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.

No description available.

The administration of raw soybeans to the diet of prepubertal gilts had no effect (p>0.05) on age to puberty, number of corpora lutea, or embryos present. Also, the number of pigs farrowed live and 28d litter weights did not differ between gilts consuming the raw soybean diet and gilts consuming the control diet. There was a reduction (p<0.05) in the number of pigs weaned in the group consuming the raw soybeans but no differences (p>0.05) in weaning weights. Gilts fed the raw soybean diet had a reduction (p=0.05) of hot carcass weights compared to gilts consuming the control diet but exhibited no differences for other carcass parameters measured. Thermal imaging was able to differentiate gilts in estrus versus diestrus. Gilts in estrus had greater (p<0.05) surface area temperatures than gilts in diestrus.

Two trials were conducted, one using crossbred steers (Trial 1; N=275; 376±24 kg) and a second using Hereford heifers (Trial 2; N=5; 420±6 kg) to evaluate the performance, carcass quality, rumen fermentation and nutrient digestibility of cattle fed wheat or corn dried distillers grains with solubles (DDGS). The control ration averaged 87.7% rolled barley grain, 5.6% supplement and 6.8% barley silage (DM basis) over both trials. Dietary treatments included replacement of barley grain at 20 or 40% of the diet (DM basis) with wheat or corn DDGS. For Trial 1, steers were slaughtered at a constant finish weight of 645 kg. Data was analyzed as a completely randomized design using pen as the experimental unit. Feeding increasing levels of wheat DDGS quadratically increased dry matter intake (DMI) (P<0.01), whereas increasing levels of corn DDGS quadratically decreased DMI (P=0.01). Average daily gain was not influenced (P=0.13) by feeding wheat or corn DDGS but cattle fed corn DDGS exhibited a quadratic increase (P=0.01) in gain:feed. As a result, a quadratic increase (P<0.01) in calculated NEg of the diet was observed as corn DDGS levels increased. A linear decrease (P=0.04) in days on feed (169, 166 and 154 days) was noted when increasing levels of wheat DDGS (0, 20 and 40%) were fed. Dressing percentage increased in a linear fashion with wheat DDGS (P<0.01) inclusion level and in a quadratic fashion (P=0.01) as corn DDGS inclusion level increased although other carcass traits were not affected (P>0.10) by treatment.<p> Trial 2 evaluated the effects of corn and wheat DDGS on rumen fermentation and nutrient digestibility parameters. Rumen pH, duration and area under rumen pH thresholds of 5.8, 5.5 and 5.2 were not affected (P>0.05) by treatment. Wheat DDGS inclusion increased (P=0.01) rumen ammonia-N levels in a linear fashion, while the inclusion of both wheat and corn DDGS resulted in quadratic (P=0.01) and linear (P=0.01) increases in butyrate concentration, respectively. Feeding corn DDGS also decreased total rumination time linearly (P=0.01) and DMI in a quadratic (P=0.04) fashion. Feeding wheat DDGS decreased (P=0.01) DM digestibility in a linear fashion. Wheat and corn DDGS inclusion quadratically increased (P=0.01) the digestibility of crude fat while feeding corn DDGS also linearly increased (P=0.01) the digestibility of crude protein. Neutral detergent fiber digestibility increased in a linear fashion (P=0.01) as both wheat and corn DDGS inclusion increased while ADF digestibility increased in a linear fashion (P=0.03) for wheat and in a quadratic (P=0.02) fashion for corn DDGS. The digestibility of both NDIN and ADIN increased (P=0.01) in a quadratic fashion for both corn and wheat DDGS inclusion level. Increased inclusions of wheat DDGS resulted in a linear decrease in gross energy digestibility (P=0.01), but neither wheat nor corn DDGS inclusion affected diet digestible energy content (P>0.05). Feeding both wheat and corn DDGS increased (P=0.01) the excretion of nitrogen and phosphorus.<p> Replacement of barley grain with up to 40% corn or wheat DDGS improved gain:feed and reduced days on feed, respectively with no detrimental effect on carcass quality grade or sub-primal boneless boxed beef yield. The results of this project also indicate that the inclusion of corn and wheat DDGS (up to 40%) in feedlot rations does not mitigate ruminal acidosis, however the inclusion of both byproducts strongly impacts nutrient (crude fat, ADF, NDF, ADIN and NDIN) digestibility.

