Article

The optimum level of protein in the supplement for dairy cows with access to grass silage

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Abstract

Grass silage with a dry-matter content of 19·4% and containing 16·7% crude protein was offered ad libitum to 42 first lactation British Friesian cows during the first 75 days post-calving. In addition the animals received supplementary concentrates containing either 10·3, 13·6, 17·3, 21·1, 25·2 or 30·3% crude protein on a fresh weight basis, with extracted soya bean meal being used as the main protein source. All concentrates were offered at an equal level of 8·0 kg per day. The relationship between milk yield and protein content of the supplement was curvilinear and was described by the following equation: Y= 8·95+ 1·0×–0·0205 × where Y = milk yield per day in kg, and × = percentage protein in the supplement. This equation indicated that maximum milk yield was obtained with a concentrate containing 24·4 % protein on a fresh weight basis. The protein content of the milk was also curvilinearly affected by the level of protein in the supplement, and it was calculated that maximum milk protein (nitrogen × 6·38) would be obtained with a supplement containing 23·9% protein. Plasma blood urea levels increased linearly with increasing protein intake. The effects on live-weight change and blood components were also recorded.

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... On the contrary, protein concentrations were less variable and differences between production systems were slight. It is well assumed that fat and protein production is highly related to nutrition (Gordon & McMurray, 1979;King et al., 1990;Walker et al., 2001), depending not only on the quantity of forage and supplements but also in the composition of them (Palmquist, 1993); Walker et al., 2004). Consequently, differences in fat and protein production depend not only on the production system, but also along the year and the region. ...
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Organic systems are highly dependent on the environment and require animals well adapted to local conditions. In Spain, organic dairy farmers are not satisfied with the productive performance of their herds and ask for technical advice to obtain suitable animals for organic systems. The milk productive performance (milk yield, nutritional composition, and somatic cell count) of Holstein-Friesian cows in organic farming in North Spain compared with conventional farms has been analysed. When breed diversity was present in the same organic farm, Holstein-Friesian milk performance was compared with other breeds and/or crosses. Holstein-Friesian cows in organic farming produce slightly less milk than grazing conventional cows, but milk was similar in composition and somatic cell count across systems. The limited data from organic farms where breed diversity exists indicate that Holstein-Friesian cows produce numerically more milk than other breeds and crosses but with statistically lower protein content. Considering that in Spain organic milk production is mostly used for liquid milk consumption and that the payment system is based only on milk volume, Holstein-Friesian cows would better fit the farmer interests than other breeds or crosses. However, in addition to productive performance, reproductive efficiency, animal health and consumer’s preferences should be fully considered when selecting a breed for organic production. If Holstein-Friesian was the selected breed, efforts should be made to identify cows within the breed that are best adapted to organic conditions. New productive, reproductive, nutritional and economic studies would be needed to develop a genetic merit index for organic systems.
... Blood urea nitrogen concentrations were higher pre-and postcalving, but were similar around calving for lasalocid-treated vs. control cows in the present study. Blood urea nitrogen concentrations reflect dietary intake of protein and nonprotein nitrogen, body catabolism, and urinary excretion of urea ( Gordon and McMurray, 1979). Monensin reduces ammonia concentration within the rumen due to reduced intraruminal protein degradation and hence has a protein "sparing" effect in the rumen (Bergen and Bates, 1984). ...
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The aim of the study was to evaluate the effect of feeding the ionophore lasalocid on the productivity and health of seasonally calving, pasture-fed dairy cows. Dairy cows (n = 1020) from 4 herds were enrolled in a split-herd, prospective intervention study. Cows were blocked by breed and age, ranked on previous production, and then assigned to 2 treatment groups. Treatment cows were each exposed to 300 to 350 mg of lasalocid/d commencing 3 wk before and ending 18 wk after the start of the seasonal calving period. Milk production was determined on 3 occasions for each cow at approximately monthly intervals (herd tests 1 to 3), body condition score was determined fortnightly, and all disease occurrences were recorded. Lasalocid treatment increased milk volume milk protein and milk fat production by approximately 2%, without altering milk composition. Fewer lasalocid-treated cows than control cows (7.3 vs. 11.6%, respectively) were diagnosed with clinical mastitis. Lasalocid treatment of pasture-fed dairy cows resulted in reduced mastitis incidence and increased milk production without changes in body condition or negative effects on metabolic processes as monitored by metabolite concentrations.
... In some instances, the responses have been linear regardless of the initial energy balance of the cow (Spörndly 1989a(Spörndly , 1989bWales et al. 2001), whereas Rook and Line (1961) reported larger responses when cows were initially underfed. The response of milk protein concentration to ME intake has been reduced when the protein concentration of the diet was low enough to reduce MP supply (Gordon and McMurray 1979). ...
