We determine optimal stocker strategies based on calving season, herd size, and the number of days of retention before marketing weaned calves. We estimate a hedonic pricing model for feeder cattle and incorporate this into a simulation model that considers the variability of cattle prices and feed costs. The profit and utility-maximizing decision for fall calving herd would be to retain weaned calves for 150-day postweaning. The producer marketing spring-born calves would prefer to sell these calves at weaning. The results are being utilized by extension to aid cattle producers in reducing their feed costs and increasing their profits.

The aim of this study was to evaluate the effect of genotype–environment interaction (GEI) on the yearling weight of Simmental cattle raised in Brazil, including the sex dimorphism in reaction norm models. The environmental gradient (EG) was formed using the average weight at 365 days of the contemporary groups. Two approaches were adopted in this study to evaluate reaction norms for weight at 365 days: a single-trait model and a multitrait model in which the data for males and females were separated and considered different traits for the analysis of sexual dimorphism. The genetic parameters were estimated using the Bayesian inference and Gibbs sampling. Analysis of the trend of the heritability estimates obtained with the single-trait model along the EG revealed a value of about 0.33 (EG: −21) in the worst environments, which decreased in the intermediate environments and reached a value of 0.24 in EG: −8, with a subsequent increase of the estimates up to 0.51 in EG: +23. Using the multitrait model, similar trends were observed for the heritability estimates, which ranged from 0.25 to 0.54 for males and from 0.23 to 0.50 for females. The results show that the weight of Simmental cattle raised in the tropics is influenced by GEI and greater genetic progress could be obtained by selecting better environments. However, no significant differences in the response to most environmental changes were observed between sexes and there is only evidence of genetic heteroscedasticity in environments with lower production levels.

Six pairs of steers were allowed to choose between two types of floors in a paired choice test. The four floors tested were a fully slatted floor, a fully slatted floor covered with rubber mats, a solid floor with sawdust bedding, and a solid floor with straw bedding. All combinations of floor types were tested and the choices were repeated eight times, using naïve animals. The animals were allowed 17 days to habituate, and on days 18-21 their behaviour was recorded by video for 72 hours. Straw was the most preferred floor type, followed by sawdust, then mats, and finally slats. During a second test period, rubber mats were compared with rubber strips, and no significant preferences were found.

The objective of this study was to evaluate conditions during transport and their effects on welfare and carcase bruising of beef cattle in Uruguay, a country with an extensive, pasture-based, production system. Twelve abattoirs were visited periodically during two years (2002-2003) and 448 trucks were inspected on arrival. The state of vehicle maintenance was deemed ‘unacceptable’ for the transport of animals in 16.5 (± 3.2)% of cases and most of the vehicles (99.1 [± 0.1]%) had a ‘guillotine-type’ door at the rear end. Both characteristics showed a significant association with the presence of carcase bruising. No overall significant difference was found with the year of vehicle manufacture (24.6 [± 0.2]% before 1990), the presence of rollers bars in 51.3 (± 0.1)% of the trucks on one or both sides of the doors, and the working experience of the men who transported the cattle (> 10 years). The average distance travelled with the animals loaded onto trucks was 240 (± 9) km and the mean journey length was 305 (± 7) min (5 h). A statistically significant effect of the distance travelled and the state of the roads on the occurrence of bruising was found. The use of devices to force animals to move, such as: electric prod (75%), sticks (3%), loud shouts (40%) and a combination of all of the above were positively correlated with bruising. After slaughter, carcase bruising was identified, quantified, and classified into three degrees of muscle injury. From 15,168 beef cattle observed, 60.0% (9,106) had at least one injury. Of the injured carcases, 33.1% (3,015) had one bruise, 25.1% (2,289) had two bruises, 16.2% (1,474) had three bruises and 25.6% (2,328) four or more bruises. Transporting animals in a humane fashion will reduce the amount of bruising on carcases, thereby increasing both the welfare of beef cattle and the profitability of the beef industry in Uruguay.