Two trials were conducted, one using crossbred steers (Trial 1; N=275; 376±24 kg) and a second using Hereford heifers (Trial 2; N=5; 420±6 kg) to evaluate the performance, carcass quality, rumen fermentation and nutrient digestibility of cattle fed wheat or corn dried distillers grains with solubles (DDGS). The control ration averaged 87.7% rolled barley grain, 5.6% supplement and 6.8% barley silage (DM basis) over both trials. Dietary treatments included replacement of barley grain at 20 or 40% of the diet (DM basis) with wheat or corn DDGS. For Trial 1, steers were slaughtered at a constant finish weight of 645 kg. Data was analyzed as a completely randomized design using pen as the experimental unit. Feeding increasing levels of wheat DDGS quadratically increased dry matter intake (DMI) (P<0.01), whereas increasing levels of corn DDGS quadratically decreased DMI (P=0.01). Average daily gain was not influenced (P=0.13) by feeding wheat or corn DDGS but cattle fed corn DDGS exhibited a quadratic increase (P=0.01) in gain:feed. As a result, a quadratic increase (P<0.01) in calculated NEg of the diet was observed as corn DDGS levels increased. A linear decrease (P=0.04) in days on feed (169, 166 and 154 days) was noted when increasing levels of wheat DDGS (0, 20 and 40%) were fed. Dressing percentage increased in a linear fashion with wheat DDGS (P<0.01) inclusion level and in a quadratic fashion (P=0.01) as corn DDGS inclusion level increased although other carcass traits were not affected (P>0.10) by treatment.<p> Trial 2 evaluated the effects of corn and wheat DDGS on rumen fermentation and nutrient digestibility parameters. Rumen pH, duration and area under rumen pH thresholds of 5.8, 5.5 and 5.2 were not affected (P>0.05) by treatment. Wheat DDGS inclusion increased (P=0.01) rumen ammonia-N levels in a linear fashion, while the inclusion of both wheat and corn DDGS resulted in quadratic (P=0.01) and linear (P=0.01) increases in butyrate concentration, respectively. Feeding corn DDGS also decreased total rumination time linearly (P=0.01) and DMI in a quadratic (P=0.04) fashion. Feeding wheat DDGS decreased (P=0.01) DM digestibility in a linear fashion. Wheat and corn DDGS inclusion quadratically increased (P=0.01) the digestibility of crude fat while feeding corn DDGS also linearly increased (P=0.01) the digestibility of crude protein. Neutral detergent fiber digestibility increased in a linear fashion (P=0.01) as both wheat and corn DDGS inclusion increased while ADF digestibility increased in a linear fashion (P=0.03) for wheat and in a quadratic (P=0.02) fashion for corn DDGS. The digestibility of both NDIN and ADIN increased (P=0.01) in a quadratic fashion for both corn and wheat DDGS inclusion level. Increased inclusions of wheat DDGS resulted in a linear decrease in gross energy digestibility (P=0.01), but neither wheat nor corn DDGS inclusion affected diet digestible energy content (P>0.05). Feeding both wheat and corn DDGS increased (P=0.01) the excretion of nitrogen and phosphorus.<p> Replacement of barley grain with up to 40% corn or wheat DDGS improved gain:feed and reduced days on feed, respectively with no detrimental effect on carcass quality grade or sub-primal boneless boxed beef yield. The results of this project also indicate that the inclusion of corn and wheat DDGS (up to 40%) in feedlot rations does not mitigate ruminal acidosis, however the inclusion of both byproducts strongly impacts nutrient (crude fat, ADF, NDF, ADIN and NDIN) digestibility.