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The composition and functional properties of cow's milk are of considerable importance to the dairy farmer, manufacturer, and consumer. Broadly, there are 3 options for altering the composition and/or functional properties of milk: cow nutrition and management, cow genetics, and dairy manufacturing technologies. This review considers the effects of nutrition and management on the composition and production of milk fat and protein, and the relevance of these effects to the feeding systems used in the Australian dairy industry. Dairy cows on herbage-based diets derive fatty acids for milk fat synthesis from the diet/rumen microorganisms (400-450 g/kg), from adipose tissues (<100 g/kg), and from de novo synthesis in the mammary gland (about 500 g/kg). However, the relative contributions of these sources of fatty acids to milk fat production are highly dependent upon feed intake, diet composition, and stage of lactation. Feed intake, the amount of starch relative to fibre, the amount and composition of long chain fatty acids in the diet, and energy balance are particularly important. Significant differences in these factors exist between pasture-based dairy production systems and those based on total mixed ration, leading to differences in milk fat composition between the two. High intakes of starch are associated with higher levels of de novo synthesis of fat in the mammary gland, resulting in milk fat with a higher concentration of saturated fatty acids. In contrast, higher intakes of polyunsaturated fatty acids from pasture and/or lipid supplements result in higher concentrations of unsaturated fatty acids, particularly oleate, trans-vaccenate, and conjugated linoleic acid (CLA) in milk fat. A decline in milk fat concentration associated with increased feeding with starch-based concentrates can be attributed to changes in the ratios of lipogenic to glucogenic volatile fatty acids produced in the rumen. Milk fat depression, however, is likely the result of increased rates of production of long chain fatty acids containing a trans-10 double bond in the rumen, in particular trans-10 18:1 and trans-10-cis-12 18:2 in response to diets that contain a high concentration of polyunsaturated fatty acids and/or starch. Low rumen fluid pH can also be a factor. The concentration and composition of protein in milk are largely unresponsive to variation in nutrition and management. Exceptions to this are the effects of very low intakes of metabolisable energy (ME) and/or metabolisable protein (MP) on the concentration of total protein in milk, and the effects of feeding with supplements that contain organic Se on the concentration of Se, as selenoprotein, in milk. In general, the first limitation for the synthesis of milk protein in Australian dairy production systems is availability of ME since pasture usually provides an excess of MP. However, low concentrations of protein in milk produced in Queensland and Western Australia, associated with seasonal variations in the nutritional value of herbage, may be a response to low intakes of both ME and MP. Stage of lactation is important in determining milk protein concentration, but has little influence on protein composition. The exception to this is in very late lactation where stage of lactation and low ME intake can interact to reduce the casein fraction and increase the whey fraction in milk and, consequently, reduce the yield of cheese per unit of milk. Milk and dairy products could also provide significant amounts of Se, as selenoproteins, in human diets. Feeding organic Se supplements to dairy cows grazing pastures that are low in Se may also benefit cow health. Research into targetted feeding strategies that make use of feed supplements including oil seeds, vegetable and fish oils, and organic Se supplements would increase the management options available to dairy farmers for the production of milks that differ in their composition. Given appropriate market signals, milk could be produced with lower concentrations of fat or higher levels of unsaturated fats, including CLA, and/or high concentrations of selenoproteins. This has the potential to allow the farmer to find a higher value market for milk and improve the competitiveness of the dairy manufacturer by enabling better matching of the supply of dairy products to the demands of the market.
... In some instances, the responses have been linear regardless of the initial energy balance of the cow (Spörndly, 1989aSpörndly, , 1989b), whereas Rook and Line (1961) reported larger responses when cows were initially underfed. The response of milk protein concentration to ME intake was reduced when the protein concentration of the diet was low enough to reduce protein supply (Gordon and McMurray, 1979). The intake of CP by cows, under a range of feeding systems, appears to have no consistent effect on the concentration of CP in milk (Walker et al., 2004). ...
Article
The aim of the thesis was to evaluate the effects of cutting frequency and planting density on biomass production, nutritive value and digestibility of Moringa oleifera and Cratylia argentea in the dry tropics in Nicaragua and to evaluate the effect of feeding foliage from Moringa and Cratylia to creole dairy cows on intake, digestibility and milk production and composition. Supplementing B. brizantha hay (BBH) with Moringa significantly increased milk production from 3.1 to 4.9 and 5.1 kg day-1 when feeding BBH hay alone or with 2 kg or 3 kg DM of Moringa, respectively. Supplementation with Cratylia increased milk production from 3.9 to 5.1 and 5.7 kg day-1 for sorghum silage alone and supplementation with 2 kg and 3 kg DM of Cratylia, respectively. Milk composition and organoleptic characteristics were not significantly affected by feeding Moringa or Cratylia. The digestibility of DM, crude protein (CP) and neutral detergent fiber (NDF) increased (P<0.05) in the diets supplemented with Moringa compared to BBH alone. Supplementation with Cratylia did not affect digestibilities significantly, with the exception of CP digestibility, which increased (P<0.05) in the diets supplemented with Cratylia compared to sorghum silage alone. The cutting frequency of 75 days resulted in the highest DM yield from Moringa, 24.7 and 10.4 Mg ha-1 year-1, during the first and second year, respectively. DM yield from Cratylia increased from 8.7 to 18.2 Mg ha-1 as harvest interval was prolonged from 8 to 16 weeks. All planting densities produced the highest DM yield at 75 days cutting frequency and at sixteen weeks harvest interval by Moringa and Cratylia, respectively. In the first year, the density of 750 000 plants ha-1 of Moringa produced the highest DM yield, 18.9 Mg ha-1, but in the second year 500 000 plants ha-1 gave the highest DM yield, 8.1 Mg ha-1. For Cratylia the density of 40 000 plants ha-1 gave the highest DM yield (18.2 Mg ha-1). During the first year of growing Moringa, DM, NDF and ash contents were highest and IVDMD was lowest in the longest cutting frequency, while CP and ADF contents were not affected significantly by cutting frequency. In the second year DM and CP contents and IVDMD were not significantly affected by cutting frequency, whereas NDF, ADF and ash contents were lowest in the cutting frequency of 60 days. Planting density had no significant effect on chemical composition and IVDMD during the first and second year. For Cratylia CP content decreased and ADF content increased as harvest interval and planting density increased from 8 to 16 weeks and from 10 000 to 40 000 plants ha-1, respectively. Planting density and harvest interval had no significant effect on NDF content. In conclussion, for intensive biomass production both species should be planted densely, 50 to 75 plants per square meter, and cut every 75 days for Moringa, and at least 40000 plants ha-1 with a harvest interval of sixteen weeks for Cratylia. Moringa and Cratylia fed at 2 kg or 3 kg DM day-1 can significantly improve DM intake and milk yields of creole dairy cattle (Reyna) without affecting milk composition or organoleptic characteristics of milk.
