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Nutritionally related disorders affecting feedlot cattle
Abstract
Digestive disorders account for approximately 25 to 33% of deaths in feedlot cattle and likely contribute to decreased performance and efficiency of production. A variety of nutritional, management, genetic, behavioural, and environmental factors seem to be involved in the development of metabolic disorders in feedlot cattle. Excessive production of acid in the rumen is often either the cause of or a significant contributing factor to metabolic and nutritional disorders, including acute or sub-acute (chronic) acidosis, liver abscesses, and feedlot bloat. Decreasing the percentage of highly fermentable concentrates in feedlot diets by increasing roughage level or limiting feed intake should decrease the incidence of these disorders, but this approach is usually not economically feasible. Careful feed bunk management is often thought to be important for decreasing the incidence of nutritionally related disorders, but research to support its importance is limited and conflicting. Certain feed additives like ionophores seem to be effective for decreasing the incidence of acidosis and feedlot bloat, presumably through decreased total feed intake, smaller and more frequent meals, and direct effects on the ruminal microbial population. The incidence of liver abscesses can be decreased by the feeding of various antibiotics. Polioencephalomalacia (PEM) can result from several causes, including thiamine deficiency; however, recent data suggests that overproduction of H2S in the rumen is an important cause of PEM when intakes (feed and water) of sulfur are high in feedlot cattle.
... The effectiveness of stockperson training programs and observational skills in identifying sick or injured animals is, therefore, a predominant limiting factor to maintaining welfare (Weary et al. 2009;Daigle and Ridge 2018). Morbidities within feedlot enterprises tend to be associated with bovine respiratory disease (Sackett et al. 2006;Cusack et al. 2007;Edwards 2010), metabolic disorders, particularly acidosis (Galyean and Rivera 2003), and heat stress (Hahn and Mader 1997;Hahn 1999;Entwistle et al. 2000;Sackett et al. 2006). The incidence of ill health typically decreases as days spent in the feedlot increase (Snowder et al. 2006), although Vogel et al. (2015) found that the greatest percentage of mortalities occurred in the midfeeding period (from 31 days on feed to 61 days before processing). ...
... On entry to feedlots, cattle are typically transitioned from a roughage-based or grazing diet to a concentrate ration within a short period of time (<30 days). If not properly managed, this transition and the nature of the diet provided, can predispose animals to metabolic disorders such as acidosis (Galyean and Rivera 2003). From a survey of Australian feedlot producers, gastrointestinal-tract disorders were estimated to account for 8.6% of mortalities. ...
... Susceptibility to acidosis may vary among individuals, and management should be tailored towards the most susceptible animals (Galyean and Rivera 2003;Bevans et al. 2005). ...
The rising global demand for animal protein is leading to intensification of livestock production systems. At the same time, societal concerns about sustainability and animal welfare in intensive systems is increasing. This review examines the risks to welfare for beef cattle within commercial feedlots in Australia. Several aspects of the feedlot environment have the potential to compromise the physical and psychological welfare of cattle if not properly monitored and managed. These include, but are not limited to, animal factors such as the influence of genetics, temperament and prior health, as well as management factors such as diet, pen design, resource provision, pregnancy management, and stock-person attitudes and skills. While current industry and producer initiatives exist to address some of these issues, continuous improvements in welfare requires accurate, reliable and repeatable measures to allow quantification of current and future welfare states. Existing measures of welfare are explored as well as proxy indicators that may signal the presence of improved or reduced welfare. Finally, potential future measures of welfare that are currently under development are discussed and recommendations for future research are made.
... Mots clé s: Antimicrobien, parc d'engraissement, bovins, chlorte´tracycline, tylosine, croissance, sous-the´rapeutique The North American beef industry is continually challenged to increase productivity, reduce environmental impact and minimize costs of production (Stackhouse-Lawson et al. 2013). High-grain diets generally improve performance and reduce feed costs as compared with high-forage diets, but also increase the incidence of digestive and metabolic disease in feedlot cattle (Galyean and Rivera 2003). The high density of cattle in feedlots also contributes to animal health challenges, including the spread of infectious disease (Cavirani 2008). ...
... The performance benefits related to average daily gain (ADG), feed intake and feed efficiency of feeding subtherapeutic antimicrobials to stressed feedlot cattle, at high risk of developing BRD (Taylor et al. 2010) or metabolic diseases (Galyean and Rivera 2003) has been well established. However, the degree to which management may control infectious and metabolic disease in feedlots without antimicrobial metaphylaxis is less clear. ...
... In a survey of 3277 feedlot cattle, incidence of BRD was estimated at 9.43% (Schneider et al. 2010), substantially higher than the 0.4 to 3.5% observed in the present study. The incidence of treatment for bloat in the present study (2 to 5%) would likely have been reduced if ionophores had been included in the diet (Galyean and Rivera 2003), but the presence of monensin in diets would have confounded the observed responses to the other subtherapeutic antimicrobials administered. Feedlot mortalities due to bloat have been estimated at between 0.1 and 0.2% in western Canada (Merrill 1994), although incidence of bloat is thought to be site dependent due to variations in bunk management, diet, grain processing and animal type (Cheng et al. 1998). ...
Two-hundred and forty steers were obtained from the same ranch in each of 2 yr. Growth performance, health status and carcass characteristics from steers fed subtherapeutic antimicrobials were compared with those of control steers without antimicrobial metaphylaxis. Experimental groups included Control, not fed antimicrobials; CTCS-700, fed 350 mg head−1 d−1 chlortetracycline (CTC) and 350 mg head−1 d−1 sulfamethazine; CTC-11, fed 11 mg kg−1 CTC; TYL, fed 11 mg kg−1 tylosin phosphate; and CTC-350, fed 350 mg head−1 d−1 CTC. Steers were housed in pens of 10 steers and fed antimicrobials during both backgrounding and finishing periods. The incidence of bovine respiratory disease, pinkeye and bloat did not differ among experimental groups, although the incidence of foot rot was lower in Control steers (P<0.05) than in steers receiving TYL. In both years of the study, overall performance (backgrounding+finishing) was not improved by subtherapeutic antimicrobials. Similarly, carcass characteristics and the incidence and severity of liver abscesses were not improved compared with Control steers by feeding subtherapeutic antimicrobials. The results of the present study demonstrate that low-risk steers may be managed in small pens with equivalent growth performance, carcass characteristics and health status to steers fed subtherapeutic antimicrobials.
... While it is generally considered that 'lead' indicators, those that facilitate corrective or preventative actions to be taken, are most informative from a welfare perspective (Barnett and Hemsworth, 2009), the benefit of 'lag' indicators such as those that could be assessed at the abattoir should not be overlooked. The collection of this data could capture issues that have been missed including injuries and bruises (Grandin, 2017;Knock and Carroll, 2019) or issues that may not be apparent externally such as liver abscesses (Galyean and Rivera, 2003) or pneumonic (lung) lesions (Fernańdez et al., 2020). This information could then be used to inform targeted action at the feedlot. ...
... This information could then be used to inform targeted action at the feedlot. For example, consistent reports of liver abscesses could indicate ruminal acidosis, suggesting that current feed management needs to be reviewed (Nagaraja and Chengappa, 1998;Galyean and Rivera, 2003). In this way, data from received in abattoir feedback can be applied to refine management, thus advancing animal welfare at a feedlot level. ...
Lot feeding of cattle has gained momentum in recent years to improve efficiency in meeting market demands for high quality protein. Concurrently, societal concern for the welfare of animals raised in intensive farming systems has increased. Thus, the reporting of animal health and welfare measures is a key goal for the Australian cattle lot-fed industry. Although feedlots vary in location, climate, capacity, cattle genotype, and feeding programs, many welfare concerns are applicable across the industry. Despite this, no recognised standardised animal welfare assessment protocol exists for the Australian lot-fed industry. This study aimed to identify relevant measures to develop an assessment protocol, by identifying key welfare issues and their relevant measures, considering the validity, reliability, and practicality of each when applied to the feedlot context. An advisory model was derived after reviewing the relevant literature and five international protocols for the assessment of beef cattle (Welfare Quality ® , AssureWel, US Beef Quality Assurance assessment tool, Canadian Feedlot Animal Care Assessment program, and an Australian Live Export industry protocol), followed by stakeholder consultation. A total of 109 measures were evaluated, with 99 environmental-, management-, resource- and animal-based measures being proposed. Piloting of the protocol on commercial feedlots will enable further refinement and validation, to provide an evidence-based, practical protocol to facilitate standardised monitoring of cattle welfare. Such a protocol could promote continued advances in animal welfare at a feedlot level and support a sustainable industry by addressing societal concerns.
... Furthermore, due to the potential risk for development of antibiotic resistance, there is a global trend toward banning the use of supplemental antibiotics (W HO, 2017). Ionophore supplementation is currently prohibited within the European Union (European Commission, 2003;Directive 1831/2003 and this trend is expanding to various countries around the world. Essential oils (EO; such thymol, eugenol, vanillin, guaiac and limonene) have been investigated as an alternative to conventional antibiotics such as MON. ...
... In warm climates the risk of higher intake variations become greater. A perceived advantage of supplemental MON is reduced variation in DMI (Galyean and Rivera, 2003), that can be particularly advantageous during period of extreme ambient conditions ...
Background: During the first stage of fattening, performance of cattle is more affected by high ambient load. A strategy to mitigate the negative effects of high ambient temperatures on energy efficiency is by monensin supplementation. However, the present concern about the use of antibiotics as feed additives has led to search for safe alternatives. Due to its nature, essential oils and supplementary vitamin D3 represent a potential substitute to monensin in cattle subjected to high environmental heat load. For this reason, The objective of this study was to compare supplemental monensin vs the novel combination essential oils plus vitamin D3 on growth performance and dietary NE of feedlot bulls exposed to elevated ambient temperature during the initial 84-d on feed. Methods: Ninety crossbreed young bulls (228.0±7.1 kg initial weight) were used in 84-d trial to evaluate a blend of essential oils plus 25-hydroxy-Vit-D3 as a feed additive to alleviate the harmful effects of the high-ambient temperature on feedlot cattle performance during the early-growing phase. Dietary treatments (9 replicates/treatment) were supplemented with: 1) 24 mg of sodium monensin/kg diet DM (MON), or with 2) 119.12 mg/kg diet DM of a combination of standardized mixture of essential oils (119 mg) plus 0.12 mg of 25-hydroxy-vitamin-D3 (EO+HyD). Average THI was 82.7±3.2. Result: There were no treatment effects on day-to-day fluctuations in DMI. However, EO+HyD tended to increase DMI (4.3%, P=0.06). Supplemental EO+HyD increased daily weight gain (8.3%, P less than 0.01) and gain-to-fed ratio (4.0%, P=0.03). Supplemental EO+HyD tended to increase estimated dietary net energy (2.5%, P=0.07) and observed-to-expected dietary NE ratio (3.0%, P=0.07). This effect can be attributed to a 7% reduction in the maintenance requirement. The combination of EO+HyD may be a valuable tool to optimize growth-performance and feed efficiency of cattle under conditions of high ambient heat load.
