical trend predicted by stoichiometric equations, whilst rumen VFA ratios were more stable than predicted in animals fed either diet. The observed content of rumen degradable protein and organic matter truly degraded in the rumen was similar for both diets. The increase in total CHO digested in the rumen observed with diet A (427 g/kg DM) compared with diet S (364 g/kg DM) can be attributed to the greater content of starch in the asynchronous diet, which had a high degradability. The efficiency of microbial protein synthesis (g N/kg OM truly degraded in the rumen) was 11–20% greater in animals fed the synchronous diet (S) than the asynchronous diet (A). It is concluded that microbial N production was more efficient when dietary energy and N supply were synchronized.
Sixty Israeli-Friesian cows were allocated, after calving, to five treatment groups of 12 cows per group according to the concentration and source of crude protein (CP) in the concentrate. Three groups received all their protein from plant sources: a basal control group (BP) was given concentrate containing 92 g CP per kg dry matter (DM), a medium-protein group (MP) was given a diet with soya-bean meal (SBM) added to give a CP concentration of 143 g/kg DM, and a high-protein group (HP) was given a diet with SBM added to give a concentration of 180 g/kg DM. Two groups were given the basal concentrate supplemented with urea (MU) or urea phosphate (MUP) up to approximately the same CP level as the MP group. The only roughage used was vetch-oats hay at a level of 350 g/kg total DM intake. The cows were given the experimental diets ad libitum throughout lactation.
No difference was found between treatments in DM intake (kg/day), mean milk and fat-corrected milk (FCM; 40 g fat per kg) yields (kg/day), milk protein concentration, days from calving to conception or services per conception, during the entire lactation period. However, FCM yields during 60 days after calving were significantly higher for cows given the CP-supplemented diets than for the BP group. The FCM yield of the cows given the HP concentrate was higher than for those given the other concentrate mixtures only during the first 15 days after calving. Milk fat concentration was higher in cows given the BP and HP concentrates than in those given the MP ration, but only a trend in this respect was observed when part of the plant protein was replaced by urea or urea phosphate.
The rate of body-weight loss after calving tended to increase with increase in amount of plant protein in the diet but was highest for the cows given the diets supplemented with non-protein nitrogen. Later in lactation, the body-weights of cows given the MP, HP and MUP diets increased immediately after they reached their lowest weight whilst cows given the BP and MU diets started gaining weight 165 and 120 days after calving, respectively.
Rumen ammonia-N and blood urea-N concentrations (mg/1) for treatments BP, MP, HP, MU and MUP were: 56 and 101; 120 and 226; 143 and 269; 191 and 227; and 179 and 212, respectively. The relationship between rumen ammonia concentrations, blood urea concentrations and CP utilization for the different treatments is discussed. Supplying urea as urea phosphate tended to improve performance by an increase in annual milk and milk protein yields as well as in live-weight gain.
Microbial fractions, comprising protozoa, large and small bacteria and whole particulate matter, have been isolated from rumen contents of sheep given a mainly concentrate diet, a mixture of hay and concentrate, and hay only. Samples of rumen contents were taken before and 2 h after feeding. The main components determined were: protein, lipid, nucleic acids, carbohydrate and ash. The amount of cell wall was estimated in terms of known cell wall constituents (diaminopimelic acid (DAP) and glucosamine). The concentration of some of the constituents varied with diet and with respect to the time of feeding. Many of the differences disappeared when the results were expressed on a polysaccharide-free basis. The amino acid composition of large and small bacteria was virtually the same. The amino acid composition of protozoa was similar except for the proportions of glutamic acid and lysine which were greater in protozoa, and alanine, glycine and DAP, the proportions of which were greater in bacteria. There were higher proportions of protein in large bacteria and protozoa than in small bacteria. Small bacteria contained more lipid, ash and DNA, and less RNA than the other two fractions. The polysaccharide content of protozoa and large bacteria increased from about 8% before feeding to about 30% after feeding, while the polysaccharide content of small bacteria increased only slightly after feeding.