... Despite a decrease in dietary CP content, milk production and composition were unchanged in one study (Bahrami-Yekdangi, Ghorbani, Khorvash, Khan, & Ghaffari, 2016). Reducing the intake of CP and rumen-degradable protein can decrease blood plasma TA B L E 1 Ingredient and nutrient compositions of diets urea levels (Gordon & McMurray, 1979;Westwood, Lean, Garvin, & Wynn, 2000) and is favorably associated with conception rate (Ferguson, Galligan, Blanchard, & Reeves, 1993). According to the Japanese Feeding Standard (JFS), 15.5% dietary CP is an optimal level during early lactation (NARO, 2006). ...
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We evaluated the influence on milk production of feeding early lactation cows a diet that included 14.5% crude protein (CP) and that did not meet methionine (Met) requirements or that met them by supplying rumen‐protected Met (RPMet). Thirty‐nine multiparous Holstein cows were allocated into two groups. For 15 weeks after calving, each group was fed one of the two total mixed rations, Control (n = 20) or Treatment (n = 19). The Treatment group received added RPMet at 0.034% (8 g/day) of the Control diet on dry matter basis. The adequacies of Met for the Control and Treatment groups were 96% and 106%, respectively, and for other amino acids, >110%. The CP level (14.5%) was 1 percentage point lower than that recommended by the Japanese Feeding Standard (2006). No between‐group differences were found in milk yield (40 kg/day), milk composition, plasma profile, rumen fermentation, nitrogen balance, or cow health. Met intake and the amount of rumen‐undegradable feed Met were higher in the Treatment group (p < 0.05). Microbial Met and total metabolizable Met did not differ between groups. Supplying RPMet in a 14.5% CP diet during early lactation did not dramatically affect milk production, because the amount of total metabolizable Met was unchanged.
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Twenty-four British Friesian dairy cattle in their first lactation were used in a change-over design experiment with four periods, each of 4 weeks duration. The aim of the experiment was to examine the effects of varying both concentrate crude-protein concentration and the proportions of concentrates and grass silage in the diet on milk yield and composition. Twelve treatments were examined in a 3 × 4 factorial arrangement. Concentrates containing four levels of crude protein (CP), ranging from 120 to 206 g/kg fresh weight were offered in diets containing either 400, 500 or 600 g concentrates per kg dry-matter (DM) intake. The grass silage offered as the basal forage had a DM concentration of 214 g/kg and a digestible organic matter concentration of 682 g/kg DM. Milk yields (kg/day) for cows offered diets containing 400, 500 and 600 g concentrates per kg DM were 17·2, 18·1 and 18·3 respectively; and 17·4, 17·6, 18·0 and 18·4 for cows offered diets with concentrates containing 120, 147, 176 and 206 g CP per kg fresh weight respectively (pooled s.e. 0·13). Increasing either the proportion of concentrates in the diet or the CP concentration of the concentrates did not significantly affect milk fat concentration, but did increase milk protein concentration. There was a trend towards a greater milk-yield response to protein supplementation with low- rather than high-concentrate diets, although it appears that this trend may only be apparent in situations where total food intake is restricted.
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Five randomized-block experiments were carried out over 2 years using British Friesian cows managed as three separate herds. The effects of offering cows different levels of concentrates, ranging from 0·8 to 7·2 kg/day, in addition to grass silage ad libitum during the winter period on reproductive performance was investigated. The effects of substituting 4 kg/day maize gluten, or 0·8 kg/day fish meal, for part or all of the standard concentrate were also examined. Neither level of concentrates nor the inclusion of maize-gluten meal significantly affected reproductive performance even where milk production and quality was considerably influenced. The inclusion of fish meal improved conception rates to all services (0·64 v. 0·44; P < 0·05) and reduced the number of services required per conception (1·62 v. 2·31; P < 0·01). Plasma urea levels were raised consistently by the feeding of fish meal and, with the exception of weeks 2 and 6 of lactation, by the feeding of higher levels of concentrates. From the 6th week of lactation levels of beta-hydroxybutyrate (BHB) in the blood were significantly higher in the group of cows receiving the highest level of concentrates. The BHB level at week 6 was correlated with the number of services required per conception. A number of relationships between production factors and fertility are also presented.
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Seventy-eight British Friesian type cows, mean calving date 13 January, were used in a 3 × 2 factorial design experiment to examine the direct and residual responses to replacing 0·8 kg/day of a concentrate containing 184 g/kg crude protein with an equal quantity of fish meal when using three levels of total supplement feeding (0·8, 4·0 and 7·2 kg/day). In addition, all animals had access ad libitum to a high-quality grass silage (in vivo digestible organic matter 750 g/kg dry matter) during the treatment period. Treatments were applied from day 8 post partum until 22 April, when all animals went to pasture, giving a mean treatment period of 91 days. At pasture the animals were rotationally grazed as three groups, based on the three levels of total supplement offered during the treatment period, at the same stocking rate. The effects of treatments in terms of direct effects during the treatment periods, residual effects at pasture and also total lactation were assessed. Also during the treatment period the effects on rumen volatile fatty acid contents and blood composition were monitored. In addition, total diet digestibility and food utilization studies were carried out on six animals per treatment. Level of supplementation significantly influenced milk output during both the treatment and full lactation periods with the total lactation responses being 2·0 and 1·0 kg milk per kg additional supplement between the food levels of 0·8 to 4·0 and 4·0 to 7·2 kg/day respectively. Level of supplementation also significantly influenced milk fat concentration during the treatment, residual and full lactation periods and milk protein concentration during the treatment period only. The replacement of 0·8 kg conventional concentrate by 0·8 kg fish meal significantly increased milk yield during the final 21 days on treatment (mean yield per day 20·6 and 21·9 (s.e. 0·44) kg for without and with fish meal treatments respectively) but there were no significant residual or total lactation effects. From the data it was calculated that at low levels of supplementation 0·8 kg fish meal could be used to replace 1·9 kg conventional concentrate but at more moderate levels of nutrition any substitution would be much lower and uneconomic.