We hypothesized that slip point of subcutaneous (s.c.) adipose tissue lipids would predict beef carcass quality. To address our hypothesis, 79 M. longissimus dorsi (LD) steaks from cattle of unknown background were used to provide information on slip points, percentage intramuscular lipid, fatty acid composition, and MUFA:SFA ratios. Overlying s.c. adipose tissue was separated from the muscle lean, which contained intramuscular (i.m.) adipose tissue. Lipids were extracted from s.c. adipose tissue and muscle lean by a modified chloroform:methanol procedure and subjected to various analyses. The hypothesis was tested by developing regression equations to determine which fatty acid variables were most useful in predicting carcass composition. There was a high correlation between s.c. MUFA:SFA ratio and s.c. slip points (P < 0.001) with an R2 of 0.557. Also, the MUFA:SFA fatty acid ratios of s.c. and i.m. adipose tissue were significantly correlated and an R2 of 0.440 was observed (P < 0.001) when regressed against each other. The current data set observed s.c. MUFA:SFA ratios (0.73) lower than previous studies, which suggests a population of young or unfinished cattle. This study demonstrated that it is possible to predict the intramuscular lipid (IML) MUFA:SFA ratio by measuring s.c. slip point (R2 of 0.097; P < 0.01). However, our hypothesis of predicting amount of marbling, hence quality grade, from the melting temperature of s.c. adipose tissue lipids proved incorrect (R2 = 0.001). Nonetheless, these data indicate that LD fatty acid composition can be estimated by measuring s.c. adipose tissue slip point.

Master of Science / Department of Agricultural Economics / Kevin C. Dhuyvetter / When purchasing feeder calves, bulls are typically discounted relative to steers. Most would agree that a discount is warranted but determining the appropriate discount to apply is considerably more difficult. Being able to calculate this discount under varying conditions would help stock operators maintain a certain level of profitability or recognize opportunities to make more profit when excessive discounts are being applied. The goals of this study were to determine how castration timing affects performance (as measured by average daily gain), morbidity, and carcass quality and how morbidity affects performance and carcass quality. Ordinary Least Squares regression and logit models were estimated to quantify the effects of various management and environmental factors on performance, morbidity, and carcass quality. These model estimates of production variables along with price and cost assumptions were used to calculate breakeven purchase prices and price discounts for bulls relative to steers, accounting for the possibility of contracting bovine respiratory disease, if owned for a short background period or if ownership is retained through slaughter. Model results confirm that late-castrated steers do indeed exhibit diminished performance and increased morbidity probabilities relative to early-castrated steers. Increased morbidity also decreases average daily gain. However, this study found that castration timing and morbidity during the backgrounding period have minimal effects on carcass quality, with morbidity only impacting hot carcass weight and castration timing significantly affecting days to market and only tending to impact hot carcass weight. Ultimately, based on 2009 market conditions, bulls should be discounted at feeder calf sales compared to steers. The average calf arrived at 459 pounds, and at this weight bulls should be discounted $4.69/cwt relative to the same weight steers. The discount increases to $5.37/cwt for 400 pound calves and drops to $4.20/cwt for 500 pound calves. If ownership is retained through slaughter, required discounts will change to $6.77/cwt, $4.91/cwt, and $7.55/cwt, respectively.

