Thermographic Screening of Beef Cattle Metatarsal Growth Plate Lesions

Lameness represents one of the main causes of decreased productive performance and impaired animal welfare in the bovine industry. Young beef bulls are predisposed to develop diseases of the growing skeleton, especially growth plate lesions. Early diagnosis is indispensable for ensuring correct treatment, fast recovery and reduction losses. However, when dealing with beef cattle, this is not always possible. Fast and reliable diagnostic imaging techniques are necessary to improve dealing with lameness in beef animals. The aim of the present study was to examine the potential of thermographic imaging as a non-invasive tool for rapidly screening beef bulls for the presence of growth plate lesions. Here, 20 Charolais and Limousine beef bulls affected by growth plate lesions in one of the rear limbs were selected. IRT was performed on both hind limbs using a digital infrared camera (ThermaCam T420 Model, Flir Systems, Boston, MA, USA), prior to radiographic imaging and clinical examination. The temperature of healthy and affected limbs was measured in two regions: the area correspondent to the growth plate (AR01) and the whole area of the metatarsus (AR02). Growth plate lesions were found to increase the maximum, mean, and minimum temperatures in AR01; and the mean and maximum temperatures in AR02, therefore, indicating the potential of IRT as a reliable, practical tool for screening growth plate lesions in beef bulls.

Sustained Effects of Muscle Calpain System Genotypes on Tenderness Phenotypes of South African Beef Bulls during Ageing up to 20 Days

The most important factor that determines beef tenderness is its proteolytic activity and the balance between calpain1 protease activity and calpastatin inhibition is especially important, while contributions could arise from calpain2 and possibly calpain3. These processes are however affected by the meat aging process itself. To determine whether genotypes in the calpaincalpastatin system can enhance tenderness throughout a 20 day aging period, South African purebred beef bulls (n=166) were genotyped using the Illumina BovineHD SNP BeadChip, through genebased association analysis targeting the cast, capn3, capn2 and capn1 genes. The WarnerBratzler shear force (WBSF) and myofibril fragment length (MFL) of Longissimus thoracis et lumborum (LTL) steaks were evaluated between d 3 d 20 of aging, with protease enzyme activity in the first 20 h postmortem. Although several of the 134 SNP associated with tenderness, only seven SNP in the cast, capn2 and capn1 genes sustained genetic associations, additive to agingassociated increases in tenderness for at least three of the four aging periods. While most genomic associations were relatively stable over time, some genotypes within SNP responded differently to aging, resulting in altered genomic effects over time. The level of aging at which genomic associations are performed is an important factor that determines whether SNP affect tenderness phenotypes.

281 The Effects of Whole Cottonseed Supplementation on Performance, Breeding Soundness Exams, and Manganese Superoxide Dismutase Concentrations in the Blood and Semen of Beef Bulls

The objective of this research was to determine the effects of whole cottonseed containing gossypol on post-pubertal beef bulls. In a two-year study, 46 Angus and Red Angus bulls (body weight 457.0 ± 85.2 kg; 16 to 20-months of age) were stratified by BW and randomly assigned to 1 of 3 levels of whole cottonseed supplementation while receiving ad libitum roughage. The treatments included: DD (n = 14, control; 3.18 kg/d of dried distillers grain, W/D (n = 16; 1.59 kg/d of whole cottonseed and 1.59 kg/d of dried distillers grain), or WW (n = 16 3.18 kg/d of whole cottonseed). Diets were formulated to be isocaloric and isonitrogenous. In both years, bulls were weighed, administered a breeding soundness exam, and morphological characteristics of spermatozoa were measured on d 0, 28, and 60. In year 1, blood and semen samples were collected on d 0, 28, and 60 to measure manganese superoxide dismutase activity. There was no treatment effect for blood or semen manganese superoxide dismutase concentration (P > 0.255). There was a treatment effect (P < 0.02) for average daily gain as bulls fed WW gained less compared to those fed WD and DD (0.96, 1.23, and 1.39 kg/d, respectively). No treatment effect was observed for scrotal circumference (P > 0.50). There were no treatment × time interactions, treatment, or time main effects for percentages of normal spermatozoa, spermatozoa with coiled or folded tails, or proximal droplets (P > 0.12). There was a treatment effect on the amount of swollen midpiece or abnormal head as bull in the DD treatment had a greater (P < 0.02) percentage of other abnormalities compared to WW, but WD was not different (P > 0.16). Inclusion of whole cottonseed may affect average daily gain, but does not affect reproductive parameters of beef bulls.