... Digestive disorders account for approximately 25-33 % of deaths in feedlot cattle (Galyean and Rivera, 2003). Fattening diets usually consist of more than 50 % concentrate feed, which can lead to painful acidosis, liver abscesses and ruminal bloat (Broom, 2021;Galyean and Rivera, 2003). ...
... Digestive disorders account for approximately 25-33 % of deaths in feedlot cattle (Galyean and Rivera, 2003). Fattening diets usually consist of more than 50 % concentrate feed, which can lead to painful acidosis, liver abscesses and ruminal bloat (Broom, 2021;Galyean and Rivera, 2003). Moreover, many feedlots lack roughage, leading to geophagy (Broom, 2021). ...
The intensification of livestock farming has led to the expansion of feedlots in many countries and Argentina is not an exception. As in any other husbandry context, there is a need to objectively adopt an evidence-based approach to monitoring animal welfare in feedlots. This research aimed to describe the stages that took part in the development process of Bienest.AR, a beef cattle evaluation protocol adapted to the different conditions of the national feedlots, respecting validity, reliability, and feasibility criteria. The process to achieve this goal included the following seven stages: 1- Identification of welfare indicators considering animal- (ABM), resource- (RBM) and management-based measurements (MBM), by organising them according to the FAWC Five Freedoms, the Five Domains Model, and the welfare principles and criteria applied by Welfare Quality® and AWIN methods; 2- Validation of Gold Standards; 3- Evaluator’s training and first reliability testing by Spearman's Rank correlation coefficient; 4- Selection of indicators through focus groups; 5- Field application on 25 farms; 6- Feasibility and second reliability testing by Kendall Correlation Coefficient; and 7- Weighing of indicators and defining the classification method. Of the 150 candidate measurements initially obtained from the literature review, 57 were pre-selected and 28 were finally selected based on their validity, reliability and practicality to integrate the final protocol (18 ABM, 8 RBM and 2 MBM). In addition, the final protocol included information about: preliminary interview; sampling order; estimated evaluation time; sample size; equipment required; and steps to follow from arrival at the farm until completion of the evaluation. The protocol was applied in 25 feedlots and 54238 animals, and required a minimum time of 290 min to a maximum of 495 min to be completed. Statistically significant (p < 0.05) concordance among the observers was found for all the selected ABM analysed using Spearman's rank correlation coefficient. Given the simplicity for its evaluation, the reliability of RBM and MBM included in this protocol has not been evaluated. This research allowed the development of the first standard welfare assessment protocol for beef cattle feedlots in Argentina. Further applications of the described welfare assessment tool in many feedlots will reinforce the validation of the proposed measurements and allow the diagnosis of the global situation of animal welfare in feedlots in Argentina and other countries applying comparable fattening systems.
... Furthermore, due to the potential risk for development of antibiotic resistance, there is a global trend toward banning the use of supplemental antibiotics (W HO, 2017). Ionophore supplementation is currently prohibited within the European Union (European Commission, 2003;Directive 1831/2003 and this trend is expanding to various countries around the world. Essential oils (EO; such thymol, eugenol, vanillin, guaiac and limonene) have been investigated as an alternative to conventional antibiotics such as MON. ...
... In warm climates the risk of higher intake variations become greater. A perceived advantage of supplemental MON is reduced variation in DMI (Galyean and Rivera, 2003), that can be particularly advantageous during period of extreme ambient conditions ...
Ninety young crossbreed bulls (approximately 25% Zebu breeding with the remainder represented by continental and British breeds in various proportions, initial weight=228.04±7.06 kg) were used in a 84-day feeding trial to assess the effects of treatments in feedlot cattle fed transition diets during high ambient temperatures. Treatments consisted of a steam-flaked corn-based diets (average 1.95 Mcal ENm/kg) supplemented with: 1) 20 mg monensin/kg diet (MON, Rumensin, Elanco Animal Health, Indianapolis, IN], and 2) 100 mg of blend of essential oils /kg diet plus 0.1 mg 25-hydroxy-vitamin-D3/kg diet (EO+HyD; CRINA® Ruminants and HyD®, DSM Nutritional Products, Basel, Switzerland). Both dry matter intake (DMI) and climatic variables were measured daily and the temperature humidity index (THI) was estimated. Daily maximal THI remained over 80 during the whole trial (avg. THI = 82.67). Cattle supplemented with EO+HyD increased average daily gain in 8.7% (1.446 vs. 1.320 kg/day, P < 0.01), gain-to-fed ratio in 4.5% (0.199 vs. 0.190; P = 0.03), final weight in 10.05 kg (349.48 vs. 339.43; P = 0.04) and tended (P = 0.07) to shown greater dietary net energy (2.5%) and observed-to-expected dietary NE ratio (3%). Even when EO+HyD tended to increase (4.3%; P = 0.06) DM intake, intake pattern variation were not different (P = 0.38) between MON and EO+HyD (Figure 1). Then, difference in ADG and final BW between MON and EO+HyD was not only a reflection of difference in energy intake, was also caused by difference in efficiency of energy utilization during conditions of high ambient temperature (a reduction of 7% in the estimated increase of coefficient of maintenance by heat load). Results indicate that supplementation with a combination of essential oil blend plus 25-hydroxy-vitamin-D3 can have greater beneficial effects than supplemental monensin on daily weight gain, final weight and feed intake during initiation-transition phase of cattle raised under high ambient temperature.
... While feeding high concentrate-based rations of rapidly fermentable carbohydrates favors growth and performance, it does come with the challenge of increased likelihood of metabolic disorders such as acidosis [3]. Digestive disorders account for approximately 25% to 33% of deaths in the feedlot and can have a marked impact on cattle health and efficiency of production [4]. The grain source used in feedlot rations can have an influence on both rumen environment and function [5]. ...
... 22 h post-feeding. Variation in ruminal temperature hour post-feeding also displayed a diet by hour post-feeding interaction (p < 0.01; Figure 5), where corn-fed steers had greater (p = 0.02) variation in ruminal temperature at 2 h post-feeding than barley-fed steers; however, barley-fed steers had greater (p ≤ 0.02) variation in ruminal temperature than cornfed steers at 3,4,5,7,8,9,10,11,15,16, 17 and 18 h post-feeding. . Diurnal ruminal temperature coefficient of variation (CV, %) patterns of beef steers fed once daily (0800) barley-or corn-based feedlot diets. ...
This study evaluated the effects of corn or barley finishing diets on ruminal pH and temperature and their relationship to feed intake events using continuous reticulorumen monitoring of feedlot steers. Average daily ruminal pH and temperature were not impacted (p ≥ 0.17) by diet. However, diet did affect daily variation of ruminal pH and temperature (p < 0.01). Average hourly ruminal pH displayed a diet by hour post-feeding interaction (p < 0.01), where barley-fed steers had greater (p < 0.01) ruminal pH than corn-fed steers at 0, 1, 18, 19, 20, 21, 22 and 23 h post feeding, but had lower (p ≤ 0.05) ruminal pH than corn-fed steers at 6, 7, and 8 h post-feeding. Variation in ruminal pH hour post-feeding also displayed a diet by hour post-feeding interaction (p < 0.01), where barley-fed steers had greater (p ≤ 0.03) variation in ruminal pH at hours 1–17 post-feeding but did not differ (p ≥ 0.16) at 0, 18, 19, 20, 21, 22 and 23 h post-feeding. Additionally, average hourly ruminal temperature exhibited a diet by hour post-feeding interaction (p < 0.01). In summary, basal grain interacted with time post-feeding influencing ruminal pH and temperature in feedlot steers.
... Thus, the nutritive value of the barley-based diets are manipulated by including wDDGS which can be used to overcome shortcomings of barley dominated diets for beef cattle., 2005), with feedlot rations containing up to 90% barley grain (). However, barley has high ruminal rate and extent of starch degradation (>80%;Hart et al. 2008;) which results in digestive disorders such as bloat and acidosis (Galyean and Rivera, 2003) with serious economic impacts on the feeding program (). Furthermore, high inclusion of barley results in shortage of protein for optimal microbial protein synthesis which results in the requirement for protein rich supplements to balance the ration (). ...
... This often results in problems in feedlot cattle with barley-based diet, including: 1) digestive disorders, e.g. bloat and acidosis of cattle (Galyean and Rivera, 2003) and 2) an inefficient utilization of barley components. These can affect negatively on industry profitability () and environment (Nocek and Tamminga, 1991;McGinn et al., 2009). ...
Recently, bio-fuel processing produces a large amount of bio-fuel co-products. This research program aims to develop strategies to more efficiently utilize cereal grains (barley, corn, and oat) in conjunction with natural feed additive - bioethanol co-products in an effort to develop low-cost feeding strategies for the beef industry. Specific objectives were to determine (1) effects of replacing feed grain (barley, corn, and oat) by wheat –based dried distillers’ grains with solubles (wDDGS) on the feed nutritive value in terms of detailed chemical profile, energy values, protein, and carbohydrate subfractions, in situ rumen degradation kinetics, degradation ratios, modeling protein supply to cattle, and molecular structures in terms of protein, carbohydrate, and lipid; and (2) the effect of dietary optimal or suboptimal rumen available protein to energy ratios generated by substituting barley grain by wDDGS on finishing feedlot cattle performance and carcass traits.
... Thus, subacute and acute ruminal acidosis are important issues in beef feedlot production. 5,6 Management of ration ingredients and feed bunks and the use of monensin to decrease meal size are examples of different practices the feedlot industry has adopted to regulate rumen pH and maximize cattle health and performance outcomes. [7][8][9] In cattle, highly fermentable carbohydrates are considered the primary cause for clinical and subclinical ruminal acidosis, which contribute to the subsequent development of liver abscesses. ...
OBJECTIVE To evaluate the reticulorumen pH of beef feedlot steers throughout the feeding period and to assess the association between the respective durations that the reticulorumen pH was ≤ 5.6 (subacute ruminal acidosis) and ≤ 5.2 (acute ruminal acidosis) and liver abscess severity.
ANIMALS 59 feedlot steers (mean body weight, 349.5 kg).
PROCEDURES On day 0, each steer was orally administered an electronic bolus that monitored the reticulorumen pH every 10 minutes for 150 days. Steers were transitioned from a starter to intermediate ration on day 8 (transition 1) and from the intermediate to finish ration on day 19 (transition 2). The ration carbohydrate and megacalorie contents increased with each transition. During each transition, the lower megacalorie ration was fed at the 8:00 am feeding and the higher megacalorie ration was fed at the 2:00 pm feeding for 3 days before the higher megacalorie ration was fed extensively. Steers were sent to slaughter after 182 days; each carcass was assessed for liver abscesses.