Article
Twenty-four British Friesian dairy cows in early lactation were used in a change-over design experiment with three periods, each of 4 weeks duration. The aim of the experiment was to assess the effects of both the type of concentrate and the level of concentrate supplementation on the utilization of grass silage for milk production. Four treatments consisted of offering 10 kg/day of either a barley (10B) or a sugar beet pulp-based concentrate (10S), each concentrate being offered at two crude protein concentrations of 175 (low) and 245 (high) g/kg dry matter. In a further two treatments the barley-based concentrates containing the low and high protein concentrations were offered at 7 kg/day (7B). All concentrates were offered in addition to the cows having ad libitum access to grass silage containing a dry-matter concentration of 213 g/kg and a digestible organic matter concentration of 668 g/kg dry matter. Silage dry-matter intakes (kg/day) for cows given the low- and high-protein concentrates respectively were: 9·06 and 9·28 for the 7B treatments; 8·21 and 8·33 for the 10B treatments; and 8·04 and 7·97 for the 10S treatments (pooled s.e. 0·11). Fat-corrected milk yields for cows given the low- and high-protein concentrates respectively were: 24·0 and 24·1 for the 7B treatments; 25·9 and 27·0 for the 10B treatments; and 25·7 and 26·2 for the 10S treatments (pooled s.e. 0·57). The higher level of concentrate feeding significantly increased milk yield ( P < 0·001) whereas neither energy source nor protein concentration in the concentrates had a significant effect on milk yield ( P > 0·05). There was a trend towards a greater response to increased protein concentration at the higher level of feeding.
Article
A total of 140 British Friesian cows in their second or later lactation and with a mean calving date of 27 October (s.D. 18 days) were used in a randomized-block experiment over a 3-year period. The experiment was designed to examine the effects of level of concentrate given during the winter period, in addition to ad libitum access to grass silage, on total lactation performance. The silage had a mean dry-matter content and digestible organic matter in the dry matter of 206 and 698 g/kg respectively and the mean inputs of concentrates on the five treatments were 0–64, 0–89, 1–14, 1–38 and 1·59 t/cow (treatments 1–5 respectively). Sixteen replicates per treatment were housed in individual stalls during the winter period in order to facilitate the measurement of silage intake and the remaining animals in each year were maintained as a single group. All animals in each year grazed together as a single group at pasture at a mean stocking rate of 6–0 cows/ha and without supplementary concentrates. Level of concentrate supplementation had a significant linear effect on the intake of silage dry matter with the relationship between total intake of silage dry matter over the winter period (kg, y ) and concentrate dry matter input (kg, x ) being described by equation (1)
Article
Four concentrate supplements differing in crude protein (CP) and undegradable protein (UDP) content were offered to 16 lactating Friesian cows together with grass silage (dry matter (DM) 196 g/kg, pH 4·38, CP 160 g/kg DM, in vitro DM digestibility 0·68) ad libitum in a Latin-square trial with 3-week periods. The supplement treatments were: (1) barley 122 g CP per kg DM, degradability (dg) 0·77; (2) barley/soya-bean meal 210 g CP per kg DM, dg 0·69; (3) barley/soya-bean meal/fish meal 190 g CP per kg DM, dg 0·61; (4) barley/soya-bean meal/fish meal 219 g CP per kg DM, dg 0·59. Supplements were given at 8 kg/day. Total daily intakes of silage (kg DM), CP and UDP (g) on treatments 1 to 4 were 7·77, 2087, 375; 8·35, 2804, 655; 8·29, 2676, 717; 8·70, 2917, 826, respectively. Milk yield (kg/day) and yields of fat, protein and lactose (g/day) on the four treatments were 21·3, 791, 617, 984; 23·0, 816, 688, 1055; 23·0, 818, 696, 1050; 23·6, 813, 735, 1071 for treatments 1 to 4 respectively. Yield and concentration of protein and lactose were significantly lower on treatment 1 than on the other treatments, while the of blood metabolites indicated treatment effects on blood glucose, non-esterified fatty acids, plasma protein and urea. Digestibility of organic matter and non-ammonia nitrogen (NAN) flow to the abomasum (g/day), measured in sheep given a fixed silage/supplement ratio at maintenance, were 0·81 and 18·4, 0·81 and 20·8, 0·82 and 21·4, 0·82 and 22·4 for treatments 1 to 4 respectively. The NAN flow was significantly greater on treatment 4 than on treatment 1.