The overall aim of this thesis was to investigate the genetic control of beef quality in a commercial population of Aberdeen Angus-sired cattle with a view to trait improvement. The population studied included 500 Angus-cross animals, all with purebred Aberdeen Angus sires, from a selection of farms throughout Scotland. A number of carcass-related weight traits and taste panel assessed sensory traits were measured on these animals. A population of 265 Charolais cross cattle (all with purebred sires) was then used to explore the extrapolation of results across breeds. The first aim of this thesis was to investigate heritabilities for important carcass and meat quality traits and to assess the quality of a number of taste-panel derived meat quality traits by calculating three consistency statistics. Consistency statistics (parameter range 0 to 1) for the taste panel traits were moderately high, particularly for panel member consistency and reproducibility, with values ranging from 0.48 to 0.81 and 0.43 to 0.73, respectively. Estimated heritabilities were low for most of the sensory taste-panel-evaluated traits, where the maximum value was 0.16 for overall liking, but were higher for carcass traits where carcass weight heritability was 0.7. To perform these analyses it was first necessary to confirm paternity using a number of genetic markers. Therefore, a comparison of the power of both microsatellite and SNP markers for paternity exclusion was carried out to determine the more effective method. Results indicated that approximately three times as many SNP markers than microsatellite markers were required for parentage exclusion, and a panel of 15 microsatellite markers was used to assign paternity before subsequent data analysis was carried out. The remaining aims of this thesis centred on exploring genetic markers for carcass and meat quality. Firstly, the Angus animals were genotyped for the del11 myostatin mutation which was found to be segregating at a relatively low frequency (0.04) and was shown to be associated with a 17.4 kg increase in carcass weight (P < 0.05) in the heterozygous animals when compared to the homozygous wild-type animals. By analysing the haplotype associated with the mutant allele, it was determined that there have been at least two separate introductions of the mutant allele into the Aberdeen Angus breed. A number of SNPs were also tested for their effects on the carcass and meat quality traits in the Angus animals. The SNPs fell into two groups: eight that have been incorporated into commercially available tests and a further 28 from alternative candidate genes that have effects in different breeds and species. In total, 17 SNPs significantly affected at least one of the traits measured. Of these significant associations, a number have been seen previously, such as the association between calpain and tenderness (P = 0.01) and growth hormone and eye muscle area (P = 0.05), and some of which were novel, such as the association between growth hormone receptor and steak odour (P = 0.02) and corticotrophin releasing hormone and gristle distance from fat (P = 0.004). A further six SNPs, identified by resequencing of the malic enzyme 1 (ME1) and small heterodimer partner (SHP) genes, were tested for their effects on the traits measured in this thesis. Five of the SNPs, including one which caused a non-synonymous amino acid change, had a significant effect on at least one of the traits tested including fat class (P = 0.002), eye muscle area (P = 0.01), sirloin weight before maturation (P = 0.03), sirloin steak tail length (P = 0.004) and juiciness (P = 0.004) where the effect sizes were 1.79 units, 565 mm2, 0.36 kg, 17.12 mm and 0.23 taste panel units, respectively. To assess the effect of the genotyped SNPs on intramuscular fat (IMF), a simple method of visible IMF quantification in the sirloin steak was developed using digital photographs and an image analysis program. Results showed that two SNPs in the calpain gene, known to be linked with an increase in meat tenderness, were associated with an increase in visible IMF% and the del11 mutation was associated with a reduction in visible IMF%. The heritabilities, SNP association validations and novel SNP-trait associations identified in this thesis provide tools for use in breeding programs, possibly via marker assisted selection to improve meat quality traits. However, the results seem breed-specific, as most of the significant effects were not replicated in the Charolais population.