Livestock transport regulations in many countries require that cattle be unloaded for feed, water and rest when they are being transported long distances, but there are few evidence-based guidelines about how to most effectively manage and provide these requirements at rest stops. The aim of this study was to assess whether available feeding space at a commercial rest facility affected eating behaviour and general activity. Twenty-four trailer loads of cattle were selected for study, and each load was divided into two groups. The control group was provided ad libitum access to a single, round, hay-bale feeder. The treatment group had two round, hay-bale feeders and thus twice as much feeding space per animal. Cattle behaviour was recorded during a 5-h rest period using instantaneous scan sampling every 5 min. This was performed at the group level by counting the number of animals engaged in pre-defined activities, as well as individually by tracking a subset of focal animals from each group. Behaviour was categorised as one of the following: eating, drinking, lying, or ‘other’. Interruptions to eating were also quantified. Eating was counted as interrupted when, instead of being followed by a consecutive eating observation, it was interspersed by another behaviour. Doubling feeding space increased the mean proportion of cattle eating by 30%, decreased interruption of eating bouts and had no effect on drinking and lying behaviour. Increased access to feed has potential welfare and health benefits. These data can be used to inform standards for feeding beef cattle at rest stops during long distance travel.

One challenge with animal welfare assessment programmes is that standards that make a meaningful difference to welfare can be difficult for a broad spectrum of producers to meet, thereby preventing many from engaging at all. Global Animal Partnership's (GAP's) 5-Step™ Animal Welfare Rating Standards are unique in that they are designed as a multi-tiered system that encourages continuous welfare improvement. The 5-Step program allows for a wide variety of production models — from small farms raising fewer than 50 animals in extensive, outdoor systems to larger, indoor operations raising tens of millions — and allows producers to move up the Steps as they choose. Each additional Step provides a four-fold benefit: the animals have improved welfare, the producer has the opportunity of greater rewards and more accurate representation of her or his farming practices, retailers can provide wider product selection to meet their customer demands, and consumers have the guarantee of ever-increasing, welfare-friendly choices as well as a transparent source of information on how their meat was raised. GAP began piloting its 5-Step program in 2008 with comprehensive on-farm/on-ranch and transport standards for meat chickens, pigs and beef cattle in an exclusive, two-year partnership with Whole Foods Market (WFM), North America's largest natural-foods grocer. The variety of farms and ranches supplying WFM provided a thorough testing ground for the programme. Chicken, pork, beef and turkey products ranging from Step 1 to Step 5+ are available regionally in WFM stores in the USA and Canada. Having successfully completed this pilot phase with WFM, GAP is now negotiating with other retailers, both restaurants and grocers, as well as further-processors, in North America and beyond. The essence of the Steps is captured by the following phrases: Step 1 — no crowding, cages or crates; Step 2 — an enriched environment; Step 3 — enhanced outdoor access; Step 4 — pasture centred; Step 5 — animal-centred: bred for the outdoors; and Step 5+ — animal-centred: entire life on the same farm. As of 1 December 2011, more than 1,740 third-party audited and certified farms and ranches are raising more than 140 million animals annually according to GAP's 5-Step Animal Welfare Rating Standards.

We investigate differences in profitability of three Aberdeen-influenced breeds, Angus, Red Angus, and American Aberdeen. Using data from North Dakota, we measure differences in birth weights, calving intervals, weaning weights, cow weights, and profitability. Weaning weights differ between breeds, setting up a trade-off between lower feed costs for smaller cows and higher revenue for larger cows. American Aberdeen-influenced cows bred to Red Angus bulls have $1–$6 per acre higher returns than Angus or Red Angus-influenced cows. Aberdeen sires have the lowest returning calves.

We estimate a hedonic pricing model to determine producers’ value for bull expected progeny differences (EPDs), genomic-enhanced EPDs, and phenotypic traits. Birth weight EPD, ribeye area EPD, sale weight, age, frame score, and other factors had a statistically significant impact on bull prices. GE-EPDs were not associated with a change in the bull sales prices expect for weaned calf value and birth weight EPDs. Including weaned calf value and GE-EPDs in a bull hedonic pricing model provides a unique contribution. The results from this work will inform educational programming for bull purchasers on using new economic selection indices and GE-EPDs.

This study determines which factors are associated with the use of rotational grazing and the frequency with which Tennessee producers rotate cattle during the summer months. Survey data were used to estimate an ordered response model with sample selection. Most respondents used rotational grazing, and the most frequent rotational schedule was rotating cattle one to two times per month. Factors including labor, capital, knowledge, and water availability influenced the use of rotational grazing and the frequency of rotating cattle. The insights from this study can inform the development of incentives to promote more intensive use of rotational grazing.