Article
Twenty-four lactating British Friesian cows were used in a four-period partially balanced change-over design experiment to evaluate eight treatments consisting of two silage types (wilted and unwilted), each offered in addition to supplements containing both two crude protein (CP) levels (160 and 210 g/kg fresh weight) and two energy levels (10·8 and 12·9 MJ metabolizable energy (ME) per kg fresh weight) obtained by including 100 g spray-dried tallow per kg, in a 2 × 2 × 2 factorial arrangement. All supplements were offered at ttie same rate of 6·8 kg/day and total diet digestibility and food utilization studies were carried out on all animals at the end of the final period of the experiment. A separate two-period change-over design expeximent, using two lactating cows fitted with rumen cannulae, was undertaken to determine the influence of the two silages on volatile fatty acid (VFA) proportions in the rumen and to measure the rates of disappearance of dry matter (DM) and nitrogen in the silages and supplements from the rumen. There were no significant interactions between silage and supplement type in terms of animal performance. Animals offered unwilted silage consumed proportionately 003 less DM but produced 0·03 more milk than those offered wilted silage. Although total diet digestibility was not influenced by silage type because of the higher gross energy concentration of the unwilted silage the ME intake with this diet was higher than with the diet based on wilted silage and the ratios of milk energy output to ME available for production (0·54) were similar with both silages. Silage type had no effect on the rumen VFA proportions but influenced the jates of disappearance of DM and nitrogen from the rumen. Increasing the CP concentratioryof the supplement had no effect on the intake of silage DM but resulted in a significant incrase in milk yield (0·55 kg/day) but due to a reduction in milk fat concentration there was np etfect on yield of either fat-corrected milk or milk energy. The use of the higher energy supplement depressed the intake of silage DM by 0·46 kg/day but resulted in an increase in milk yield of 0·74 kg/day. Neither CP nor energy concentration of the supplement had any effect on DM or energy digestibility of the total diet but there were considerable differences between supplements in the patterns of nitrogen and DM disappearance from the rumen.
Article
Following a 3-week covariance period, 30 group-housed dairy cows were individually given one of three diets from week 4 to week 13 of lactation to determine any possible advantage in milk yield and production of feeding levels of undegradable protein (+UDP) or rumen-degradable protein (+RDP) above the minimum levels (control) proposed by the Agricultural Research Council (ARC, 1984). The three concentrates given were formulated to be of equivalent metabolizable energy (ME, 13·5 MJ/kg dry matter (DM)) concentration and each consisted of rolled barley plus a protein supplement: control (crude protein (CP), 129 g/kg DM) 0·35 kg DM fish meal per day; +UDP (CP, 167 g7kg DM) 1·0 kg DM fish meal per day; and +RDP (CP, 167 g/kg DM) 1+5 kg DM soya per day. For each group the total ‘concentrate’ allowance per animal per day was 11·6 kg fresh weight and was given in three equal feeds. Grass silage (CP 122 g/kg DM, ME 106 MJ/kg DM) was given ad libitum. For the control, +UDP and +RDP treatments, respectively, mean grass silage intakes were 8·29, 8·62 and 8·65 kg/day and mean milk yields were 26·6, 26·3 and 26·1 kg/day. These were not significantly different (P > 0·05). Milk fat concentration was lower (P < 0·05) for the +UDP treatment (36·4 g/kg) in comparison with the control (38·6 g/kg) or the +RDP treatment (39·7 g/kg) but no other milk constituent was significantly influenced by treatment. There was a trend for a greater live-weight gain with treatment +UDP (0·81 kg/day) compared with the other two treatments (control 0·50, +RDP 0·51 kg/day) but there were no differences in condition-score change between treatments. In this trial there was no advantage to feeding formulated levels of UDP or RDP above those proposed by ARC (1984).
Article
Twenty-four lactating British Friesian type cows were used in a four period, partially balanced, changeover design experiment to evaluate eight treatments consisting of four protein sources in the supplement (soya-bean meal, formaldehyde treated soya-bean meal, fish meal and a mixture supplying equal crude protein levels from fish and soya-bean meal (respective degradabilities of total supplement nitrogen (N) were 0·56, 0·37, 0·32 and 0·44), each offered in supplements formulated to contain 150 and 200 g crude protein per kg fresh weight in a 4 × 2 factorial design. All supplements were offered at 8·0 kg/day in addition to ad libitum access to a medium digestibility grass silage (digestible organic matter as proportion of dry matter (DM), 0·66); with a relatively poor quality fermentation (pH, 4·5; ammonia-N proportion of total N, 0·21). There were no significant interactions between source and level of protein on any of the animal performance variables. Source of protein did not influence milk output or milk composition but increasing protein intake significantly increased milk yield (26·0 and 26·7 (s.e. 0·19) for the low and high protein supplements respectively). Blood urea levels were significantly influenced by both protein source and level. Total diet digestibility and energy and N utilization studies were undertaken with six replicates per treatment and the full data are presented. Neither protein source nor level had any significant effect on DM or energy digestibility. N digestibility was significantly reduced following formaldehyde treatment of soya-bean meal (0·69 v. 0·72 (s.e. 0·01)) and most N utilization variables were influenced by the level of protein intake but not by protein source.
Article
A randomized block experiment was used to assess the effects of wilting of herbage prior to ensiling. Three silages, each a composite of three harvests taken over the season, were prepared by ensiling herbage as unwilted, medium-wilted or high-wilted material with mean dry-matter contents in the resulting silages of 192, 254 and 455g/kg respectively. The silages were ensiled in bunker silos using the same harvesting machinery and with formic acid applied at the rate of 2 81/t of herbage. The silages were offered to 81 January- and February-calving cows from the 8th day post partum until going to pasture on 27 April, with a mean period on treatmen t of 92 days. In addition, all animals received a fixed concentrate allowance of 7·6 kg/day. Wilting increased silage dry-matter intake, the mean intakes being 9·2, 9·4 and 10·0kg/day for the unwilted, medium-wilted and high-wilted material respectively, but resulted in a significant depression in milk yield, with the yields obtained during the final 14 days on treatment being 23·6, 21 -8 and 21·5kg/day respectively. Milk composition, live weight, body condition, total ration digestibility and nitrogen-balance data are also presented.