RESULTS The diurnal reticulorumen pH pattern was characterized by a peak at 7:00 am and nadir at 8:00 pm. The mean percentages of time that the reticulorumen pH was ≤ 5.6 and ≤ 5.2 were more than 10-fold greater during transition 1, compared with during transition 2, and were significantly greater for steers with extensive liver abscesses than for steers without extensive liver abscesses.
CONCLUSIONS AND CLINICAL RELEVANCE Efforts to minimize the duration that the reticulorumen pH is ≤ 5.6 might mitigate liver abscess formation in feedlot cattle.
... According to Bartely et al. (1983), monensin is effective in controlling bloating, that is often reported as an important cause of death in feedlot cattle. Bloat usually occurs when the animal is prevented from expelling ruminal gas, which places pressure on the diaphragm and lungs, thereby affecting breathing and potentially resulting in death (Galyean and Rivera 2003). Monensin can inhibit Gram-positive bacteria, specially the lactic acid and mucopolysaccharide-producing species (e.g. ...
This study was conducted to evaluate the growth performance and carcass characteristics of finishing steers fed diets containing different feed additives: control (CTL; no feed additives); monensin [26 mg/kg dry matter (DM); MON]; a blend of cinnamaldehyde, eugenol, and capsicum (120 mg of a commercial product/kg DM; XT), or the combination of monensin and the blend of cinnamaldehyde, eugenol, and capsicum (26 mg/kg DM and 120 mg of a commercial product/kg DM, respectively; MON + XT). A total of 860 steers [initial body weight (BW) = 334 kg] were fed the basal diet (7% alfalfa hay and 93% concentrate; DM basis) containing the treatments during 154 days. Feed additives did not affect final BW, DM intake, average daily gain, and feed efficiency of finishing steers (P ≥ 0.12). Dressing percentage was lower for MON + XT than MON and XT (P = 0.01). Feeding XT tended to increase the percentage of the carcass with a small marbling score compared to MON (P = 0.09). The proportion of carcass grading premium choice tended to be greater for steers fed MON compared to XT (P = 0.07). The feed additives evaluated herein did not affect the growth performance of finishing beef steers and had little effects on carcass characteristics.
... Bulls were gradually built up to ad libitum concentrates in this study, thus allowing the rumen time to adjust. This, together with the provision of adequate forage in the diet, is thought to be key in preventing nutritional disorders of this kind [38]. ...
The aim of this study was to evaluate the effect of production system on the health, performance, carcass characteristics, and meat quality of autumn born (AB) and spring born (SB) Holstein bulls. The study involved a total of 224 Holstein bulls and was conducted over two years (2017/18, 2018/19). The four production system treatments differed during the grower period and consisted of: (i) grazed with no concentrate supplementation (G), (ii) grazed with 2 kg concentrate supplementation per day (G2), (iii) grazed with ad libitum access to concentrates (GA) and (iv) housed with ad libitum access to concentrates and grass silage (HA). All bulls were finished on ad libitum concentrates and grass silage and were slaughtered at a mean age of 15.5 months. Total grower dry matter intake (DMI) (p < 0.001) and total finishing DMI (p < 0.001) differed between production systems for both AB and SB bulls, with that of GA bulls being the greatest in both cases. Average daily gain (ADG) during the grower period was greatest (p < 0.001) for the HA production system in the AB bulls and the GA and HA production systems for the SB bulls. However, during the finishing period, G bulls had the greatest (p < 0.001) ADG of the AB bulls, while that of the SB bulls was from the G2 production system (p < 0.001). For both AB and SB, bulls on the GA and HA production systems produced heavier cold carcass weights than the G and G2 bulls (p < 0.001). There was no significant difference (p > 0.05) in health, carcass conformation, fat classification, or meat quality between production systems.
... Ruminal acidosis results from the consumption of high amounts of rapidly fermentable carbohydrates (CH). (Galyean & Rivera 2003, Nagaraja & Lechtenberg 2007. Ruminal bacteria respond to the increased availability of fermentable substrates by increasing growth rates and fermentative activities, that is, the introduction of this highly fermentable CH in the diet leads to a reduction in fibrolytic bacteria, the rapid growth of amylolytic bacteria and a decrease in ruminal pH (Bevans et al. 2005). ...
This review reports the leading causes of death in feedlot beef cattle. It describes economic losses resulting from these deaths and suggests control alternatives. Diseases associated with the respiratory and digestive systems were the most frequently observed. In different geographical areas, the importance of each one might vary. Outbreaks of diseases such as botulism occur occasionally and can cause important economic losses. Cattle tick fever can cause significant losses in zones of enzootic tick instability. Technical assistance and sanitary and food management are critical for the best productivity in feedlot cattle.
... In addition, researchers reported that supplementing thiamine to ruminant diets helps to alleviate or to prevent poliomyelitis in animals [59][60][61]. Meanwhile, others reported that the involvement of thiamine in S-induced poliomyelitis is unclear [62]. The causative mechanisms of poliomyelitis, for instance; long-term thiamine deficiency or increased hydrogen sulfide gas concentration, may influence the chances or the efficacy by which thiamine supplementation may prevent poliomyelitis in ruminants fed with an increased dietary S. Due to this, studies have been conducted studies to determine the effective level or concentration of thiamine that is necessary to alleviate or prevent poliomyelitis. ...
Hydrogen sulfide is a Janus-faced molecule with many beneficial and toxic effects on the animal health. In ruminants, rumen fermentation plays a vital role in the digestion and absorption of nutrients. During rumen fermentation, the production of hydrogen sulfide can occur, and it can be rapidly absorbed into the body of the animals through the intestinal wall. If the production of hydrogen sulfide concentration is higher in the rumen, it can cause a toxic effect on ruminants known as poliomyelitis. The production of hydrogen sulfide depends on the population of sulfate-reducing bacteria in the rumen. In rodents, H 2 S maintains the normal physiology of the gastrointestinal tract and also improves the healing of the chronic gastric ulcer. In the gut, H 2 S regulates physiological functions such as inflammation, ischemia-reperfusion injury and motility. In this review article, we summarize the toxicity occurrence in the body of animals due to high levels of hydrogen sulfide production and also recent progress in the studies of physiological function of H 2 S in the gut, with a special emphasis on bacteria-derived H 2 S is discussed in this review.
... Low-roughage, highly fermentable diets improve feed efficiency and reduce feed costs (Owens et al., 1997), but prevalence of acidosis, bloat, and liver abscesses is increased. These digestive disorders account for about one-quarter to one-third of the deaths in feedlot cattle (Galyean and Rivera, 2003). ...
High grain diets are fed to finishing beef cattle to maximize animal performance in a cost-effective manner. However, a small amount of roughage is incorporated in finishing diets to help prevent ruminal acidosis, although few studies have examined optimum roughage inclusion level in barley-based diets. The objective of the study was to evaluate the effects of roughage proportion in barley-based finishing diets on growth performance, feeding behavior and carcass traits of feedlot cattle. Crossbred beef steers (n = 160; mean body weight ± SD, 349.7 ± 21.4 kg) were allocated to 20 pens that were assigned randomly to 4 dietary treatments (5 pens of 8 steers per treatment). The treatment diets contained barley silage at 0, 4, 8, and 12% of dietary dry matter (DM). The remainder of the diets (DM basis) consisted of 80, 76, 72, and 68% barley grain, respectively, 15% corn dried distiller's grains, 5% mineral and vitamin supplement, and 32 mg monensin/kg diet DM. The diets were fed as total mixed rations for ad libitum intake (minimum of 5% refusal) once per day. Cattle were weighed on 2 consecutive days at the start and end of the experiment and on 1 d every 3 wk throughout the experiment (124 days). Two pens for each treatment group were equipped with an electronic feeding system (GrowSafe Systems Ltd., Calgary, Alberta) to monitor feed intake and feeding behavior of individual cattle. The data for dry matter intake (DMI), average daily gain (ADG), gain:feed (G:F) ratio, and carcass traits were analyzed as a completely randomized design with fixed effect of barley silage proportion and pen replicate as experimental unit. Feeding behavior data were analyzed similarly, but with animal as experimental unit. Averaged over the study, DMI increased linearly (11.1, 11.3, 11.7, 11.8 kg/d; P = 0.001) as barley silage proportion increased from 0, 4, 8, and 12% of DM, but ADG was not affected (carcass-adjusted,1.90, 1.85, 1.87, 1.89 kg/d; P ≥ 0.30). Consequently, G:F ratio decreased linearly (carcass-adjusted, 168.9, 163.8, 158.5, 160.6 g/kg DMI; P = 0.023). When averaged over the study, proportion of barley silage in the diet had no linear or quadratic effects (P > 0.10) on meal frequency, duration of meals, intermeal duration, or meal size, but eating rate decreased linearly with increasing silage proportion (P = 0.008). There was no diet effect on liver abscesses (P ≥ 0.92), and effects on carcass characteristics were minor or non-existent. We conclude that increasing the proportion of barley silage in a feedlot finishing diet at the expense of barley grain to minimize the incidence of ruminal acidosis may decrease feed conversion efficiency.
... There are often economic incentives to feed high grain diets, but there are also health risks resulting indirectly fro m ruminal acid production including bloat, overload, laminitis, and liver abscesses (Galyean and Rivera, 2003). As well, excess starch and/or lack of fibre can reduce dry matter and energy intakes resulting in reduced energy intakes and even gains. ...
The Beef Cattle Research Center of China Agricultural University has organized the First Symposium on the Chinese National Beef Cattle Nutrition, Feeding and Industry Economics in June, 2015 in Beijing (http://www.bovine-online.org). Experts from the United States, Canada, Australia, France, Denmark, and FAO of the United Nations have been invited to give plenary lectures at the Symposium. The goal of this Symposium was to introduce advanced concepts and practices in beef cattle to China and promote the modernization of China’s beef cattle industry. There was approximately 500 participants to the Symposium, among which 60% are from industry, 20% are graduate students, 10% are local government officials, and 10% are university professors. Chinese/English simultaneous interpretation has been provided during the conference. This symposium has been sponsored by the Beef Cattle Research Center of China Agricultural University and the China-France Center for Beef Cattle Research and Development. This article are abstracts of the plenary lectures by experts from the United States, Canada, Australia, France, Denmark, and FAO of the United Nations, which have been previously published in Chinese Journal of Animal Science (June 2015, volume 51).
... However, when diets are energetically dense and highly digestible, such as high-concentrate diets, intake becomes primarily a function of metabolic control (Waldo, 1986). In general, other studies have shown that increasing the percentage of highly fermentable concentrates in feedlot diets by decreasing roughage or limiting feed intake increases the incidence of digestive disorders (Galyean & Rivera, 2003). Thus, we could expect problems associated with the health and welfare of the lambs if the period without straw was prolonged. ...