This study aims to determine the effects of dietary crude protein (CP) content of early-weaned calves; and the influence of flint maize processing methods on intake, total tract nutrient digestibilities and performance of Nellore heifer calves. Fifteen early-weaned Nellore female calves (4 ± 0.5 months; 108 ± 13.1 kg) were used. In phase 1, animals were fed one of the following diets for 112 days: 130, 145 or 160 g CP/kg dry matter (DM). In phase 2, animals received one of the two diets for 84 days: 0.60 dry ground maize grain, 0.30 whole-plant maize silage plus 0.10 mineral-protein supplement or 0.90 snaplage plus 0.10 mineral-protein supplement. In phase 1, intake and digestibility of dietary components were not affected (P > 0.05) by increasing dietary CP content. Daily total urinary nitrogen (N) and urinary urea N increased (P < 0.05) in response to increasing dietary CP content. Animal performance was not affected (P > 0.05) by dietary CP content. In phase 2, maize processing methods did not affect (P > 0.05) intake and digestibility of dietary components as well as animal performance, carcase characteristics and carcase composition. Therefore, based on the current experimental condition, we conclude that dietary CP concentrations of 130 g/kg DM can be indicated for early-weaned Nellore calves. However, more studies are recommended to validate this result and to evaluate concentrations below 130 g CP/kg DM for early-weaned Nellore calves. Moreover, snaplage could be used as an exclusive fibre and energy source for finishing cattle in feedlot.

In this study it is hypothesized that there are differences between immunoglobulin G (IgG) content in colostrum from beef (Chianina, Podolica) and dairy (Holstein Friesian) cows and that variables such as breed, and parity can influence IgG content. The further objective was to determine if these factors may vary in terms of sensitivity, specificity and the cut point when data obtained with the digital Brix refractometer is compared with the gold standard radial immunodiffusion assay (RID). A total of 90 samples of first-milking colostrum were collected within 2 h after parturition. IgG concentration was determined indirectly by digital Brix refractometer and directly by RID. Results obtained by RID were compared among breed and parity. For the digital Brix refractometer, sensitivity and specificity to detect colostrum with an IgG concentration lower than 50 g/l were calculated and the optimal cut-point was selected for each breed. Samples containing less than <50 g/l IgG accounted for 15.9% of the total. Parity influenced colostral IgG concentration and beef cows had a higher mean concentration of IgG (101.1 g/l in Chianina and 90.6 g/l in Podolica) than dairy cows (71.1 g/l in Holstein Friesian) First parity Chianina cows had the highest IgG mean content (116.1 g/l). At the optimal cut-point for Brix refractometer (20%) sensitivity and specificity were 0.93 (0.84–0.97) and 0.81 (0.70–0.88), however, a breed-related cut-point could be used to reduce evaluation error. Linear regression modeling showed that refractometer data were related to RID (r = 0.78). Results obtained suggest that breed and parity can influence IgG content of colostrum and, despite the Brix refractometer being an excellent on-farm tool, a breed-based definition of optimal cut point is needed.

Assessment of behavior is a longstanding strategy to assist the diagnosis of clinical bovine respiratory disease (BRD) in beef cattle. Cattle with systemic inflammation caused by infectious pathogen(s) display predictable behavioral adaptations compared to healthy cohorts. Behavioral alterations in BRD-affected cattle include lethargy, social isolation, and anorexia. However, behavior assessment to support BRD case definition in the production setting is challenging because: (1) other bovine diseases cause behavior alterations similar to BRD; (2) cattle have inherent prey instinct to disguise sickness behavior during human evaluation; (3) labor constraints dictate very brief observation of animal behavior; and (4) traditional behavior assessment is subjective and agreement is often poor. Some of these challenges may be overcome with the use of advanced technologies that allow continuous, remote, and objective behavior assessment of individual cattle. Automated methodologies for behavior assessment include three-axis accelerometers that quantify physical behaviors, systems that document feeding/watering behavior, and triangulation systems that document spatial behavior. Each of these behavior-monitoring approaches generates unique information and may facilitate early detection of BRD compared to traditional methods. Nevertheless, adoption of behavior assessment technologies for BRD diagnosis in beef operations hinges upon improved detection, positive return on investment, and successful integration within existing BRD management practices.

