The estimation of the age of cattle by the measurement of thermal stability of tendon collagen

Comparison of Dental Carcass Maturity in Non-Castrated Male F1 Angus-Nellore Cattle Finished in Feedlot

Dental classification of carcasses is used as a parameter of cattle maturity at slaughter, and it can influence carcass and meat quality traits. Brazilian beef-packing companies use the number of permanent incisor (PI) teeth as a parameter for bonus and certification of carcasses with superior quality. However, when non-castrated male such as F1 Angus-Nellore (Bos taurus×Bos indicus) are slaughtered, only animals without PI teeth are subsidized by the breed association. We evaluated these animals finished in feedlot for 180 days with zero versus two PI teeth on the carcass and meat quality traits. At the time of slaughter, 88 carcasses were selected, forming two treatments according to dental carcass maturity (0 versus 2 PI teeth; 44 animals per category). It was demonstrated that the number of PI teeth (0 versus 2 PI) did not influence (p>0.05) carcass (weights, yield, cooling loss, ribeye area and the backfat thickness) and meat quality traits (Longissimus thoracis chemical composition, color, cooking losses, shear force and pH). Thus, dental carcass maturity (zero versus two PI teeth) does not influence non-castrated male F1 Angus-Nellore finished in feedlot for 180 days. This is the first study to demonstrate that carcasses of non-castrated male F1 Angus-Nellore with two PI teeth should be subsidized in a similar way to those with zero PI teeth. Moreover, Brazilian beef-packing companies could produce heavier and leaner carcasses of acceptable quality though the use of crossbred cattle such as non-castrated F1 Angus Nellore.

Applicability of teeth examination as a tool for age estimation in a semi-arid cattle production environment in Namibia

Regression analysis was used to evaluate teeth examination as a tool for estimating age in beef and dairy cattle at Neudamm farm, Namibia, in 2018. There was a significant difference in age (months) between the overall mean actual age (M=60, SD=4.57) and the mean estimated age (M=57, SD=4.52 months) in beef cattle; t(74) = 3.61, p<0.001. There was no significant difference between the overall mean estimated age and the mean actual age (M=42.5, SD=5.18) and (M=41.3, SD=5.21 months) in dairy cattle; t(30) = 1.45, p=0.16. There was a very strong positive relationship between the overall teeth examination-estimated age and actual age in beef cattle [r (74) = 0.98, p<0.001]. There was a very strong positive relationship between the overall teeth examination-estimated age and actual age in dairy cattle [r (30) = 0.99, p<0.001]. A very strong positive relationship was also evident between the teeth examination-estimated age and actual age in beef cattle aged 45 months and below [r (37) = 0.93, p<0.001]. There was a very strong positive relationship between the teeth examination-estimated and actual age in dairy cattle aged 45 months and below [r (20) = 0.97, p<0.001]. There was a very strong positive relationship between the teeth examination-estimated age and actual age in beef cattle aged over 45 months [r (35) = 0.93, p<0.001]. There was a very strong positive relationship between the teeth examination-estimated age and actual age in dairy cattle aged over 45 months [r (8) = 0.97, p<0.001]. It was therefore concluded that under the given conditions of the study and the range of ages and the breeds under study, age estimation through teeth examination is reliably applicable for aging cattle in general. Age estimation through teeth examination was found to be more accurate in dairy than in beef cattle.