Article
A change-over design experiment, comprising four periods each of 4 weeks' duration, was used to evaluate three silage types each fed with two levels of protein in the supplement in a 3×2 factorial arrangement. The three silages were high digestibility unwilted (A), high digestibility wilted (B) and low digestibility unwilted (C). The supplements had crude protein contents of 152 and 240 g/kg dry matter, and were offered at a standard rate of 10 kg undried weight daily. The mean silage intakes were 9·3, 9·5 and 8·6 ±0·19 kg dry matter/day for A, B and C respectively, but protein content of the supplement had no significant effect on the intake of silage. Milk yield was significantly affected by both silage type and protein content of the supplement, with the mean yields being 23·6, 23·9 and 22·0 ± 0·49 kg/day for A, B and C respectively, and 22·4 and 24·0 ±0·40 kg/day for the medium and high protein supplements respectively. Although there was no significant interaction between silage type and protein content of the supplement, the greatest response to increased protein was obtained with B. Neither silage type nor protein content ofthe supplement affected animal live weight or milk composition (other than fat content, which was significantly affected by silage type). Blood plasma urea levels were 281 and 405 ± 28·0 mg/1 for the medium and high protein supplements respectively. Total ration digestibility and nitrogen balances were carried out on three animals per treatment. The digestibility of dry matter, organic matter and nitrogen was significantly affected by both silage type and level of protein in the supplement. The output of nitrogen in the urine was also significantly affected by both these factors.
Article
In two experiments, 165 dairy cows were allotted to groups given post-partum diets ad libitum containing either 150 g (LP) or 190 to 200 g (HP) crude protein (CP) per kg dry matter (DM). In experiment 1, which lasted 21 weeks after calving, cows were given pre-partum two amounts of energy (National Research Council (NRC) recommended amount v. 1·4 × NRC recommended amount). Pre-partum amounts of energy did not affect DM intake, milk yield or milk composition. Protein intake, including that for maintenance, was 84 and 116 g CP per kg milk in the LP and HP groups, respectively. During 2 to 6 weeks after calving the HP concentration in a diet containing 850 g concentrates and 150 g hay per kg, decreased DM intake, whereas in a diet containing 650 g concentrates and 350 g hay per kg, the HP concentration increased DM intake. During weeks 12 to 21 after calving, the HP concentration decreased milk yield from 33·0 to 28·7 kg and increased milk fat concentration from 24·1 to 29·3 g/kg. Rumen fluid ammonia-N concentrations were 135 and 200 mg/1 in cows given the LP and HP diet, respectively. Plasma urea-N concentrations were 114 and 172 mg/1 in the same groups, respectively. In experiment 2, three groups of cows were given, during 15 weeks after calving, diets LP, HP and HP containing soya-bean meal treated with formaldehyde (HPSP). Protein intake, including that for maintenance, was 71, 82 and 86 g CP per kg milk in the three groups, respectively. Mean daily milk yields during 15 weeks after calving were 37·5, 39·2 and 39·3 kg in groups LP, HP and HPSP, respectively. Cows given the LP and HP diets lost, after parturition, 22·5 kg body weight, whereas cows given the HPSP diet lost only 6·0 kg. Rumen fluid ammonia-N concentrations were 95, 175 and 81 mg/1 and plasma urea-N concentrations were 80, 200 and 143 mg/1 in cows given the LP, HP and HPSP diets, respectively. It is concluded that on certain diets high-yielding dairy cows can be given, in addition to that for maintenance, as little as 60 g CP per kg milk. Formaldehyde-treated soya-bean meal may increase milk yield during the first 3 weeks after calving, and reduce body weight loss.
Article
An experiment was conducted in which 30 stall-fed dairy cows were fed a basal ration of either good or poor quality pasture (approx. 7 kg DM) and supplemented with varying amounts of either crushed wheat or a pelleted. high energy supplement (0, 4 kg/clay or ad libitum). The cows were in their third month of lactation and were fed their allotted rations for 5 weeks. Where no supplements were fed, the approximate 9% difference in digestibility between pasture types resulted in differences in daily production of 2.4 kg milk/cow, 0.07 kg milk fat/cow and 0.06 kg milk protein/cow, and a difference of 0.4 units of body condition over a 5-week period. Where supplements were fed, responses depended on the interaction between a supplement and basal ration. With good quality pasture as the basal ration, the type of supplement was not important; marginal returns of milk products to extra feeding were similar for both supplements, for example, 1.0 kg milk/cow.day was produced for each additional kg of concentrate consumed. There was a reduction in milk fat production when more than about 5-6 kg DM of supplement was fed. This was due to a depression in the fat content of the milk which was associated with low dietary fibre (<250 g/kg of dietary neutral detergent fibre). However. when pellets were fed to cows offered poor quality pasture. a reduction in milk fat yield did not occur. When wheat supplemented poor quality pasture, on the other hand, deficiencies other than fibre were implicated. While fibre was the most important limitation to productivity when good quality pasture was supplemented with concentrates, protein was the most likely nutrient to limit productivity first when poor quality pasture formed the basal ration. The potential exists for major imbalances of nutrients to occur unless the composition of dietary components is known.
