The objective of this study was to characterize genetic relationships between growth and carcass traits measured in commercial feedlot and purebred cattle that would aid in determining the effectiveness of combined crossbred and purebred selection (CCPS) strategies for sire selection. Data included 2,183 steers and 418 heifers enrolled in the Tri-County Steer Carcass Futurity (TC). Feedlot traits evaluated were initial body weight at time of delivery (IBW) and final BW at time of harvest (FBW) and carcass backfat thickness at the 12th rib (CFAT), marbling score at the 12th rib (CMAR) and ribeye area at the12th rib (CREA). Purebred data from the American Angus Association (AAA) included records of 139,602 bulls, 130,944 heifers and 6,656 steers for weaning weight (WW); 85,702 bulls, 76,603 heifers and 1,908 steers for yearling weight (YW); and 62,752 bulls and 45,958 heifers for ultrasound measures of backfat thickness at the 12th rib (UFAT), intramuscular fat percentage at the 12th rib (UMAR) and ribeye area at the 12th rib (UREA). The genetic correlations between IBW and WW, FBW and YW, CFAT and UFAT, CMAR and UMAR, and CREA and UREA were 0.01 ° 0.21, 0.43 ° 0.22, 0.66 ° 0.19, 0.65 ° 0.17, and 0.92 ° 0.12, respectively. Regressions of TC traits on corresponding sire EPD resulted in coefficients of 0.23 ° 0.19, 0.57 ° 0.16, 0.67 ° 0.19, 93.3 ° 12.3, and 1.08 ° 0.17 for IBW, FBW, CFAT, CMAR, and CREA, respectively. Three selection indices were evaluated on the basis of relative efficiency of genetic progress toward TC goal traits. The index including AAA records on an individual sire with TC records on his progeny was most effective, thus indicating the benefit of CCPS. / Master of Science

Video Image Analysis (VIA) is a digital camera based technology that extracts relevant information from images using purpose tailored image processing software. In the present work, the VSS2000 image analysis system from E+V Technology GmbH has been used in a large lamb abattoir to determine the value of carcasses in an objective, consistent and automated way. In this thesis results are reported of several experiments conducted within the framework of two UK-funded projects. The aims of the research were (i) the calibration and validation of the VIAtechnique for the evaluation of lamb carcasses under UK abattoir conditions, with the view to scientifically examine the accuracy and precision of information from the VIA systems as the basis for a value-based marketing system, (ii) to investigate the use of VIA measurements (weights of primal meat yields and carcass dimensional measurements) in sheep breeding programmes to improve carcass and meat quality and (iii) to evaluate the potential of this technology to reward increased carcass quality associated with the use of breeding strategies based on the inclusion of a quantitative trait locus (QTL) for improved muscularity. Accuracy, precision and consistency of The Meat and Livestock Commission (MLC) carcass classification scheme, currently used in UK abattoirs to evaluate carcass quality, was compared against the VIA system in the prediction of various primal joint weights. The results highlighted the advantage of the VIA system being on average 2% more accurate (measured as coefficient of determination: R2) and 12% more precise (measured as root meat squared error: RMSE) in predicting weight of primal meat yields (leg, chump, loin, breast and shoulder) of the lamb carcasses than the MLC carcass classification scheme. The genetic analysis of VIA-based predicted primal joint weights showed substantial additive genetic variance, suggesting that their use in sheep breeding programmes could improve carcass quality either by an improvement of conformation or by an increased weight of the most valuable primal cuts, without an increase in fatness. Favourable associations between VIA primal weights and performance traits indicate that selection based on VIA traits is possible without a negative effect on average daily gain, live weight and cold carcass weight. Although computer tomography (CT) and dissection found in related studies significant effects of a Texel muscling-QTL (TM-QTL) for increased muscularity in the loin region, in the present study they could not be identified by both, the current industry carcass evaluation system for conformation and fatness and the VIA system. A calibration of the VIA system against CT measurements resulted in improved VIA prediction equations for primal meat yields and also showed a moderate potential to estimate loin muscle traits measured by CT and to detect partially the effect of the TM-QTL on these traits. The results of the research demonstrated that VIA is a consistent method to measure carcass composition and that it improved the prediction (accuracy and precision) of primal meat yields compared to the present MLC scoring system. The estimated genetic parameters for VIA primal meat yields suggested that selection for increased lean meat yield from lamb carcass measured using VIA can contribute to genetic improvement of carcass quality without increasing carcass fatness. The results suggest that VIA technology installed in abattoirs could provide the means for the development of a value-based marketing system by paying for weights of the most valuable primal cuts measured using VIA.