Breeding values for feed intake and feed efficiency in beef cattle are generally derived indoors on high-concentrate (HC) diets. Within temperate regions of north-western Europe, however, the majority of a growing beef animal’s lifetime dietary intake comes from grazed grass and grass silage. Using 97 growing beef cattle, the objective of the current study was to assess the repeatability of both feed intake and feed efficiency across 3 successive dietary test periods comprising grass silage plus concentrates (S+C), grazed grass (GRZ) and a HC diet. Individual DM intake (DMI), DMI/kg BW and feed efficiency-related parameters, residual feed intake (RFI) and gain to feed ratio (G : F) were assessed. There was a significant correlation for DMI between the S+C and GRZ periods (r = 0.32; P < 0.01) as well as between the S+C and HC periods (r = 0.41; P < 0.001), whereas there was no association for DMI between the GRZ and HC periods. There was a significant correlation for DMI/kg BW between the S+C and GRZ periods (r = 0.33; P < 0.01) and between the S+C and HC periods (r = 0.40; P < 0.001), but there was no association for the trait between the GRZ and HC periods. There was a significant correlation for RFI between the S+C and GRZ periods (r = 0.25; P < 0.05) as well as between S+C and HC periods (r = 0.25; P < 0.05), whereas there was no association for RFI between the GRZ and HC periods. Gain to feed ratio was not correlated between any of the test periods. A secondary aspect of the study demonstrated that traits recorded in the GRZ period relating to grazing bite rate, the number of daily grazing bouts and ruminating bouts were associated with DMI (r = 0.28 to 0.42; P < 0.05 - 0.001), DMI/kg BW (r = 0.36 to 0.45; P < 0.01 - 0.001) and RFI (r = 0.31 to 0.42; P < 0.05 - 0.001). Additionally, the number of ruminating boli produced per day and per ruminating bout were associated with G : F (r = 0.28 and 0.26, respectively; P < 0.05). Results from this study demonstrate that evaluating animals for both feed intake and feed efficiency indoors on HC diets may not reflect their phenotypic performance when consuming conserved forage-based diets indoors or when grazing pasture.

Ruminants fed high-forage diets usually have a low feed efficiency, and their performances might be limited by methionine (Met) supply. However, the INRA feeding system for growing cattle does not give recommendation for this amino acid (AA). This study aimed to assess the effects of Met-balanced diets on animal performance and N metabolism in young bulls fed high-forage diets formulated at or above protein requirements. Four diets resulting from a factorial arrangement of two protein levels (Normal (13·5 % crude protein) v. High (16·2 % crude protein)) crossed with two Met concentrations (unbalanced (2·0 % of metabolisable protein) v. balanced (2·6 % of metabolisable protein)) were tested on thirty-four fattening Charolais bulls for 7 months before slaughter. Animal growth rate was greater in Met-balanced diets (+8 %; P = 0·02) with a trend for a greater impact in High v. Normal protein diets (P = 0·10). This trend was observed in lower plasma concentrations of branched-chain AA only when Met supplementation was applied to the Normal protein diet (P ≤ 0·06) suggesting another co-limiting AA at Normal protein level. Feed conversion efficiency and N use efficiency were unaffected by Met supplementation (P > 0·05). However, some plasma indicators suggested a better use of AA when High protein diets were balanced v. unbalanced in Met. The proportion of total adipose tissue in carcass increased (+5 percent units; P = 0·03), whereas that of muscle decreased on average 0·8 percent units (P = 0·05) in Met-balanced diets. Our results justify the integration of AA into dietary recommendations for growing cattle.

Protein turnover is an energy-consuming process that is essential for ensuring the maintenance of living organisms. Gold standard methods for whole-body protein turnover (WBPT) measurement have inherent drawbacks precluding their generalization for large farm animals and use during long periods. Here, we proposed a non-invasive proxy for the WBPT over a long period of time and in a large number of beef cattle. The proxy is based on the rate at which urine-N and plasma proteins are progressively depleted in terms of 15N after a slight decrease in the isotopic N composition of the diet (i.e. diet switch). We aimed to test the ability of this proxy to adequately discriminate the WBPT of 36 growing-fattening young bulls assigned to different dietary treatments known to impact the WBPT rate, with different protein contents (normal v. high) and amino acid profiles (balanced v. unbalanced in methionine). The 15N depletion rate found in plasma proteins represented their fractional synthesis rate, whereas the slow depletion rate found in urine was interpreted as a proxy of the WBPT. The proxy tested in urine suggested different WBPT values between the normal- and high-protein diets but not between the balanced and unbalanced methionine diets. In contrast, the proxy tested in plasma indicated that both dietary conditions affected the fractional synthesis rate of plasma proteins. We considered that the rate at which urine is progressively 15N-depleted following an isotopic diet switch could be proposed as a non-invasive proxy of the WBPT rate in large farm animals.