Article
To investigate strategies for concentrate allocation, 155 multiparous Holstein-Friesian cows received grass silage ad libitum during lactation weeks 4 to 22 in two experiments. A standard concentrate (196 g crude protein (CP) per kg dry matter (DM)) was offered at the same average amount across the lactation period either at aflat rate or as two rates with a change of 6 kg in week 13. Treatments, described as kg concentrate DM per day in the first and second periods of lactation, were 3: 3, 6: 0, 3: 9 (experiment 1), 6: 6, 9: 3, 9: 9 and 12: 6 (experiments 1 and 2). In experiment 2, two additional treatments maintained CP supply from concentrate after a change from 9 and 12 kg DM by giving 3 and 6 kg high-protein concentrate (HP) DM per day (575 and 383 g CP per kg respectively). Generally as concentrate intake increased silage intake fell, DM intake rose and yields of milk and all milk solids increased linearly. However, in experiment 1 from a base of 3 kg DM, as concentrate intake increased so did fat yield overall and protein yield in mid-lactation but at a declining rate. Fat concentration was depressed at the lowest and highest concentrate levels. Protein concentration rose as concentrate allowance increased particularly at low levels. Increasing concentrate in mid lactation improved protein but not fat concentration. Additional concentrate either spared weight loss or increased weight gain. Distributing more of a fixed allowance of concentrate to early lactation did not affect cow performance overall. Silage intake, milk, protein and lactose yields and protein concentration increased and fat concentration was reduced by giving HP concentrates, effects being greater with 3 than with 6 kg DM per day. Reducing concentrate level while maintaining CP intake did not influence milk and solids yields. The ratios of responses to concentrate CP (3 kg DM per day HP v. 3 kg DM per day standard) compared with concentrate energy (9 kg DM per day standard v. 3 kg DM per day HP) were 2·1, 2·2, 7·4 and 1·9 for milk, fat, protein and lactose yields respectively. The results suggest feeding strategies for manipulating the production and quality of milk from grass silage diets.
Article
Full-text available
DIETARY PROTEIN AND DAIRY COW FERTILITY: Feeding more dietary protein has been negatively associated with dairy cow fertility in some but not all studies. We used meta-analysis to examine the relationship between dietary crude protein and conception rate. While a higher intake of dietary crude protein significantly lowered conception rate, the potential for feeding less degradable dietary protein to modify this relationship was not demonstrated. MILK UREA CONCENTRATIONS AND DAIRY COW FERTILITY: The use of milk urea as an indicator of dietary energy and protein intake and as an indicator of reproductive performance has been questioned. We found that changes in urea concentration in body fluids explained only 25% (p = 0.08) of the variance in conception rate after conducting a meta-analysis of available studies. INTERPRETATION OF MILK UREA CONCENTRATIONS: High intakes of dietary protein may induce adaptations in urea metabolism, and the negative relationship identified between high intakes of dietary protein and fertility for Northern Hemisphere dairy herds may not necessarily apply in Australasian dairy herds. Because of the potential for cows to adapt to high protein diets, the use of a single milk urea determination on a herd will have limited value as an indicator of nutritional status and little value as a predictor of fertility.
Article
Grass silage with a dry-matter (DM) content of 253 g/kg and containing 142 g crude protein and 670 g digestible organic matter/kg DM was offered ad libitum to 56 first- and second-lactation British Friesian cows during the first 75 days post-calving. In addition the animals received supplementary concentrates containing either 95 (T1), 137 (T2), 174 (T3) or 209 (T4) g crude protein per kg fresh weight, with extracted soya bean meal being used as the protein source. All concentrates were offered at equal levels across treatments, the amounts being 8 kg for first- and 10 kg per day for second-lactation animals. The silage DM intakes recorded over the period were 514, 524, 548 and 545 ± 19·9 kg and milk outputs were 1349, 1451, 1533 and 1628 ±40·2 kg for treatments Tl to T4 respectively. The rate of live-weight change and the milk fat, solids-not-fat, protein, lactose and ash contents of the milk were not affected significantly by any of the treatments. Diet digestibilities were determined using three animals per treatment. The digestibility coefficients were for DM 0·738, 0·746, 0·776 and 0·772 ± 0·0088 and nitrogen 0·597, 0·641, 0·707 and 0·727 ±0·0126 for treatments T1 to T4 respectively.
Article
Prices of protein-rich foods increased dramatically in the summer of 1973. This caused considerable concern amongst BSAP members and a meeting of 36 scientists involved in studies of protein or allied aspects of nutrition was convened by the BSAP and held at the NIRD. The objective was to provide a statement of present knowledge on the protein requirements of the dairy cow. The Chairman of the day-long meeting was Dr C. C. Balch. A vigorous and wide-spanning discussion took place and while a definitive statement of quantitative requirements for protein was not produced, in compensation for this the state of the present knowledge on protein was revealed, so that it may be hoped that further studies will be prompted by these findings. This paper and the following one present respectively the minutes and an interpretation of the discussion.
A series of five roughage rations providing increasing amounts of nitrogen (6.8, 16.8, 23.5, 37.3, and 46.3 g/day) and some changes in dry matter intakes (720, 710, 704, 1056, and 1408 g/day) was offered to sheep. The first four rations were given hourly and the fifth ad libitum. Urine outputs, urine total nitrogen, urine urea nitrogen, and urea clearance values increased with nitrogen intakes. Water intakes were linearly related to dry matter intakes. Plasma urea nitrogen and rumen ammonia levels both increased linearly to about 30 mg/100 ml, but did not increase further on higher levels of nitrogen intake. At these levels of intake both plasma urea nitrogen and rumen ammonia levels were no longer related to urine nitrogen excretion rates. The results are discussed in relation to the role of the kidney tubules in nitrogen excretion in the sheep.