The objectives of this study were to investigate the different characteristics of the newly introduced breed, Waguli (Wagyu x Tuli) when comparing it with the Brahman breed. Twenty-four animals were used. Six steers of each breed were fed 94% concentrate diet (94C) and the other six were fed 86% concentrate diet (86C). Eight steers, two from each group, each were harvested at 128 days, 142 days, and 156 days on feed. Feedlot performance data indicated that Waguli steers were highly efficient (P < 0.05) and gained more than Brahman steers on a daily basis (P < 0.05). Carcass characteristic data showed that Waguli steers have larger ribeye area with more 12th rib fat thickness, marbling score and higher quality grade (P < 0.05). It is well known that Wagyu is a highly marbled and tender Japanese breed. It was found that the reason for the Waguli tenderness and low shear force values to be the low level of calpastatin activity (P < 0.05), the inhibitor of the postmortem proteolytic enzyme-calpain. While the toughness of the Brahman meat was due to the high level of calpastatin activity. The calpain activity did not differ between the two breeds. Shear force values agreed with the calpain and calpastatin activities data, in which the Waguli steaks showed less shear force values at day 7 and 10 postmortem than the Brahman steaks (P < 0.05). However, at day 14 postmortem there was no difference in shear force values between the two breeds (P < 0.05). Fatty acid data analysis indicated that Waguli steers had a profile with less saturated fatty acids (SFA) and more unsaturated fatty acids (UFA) content than those in Brahman steers fat. Looking at the ratio of unsaturated fatty acids (UFA) to saturated fatty acids (SFA), it is observed that Waguli steers had a greater ratio than Brahman steers. In conclusion, Waguli steers produce tender meat with good marbling ability, which likely to satisfy the consumers demand. In addition, they have a desirable average daily gain and feed efficiency with high polyunsaturated fatty acids comparatively with Brahman steers.

Orientador: André Mendes Jorge / Banca: Guilherme Fernando Alleoni / Banca: Roberto de Oliveira Roça / Resumo: O presente trabalho objetivou avaliar o efeito da suplementação mineral protéica com adição de cromo orgânico no desempenho produtivo, com avaliações de carcaça por meio de ultra-som, e na qualidade da carne de bovinos terminados em regime de pastagem. Foram utilizados 18 Nelore e 18 F1 Brangus x Nelore castrados, com idade inicial de 16 meses e abatidos aos 22 meses, distribuídos igualmente em dois tratamentos de suplementação mineral protéica com e sem adição de cromo orgânico. Não se observou diferença entre grupos genéticos quanto ao ganho peso vivo, entretanto animais suplementados com cromo apresentaram maior ganho (494 g/animal/dia) que os animais controle (420 g/animal/dia). Não se observou diferenças entre os tratamentos experimentais quanto à área de olho de lombo, espessura de gordura subcutânea do dorso e da garupa, tomados por meio do ultrasom, obtendo-se respectivamente valores médios finais de 63,42 cm2, 5,46 mm e 5,58 mm. Foi observado um peso médio de carcaça quente de 235,01 kg e rendimento médio de carcaça quente de 52,09%, com superioridade do tratamento cromo (238 kg e 52,9%) frente ao controle (231 kg e 51,2%), e sem diferença entre os grupos genéticos; e obtenção de carne de qualidade em todos os tratamentos experimentais estudados. Os Nelore e F1 Brangus x Nelore apresentam potencial similar de produção de carne de qualidade a pasto, e que a suplementação mineral protéica com adição de cromo orgânico incrementa o ganho de peso e o rendimento de carcaça, não influenciando nos parâmetros qualitativos avaliados da carne. / Abstract: The present work aimed to evaluate the effect of mineral protein supplementation with organic chromium addition on productive performance, with carcass evaluations by means of ultrasound measures, and beef quality in steers finished on pasture system. For this, 18 Nellore and 18 F1 Brangus x Nellore steers were used, with 16 months of average initial age and sloughed at 22 months, distributed equally in two treatment of mineral protein supplementation with and without organic chromium addition. There was no observed difference between genetic groups regarding average daily gain (ADG). On the other hand, animals supplied with chromium showed better ADG (494 g) than control animals (420 g). Once again, there was no observed difference among experimental treatments regarding rib eye area, subcutaneous fat thickness at the back and at the rump, measured by ultrasound, reaching final mean values of 63,42 cm2, 5,46 mm e 5,58 mm, respectively. It was observed an average of 235.01 kg for hot carcass weight and 52.09% for average carcass yield, with a superiority for the chromium treatment (238 kg and 52.9%) versus control (231 kg and 51.2%), and without difference between genetic groups; also obtained quality beef in every experimental treatment evaluated. The Nellore e F1 Brangus x Nellore steers show equal production potential of the quality beef on pasture, and that mineral protein supplementation with organic chromium increase the weight gain and carcass yield, not influencing the evaluated beef quality parameters.