The aim was to evaluate the effect of size (long or chopped wheat straw), type (barley or wheat) and presence/absence (1 week) of straw supplementation on behaviour and welfare of fattening lambs. Sixteen lambs (65 days) were individually housed to be used in two simultaneous experiments (8 lambs each) for 5 weeks of fattening. After a habituation period, they were offered straw that differed either in size (Experiment 1) or type (Experiment 2), which was followed by a week without straw and then reallocation of straw. Maintenance behaviours, play and stereotypies were analysed using video recording. Physiological stress responses were measured using blood samples taken at the end of the week without straw and after the reallocation of the straw. A preference test was performed during the last week. Concentrate and roughage consumption, average daily gain and conversion index were estimated. Lambs provided with long straw spent more time eating forage, playing and performed fewer stereotypies (Experiment 1). Lambs given wheat straw increased their play behaviour compared with those given barley straw, without affecting stereotypies (Experiment 2). When the straw was removed, lambs performed more behaviours associated with stress; however, this was not reflected in blood stress indicators. Lambs clearly preferred long straw over chopped straw, but no clear preference was observed between wheat and barley straw. The amount of forage intake was consistent with the time spent eating forage, but the amount of concentrate intake did not vary with eating concentrate behaviour, since the amount of concentrate intake was higher when the straw was removed, especially in Experiment 2. Our results show that size more than type of straw supplement impact the behaviour of lambs. Long straw reduces the stereotypies and increases play. This may improve the welfare and performance of fattening lambs, adding ethical value to a highly appreciated product.
... These investigations have provided important information on the possible links between steroidal saponins in plant tissue, rumen metabolism, and the absorption of the derived compounds leading to the formation of crystals capable of blocking the bile ducts Badiei et al. 2009). In addition, steroidal saponins that have escaped from the rumen may cause infection and inflammation to the liver (Galyean and Rivera 2003). The pathogenic toxins may damage the rumen wall which allows entry of both toxin and normal microflora found in the rumen into the circulatory system and eventually reaching the portal bloodstream. ...
Brachiaria decumbens is an extremely productive tropical grass due to its aggressive growth habit and its adaptation to a varied range of soil types and environments. As a result of the vast availability, treated B. decumbens demonstrates as a promising local material that could be utilised as an improved diet for sheep and goats. Despite the fact that the grass significantly increases weight gains in grazing farm animals, there were many reports of general ill-thrift and sporadic outbreaks of photosensitivity in livestock due to the toxic compound of steroidal saponin found in B. decumbens. Ensiling and haymaking were found to be effective in removing toxin and undesirable compounds in the grass. Biological treatments using urea, activated charcoal, polyethylene glycol, and effective microorganisms were found to be useful in anti-nutritional factor deactivation and improving the nutritive values of feedstuffs. Besides, oral administration of phenobarbitone showed some degree of protection in sheep that fed on B. decumbens pasture. In this review, we aim to determine the effect of B. decumbens toxicity and possible treatment methods on the grass to be used as an improved diet for small ruminant.
... Long, fibrous feed particles require more chewing, consequently increasing the production of bicarbonate-rich saliva [3], which buffers rumen pH. In contrast, highly fermentable grainbased diets can cause excessive acid production in the rumen, leading to acute or subacute ruminal acidosis [4][5][6]. When given the opportunity, cattle experiencing ruminal acidosis make diet choices that ameliorate low rumen pH: they preferentially sort for longer feed particles [7][8][9] and prefer alfalfa in the form of long-stemmed hay rather than pellets [10]. ...
Domestic cattle (Bos taurus taurus) are adapted to digest high-roughage diets, but in confinement they are commonly fed low-roughage, high-energy diets. This practice may leave cattle with an unfulfilled need to consume forage. A way to quantify motivation is to require animals to work to access a resource. Using this method, we evaluated cattle motivation to obtain forage when fed high- or low-roughage diets during and 30 d before the study. Individual heifers were fed Sudan grass (Sorghum × drummondii) hay (high roughage, n = 6) or a diet with 12% forage (as fed, low roughage, n = 6) in an open feed trough. In a second trough, 200 g/d of Sudan grass hay were fed behind a push gate, to which additional weight was added daily until heifers no longer pushed. We predicted heifers would push heavier weights, show a shorter latency, and spend more time pushing the gate when fed a low- vs. high-roughage diet. Indeed, heifers fed a low-roughage diet pushed the gate immediately after hay delivery (1.7 min) and much sooner than those fed a high-roughage diet (75.7 min). On the day before they no longer pushed the gate, latency for heifers in the low-roughage treatment remained only 3.2 min after hay delivery. The suddenness with which they ceased pushing the next day suggests they were unable to move heavier weights to express their motivation. This may explain why maximum weight pushed and time spent pushing the gate did not differ between treatments. The gate pushing by heifers with unrestricted hay access is the first demonstration by cattle of contrafreeloading: performing work to obtain a resource that is simultaneously available for free. In conclusion, consuming forage is important to cattle and is affected by both their primary diet and an internal motivation to work to obtain feed.
... Semi-intensive and intensive production practices are growing in mixed crop-livestock and agro-pastoral production systems, especially in communities where land for grazing has become limiting (Bouwman et al., 2005). However, most of the changes in the T production systems occur with limited knowledge on the influence of diets on rumen environment, passage kinetics and the digestibility of feeds which have bearing on the health (Galyean and Rivera, 2003;Mickdam et al., 2016) and performance (González et al., 2012;Shoukun et al., 2016) of the animals. Moreover, the compositions of animal products such as saturated fatty acids in milk are also influenced by the rumen fermentation patterns (Shingfield et al., 2008). ...
... In many countries, beef cattle are commonly reared in grazing systems and finished in feedlots, where they are transitioned to highenergy diets based on grain concentrates (e.g., in the US, 48% of cattle in the finishing phase are fed > 75% concentrate on a dry-matter basis; USDA, 2013). To date, much of the research on the animal welfare implications of feeding high-energy diets has focused on health consequences (i.e., ruminal acidosis, reviewed by Owens et al., 1998;Galyean and Rivera, 2003;Nagaraja and Lechtenberg, 2007). To our knowledge, however, no previous studies have quantified the motivation of beef cattle to consume high-energy feeds. ...
Beef cattle may be fattened before slaughter using a high-energy, grain-based diet. Although previous research suggests cattle prefer grain, their motivation to obtain this feed has not been quantified. The objective of this study was to evaluate the motivation of naïve feedlot cattle to consume grain relative to hay. One method for quantifying motivation is to allow animals to perform work (e.g., push a weighted gate) for access. However, as previous research has suggested gate pushing may be rewarding, a second objective was to evaluate whether adding an aversive element (protruding studs) to the gate would increase the cost of pushing. Twenty-four individually-housed Angus-Hereford heifers were fed Sudan and alfalfa hay (3:1 ratio) in an open feed bunk with unrestricted access. In a second bunk, 200. g of either the primary diet (hay, final n = 9) or calf starter (grain, final n = 8) was fed behind a gate that required pushing for access. Additional weight was added to the gate at each feeding until heifers no longer pushed. We predicted heifers would show motivation to obtain grain by pushing heavier weights, showing a shorter latency to use the gate after feed delivery, and spending more time using the gate than those offered the additional portion of hay. Instead, heifers spent more time using the gate when offered hay vs. grain [back-transformed means: 0.4 vs. 1.8. min/12. h, respectively; 95% confidence intervals (CI): 0.1-1.0 vs. 0.9-3.3. min/12. h], likely because fibrous feed took longer to consume. Heifers offered hay or grain showed similar latencies to use the gate (back-transformed means: 88.6 vs. 59.8. min, respectively; CI: 53.7-157.0 vs. 37.6-101.1. min) and pushed similar maximum weights (mean. ±. SEM: 15.0. ±. 1.8 vs. 18.2. ±. 1.9% of bodyweight). The heifers offered hay demonstrated contrafreeloading by working to obtain a resource that was simultaneously and freely available. To further evaluate responses to novelty, we recorded the amount of time each heifer spent in proximity to (within a 1-m radius) and investigating (in proximity and with the head <0.85. m from the ground) novel carrots in a 15-min test in an unfamiliar arena. Heifers that pushed heavier maximum weights spent more time in proximity to (R² = 0.45) and investigating (R² = 0.46) carrots, suggesting an underlying personality trait perhaps reflecting neophobia, exploratory tendency, or motivation to exert control over their environment.
... The heaviest carcasses in our study were for calves from intensive farms and the lowest, although more variable, were for organically reared calves. The high proportion of concentrate, and hence energy, in the feed ration of intensively reared animals leads to higher fat deposition and energy retention (Galyean & Rivera, 2003) compared with animals from organic farms where forage is the main dietary component; it is well known that herbivores fed with a higher proportion of roughage but few concentrates need more time to fatten (Nielsen & Thamsborg, 2005). ...
The objective of this study was to analyse how beef-cattle farming in NW Spain on organic farms compares with intensive and conventional systems in terms of impacts on the safety and quality of cattle products. Data on the hygiene and quality of 244, 2596 and 3021 carcasses of calves from organic, intensive and conventional farms, respectively, were collected at the slaughterhouse. Organic calves generally had fewer condemnations for liver, kidney and heart pathologies. Liver parasitic infections were 2 fold higher in organic calves than those from other types of farm. Farm processes and resultant food product quality are linked through the health of the animal and its disease status. Overall better health status was not reflected by carcass performance as this was significantly lower for organic calves than for calves from conventional and intensive farms. Carcass performance seemed to be more determined by dietary component than by health status in the animals in our study.
... In addition to their effects on the rumen, the osmotic pressure of these agents causes systemic dehydration and hypovolemia by pulling fluid from the circulation into the rumen, resulting in a reduction in tissue perfusion. 5,14 The loss of circulating blood volume leads to cardiovascular collapse, reduced renal perfusion, and anuria. Reduced peripheral circulation also leads to anaerobic cellular metabolism and systemic acidosis. ...
Clinical rumen acidosis is an important cause of morbidity and mortality in both large and small ruminants. Feeding and management practices that lead to the consumption of large amounts of readily fermentable carbohydrates precipitate clinical disease. The fermentation of carbohydrates into volatile fatty acids and lactate causes acidosis (local and systemic), rumen ulceration, cardiovascular compromise, and organ dysfunction. Animals affected with acidosis can suffer from numerous sequelae. Treatment of animals with clinical rumen acidosis is focused on addressing plasma volume deficits, correcting acid-base disturbances, and restoring a normal rumen microenvironment.
... Cattle are extremely variable in their tolerance of highly fermentable diets (Bevans et al., 2005). When animals are fed a total mixed ration (TMR), and particularly with high-grain diets, their sorting behaviour is limited, and therefore digestive upsets such as ruminal acidosis can be a persistent problem (Galyean and Rivera, 2003). Two studies (Moya et al., 2011;2014) were conducted to determine if, when offered a choice of ingredients, beef cattle would select a diet that modulates ruminal fermentation while keeping the same growth performance as when fed a TMR. ...