Article
Seventy-two lactating dairy cows were used in a 4x 3 factorial experiment to assess the effects of the protein content of concentrates on the response to concentrate feeding level. Concentrates containing 12,18 and 24% crude protein in the dry matter were given at each of four levels of feeding: 0·25, 0·36, 0·47 and 0·58 kg/kg milk for a 7-week experimental period. Milk yield, milk energy output, liveweight change and the percentage solids-not-fat and protein in the milk were significantly affected by both the level of concentrate feeding and the protein content of the concentrate. Response curves for the effect of level of concentrate feeding on milk output and liveweight change were computed for each of the three protein levels, and although there was no significant interaction between these two main factors the benefit from increased protein in the concentrate was shown to depend partly on the level of feeding at which the concentrate was used. At low feeding levels the response to an increase in protein content of the concentrate tended to be smaller than that obtained at high feeding levels. At no stage was there any marked response to protein content in the concentrate above 18%. The response curves have been used to demonstrate the interchangeability of level of concentrate feeding and protein content of the concentrate as means of supporting a given level of milk production.(Received December 23 1976)
Article
Serial blood samples were obtained from six single-suckled calves over the first 96 h of life. The samples were analysed for packed cell volume, haemoglobin, albumin, globulin, urea, phosphate, whole blood copper, plasma copper, caeruloplasmin and plasma zinc. Using packed cell volume measurements as a marker for changes in plasma volume the corrected concentration of each component was calculated. It was therefore possible to compare the net change in each component within the circulating plasma pool. The observed changes are discussed in relation to problems that might be encountered in using measurements of this type to monitor metabolism in normal and diseased animals.
Article
Cows were fed either 75 or 100% of the recommended intake levels for protein and 100% of recommended energy levels (Agricultural Research Council, 1965) from 8 weeks pre-calving until 14 weeks post calving. From 14 weeks post calving and to the end of lactation all the cows received 100% of the recommended protein and energy intakes. The mean of the 305-d milk yields of the 2 groups was not significantly different and although cows on the lower protein intake produced less lactose during the first 14 weeks of lactation there was no significant difference in total lactose, fat, protein or total solids production between the groups. In both groups blood packed-cell volume, red cell count and haemoglobin decreased during the first 10 weeks of lactation and then began to increase in the high-protein group. The cows receiving the low-protein diet showed a similar increase only when they received the high-protein ration from 14 weeks post calving. The mean interval from calving to conception was 27·5 weeks in the high-protein group and 20 weeks in the low-protein group. It is concluded that feeding 75% of protein requirements to dairy cows during the first 14 weeks of lactation does not reduce milk yield or quality significantly and probably has no adverse effect on fertility.
Article
SUMMARY Three experiments were conducted with growing lambs to determine if plasma urea nitrogen (PUN) levels could be manipulated by dietary protein in such a way that desired PUN levels could be maintained over time and to ascertain whether or not the control of PUNs within a suitable range would result in im- proved performance. The data indicate that if animals are segregated on the basis of PUN levels after being fed a standard diet for 21 days and then fed a protein level designed to maintain PUN at about 15 mg/lO0 ml, superior performance will result. The desired PUN level was easier to achieve in individually fed lambs than in lot fed groups. The combined experi- ments demonstrate that PUN levels in individ- ual lambs can be controlled and that initial PUN can be used to allocate lambs to control- led levels of dietary protein intake and thereby increase their performance. By careful stratifi- cation of the lot fed animals, it should be possible to maintain the desired levels through- out a feeding period and obtain superior gains with less dietary protein than if animals are fed without consideration of PUN levels.
Article
A survey of the blood chemistry of 75 dairy herds is reported. Most of the variation in blood chemistry was due to differences between herds, and to a lesser extent to differences between groups of cows giving various milk yields on the day of the test. Seasonal trends also appeared to be important though these need to be defined with greater precision.
Article
A survey of the results of metabolic profile tests on 191 herds is reported. The mean values for the concentrations of various blood components were similar to those determined in two previous surveys. In addition the importance of seasonal trends was established. Thus sodium concentrations were lower in summer than winter whilst urea, haemoglobin and albumin showed the reverse trend. These effects appear to reflect the input/output balances prevalent under indoor winter feeding as opposed to summer grazing conditions.
Sources and levels of proteins in cattle feeds
  • Parey
  • Hamburg
  • T M Butler
Parey, Hamburg. BUTLER, T. M. 1972. Sources and levels of proteins in cattle feeds. Ir. Grassld Anim. Prod. Assoc. J. 8: 24-31.
Energy and protein supplementation of grass silage for lactating cows
  • T M Butler
  • P A Gleeson
BUTLER, T. M. and GLEESON, P. A. 1973. Energy and protein supplementation of grass silage for lactating cows. An Foras Taliintais Anim. Prod. Res. Rep., pp. 98-99 (Abstr.).
The effect of varying protein level in a compound diet fed in conjunction with grass silage
  • Cuthbert
CUTHBERT, N. H., THICKETT, W. S. and WILSON, P. N. 1973. The effect of varying protein level in a compound diet fed in conjunction with grass silage. Proc. Br. Soc. Anim. Prod. (New Series) 2: 70 (Abstr.).
Blood urea and rumen ammonia in sheep as affected by level and source of carbohydrate and protein.
  • Preston
PRESTON, R. L., BREUER, L. H. and PFANDER, W. H. 1961. Blood urea and rumen ammonia in sheep as affected by level and source of carbohydrate and protein. /. Anim. Sci. 20: 947 (Abstr.).
Sources and levels of proteins in cattle feeds.
  • Butler
Comparison of results from long term dairy cattle feeding experiments with calculated N-requirements
  • F J Gordon