Thirty-seven Columbia and Cormo Crossbred July-weaned weather lambs were utilized in this study. A feeding trial was conducted to evaluate feed efficiency, average daily gain, feed cost per pound of gain, wool growth per day and per pound of grain, and average wool fiber diameter and distribution of fiber population of the wool. Lambs were raised to a uniform market weight of between 115 and 125 pounds and slaughtered to evaluate carcass weight, backfat thickness, loin eye area, internal body fat, leg circumference, dressing percentage, untrimmed wholesale cuts, trimmed retail cuts, and yield and quality grades. Suffok x Cormo/Rambouillet lambs were most efficient (P

A 2-year winter grazing and feedlot finishing trial (Exp 1) and subsequent in-situ nutrient disappearance study (Exp 2) were conducted to evaluate the effects of swath grazing forage barley (Hordeum vulgare, cv. Ranger) or foxtail millet (Setaria italica, cv. Golden German) compared to grass-legume hay fed in drylot on calf performance. In trial1 in each of 2 years, 120 spring born Angus calves (60 steers, 60 heifers) were fall weaned, stratified by weight, allocated into 20-head groups then assigned randomly to one of the three replicated (n=2) backgrounding (BG) systems. Backgrounding systems were (i) swath graze barley (BR); (ii) swath graze millet (ML); and (iii) bunk fed ground hay drylot (DL). Swath grazed calves were limit fed in 8 ha paddocks with 3 d grazing periods, using electric fencing for 96 d each year. All groups received a pelleted supplement at 0.62% BW. Calves were weighed at start, every 21 d and end of background period. Following the BG period, calves were placed in feedlot, separated by sex and BG treatment and fed a similar finishing ration and harvested at a targeted endpoint of 12 mm back fat. Forage samples collected every 21 d were analyzed for DM, CP and digestible energy (DE) and change in nutritive quality over the grazing period. DE content was greatest (P<0.05) for BR (2.6 Mcal/kg) and least for DL hay (2.2 Mcal/kg). Quality of all the three forages did not change over the grazing period except for an increase (P<0.05) in NDF of millet. Calf ADG was greatest (P <0.05) for BR compared to ML or DL, while dry matter intake (DMI) of the BR calves tended to be greater (P=0.11) than ML or DL calves. No treatment differences were observed in the finishing ADG (P>0.05) and carcass characteristics (P>0.05) of calves from the three backgrounding systems. In Exp 2, four dry ruminally cannulated Holstein cows fed ground grass hay were used in an in-situ degradability study to determine the extent of degradation and rumen kinetic parameters of the 3 forages used in Exp 1. Effective degradability of DM and CP iii were similar for barley and millet and greater (P<0.05) than grass legume hay while NDF degradability (P<0.05) of millet was greater than that of barley or grass legume hay. These findings indicate that swath grazing barley or foxtail millet fed to beef calves resulted in similar or decrease performance compared to a traditional drylot pen system. Cost of gain for the barley swath grazed backgrounding system calves was 43 and 60.5% lower compared to a swath grazed millet or drylot system, respectively. The economics of these systems would indicate that backgrounding of calves on swath grazed barley is a more efficient and low cost system compared to drylot.