... The decrease of the NDF amount associated with a faster ruminal passage rate due to increased concentrate level (Russel et al., 1992) provides a decrease of rumination, salivation, and ruminal pH. This scenario can lead to a reduction in intake and the appearance of metabolic disorders (Owens et al., 1998;Galyean and Rivera, 2003). Even with high concentrate levels and lipid content, diets with low roughage levels presented the same DMI as diets with 50% of roughage. ...
The objective of this study was to evaluate the nutrient intake and performance of feedlot lambs using 2 roughage to concentrate ratios and 2 types of soybean, whole (WS) or thermally processed (PS). Twenty male noncastrated market lambs weighting 23.26 ± 2.18 kg were used. The design was completely randomized in a factorial arrangement of 2 × 2. Diets were formulated with 50:50 and 20:80 of roughage to concentrate ratio on DM, and the thermal processing was realized in an autoclave at 120°C during 1 h. The end of the experimental period was determined by animal BCS, that is, the animals were slaughtered with a BCS between 3 and 3.5. The animals fed with 50% of roughage spent more time consuming feed (P < 0.01) and ruminating (P < 0.01). Thermally processed soybean provided more time consuming (P < 0.05) and less leisure time (P < 0.05) compared with WS. Diet with 20% of roughage provided increased ADG (P < 0.01) and better feed conversion (FC; P < 0.01). The utilization of PS resulted in decreased feedlot period (FP; P < 0.01), increased ADG (P < 0.05), decreased DMI (P < 0.01), and consequently better FC (P < 0.01). Diet with PS decreased the intake of ADF (P < 0.01). There was interaction between the roughage to concentrate ratio and soybean, wherein the diet with 50% of roughage and WS provided increased intake of NDF (P < 0.05). The use of thermally processed soybean provided better performance of lambs, and when this feed is associated with higher concentrate proportion, it reduces the intake of fibrous fraction of the diet. © 2015 American Society of Animal Science. All rights reserved.
... Although there has been virtually no work to ascertain the welfare implications of feeding high-grain diets, there have been some behavioural indicators reported in the veterinary and nutritional literature, suggesting that the welfare of feedlot cattle is compromised to some extent when fed diets that cause acute or subacute ruminal acidosis. Rumen acidosis occurs when the pH of the rumen drops rapidly to between 5.0 and 5.5 (Penner et al. 2009), and this is thought to account for 25–30 % of all feedlot deaths (Gaylean and Rivera 2003). This, combined with the direct impact on liver abscesses (Nagaraja and Chengappa 1998), results in substantial economic losses to the feedlot industry. ...
In many countries around the world genetic selection strategies have produced farm animals with a high productive (meat, milk, and eggs) potential. These high-producing animals need to be fed and housed under optimum conditions to ensure that the expression of their genetic potential does not compromise welfare. To strive for the highest level of welfare for food-producing animals, one must consider the animal’s health and biological functioning and its affective state as well as ensure provision of environments where the animals can engage in behaviours they are highly motivated to perform. Animal-based models, including growth rate, body condition score, lameness, morbidity, and mortality, and environment-based indexes such as temperature, stocking density, and bedding quality are useful metrics to ensure a minimum level of welfare. However, their use on a particular farm can only be as good as the records kept on the farm. This chapter reviews the main nutritional challenges to welfare in farm animals and provides an overview of possible welfare indicators for cattle, swine, and poultry, with a special emphasis on those aspects related to nutrition.
... Neste sentido, a adição do antibiótico monensina em dietas de confinamentos é utilizada como forma de inibir bactérias produtoras de ácido láctico (Dennis e Nagaraja, 1981), o que somado com uma freqüência potencialmente maior de refeições menores, podem diminuir os efeitos da alta produção de ácido no rúmen (Galyean e Rivera, 2003). ...
The effect of adding live yeast culture (Saccharomyces cerevisiae, strain 1026), monensin or the combination of both additives to high grain diets on feedlot performance and digestibility of steers, was studied. Nellore steers (n= 72, 339 kg BW, 20 months-old) were fed for 84 days a basal ration (2.58 Mcal EM/kg DM, 14% CP) without additives (control), or with yeast culture (0.6 g Beef Sacc®/ kg DM), monensin (0.3 g Rumensin®/ kg DM) or the combination of both additives to evaluate feedlot performance through individual measurements of dry matter intake, average daily gain and ultra-sound scanning of carcass subcutaneous fat thickness upon Longissimus (12 th rib) and Biceps femoris muscle and rib eye area. Other four steers were randomly allotted to one of the treatments in a 4 x 4 latin square design in order to assess digestibility of dry matter, crude protein, neutral detergent fiber and acid detergent fiber fractions of the diet. There were no effects of additives on dry matter intake and rate of growth of carcass fat thickness and rib eye area. Yeast culture tended to decrease average daily gain and increase feed conversion (p<0.10). Digestibility was not affected by treatments (p>0.10). Supplementation of live yeast culture, monensin or the combination of both may not be important on finishing beef steers fed high grain diets in feedlot.
... Upon arrival at the feedlot, 58% of US cattle are fed a diet that is at least 50% concentrates; 83% of cattle in the finishing phase are fed this type of diet (United States Department of Agriculture or USDA, 2011b). High concentrate feeding has been associated with nutritional disease, the most common of which include acidosis, liver abscesses and laminitis; the latter two occurring secondary to acidosis (Nocek, 1997;Galyean and Rivera, 2003;Nagaraja and Lechtenberg, 2007a). Acidosis is the result of excessive acid production in the rumen (Owens et al., 1998;Penner et al., 2011) and can be defined as either acute (clinical acidosis) when the pH is <5.0 or sub-acute ruminal acidosis (SARA) when ruminal pH < 5.8 for more than 12 h day −1 (Schwartzkopf-Genswein et al., 2003). ...
This review identifies priorities for beef cattle welfare research in the USA. Based on our professional expertise and synthesis of existing literature, we identify two themes in intensive aspects of beef production: areas where policy-based actions are needed and those where additional research is required. For some topics, considerable research informs best practice, yet gaps remain between scientific knowledge and implementation. For example, many of the risk factors and management strategies to prevent respiratory disease are understood, but only used by a relatively small portion of the industry. This is an animal health issue that will require leadership and discussion to gain widespread adoption of practices that benefit cattle welfare. There is evidence of success when such actions are taken, as illustrated by the recent improvements in handling at US slaughter facilities. Our highest priorities for additional empirical evidence are: the effect of technologies used to either promote growth or manage cattle in feedlots, identification of management risk factors for disease in feedlots, and management decisions about transport (rest stops, feed/water deprivation, climatic conditions, stocking density). Additional research is needed to inform science-based recommendations about environmental features such as dry lying areas (mounds), shade, water and feed, as well as trailer design.
... There are often economic incentives to feed high grain diets, but there are also health risks resulting indirectly fro m ruminal acid production including bloat, overload, laminitis, and liver abscesses (Galyean and Rivera, 2003). As well, excess starch and/or lack of fibre can reduce dry matter and energy intakes resulting in reduced energy intakes and even gains. ...
The First Symposium on the Applied Techniques and Industry Economics in Chinese Beef Cattle Production.
The Beef Cattle Research Center of China Agricultural University has organized the First Symposium on the Chinese National Beef Cattle Nutrition, Feeding and Industry Economics in June, 2015 in Beijing (http://www.bovine-online.org/). Experts from the United States, Canada, Australia, France, Denmark, and FAO of the United Nations have been invited to give plenary lectures at the Symposium. The goal of this Symposium was to introduce advanced concepts and practices in beef cattle to China and promote the modernization of China’s beef cattle industry. There was approximately 500 participants to the Symposium, among which 60% are from industry, 20% are graduate students, 10% are local government officials, and 10% are university professors. Chinese/English simultaneous interpretation has been provided during the conference. This symposium has been sponsored by the Beef Cattle Research Center of China Agricultural University and the China-France Center for Beef Cattle Research and Development. This article are abstracts of the plenary lectures by experts from the United States, Canada, Australia, France, Denmark, and FAO of the United Nations, which have been previously published in Chinese Journal of Animal Science (June 2015, volume 51).
... The decrease of the NDF amount associated with a faster ruminal passage rate due to increased concentrate level (Russel et al., 1992) provides a decrease of rumination, salivation, and ruminal pH. This scenario can lead to a reduction in intake and the appearance of metabolic disorders (Owens et al., 1998;Galyean and Rivera, 2003). Even with high concentrate levels and lipid content, diets with low roughage levels presented the same DMI as diets with 50% of roughage. ...
The objective of this study was to evaluate the nutrient intake and performance of feedlot lambs using 2 roughage to concentrate ratios and 2 types of soybean, whole (WS) or thermally processed (PS). Twenty male noncastrated market lambs weighting 23.26 ± 2.18 kg were used. The design was completely randomized in a factorial arrangement of 2 × 2. Diets were formulated with 50:50 and 20:80 of roughage to concentrate ratio on DM, and the thermal processing was realized in an autoclave at 120°C during 1 h. The end of the experimental period was determined by animal BCS, that is, the animals were slaughtered with a BCS between 3 and 3.5. The animals fed with 50% of roughage spent more time consuming feed ( < 0.01) and ruminating ( < 0.01). Thermally processed soybean provided more time consuming ( < 0.05) and less leisure time ( < 0.05) compared with WS. Diet with 20% of roughage provided increased ADG ( < 0.01) and better feed conversion (FC; < 0.01). The utilization of PS resulted in decreased feedlot period (FP; < 0.01), increased ADG ( < 0.05), decreased DMI ( < 0.01), and consequently better FC ( < 0.01). Diet with PS decreased the intake of ADF ( < 0.01). There was interaction between the roughage to concentrate ratio and soybean, wherein the diet with 50% of roughage and WS provided increased intake of NDF ( < 0.05). The use of thermally processed soybean provided better performance of lambs, and when this feed is associated with higher concentrate proportion, it reduces the intake of fibrous fraction of the diet.
... Continuous decline in productivity of pasturelands and increased demand for mutton forced sheep producers to switch from the traditional ranging to more intensive production systems based on concentrate feed with locally produced barley grain as the principal energy source. It is well documented that barley starch is quickly fermented (Horadagoda et al., 2008) which could lead to increased rumen dysfunctions such as acidosis (Galyean and Rivera, 2003). Extensive research has also shown that feeding a mixture of cereal grains of differing fermentation rates could reduce excessive rumen VFA production, preventing rapid drop in ruminal pH resulting in better rumen function and animal performance (Allen, 1997;Khorasani et al., 2001;Haddad and Nasr, 2007;Lehmann and Meeske, 2007). ...