Three ruminally and duodenally cannulated, lactating Holstein cows were used in a 3 x 3 Latin square experiment to study the effects of differing levels of nonstructural carbohydrate and degradable intake protein on ruminal digestibility and microbial protein production. Three diets were formulated to contain 1) 38 and 13.2%, 2) 31 and 11.8%, and 3) 24 and 9% nonstructural carbohydrate and degradable intake protein as percentages of the DM, respectively. Dry matter intakes were similar for all diets (21.9, 21.1, and 18.3 kg/d for diets 1, 2, and 3, respectively). Likewise, microbial efficiency, as estimated from purine analysis, was unaffected by diet and averaged 24 g of microbial N/kg of OM digested for all treatments. Ruminal digestion of OM averaged 66.6, 65.1, and 55.7% for diets 1, 2, and 3, respectively, resulting in lower microbial N flow per day for diet 3 (317, 333, and 202 g, respectively). Digestion of nonstructural carbohydrate and CP followed similar trends as did OM digestion, whereas NDF digestion remained similar across all diets. These results indicate that nonstructural carbohydrate greater than 24% and ruminally degradable protein greater than 9% of DM will enhance microbial protein flow from the rumen.
Establishing conditions under which rumen fermentation will be optimized requires an understanding of the nutrient requirements of the mixed microbial population. The major nutrients required by rumen microbes are carbohydrates and proteins, but the most suitable sources and quantities needed to support maximum growth have not been determined. Digestion of proteins results in the production of peptides, which can accumulate in the rumen. Peptides are further hydrolyzed to amino acids, some of which are deaminated, producing ammonia. Although peptides, amino acids, and ammonia all may individually serve as sources of N for various microbes, the total population achieves the highest growth rate on mixtures of all three sources. In a somewhat analogous manner, carbohydrates are digested by exoenzymes to oligosaccharides that are available for crossfeeding by the mixed microbial population. Based on data from both in vitro and in vivo studies, there is general agreement that rate of digestion of carbohydrates is the major factor controlling the energy available for microbial growth; in addition, rate of digestion of total carbohydrate is directly related to proportion of starches, pectins, and sugars. Proteins affect both total fermentation and production of microbial DM per unit of carbohydrate fermented. It appears that the quantity of ruminally available protein needed to optimize microbial growth may, under some conditions, be as high as 14 to 15% of diet DM.
Two experiments were conducted to determine the effects of frequency of feeding on ruminal fermentation, blood parameters, milk yield, and milk composition in cows fed a 60% pelleted concentrate and 40% chopped alfalfa hay (DM basis) diet. In Experiment 1, four ruminally cannulated cows were fed concentrates in 12 equal portions at 2-h intervals or in two equal portions at 0500 and 1500 h in a crossover design. In Experiment 2, treatments were as in Experiment 1 plus an additional treatment consisting of a total mixed diet fed at 2-h intervals in a 3 x 3 Latin square design. All treatment periods were 2 wk. In Experiment 1, increased frequency of concentrate feeding tended to result in elevated ruminal pH and increased acetate to propionate ratio. Plasma insulin concentration tended to be higher (1.54 vs. 1.04 ng/ml) and milk fat percentage increased from 2.21 to 2.60% for 2 and 12 times daily feeding, respectively. In Experiment 2, frequency of feeding concentrate or total mixed diet did not affect ruminal and blood parameters or milk yield. In both experiments, milk protein and lactose concentrations were not influenced by feeding frequency. Results suggest that where intake is kept constant, increased feeding frequency will not influence milk yield but could result in elevated milk fat percent in animals fed fat-depressing diets.
A 4 x 4 Latin square design with four multiparous cows in midlactation fitted with duodenal cannulae was used to determine the effect of synchronization of protein and starch degradation in the rumen on nutrient availability in lactating cows. As major starch and protein sources, diets contained: barley plus cottonseed meal; barley plus brewers dried grains; milo plus cottonseed meal; and milo plus brewers dried grains. Experimental periods were 12 d and consisted of 8 d adjustment and 4 d collection. Chromium oxide was used as the marker to determine digestibility and nutrient flow from the rumen. Microbial protein synthesis was estimated from nucleic acid content in duodenal samples. Apparent and corrected rumen digestibilities of DM, organic matter, CP, and starch were higher for diets containing barley than milo but were not affected by protein source. For diets containing barley and milo, starch digested postruminally averaged 820 and 2190 g/d and percentage digestibility was 70 and 77%. No difference among diets was found in DM, organic matter, and CP flow to the small intestine; however, microbial N synthesis was higher in diets containing barley than in diets containing milo.