The National Beef Quality Audit – 2011 assessed the current status of quality and consistency of fed steers and heifers. Beef carcasses (n = 9,802), representing approximately 10 percent of each production lot in 28 beef processing facilities, were selected randomly for the survey. Carcass evaluation for the cooler assessment of this study revealed these traits and frequencies: steer (63.5%), heifer (36.4%), cow (0.1%), and bullock (0.03%) sex classes; dark-cutters (3.2%); blood splash (0.3%); yellow fat (0.1%); calloused ribeye (0.05%); A (92.8%), B (6.0%), and C or greater (1.2%) overall maturities; native (88.3%), dairy-type (9.9%), and Bos indicus (1.8%) estimated breed types; and United States (97.7%), Mexico (1.8%), and Canada (0.5%) country of origin. Certified or marketing program frequencies were age and source verified (10.7%), ≤ A40 (10.0%), Certified Angus Beef (9.3%), top Choice (4.1%), natural (0.6%), and Non-Hormone Treated Cattle (0.5%), and there were no organic programs observed. Mean USDA YG traits were USDA YG (2.9), HCW (374.0 kg), AFT (1.3 cm), LM area (88.8 cm2), and KPH (2.3%); Frequencies of USDA YG distributions were YG 1 (12.4%), YG 2 (41.0%), YG 3 (36.3%), YG 4 (8.6%), and YG 5 (1.6%). Mean USDA QG traits were USDA QG (Select93), marbling score (Small40), overall maturity (A59), lean maturity (A54), skeletal maturity (A62). Frequencies of USDA QG distributions were Prime (2.1%), Choice (58.9%), Select (32.6%), and Standard or less (6.3%). Marbling score distribution was Slightly Abundant or greater (2.3%), Moderate (5.0%), Modest (17.3%), Small (39.7%), Slight (34.6%), and Traces or less (1.1%). Carcasses with QG of Select or greater and YG of 3 or numerically less represented 85.1% of the sample. This is the fifth benchmark study measuring targeted carcass characteristics, and information from this survey will continue to help drive progress in the beef industry. Results will be used in extension and educational programs as teaching tools to inform beef producers and industry professionals of the current state of the U.S. beef industry.

A 2-year winter grazing and feedlot finishing trial (Exp 1) and subsequent in-situ nutrient disappearance study (Exp 2) were conducted to evaluate the effects of swath grazing forage barley (Hordeum vulgare, cv. Ranger) or foxtail millet (Setaria italica, cv. Golden German) compared to grass-legume hay fed in drylot on calf performance. In trial1 in each of 2 years, 120 spring born Angus calves (60 steers, 60 heifers) were fall weaned, stratified by weight, allocated into 20-head groups then assigned randomly to one of the three replicated (n=2) backgrounding (BG) systems. Backgrounding systems were (i) swath graze barley (BR); (ii) swath graze millet (ML); and (iii) bunk fed ground hay drylot (DL). Swath grazed calves were limit fed in 8 ha paddocks with 3 d grazing periods, using electric fencing for 96 d each year. All groups received a pelleted supplement at 0.62% BW. Calves were weighed at start, every 21 d and end of background period. Following the BG period, calves were placed in feedlot, separated by sex and BG treatment and fed a similar finishing ration and harvested at a targeted endpoint of 12 mm back fat. Forage samples collected every 21 d were analyzed for DM, CP and digestible energy (DE) and change in nutritive quality over the grazing period. DE content was greatest (P<0.05) for BR (2.6 Mcal/kg) and least for DL hay (2.2 Mcal/kg). Quality of all the three forages did not change over the grazing period except for an increase (P<0.05) in NDF of millet. Calf ADG was greatest (P <0.05) for BR compared to ML or DL, while dry matter intake (DMI) of the BR calves tended to be greater (P=0.11) than ML or DL calves. No treatment differences were observed in the finishing ADG (P>0.05) and carcass characteristics (P>0.05) of calves from the three backgrounding systems. In Exp 2, four dry ruminally cannulated Holstein cows fed ground grass hay were used in an in-situ degradability study to determine the extent of degradation and rumen kinetic parameters of the 3 forages used in Exp 1. Effective degradability of DM and CP iii were similar for barley and millet and greater (P<0.05) than grass legume hay while NDF degradability (P<0.05) of millet was greater than that of barley or grass legume hay. These findings indicate that swath grazing barley or foxtail millet fed to beef calves resulted in similar or decrease performance compared to a traditional drylot pen system. Cost of gain for the barley swath grazed backgrounding system calves was 43 and 60.5% lower compared to a swath grazed millet or drylot system, respectively. The economics of these systems would indicate that backgrounding of calves on swath grazed barley is a more efficient and low cost system compared to drylot.