This study investigated the effects of substituting barley (B) with sorghum (S) on site and extent of in vivo disappearance of dry matter (DM), starch and nitrogen in the gastro-intestinal tract (GIT), microbial protein synthesis and growth in finishing lambs. 18 male Iranian Baluchi lambs were randomly allocated to three dietary treatments in a complete randomized design (CRD). Dietary grain treatments were: barley (B) as control, barley: sorghum (BS) (in equal amount) and sorghum (S). At the end of the feeding trial, the lambs were euthanized and digesta contents in the different sections of the GIT were collected to determine DM, starch and nitrogen disappearance. Starch intake of lambs on barley (B) diet was lower than those fed S and BS but lambs on B diet had higher (P<0.05) ruminal DM content and starch disappearance resulting in lower (P<0.05) ruminal pH than those fed diets containing sorghum. Although lambs on B diet had higher (P<0.05) volatile fatty acids (VFA) concentration in the rumen, highest ruminal microbial protein synthesis was recorded in lambs fed BS diet, presumably due to the more synchronized release of energy and nitrogen together with the higher rumen pH appropriate for microbial growth. Although a higher (P<0.05) outflow rate (g/d) of starch into the small intestine was observed for high sorghum (S) diet than the BS and control (B) diets, lambs on S diet had the lowest microbial-N flow to small intestine, resulting in the lowest N and starch digestibility in the small intestine and total track. There was a clear positive relationship between microbial N (MN) synthesis and starch disappearance in the small intestine, with BS lambs producing the highest and S lambs lowest MN yield (32.2 and 24.1 g/d, respectively) and corresponding starch disappearance was 0.87 and 0.58, respectively. The majority of the post-ruminal nutrients (DM, N and starch) were hydrolyzed in the distal-duodenum and anterior segments of jejunum. It can be concluded that substitution of barley with 0.50 sorghum increased outflow of starch from the rumen, enhanced starch digestibility and absorption in the small intestine and resulted in higher growth rate as evident by the higher average daily gain (ADG) and more efficient feed conversion ratio (FCR) recorded for lambs on the BS diet.
... Korkeiden väkirehutasojen tiedetään lypsylehmillä ja kasvavilla lihanaudoilla aiheuttavan pötsin happamuutta, josta voi pahimmillaan seurata merkittäviä terveys-, tuotos-ja hyvinvointiongelmia (mm. rehun syönnin väheneminen, juoksutusmahasairaudet, ongelmat jalkaterveydessä) (Nocek 1997, Galyean & Rivera 2003, Krause & Oetzel 2006. Tämän kirjallisuusselvityksen tarkoituksena oli kerätä tutkimustietoa eri väkirehuvaihtoehtojen käytön vaikutuksista vasikoiden tuotokseen ja terveyteen. ...
... rumen acidosis) due to a high starch load (Krause and Oetzel 2006). Further, rumen acidosis is known to be related to diseases such as ruminitis, rumen paraketosis, liver abscesses, laminitis and bloat (Nocek 1997, Galyean and Rivera 2003, Krause and Oetzel 2006. Due to a more stable rumen pH throughout the day it can be expected that compared to separate feeding TMR could reduce the risk of rumen acidosis and thereby improve the performance of the growing cattle fed high concentrate proportions. ...
A randomised complete block design was used to study the effects on animal performance of (1) the increasing level of supplementary concentrate with grass silage (GS), and (2) feeding GS and concentrates separately or as a total mixed ration (TMR). A feeding experiment comprised 32 dairy bulls with average initial live weight of 145 kg. The feeding treatments were: (1) GS (660 g kg-1 dry matter intake) plus medium level of rolled barley (330) offered separately, (2) GS (660) plus medium level of rolled barley (330) offered as TMR, (3) GS (330) plus high level of rolled barley (660) offered separately, and (4) GS (330) plus high level of rolled barley (660) offered as TMR. During the experiment (398 days) the bulls were fed ad libitum either GS or TMR. The increasing concentrate level increased energy intake, carcass gain and dressing proportion of the bulls but had no effects on carcass conformation or fat score. TMR feeding had no effects on carcass gain, dressing proportion, carcass conformation or fat score but increased dry matter and energy intake compared to the separate feeding.
Background and objectives: Barley as native cereal is the single source of
carbohydrate in fattening sheep. But barley causes some problems due to the fast
degradation in the rumen like acidosis and decrease in growth performance. So the
replacement of barley with another cereal like corn is necessary because corn has
slow degradability in the rumen. On the other hand, any change in the ration
composition has economical and financial effects in addition to the nutritional
effects. Ignoring these financial and economic effects in decision making about the
ration composition or changing it, could results in negative consequences. Different
ration compositions could simultaneously have different cost and revenue effects
and eventually different profitability consequences.
Materials and methods: This study has tried to investigate all positive and negative
economic consequences of replacement barley with different processed corn in
fattening lambs. For this purpose, the used feeds in fattening period were balanced
based on the experimental treatments with fixed quantity of protein and energy and
7 treatments/diets including 1) 100% Barley, 2) 50%:50% Barley & Grinding
Corn, 3) 100% Grinding Corn, 4) 50%:50% Barley & Steam Flaking Corn, 5)
100% Steam Flaking Corn, 6) 50%:50% Barley & Pelleting Corn and 7) 100%
Pelleting Corn. Every treatment included five lambs and each of 35 lambs was
individually experimented during 84 days.
Results: The results indicated that the rations control treatment and 100% steam
flaking corn respectively have the least and the most cost increase for all periods.
Also, the rations control treatment and 100% pelleting corn respectively have the
least and the most revenue increase for all periods.
Conclusion: Totally, and based on the partial budgeting results the rations 100%
steam flaking corn and 100% pelleting corn respectively have the least and the
most effects on relative profitability for all periods.
Lactic acid bacteria (LAB) selected on the basis of probiotic characteristics were administered to beef feedlot catlle and the effect on body condition/growth and nutritional-metabolic status as well as on E. coli O157:H7 fecal shedding, were investigated. A feeding trials involving 126 steers were used to evaluate the effects of Lactobacillus acidophilus CRL2074, Limosilactobacillus fermentum CRL2085 and Limosilactobacillus mucosae CRL2069 and their combinations (5 different probiotic groups and control) when 107-108 CFU/animal of each probiotic group were in-feed supplemented. Cattle were fed a high energy corn-based diet (16 to 88%) and samples from each animal were taken at 0, 40, 104 and 163 days. In general, animals body condition and sensorium state showed optimal muscle-skeletal development and behavioral adaption to confinement; no nasal/eye discharges and diarrheic feces were observed. The nutritional performance of the steers revealed a steady increase of biometric parameters and weight. Animals supplied with L. mucosae CRL2069 for 104 days reached the maximum mean live weight (343.2 kg), whereas the greatest weight daily gain (1.27 ± 0.16 Kg/day) was obtained when CRL2069 and its combination with L. fermentum CRL2085 (1.26 ± 0.11 kg/day) were administered during the complete fattening cycle. With several exceptions, bovine cattle blood and serum parameters showed values within referential ranges. As a preharvest strategy to reduce Escherichia coli O157:H7 in cattle feces, CRL2085 administered during 40 days decreased pathogen shedding with a reduction of 43% during the feeding period. L. fermentum CRL2085 and L. mucosae CRL2069 show promise for feedlot cattle feeding supplementation to improve metabolic-nutritional status, overall productive performance and to reduce E. coli O157:H7 shedding, thus decreasing contamination chances of meat food products.
Two experiments were performed to evaluate the effects of bismuth subsalicylate (BSS) and calcium-ammonium nitrate (CAN) on in vitro ruminal fermentation, growth, apparent total tract digestibility of nutrients, liver mineral concentration, and carcass quality of beef cattle. In Exp. 1, 4 ruminally cannulated steers [520 ± 30 kg body weight (BW)] were used as donors to perform a batch culture and an in vitro organic matter digestibility (IVOMD) procedure. Treatments were arranged in a 2 × 2 factorial with factors being BSS [0 or 0.33% of substrate dry matter (DM)] and CAN (0 or 2.22% of substrate DM). In Exp. 2, 200 Angus-crossbred steers (385 ± 27 kg BW) were blocked by BW and allocated to 50 pens (4 steers/pen) in a randomized complete block design with a 2 × 2 + 1 factorial arrangement of treatments. Factors included BSS (0 or 0.33% of the diet DM) and non-protein nitrogen (NPN) source [urea or encapsulated CAN (eCAN) included at 0.68 or 2.0% of the diet, respectively] with 0.28% ruminally available S (RAS). A low S diet was included as a positive control containing urea (0.68% of DM) and 0.14% RAS. For Exp. 1, data were analyzed using the MIXED procedure of SAS with the fixed effects of BSS, CAN, BSS × CAN, and the random effect of donor. For Exp. 2, the MIXED procedure of SAS was used for continuous variables and the GLIMMIX procedure for categorical data. For Exp. 1, no differences (P > 0.230) were observed for IVOMD. There was a tendency (P = 0.055) for an interaction regarding H2S production. Acetate:propionate increased (P = 0.003) with the addition of CAN. In Exp. 2, there was a NPN source effect (P = 0.032) where steers consuming urea had greater carcass-adjusted final shrunk BW than those consuming eCAN. Intake of DM (P < 0.001) and carcass-adjusted average daily gain (P = 0.024) were reduced by eCAN; however, it did not affect (P = 0.650) carcass-adjusted feed efficiency. Steers consuming urea had greater (P = 0.032) hot carcass weight, and a BSS × NPN interaction (P = 0.019) was observed on calculated yield grade. Apparent absorption of S decreased (P < 0.001) with the addition of BSS. Final liver Cu concentration was reduced (P = 0.042) by 58% in cattle fed BSS, indicating that BSS may decrease Cu absorption and storage in the liver. The results observed in this experiment indicate that BSS does not have negative effects on feedlot steer performance whereas CAN may hinder performance of steers fed finishing diets.
Objectives
Measurement of ruminal pH throughout a 148‐day feeding period in cattle fed commercial diets and to relate this to feed intake, growth rate and feed conversion ratio. Factors contributing to variation in rumen pH, including meal frequency, duration and weight, and, total daily intake, were also evaluated.
Methods
Forty‐eight cattle were randomly allocated to two pens and 12 randomly selected from each pen had rumen pH monitoring boli inserted. Ruminal pH was measured every 10 min and feed intake was measured continually. The cattle were fed a commercial feedlot diet for 148 days and weighed into and out of the feedlot to measure growth rate and to calculate feed conversion ratio. Cattle from both pens were registered to collect individual feed intake data using the GrowSafe® feed management system.
Results
Mean ruminal pH decreased with days on feed. Mean daily dry matter intake was the major contributor to greater average daily gain and lower ruminal pH. Lower mean ruminal pH was associated with greater average daily gain and lower feed conversion ratio, where it remained above the threshold of 5.6. There was no association between ruminal pH and average daily gain or feed conversion ratio for mean ruminal pH below 5.6.