Orientador: Maria Cristina Thomaz / Banca: Jane Maria Bertocco Ezequiel / Banca: Dirlei Antônio Berto / Resumo: Foram conduzidos dois ensaios para avaliar a utilização da casca de soja em programas de restrição alimentar qualitativa para suínos com elevado peso de abate. No primeiro ensaio foram utilizados 16 suínos machos castrados da linhagem Topigs, com peso inicial de 80,05 ± 0,16 kg, para a avaliação biológica da casca de soja. Por apresentar 2752 kcal de ED/kg, 65,42% de fibra em detergente neutro e 49,49% de fibra em detergente ácido, a casca mostrou-se como um ingrediente viável de ser utilizado em programas de restrição alimentar qualitativa. No segundo ensaio foram utilizados 36 suínos machos castrados com peso inicial de 80,40 ± 5,82 kg, recebendo rações com níveis de 0, 8, 16 e 24% de casca de soja. Os animais foram abatidos com peso próximo de 130 kg, sendo avaliados quanto a digestibilidade das dietas, desempenho, parâmetros séricos, produção e características das fezes, características de carcaça, qualidade da carne, perfil de ácidos graxos, pesos de órgãos do trato digestório e avaliação econômica do uso das dietas. A inclusão de níveis entre 11,50 a 14,00% de casca de soja nas rações influenciam as características e qualidade da carcaça. Além disso, a diluição energética da dieta pode se constituir em importante ferramenta para diminuir o potencial de impacto ambiental da suinocultura, além de ser viável com a inclusão de 14,79% de casca de soja, pois neste nível o custo com a alimentação foi menor, além das receitas brutas e líquidas não terem sido afetadas / Abstract: Two assay were conducted to evaluate the use of soybean hulls in qualitative feed restriction for pigs with high body weight. In the first assay, 16 barrows of Topigs lineage with 80.05 ± 0.16 kg of body weight were used to determine the biological value of soybean hulls. For present 2.752 kcal DE/kg, 65.42% neutral detergent fiber and 49.49% acid detergent fiber, and was considered as a viable ingredient to be used in qualitative feed restriction programs. In the second assay, 36 barrows initially weighing 80,40 ± 5,82 kg were allotted into four diets with different levels of 0, 8, 16 and 24% of soybean hulls. Animals were fed until they reached 130 kg. At this moment, pigs were abated and the effects on digestibility of diets, on performance, serum parameters, production and fecal characteristics, carcass traits, meat quality, fatty acid profile, weight of gastrointestinal tract organs and economical analysis were evaluated. The inclusion of levels between 11.50 to 14.00% of soybean hulls in diets affects the characteristics and carcass quality. Moreover, the energy dilution of the diet may be an important tool to reduce the potential environmental impact of swine production, besides being feasible with the inclusion of 14.79% of soybean hulls, because at this level the cost of feeding was smaller than the gross and net revenues were not affected / Mestre

A study was conducted to evaluate the quality characteristics in a comparative manner of grass-fed and grain-fed beef. Thirty two commercially bred beef steers were used. These steers were assigned to one of four treatments; grain-fed, grass/grain-fed, grass-fed and irrigated. These treatments were each reflective of the ration that would be provided to the animal. Individual animal weights were recorded every 28 days throughout the portion of the study. The grain-fed animals realized the highest (P<0.05) average daily gain with the grass-fed and irrigated having the lowest. The steers were harvested when they reached the pre-determined criteria, which was 0.4 inch back fat as measured at the 12th rib via ultrasonography, for the grain-fed or 800 pounds for the grass-fed animals. All animals, once harvested, were graded based upon USDA quality grades with results mirroring those previously mentioned. Carcasses were involved in an aging study in which all left sides of the carcasses were fabricated into primal cuts, vacuumed packaged and aged for 14 days while the right sides were dry aged during the same period. Shear force data were collected to provide for a measure of tenderness. All samples were significantly (P<0.05) more tender following aging with no difference being realized between aging techniques. Percent cutout was also calculated for the two techniques to quantify what difference, if any, existed. No significant difference (P>0.05) was shown between wet and dry aging with regard to percent cutout. Sensory evaluation was also conducted based upon the attributes of juiciness, tenderness and flavor intensity. For all three attributes grain-fed beef was favored (P<0.05). The panelists detected no difference in aging technique for any of the treatments (P>0.05).Carcass soft tissue chemical composition (lipid, protein and moisture) was also evaluated for the treatments. Grain-fed beef was shown to be highest (P<0.05) for overall percent lipid and lowest for percent moisture and protein. The grass-fed carcasses were the opposite, being highest for overall moisture and protein and lowest for lipid (P<0.05).