We hypothesized that subcutaneous (s.c.) adipose tissue would differ in monounsaturated (MUFA) and saturated fatty acid (SFA) composition among different depots throughout a beef carcass. To test this, 50 carcasses from a variety of breed types and backgrounds were sampled. External fat samples were collected from eight different carcass locations: round, sirloin, loin, rib, chuck, brisket, plate and flank. Samples were used to provide information on slip points, fatty acid composition and MUFA:SFA ratios. Lipids were extracted from s.c. adipose tissue by a modified chloroform:methanol procedure, and fatty acid composition and slip points were measured. The brisket was significantly lower in palmitic (16:0) and stearic (18:0) acid than the other seven sampling sites (P = 0.001). The brisket demonstrated the highest values of MUFA (P = 0.001) with the exception of possessing the lowest value of transvaccenic (18:1t11) acid (P = 0.002). There were also significant differences in the amounts of PUFA among the eight sampling sites. The lowest values were from the brisket with a mean of 25.1. The flank had the highest slip point with a mean of 39.0 (P < or = 0.001). There was a high negative correlation shown between palmitoleic and stearic acid (R2 = 0.827). The brisket displayed the highest values for MUFA:SFA ratios (P = 0.001), whereas the flank was the lowest. Due to the significant differences amongst fat depots within bovine carcasses in their fatty acid composition we conclude that substantial differences exist across fat depots.

Toe trimming within the turkey industry has been used for over four decades as a method for controlling carcass scratching, and by doing so, achieving better grades and lower condemnation rates. The industry has changed greatly since the 1970’s, when the majority of the research on the procedure was completed. The technology used for toe trimming has switched from a hot-blade to the use of microwave energy, which will effect healing and toe length trimmed. The birds are larger now, which will impact mobility both before and after trimming, and in a consumer-driven trend, the industry is re-examining its codes of practice to ensure the highest level of welfare possible. As there is little pertinent research regarding these changes, the toe trimming procedure was re-examined under modern conditions and with focus on both production and welfare effects to determine if the practice can still be recommended. Hybrid Converter toms were raised to 140 d of age, with half (153) being toe trimmed at the hatchery using a Microwave Claw Processor (MCP) and the other half (153) left with their toes intact. The birds had feed consumption, body weight, mortality, toe length, stance, behaviour, and gait scores monitored throughout the trial with carcass damage assessed at processing. Means were considered significantly different when P≤0.05. Toe trimming caused a reduction in both feed consumption and body weight in the later stages of the experiment. Final weights for non-toe trimmed and toe trimmed toms were 21.70 kgs and 21.15 kgs, respectively. Feed efficiency with and without being corrected for mortality was unaffected by the procedure. Overall mortality and mortality by age group were also unaffected; however it was found that toe trimmed toms experienced higher levels of rotated tibia at 3.27% versus 0.65% for untrimmed birds. Toe length measurements found that trimmed toes were, on average, 91.9% the length of an intact toe, and that variability in length increased with trimming. The procedure was not found to impact stance or gait score, although behaviour at all ages measured demonstrated reduced mobility with trimming. In particular, reduced activity in poults for 5 d post-treatment indicates that the MCP treatment caused pain or discomfort. The percentage of carcasses which exhibited scratching was 15.6% for the non-trimmed treatment and 13.3% for the trimmed, which were not significantly different. Also, no significant effect of trimming was found for any other carcass damage category. Based on the negative impacts of toe trimming on both bird production and welfare found in this research, MCP treatment should not be recommended to turkey producers when raising heavy toms.