Conclusions
Ruminal acidosis can occur at any time during the feeding period, and the risk could be greater as days on feed increase. Feedlot production outcomes are not improved by ruminal pH depression below the threshold of 5.6.
Foi avaliado o efeito da adição de cultura de leveduras vivas (Saccharomyces cerevisiae, cepa 1026), da monensina e da combinação dos dois aditivos em dietas de alto concentrado, sobre as características de desempenho de novilhos confinados e sobre a digestibilidade aparente da dieta. Novilhos Nelore (339 kg PV, 20 meses de idade, n= 72) foram alimentados por 84 dias com uma dieta basal (2,58 Mcal EM/kg MS, 14% PB) sem aditivos (controle) ou suplementada com levedura (0,6 g de Beef Sacc®/kg de matéria seca), monensina (0,3 g de Rumensin®/kg de matéria seca) ou a adição de ambos aditivos para avaliar o desempenho em confinamento por meio da mensuração individual do consumo, ganho de peso e medidas de ultra-som da espessura de gordura subcutânea nos músculos Longissimus (12ª costela) e Biceps femoris. Outros quatro novilhos foram designados aleatoriamente aos tratamentos seguindo um delineamento em quadrado latino a fim de determinar os efeitos dos tratamentos sobre a digestibilidade aparente da matéria seca, proteína bruta, fibra em detergente neutro e ácido da dieta. Não houve efeitos dos aditivos sobre o consumo de matéria seca e na taxa de aumento da espessura de gordura subcutânea e em área do músculo Longissimus, entretanto, a levedura tendeu a diminuir o ganho de peso médio diário e aumentar a conversão alimentar (p0,10). A adição de leveduras vivas, monensina ou da combinação de ambos pode não ser importante sobre a terminação de bovinos de corte confinados com dieta de alto concentrado.
Ruminal acidosis in ruminants is a metabolic disorder of gastrointestinal origin that occurs in animals with a high feed intake of cereal grains diets, which affect the performance. According to clinical manifestations it can be classified as: a) acute lactic acidosis with prolonged exposure to ruminal pH ≤ 5.0, triggering a systemic acidosis, with clinical manifestations and changes in biochemical patterns, starting the first twelve hours of ruminal acidosis and it takes 48 to 120 hours to reestablish, b) subacute ruminal acidosis (SARA), it has no clinical manifestations, rumen pH decreases in a range of 5.5 to 5.0 and is held for 111 to 180 minutes in 24 hours, this decrease causes an imbalance in the ruminal metabolism, as well as the fluid balance. Ruminal acidosis can be prevented by adding sodium bicarbonate to the ration, or zootechnic additives such as Saccharomyces cereviseae and Megasphaera elsdenii as well as essential oils (cinnamaldehyde and eugenol). It is also important to consider the forage/concentrate ratio, the forage particle size, the NDF content of the ration, as well as the cereal's rate of degradation in the rumen. The objective of this review was to address the ruminal acidosis pathophysiology, its effects on animal welfare and control strategies to minimise the detrimental impact on animal production.
Ruminal acidosis and ruminal bloat represent the most common digestive disorders in feedlot cattle. Ruminants are uniquely adapted to digest and metabolize a large range of feedstuffs. Although cattle have the ability to handle various feedstuffs, disorders associated with altered ruminal fermentation can occur. Proper ruminal microorganism adaptation and a consistent substrate (ration) help prevent digestive disorders. Feed bunk management, sufficient ration fiber, consistent feed milling, and appropriate response to abnormal weather are additional factors important in prevention of digestive disorders. When digestive disorders are suspected, timely diagnosis is imperative.
The aim of this study was to evaluate the effects of two dietary selenium (Se) sources in dairy goat's milk and cheese. Twentyone goats were allocated to 3 dietary treatments: control (C) with 0.07 mg of Se/kg dry matter (DM); Se yeast (SeY) with 0.14 mg of total Se/kg DM; and sodium selenite (SeNa) with 0.14 mg of total Se/kg DM supplementation. Individual blood and milk samples were collected to determine the Se content. Three cheese wheels were made from each group at three different time, and the Se content was determined. The enumeration of dairy microorganisms was also performed. The SeY group showed a significantly higher milk Se content (P<0.05) than the SeNa group with 44.71 vs 39.29 μg/l, respectively. Both values were also significantly higher (P<0.01) than that of the group C (31.19 μg/l). The SeY group showed a significantly higher Se carryover value (31.29%, P<0.05) than the SeNa group (26.95%). Both values were significantly (P<0.01) lower than in the C group (49.66%). Significant differences were also observed in cheese Se content among the 3 groups. The average Se content in cheeses from groups C, SeY, SeNa was 230 μg/kg, 353 μg/kg and 306 μg/kg, respectively. Se yeast supplementation influenced Se concentration in goat's milk and cheese but, unlike other authors, we also observed an increase of Se concentration in milk and cheese supplemented with SeNa, although to a smaller extent. Our results indicate that Se yeast supplementation seems to be the best fortification source for dairy goat's products. In several countries the selenium intake is considered to be low in the human diet, the consumption of Se-enriched products could represent a good way to prevent the deficit in the Se intake currently reported in many countries.
Ruminants are herbivores that have developed themselves in biosphere in order to consume forages (grasses and legumes), which are characterized by the high content of cell wall; although there are variations related to ruminants’ species regarding their capacity to select plants with smaller contents of these compounds (Van Soest et al. 1991). The intake of this type of diet keeps the reticulum-rumen (main digestive compartment of these animals) with a set of physical and chemical characteristics that are considered appropriate to maintain the animal’s ruminal microbiota and health. However, due to the need to increase (beef and milk) production, ruminants have been subjected to different diet conditions, from those that they evolved consuming, which may contain large amounts of carbohydrates that quickly ferment in the rumen and cause a series of digestive and metabolic disorders like ruminal and metabolic acidosis, rumenitis, bloat, liver abscesses and laminitis (González et al. 2012).
Sulphur is an essential element for the metabolism of ruminant animals. However, high dietary concentrations of sulphur are potentially harmful. The purpose of this study was to measure the forage and water sulphur content in samples from 45 beef herds from the La Araucanía, Los Ríos y Los Lagos regions of Chile. Additionally, ruminal gas hydrogen sulphide (H 2S) concentrations were obtained from 5 animals on each farm. Samples were collected during the spring 2008 and summer 2009. Pasture sulphur content was 1,482 ± 592 ppm in the spring and 1,471 ± 448 ppm in the summer. Water sulphur concentrations in all farms was < 1.5 ppm each season. Ruminal gas H 2S concentrations in animals was 273 ± 187.5 ppm and 245.4 ± 173 ppm in spring and summer, respectively. Positive and significant correlations were found between pasture sulphur content and ruminal H2S concentration for both periods. Estimated total sulphur intake considering pastures and water was < 0.2% sulfur on a dry matter basis. The results of this study suggest that forage and water sulphur concentrations in Southern Chile do not represent a potential risk of intoxication in grazing beef cattle.
The onset of displaced abomasum （DA） becomes increasingly more frequent, especially at feeder stock farms in Japan. However, no detailed investigations with a focus on DA including left DA （LDA） and right DA （RDA） have been performed in beef cattle to date. To elucidate the pathogenesis, proposed mechanism, and prognostic judgment, the current status of DA was first assessed based on retrospective reports from Miyagi prefecture, a southern Tohoku region in Japan. Next, the breed-related differences in LDA were examined between the beef cattle, namely, Japanese Black （JB） cattle and crosses （F1） of JB and Holstein dairy cattle, in a mega-farm at Miyagi. Moreover, changes in clinical signs, blood examination, and plasma and serum biochemistries were studied using F1 cattle with LDA together with analyses of the abomasal fluid composition. Finally, specific prognostic items were explored before and after surgery.In Chapter Ⅰ, to examine the occurrence and clinical feature in beef cattle with LDA and RDA, the cumulative data were retrospectively analyzed. The age （15〜17 months） at onset of DA in beef cattle was in good agreement with the age at onset of reduced serum vitamin A concentrations. This implies that long-term feeding of a vitamin A-deficient diet, which is carried out to facilitate the quality of marbled meats in general, may trigger the occurrence of DA. Additionally, the incidence of LDA was considerably higher than that of RDA. However, mortality in beef cattle with RDA was significantly higher than that in those with LDA. This was presumably due to complications such as hepatitis and bronchitis and imbalances in serum electrolytes in beef cattle with RDA. The medical treatment times were also significantly higher in beef cattle with RDA than in those with LDA. Surgical repositioning was shown to be the best way for the treatment of DA. In Chapter Ⅱ, to ascertain the breed-related difference between JB and F1 cattle with LDA, clinical signs, blood examination, and serum biochemistry were examined on the first day of onset. Statistically significant differences in serum biochemistry items were much greater in F1 cattle than in JB cattle, because F1 cattle were given the vitamin A-deficient diet with a high starch component for a long period of time starting from a young age. In fact, F1 cattle with LDA had significantly lower serum vitamin A levels than did JB cattle with LDA. Abomasal pH in F1 cattle with LDA was significantly lower than that in healthy cattle, and Pseudomonas spp, Clostridium spp and Candida spp was present in the abomasal fluid, owing to the accelerated influx of ruminal fluid into the abomasum. The findings demonstrate that F1 cattle with LDA may develop vitamin A deficiency due to maldigestion of starch, leading to high acidic abomasal fluid.In Chapter Ⅲ, to identify specific item for the prognostic judgment in F1 cattle with LDA, changes in plasma and serum biochemistries were examined before and after surgery. The cattle were divided into three groups; the healthy group, poor prognostic group and bad prognostic group. High plasma glucose and low serum insulin concentrations were observed either before or after surgery only in the poor prognostic group. In the glucose tolerance test, lower serum insulin and higher plasma glucose were noted 60 min and 90 min, respectively, after the glucose loading in F1 cattle with LDA than in healthy cattle. The mechanism by which these events occurred may involve dysfunction of the pancreatic β cells, leading to lowered insulin release in response to glucose. The results suggest that the measurement of plasma glucose and serum insulin before and after surgery is a useful and expedient tool for diagnosing LDA in F1 cattle.