Strongyle infection is an important issue in horse breeding. It impairs horse health and performance, with young horses being the most sensitive. Strongyle control has long relied on the systematic use of chemical treatments. However, expanding anthelmintic resistance among strongyles calls for alternative options. Mixed grazing is assumed to reduce strongyle load on the pasture as the result of a dilution effect. This has been shown in small ruminants grazing with cattle, but the putative benefits of co-grazing between horses and cattle have not yet been evaluated. Here, we conducted field surveys and face-to-face interviews on 44 farms from two contrasted saddle-horse production areas, Normandy and northern Massif Central, to compare equine strongyle management practices between specialized systems and mixed horse-cattle systems. Our goals were (i) to quantify breeders’ awareness of the putative benefits associated with the co-grazing of horses and cattle, (ii) to establish whether mixed farming was associated with different strongyle management strategies and (iii) to test whether strongyle egg excretion was reduced in horses grazed with beef cattle. Every breeder relied on systematic calendar treatments, and only 8 out of the 23 mixed breeders were aware that co-grazing of horses with cattle could be used as part of their strongyle control strategy. Management practices were similar across both systems in Normandy. In Massif Central, mixed breeders formed a distinct cluster from their specialized counterparts: deworming was less frequent and stocking density was higher in mixed farms, while specialized breeders seemed more willing to integrate herd and plot management into control strategies. Faecal egg counts measured in horses from Massif Central were significantly reduced when horses were grazed with cattle. This was the result of an increased reliance on macrocyclic lactones in mixed farms (P < 0.01) and a significant dilution effect (P < 0.01). When considering a subsample of horses treated with macrocyclic lactones only, young horses grazed with cattle had 50% fewer strongyle eggs excreted in their faeces than horses grazed in equine-only pastures (P < 0.01). This is the first evidence of the benefits of mixed grazing with cattle as an alternative to control strongyle infection in horses, although this promising alternative remains largely unknown by horse breeders.

A greater understanding of the rumen microbiota and its function may help find new strategies to improve feed efficiency in cattle. This study aimed to investigate whether the cattle breed affects specific ruminal taxonomic microbial groups and functions associated with feed conversion ratio (FCR), using two genetically related Angus breeds as a model. Total RNA was extracted from 24 rumen content samples collected from purebred Black and Red Angus bulls fed the same forage diet and then subjected to metatranscriptomic analysis. Multivariate discriminant analysis (sparse partial least square discriminant analysis (sPLS-DA)) and analysis of composition of microbiomes were conducted to identify microbial signatures characterizing Black and Red Angus cattle. Our analyses revealed relationships among bacterial signatures, host breeds and FCR. Although Black and Red Angus are genetically similar, sPLS-DA detected 25 bacterial species and 10 functions that differentiated the rumen microbial signatures between those two breeds. In Black Angus, we identified bacterial taxa Chitinophaga pinensis, Clostridium stercorarium and microbial functions with large and small subunits ribosomal proteins L16 and S7 exhibiting a higher abundance in the rumen microbiome. In Red Angus, nonetheless, we identified the poorly characterized bacterial taxon Oscillibacter valericigenes with a higher abundance and pathways related to carbohydrate metabolism. Analysis of composition of microbiomes revealed that C. pinensis and C. stercorarium exhibited a higher abundance in Black Angus compared to Red Angus associated with FCR, suggesting that these bacterial species may play a key role in the feed conversion efficiency of forage-fed bulls. This study highlights how the discovery of signatures of bacterial taxa and their functions can be used to harness the full potential of the rumen microbiome in Angus cattle.