Two trials were conducted to examine the influence of flake density (FD) on the feeding value of steam-flaked corn. Treatments consisted of corn that had been steam-flaked to mean densities of .42, .36 and .30 kg/liter (28, 24 and 20 lb/bu). In Trial 1, treatment effects on characteristics of digestion were evaluated using three crossbred steers with cannulas in the rumen and proximal duodenum. In Trial 2, treatment effects on feedlot performance were evaluated in a 112-d finishing trial involving 72 crossbred steers with an average initial weight of 312 kg. Flake density was directly related to flake thickness (P less than .01) and inversely related (P less than .01) to in vitro enzymatic digestibility of starch. Decreasing the FD resulted in a linear decrease (P less than .01) in ruminal pH and linear increases (P less than .05) in postruminal and total tract digestibility of starch. Postruminal digestibility of N and total tract digestibility of OM, N and energy also increased linearly (P less than .05) with decreasing FD. Flake density did not influence (P greater than .10) feedlot performance or carcass merit. There was a tendency (P greater than .10) for depressed rate and efficiency of gain for steers fed the 30 kg/liter FD corn. Improvements in digestibility and N utilization of SF corn-based diets as a result of decreasing FD from .42 to .30 kg/liter did not enhance feedlot performance. This may be due to digestive dysfunction, perhaps related to processing effects on ruminal pH.
Three rumen-cannulated Holstein cows in mid to late lactation were randomly assigned to a 3 x 3 Latin square with the following concentrate feeding frequencies: one, two, and four times daily. Cows were fed ad libitum a diet containing 55% corn silage and 45% concentrate (DM basis). The forage portion of the diet was fed twice daily to all cows separately from the concentrate. Each experimental period was 20 d in duration. After a 12-d adaptation, daily individual feed consumption and milk production were measured. Rumen digesta were collected prior to (0 h) and at 2, 4, and 8 h after the morning feeding to measure postprandial changes in protozoa numbers, pH, VFA, and NH3 N. Chromium-EDTA and ytterbium chloride were used as liquid and particulate markers to estimate liquid and solid digesta turnover rate in the rumen. Concentrate and forage DM intake, ruminal protozoa numbers, pH, VFA, and NH3 N concentrations, and digesta turnover rate were not affected by concentrate feeding frequency. There was a significant concentrate feeding frequency with sampling time interaction influence on NH3 N in which feeding concentrate four times daily minimized postprandial fluctuation of rumen NH3 N concentration. Feeding concentrate four times daily increased milk fat and protein production.
Sixty high producing Holstein cows were randomly assigned in a 3 x 2 factorial to evaluate three sources of carbohydrates that differed in solubility and degradability (corn, barley, and dried whey) with two sources of CP solubility (soybean meal and urea) during wk 4 through 14 postpartum. Total mixed diets, formulated to be isonitrogenous at 16% CP, contained (DM basis) 40% corn silage, 10% chopped alfalfa hay, and 50% of the respective concentrate mix. Milk production (32.8, 31.5, and 31.3 kg/d) was highest for cows fed corn, whereas 4% FCM (30.0, 27.9, and 29.5 kg/d) was similar for cows fed corn and dried whey and lower for cows fed barley. Percentages of fat (3.37, 3.36, and 3.51) and protein (3.05, 3.00, and 2.98) were similar for cows fed all carbohydrate sources. Solubility of protein (soybean meal versus urea) did not affect production of milk (32.2 and 31.5 kg/d) and 4% FCM (29.4, and 28.9 kg/d). Intake of DM was lowest for cows fed barley (20.4, 18.8, and 20.5 kg/d), and intakes were similar (19.9 and 19.9 kg/d) for cows fed soybean meal and urea. Providing sources of carbohydrates in the diet that are more soluble and degradable (i.e., barley or dried whey) did not give the expected increase in utilization of a highly soluble CP source (urea) for milk production.
A milk production and digestibility trial with 32 cows (2 X 2 factorial with 8 cows per treatment) was conducted to test animal response to varying rumen degradation of dietary starch and protein. Four rations (barley-cottonseed, barley-brewers dried grains, milo-cottonseed, and milobrewers dried grains) were compared in early lactation cows fed 65% concentrate and 35% forage for 60 d. Digestibilities of starch were higher for barley than milo diets; whereas, those for organic matter were higher for cottonseed meal than brewers dried grains. Milk production was highest on barley-cottonseed with mean adjusted values of (kg/d): 37.4, 34.9, 34.2, and 34.6 for respective treatments. Dry matter intakes were not different among rations. Milk fat was higher on milo than barley with respective diets averaging (%): 3.1, 2.9, 3.4, and 3.6, and resulting in lowest FCM for the barley-brewers dried grains diet. Milk protein was not altered by treatment. These data suggest that responses to varying protein degradability can be altered by rate of starch breakdown in the rumen.