The ruminants do not directly compete with human beings for food resources, unlike simple-stomach animals, such as poultry or swine. However, if high levels of animal productivity are necessary, forage alone cannot sustain it. Thus, it is necessary to feed ruminants with grains and/or coproduct agricultural production units. Digestive disorders are the second most commonly reported health issues in North American and Brazilian feedlot operations, while respiratory issues tend to rank toward the top of the list of health problems. Ruminal fermentation is a result of fi ne-tuned cooperation between the host animal and the rumen microorganisms. Rumen provides an optimum environment for microbial population cultivation while fermentation end products serve as an energy source and microbes supply high-quality protein for the host animal. The production of end products differs according to the diet consumed by the animal, mainly due to microorganism carbohydrate preferences and affinity. Besides being the most studied digestive disorder in cattle, ruminal acidosis still presents blind spots. The fi rst intriguing fact is individual susceptibility. If one challenges animals from same herd and similar background with a high-concentrate diet protocol, animals will present a range of acidosis symptoms, ranging from no symptoms to moderate and even severe ruminal acidosis within the same feeding period. Further studies should be conducted to determine whether the differences in acidosis symptoms in one herd are based on behavior, physiological, microbial, or multifactorial effects.
Whereas its acute form is now rare, ruminal acidosis is increasing in intensive production systems in its latent form, more discrete but affecting a significant number of animals with negative financial impacts. Acute ruminal acidosis results from the accidental overconsumption of highly fermentable carbohydrates. Their fermentation conducts to a strong drop in ruminal pH (values lower than 5) related to lactate accumulation and to the decrease in the diversity of the microbial ecosystem (protozoa, bacteria) to the profit of a lactate-producing, acido-tolerant bacterial population. Latent acidosis occurs more especially during feed transitions towards diets with high energy density, and is a status of a more or less frequent or transitory imbalance. The pH fall, near to lower physiological values (mean pH between 5 and 6.25), is not related to lactate accumulation, but to that of volatile fatty acids. The acetate proportion decreases in relation to the fall of cellulolytic activity. For a moderated pH fall, the protozoa population increases and fermentations are directed towards butyrate. For lower pH, the protozoa population decreases, compensated for by an increase in amylolytic bacteria, with a propionic fermentative pattern. These ruminal events can have physio-pathological consequences in the digestive area (inhibition of ruminal motricity, diarrhoea, lesions of the ruminal wall...), by metabolic disorders or by infectious and locomotor complications. The negative consequences on performances are effective but very difficult to quantify. Indeed, acidotic diets are rich in concentrates and result in high intake and performances. Acidotic status could involve transitory decreases and irregularity in intake and productions.
This study was conducted to evaluate the effects of feeding a processed barley/canola meal pellet on feedlot performance and carcass quality of feedlot steers. Cross-bred steers (N=350) weighing 285±22kg were assigned to 1 of 12 pens and fed either pelleted (PB) or rolled (RB) barley as the concentrate. During backgrounding, cattle were fed a diet that contained 41% PB or RB based-concentrate (DM basis), which consisted of 85% barley and 15% canola meal. During finishing the diet contained 86% concentrate (DM basis), which consisted of 94% pelleted or rolled barley and 6% canola meal. Data collection included daily pen feed intake, individual body weights, ultrasound backfat (USBF) and longissimus dorsi (USLD) area measurements. Carcass data included weight, dressing percentage, marbling and liver abscess scores. Carcass fat, lean and bone percentage, fat color, and l. dorsi intramuscular fat content and fatty acid profile were determined on eight-bone rib samples from 20 randomly selected steers from each treatment. Steers fed the PB had similar ADG during backgrounding (1.29 vs. 1.23 kg d -1; P=0.30); however, during finishing (1.80 vs. 2.00 kg d -1; P <0.01) and for the total trial (1.60vs. 1.70kg d -1; P <0.01), daily gains were greater for cattle fed RB. As a result, cattle fed PB were on feed for 10 d longer (P=0.01) than RB fed cattle. DMI was lower (P <0.01) for cattle fed PB throughout the trial. Feed conversion (kg feed:kg gain) was superior for the group fed the PB during finishing (6.03 vs. 6.21; P=0.01) and the total trial (6.27 vs. 6.64; P <0.01). Both diets produced similar carcasses, but inter-muscular fat percentage was higher (P=0.03) for the RB group (60.0 vs. 57.4%). Minor differences in fatty acid profile were noted with PB fed steers having higher (P <0.01) levels of C17:0, C18:3n-3 and C20:4n-6. Results from this study indicate that PB can be used effectively in growing programs, however, further research is required to better manage feeding of PB products to avoid DMI reductions most likely due to sub-acute rumen acidosis.
Roughage plays a vital role in ruminant diets. This review considered the effects of roughage in diets for newly received cattle, the physical and physiological effects of roughage in feedlot cattle diets, the use of NDF as a means of assessing the roughage value for feedlot cattle, and potential alternatives to traditional roughages and roughage feeding practices. In newly received, stressed cattle, a meta-analysis from trials conducted at a single location indicated that receiving period morbidity (percentage of cattle pulled and treated for bovine respiratory disease) decreased slightly as roughage level increased. Nonetheless, increasing roughage level decreased receiving period ADG and G:F; therefore, unless cattle are able to compensate at later stages of the feeding period, the small decrease in morbidity with added roughage might be offset by decreased performance. For growing-finishing cattle, a meta-analysis indicated that intakes of DM and NEg increased linearly as dietary NDF concentration increased over a range of approximately 7.5 to 35% NDF. Both roughage and total dietary NDF were effective for determining the relative value of different roughage sources to achieve equal DMI in beef feedlot diets. Fiber in by-product feeds, such as wet corn gluten feed and distillers grains, dilute grain starch and might have the ability to substitute, in part, for traditional roughage; however, NDF concentration of these by-products is not an effective measure of roughage equivalency. Altering methods of roughage delivery, such as feeding a lower level of dietary roughage with intermittent delivery of additional dietary roughage or coarser forms of roughages that stimulate chewing or alter digesta passage rate, might provide a means of decreasing overall roughage use without compromising animal health and performance, but research is needed to test the merits of these approaches. Significant research questions remain to be addressed before we fully understand the chemical, physiological, and physical roles of roughage in feedlot diets.
Processed corn or sorghum grain was sieved to obtain particle size fractions and incubated ruminally, by nylon bag technique, to assess the effect of particle size and processing on dry matter and starch disappearance. Dry rolle corn, sieved to obtain fractions with mean particle sizes of 6,000, 3,000, 1,500, and 750 μm and incubated for 2, 4, 6, or 8 h, showed little difference in dry matter disappearance between 6,000 (5.0%) and 3,000, (4.5%) μm corn (averaged over time), but dry matter disappearance increased as particle size fraction was reduced further to means of 1,500 (9.7%) and 750 (18.4%) μm. Starch disappearance displayed a similar pattern. Low dry matter disappearance reflects short incubation times. In a second experiment, corn, steam flaked and then ground, showed much higher dry matter and starch disappearance within each particle size fraction and time than dry ground corn, with particle size appearing much less important in steam flaked corn. In a comparison of ground, high moisture harvested, ensiled corn and dry ground corn, dry matter and starch disappearance were greater in fractions with smaller particles. Moreover, dry matter and starch disappearance were much lower within each particle size in dry ground than high moisture corn. When dry rolled corn was incubated longer (12 and 24 h), average dry matter disappearance increased in fractions with smaller particles as during shorter periods. Particle size had similar effects in sorghum grain.
Three trials were conducted to evaluate the efficacy of laidlomycin propionate (LP) to reduce the incidence and severity of ruminal acidosis in cattle fed high-grain finishing diets. In each trial, LP was fed at 0, 6, or 12 mg/kg of diet DM. In two acidosis-challenge trials, ruminally fistulated steers were fed (DM basis) a 50% concentrate diet and then fed a 95% concentrate diet at a specific intake (2.75% BW) or steers were dosed intraruminally with a 100% concentrate diet. Laidlomycin propionate did not alter ruminal pH or total acid concentrations, but in Trial 1 the 6 mg/kg level altered (P < .10) the molar proportions of the acids, increasing total ruminal VFA and decreasing ruminal lactate. In Trial 3, a finishing trial, LP reduced (P < .10) intake day-to-day variation of individually fed steers during a 13-d adaptation period from a 65 to a 100% concentrate diet, suggesting reduced incidence of subacute acidosis. Feed intake was lower (P < .05) during the first 13 d of the trial due to LP but was not affected over the entire trial. Laidlomycin propionate improved feed efficiency (gain/feed) when calculated on a live weight basis (linear, P = .05) or carcass weight basis (linear, P = .20). Laidlomycin propionate does not prevent ruminal acidosis, but it may reduce the severity of ruminal acidosis during adaptation to a 100% concentrate diet.
Bovine lactic acidosis syndrome is associated with large increases of lactic acid in the rumen, which result from diets that are high in ruminally available carbohydrates, or forage that is low in effective fiber, or both. The syndrome involves two separate anatomical areas, the gastrointestinal tract and body fluids, and is related to the rate and extent of lactic acid production, utilization, and absorption. Clinical manifestations range from loss of appetite to death. Lactic acid accumulates in the rumen when the bacteria that synthesize lactic acid outnumber those that utilize lactic acid. The systemic impact of acidosis may have several physiological implications, including laminitis, a diffuse aseptic inflammation of the laminae (corium). Although a nutritional basis for the disease exists, etiology includes a multitude of interactive factors, such as metabolic and digestive disorders, postpartum stress, and localized trauma, which lead to the release of vasoactive substances that trigger mechanisms that cause degenerative changes in the foot. The severity of laminitis is related to the frequency, intensity, and duration of systemic acidotic insults on the mechanisms responsible for the release of vasoactive substance. The critical link between acidosis and laminitis appears to be associated with a persistent hypoperfusion, which results in ischemia in the digit. Management of acidosis is critical in preventing laminitis. High producing dairy herds attempting to maximize energy intake are continually confronted with subclinical acidosis and laminitis. Management of feeding and husbandry practices can be implemented to reduce incidence of disease.
Mortality from digestive diseases in feedlot cattle is second only to that from respiratory diseases. Acidosis and bloat are the major digestive disorders and are likely to continue because of ongoing attempts to improve the efficiency of beef production by feeding more grain and less roughage. Subacute acidosis is probably the most prevalent form of acidosis in feedlots and is difficult to diagnose because of the absence of overt clinical signs. Ruminal changes in subacute acidosis are not as dramatic as those in acute acidosis. Also, the subacute form is not severe enough to induce systemic acidosis. Ruminal acidosis is also a predisposing factor for many other ailments in feedlot cattle such as laminitis, polioencephalomalacia, sudden death syndrome, and liver abscesses. Control of acidosis is achieved largely by sound nutritional management. Antimicrobial compounds (i.e., ionophores and nonionophores), have become management tools to impart stability to ruminal fermentation, modulate feed intake, and control acidosis. Bloat in feedlot cattle can be of free gas or frothy type. Frothy bloat is more common but is rarely the reason for bloat deaths. The economic impact of bloat results mainly from decreased animal performance. The etiology of bloat is complex and is the result of interactions between three major groups of factors: animal, dietary, and microbial. Presently, an effective method to control frothy bloat in feedlot cattle is not available. Ionophore antibiotics, particularly monensin, have been shown to be effective in decreasing the incidence and severity of bloat in cattle.