Fully slatted concrete floors are labour-efficient, cost-effective and thus common in beef cattle housing. However, the welfare of cattle accommodated on them has been questioned. The objective of this study was to evaluate the effect of floor and diet on hoof health and lying behaviours of housed dairy-origin bulls, from a mean age of 8 months to slaughter at 15.5 months old. Forty-eight bulls, which had a mean initial live weight of 212 (SD = 23.7) kg, were allocated to one of four treatments, which consisted of two floors and two diets arranged in a 2 × 2 factorial design. The floors evaluated were a fully slatted concrete floor and a fully slatted concrete floor overlaid with rubber, while the diets offered were either a high concentrate diet or a grass-silage-based diet supplemented with concentrates. The mean total duration of the study was 216 days. Floor had no significant effect on claw measurements measured on day 62 or 139. However, bulls accommodated on slats overlaid with rubber had a tendency to have a higher front toe length measured pre-slaughter than those accommodated on concrete slats (P = 0.063). Floor had no significant effect on the net growth of toes or heels during the duration of the study. The number of bruises (P < 0.01) and the bruising score (P < 0.05) were significantly higher on day 62 in bulls accommodated on fully slatted concrete floors than on concrete slats overlaid with rubber, but there was no significant effect of floor on these parameters on day 139 or at the measurement taken pre-slaughter. There was a tendency for bulls accommodated on concrete slats to have a higher probability of having sole bruising at the end of the experiment than those accommodated on slats overlaid with rubber (P = 0.052). Diet had no significant effect on toe length or heel height, number of bruises, or overall bruising score at any time point of the study. There was little evidence in the current study to suggest that bulls lying on fully slatted concrete floors could not express lying postures similar to those on concrete slats overlaid with rubber.

The aim of this study was to test the hypotheses that differences in residual feed intake (RFI) of beef steers are related to diet sorting, diet nutrient composition, energy intake and apparent digestibility. To phenotype steers for RFI, 69 weaned Angus × Hereford steers were fed individually for 56 days. A finishing diet was fed twice daily on an ad libitum basis to maintain approximately 0.5 to 1.0 kg refusals. Diet offered and refused was measured daily, and DM intakes (DMI) were calculated by difference. Body weights were recorded at 14-day intervals following an 18-h solid feed withdrawal. The residual feed intake was determined as the residual of the regression of DMI versus mid-test metabolic BW (BW0.75) and average daily gain (ADG). Particle size distributions of diet and refusals were determined using the Penn State Particle Separator to quantify diet sorting. Sampling of diet, refusals and feces were repeated in four sampling periods which occurred during weeks 2, 4, 6 and 8 of the study. Particle size distributions of refusals and diet were analyzed in weeks 2, 4 and 6, and sampling for chemical analysis of refusals and feces occurred in all four periods. Indigestible neutral detergent fiber (288 h in situ) was used as an internal marker of apparent digestibility. We conclude that preference for the intakes of particles > 19 mm and 4 to 8 mm were negatively correlated to RFI and ADG, respectively. Although steers did sort to consume a different diet composition than offered, diet sorting did not impact intake energy, digestible energy or DM digestibility.

Replacing ground maize (GM) with steam-rolled maize typically increases feed efficiency in maize-silage-based diets. However, little is known about optimal carbohydrate supplementation in sugarcane silage-based diets. The objective was to quantify the effect of partially replacing GM with steam-rolled maize (SRM) or pelleted citrus pulp (PCP) at two concentrate levels (600 or 800 g/kg DM) in sugarcane-based diets on feeding behaviour, performance and blood parameters of finishing Nellore bulls. One hundred and eight young bulls were allocated to 36 pens in a randomized block design and fed for 84 d. Feeding 800 g/kg concentrate decreased time spending eating and ruminating, but improved G:F ratio, hot carcass weight and carcass dressing, compared to 600 g/kg concentrate. Bulls fed SRM and PCP diets with 600 g/kg concentrate had lower intake compared to GM. Both final weight and average daily gain decreased when bulls were fed PCP and SRM with 600 g/kg concentrate compared to GM diets, and when fed with PCP and 800 g/kg concentrate. Substituting PCP for GM decreased gain efficiency, carcass weight, rumination time and intake efficiency, indicating that the bulls consumed less feed per hour spent eating. Substituting SRM for GM increased backfat thickness and blood urea concentration. In conclusion, the replacement of GM with PCP reduces intake and enhances selection against large particles, decreasing rumination, performance and final carcass weight and dressing. Replacement of GM with SRM increases blood urea and fat deposition, with no impact on performance.