Four Holstein cows fitted with ruminal, duodenal, and ileal cannulae were used in a 4 x 4 Latin square design to measure ruminal protein degradation and small intestinal digestion of diets containing untreated soybean meal or soybean meal treated with heat and either water, xylose, or calcium lignosulfonate. Diets consisting of 40% corn silage, 10% alfalfa cubes, and 50% grain mix, and averaging 16.8% crude protein (DM basis) were fed four times daily. Approximately 50% of the total dietary protein was supplied by the respective soybean meal source. Ruminal protein degradation was 70.6, 69.6, 55.8, and 53.7% for diets containing untreated soybean meal, water-soybean meal, xylose-soybean meal, and calcium lignosulfonate-soybean meal, respectively. Duodenal non-NH3 N flow (g/d) and absorption of non-NH3 N (g/d) in the small intestine were generally not affected by treatment. Duodenal bacterial N flow (g/d) was lower with xylose-soybean meal and lignosulfonate-soybean meal than with untreated soybean meal. Treatment of soybean meal with xylose or calcium lignosulfonate was successful in decreasing ruminal protein degradation. However, it may be necessary to include a source of readily fermentable N in diets that contain protected proteins in order to supply adequate NH3 N for microbial protein synthesis.
1. The present paper reports the effects on rumen fermentation and plasma metabolites and hormones of giving fixed rations of hay and high-cereal concentrates at different meal frequencies to lactating cows. In Expt 1 the total ration was given in two and twenty-four meals daily and in Expts 2–4 the concentrates were given in two and five or six meals and the hay in two meals daily. The diets contained 600–920 g concentrates/kg.
2. In Expt I, minimum rumen pH was higher but mean pH was lower when cows were given their ration in twenty-four meals/d rather than two meals/d.
3. In all the experiments, the effects of increased meal frequency on the molar proportions of rumen volatile fatty acids (VFA) were small and not significant, although there was a general tendency for the proportion of acetic acid to increase and that of propionic acid to fall. Increasing the proportion of concentrates in the diet reduced the proportion of acetic acid and increased the proportions of propionic and n-valeric acids.
4. In Expt 3, more frequent feeding was found to reduce the concentration of non-esterified fatty acids in the blood, but changes in other metabolites were small and not significant. Increasing the proportion of concentrates in the diet reduced the concentrations of acetic acid and 3-hydroxybutyric acid and increased the concentrations of propionic acid and glucose.
5. The mean daily concentration of insulin in the blood was reduced by more frequent feeding of the higher-concentrate diet but not of the lower-concentrate diet. The concentration of glucagon also tended to fall with more frequent feeding. Increasing the proportion of concentrates in the diet increased the concentration of insulin.
6. More frequent feeding reduced the depression in milk-fat concentration caused by feeding the low-roughage diets. About three-quarters of the variation in milk-fat concentration could be related to changes in rumen VFA proportions, but the relations for the two meal frequencies had different intercepts although similar curves. The results suggest that milk-fat depression on low-roughage diets with twice-daily feeding was due to a change in rumen VFA proportions accompanied by elevated plasma insulin concentrations. The improvement in milk-fat concentration due to more frequent feeding could be explained partly by the small change in rumen VFA proportions and partly by a reduction in mean plasma insulin concentrations, but these mechanisms did not fully account for the milk-fat responses observed.
The accuracy of prediction of microbial growth in the rumen and flow of microbial protein to the small intestine is important in predicting protein and carbohydrate utilization in dairy cattle as well as the development of a protein and carbohydrate feeding system that will be an improvement over present systems. Empirical multiple and simple regression equations are presented that demonstrate the impact of body size, proportion of forage in the diet, and dry matter intake on flow of microbial protein into the small intestine from the rumen. Concepts are developed and validated for a mechanistic, dynamic approach for prediction of microbial growth and flow of microbial protein based on Michaelis-Menton equations, microbial substance affinities, and rumen liquid flow kinetics. Emphasis is placed on the importance of quantifying dynamics of rumen function, the need for experimentation to develop a carbohydrate system that will include methods for analysis, and a factorial approach to digestion and utilization.
Four multiple-cannulated steers (340 kg) were used in a 4 X 4 Latin square design with a 2 X 2 factorial arrangement of treatments. Steers were fed a diet of 50% ground hay and 50% concentrate at two intakes (1.4 and 2.1% of BW), with urea and 15N-enriched ammonium sulfate infused continuously into the rumen at .4 or 1.2% of diet DM. Ratios of purines and diaminopimelic acid-N to N in fluid-associated and particulate-associated bacteria and in protozoa were similar among treatments but were lower for protozoa than for bacteria. Diaminopimelic acid-N:N was higher for fluid-associated vs. particulate-associated bacteria. Enrichment of 15N was similar between bacteria among treatments and was 30% lower for protozoa. Turnover rates of 15N in bacteria, NH3N, and non-NH3N pools were faster for steers infused with 1.2 than those infused with .4% urea, indicating less efficient usage of ammonia with higher urea. A method is described to estimate the proportion of duodenal nitrogen comprising bacterial and protozoal nitrogen.
1. In four feeding experiments with sheep the utilization of proteins contained in lucerne hay and of those in toasted soya-bean meal (SBM), representing a roughage and concentrate feed respectively, were examined. The ration of one group of animals contained lucerne hay as sole source of digestible protein and that of the other SBM.
2. Measurements of the nitrogen balance showed clearly the superiority of lucerne hay as protein source compared with soya-bean meal; this arose from the greater N retention found with the lucerne hay ration.
3. The influence of both rations on the metabolic pathways of the proteins was examined by following the changes of concentration of various metabolites in the rumen contents and of blood urea at different intervals after feeding.
4. Concentrations of urea found in the blood of the sheep given lucerne hay were lower than those of the other group, a finding which is in agreement with the results of the balance experiments.
5. The concentrations of NH 2 -N and of aminoacids in the rumen liquor were higher in sheep given lucerne hay than in those given SBM. These concentrations appeared to be related to the differences between the soluble non-protein N contents of the two feeds.
6. The results agree with the finding from in vitro experiments that rumen liquor from sheep receiving lucerne hay promoted greater synthesis of protein than rumen liquor from sheep receiving SBM.
7. Total bacterial activity as measured by the reduction of triphenyltetrazolium chloride (dehydrogenase activity) was much higher in the rumen liquor of sheep given lucerne hay than when SBM was given.
8. The concentrations of volatile fatty acids (C 2 -C 6 ) were much higher in the rumen liquor in sheep on the lucerne hay diet than in those on the SBM diet. After meals of the lucerne hay diet, the concentrations of acids higher than C 2 , particularly those of valeric acid, exceeded those present in the rumen liquor of the animals kept on the SBM diet.
9. Proline and alanine appeared in relatively higher concentrations in the rumen liquor than the other amino acids determined, and these two acids together with valine disappeared very rapidly. The possible conversion of these amino acids into valeric acid is considered. It is suggested that valeric acid found in relatively high concentrations in rumen liquor of sheep given lucerne hay may be due in part to the deamination of proline, which likewise disappeared very rapidly together with alanine and valine.
In Experiment 1, 24 multiparous cows in early lactation were fed a basal diet for ad libitum intake consisting of 24.3% (DM) corn silage, 25.9% whole crop barley silage, 33.1% alfalfa silage, and 16.7% of a protein supplement. Raw barley grain, or barley flame roasted to reduce its rate of rumen degradation, was fed twice daily or seven times daily. Of the 24 cows offered roasted barley, 3 refused to consume it even after 2 wk. Thus, results are for the 21 cows that consumed raw and roasted barley. Cows fed raw barley seven times ate more DM, OM, NDF, and CP than cows fed raw barley twice daily and also produced more milk, protein, and lactose. Cows fed roasted barley twice daily ate more NDF than those fed raw barley twice daily and also produced more milk, protein, and lactose. No benefit resulted from increasing the feeding frequency of roasted barley from two to seven times daily. Experiment 2, conducted to investigate the apparent unpalatability of roasted barley, showed that cows fed a TMR containing 40% (DM) of the roasted barley used in Experiment 1 consumed less NDF but tended to produce more lactose. Based on results of both experiments, if raw barley is fed alone, it should be fed multiple times per day to maximize production. However, infrequent feeding of roasted barley is an acceptable alternative, if the cows will consume the roasted barley. When barley can be fed multiple times per day or in a TMR, benefits of roasting appear to be negligible.