Sire Effects on Carcass of Beef-Cross-Dairy Cattle: A Case Study in New Zealand

Abstract

There is interest in increasing the carcass value of surplus calves born in the dairy industry that are reared for beef production in New Zealand. This experiment evaluated the carcass of Angus and Hereford sires via progeny testing of beef-cross-dairy offspring grown on hill country pasture. Weight and carcass traits were analyzed from 1015 animals and 1000 carcasses of 73 sires. The mean of the progeny group means was 567 kg for live weight at slaughter, 277 kg for carcass weight, 48.9% for dressing-out, 240.3 cm for carcass length, 73.6 cm2 for eye muscle area, 7.4 mm for rib fat depth, 0.91 for marble score, 3.05 for fat color score, 3.01 for meat color score, and 5.62 for ultimate pH. Sire affected (p < 0.05) carcass size and fat traits, but not fat color, meat color, or ultimate pH (p > 0.05). There was a 46 kg increase in carcass weight between the best and worst sires tested. Carcass fat traits were the most variable among sires. The use of genetically superior beef-breed sires over dairy-breed cows has the potential to increase carcass weights from surplus calves born in the dairy industry, while maintaining adequate fat levels and carcass quality.

Estimated Breeding Values of Beef Sires Can Predict Performance of Beef-Cross-Dairy Progeny

“…Given that the cattle in this study were slaughtered at a common age (which depended on the contemporary group reaching a mean target weight, rather than selecting those animals with the right finishing attributes, such as good fat cover over the back and tail), then it is possible that Hereford cattle were not as physiologically mature as the Angus cattle. This is supported by the fact that Hereford-sired cattle had longer carcasses than Angus-sired animals in this study [2.0cm difference, p <0.05 ( Martín et al, 2021 )], indicating that Hereford were larger-framed and less mature compared with Angus cattle, at the same carcass weight ( Thonney, 2015 ). In addition, New Zealand Angus breeders have been putting emphasis on marbling through the AngusPure Index.…”

“…Angus sires used in the experiment had a wider range of EBV for IMF compared with Hereford sires (6.5 and 3.0% IMF spread of EBV, respectively, although this is a reflection of the spread within each breed rather than a difference in sampling). Moreover, Angus-sired progeny had higher marble scores compared with Hereford-sired cattle [0.21 scores greater, p <0.05 ( Martín et al, 2021 )], even though the range of scores was 0–3 for both breeds. Accordingly, more Angus sires had higher marble scores than Hereford sires in this experiment.…”

“…After slaughter, the bodies were dressed to New Zealand commercial specifications ( Animal and Animal Products Directorate, 2017 ), and hot carcass weight (kg) was recorded prior to the carcasses going into the chiller ( Martín et al, 2021 ). Carcasses were chilled (4±1°C) overnight, and the following morning, one side of the carcass was cut between the 12th and 13th rib to expose the eye muscle ( M. longissimus thoracis ) for in-chiller assessment of rib fat thickness (mm), eye muscle area (EMA in cm 2 ), and marbling score.…”

“…Previous studies in New Zealand (Martín et al, 2020(Martín et al, , 2021Coleman et al, 2021) have demonstrated considerable variation in performance among Angus and Hereford sires for birth, growth, and carcass traits. However, it was not explored how the sire performance related to their EBV.…”

“…The authors gratefully acknowledge Limestone Downs farm staff, Greenlea Premier Meats staff and Massey University technical staff for their valuable support and assistance in data collection. The data presented in this manuscript have previously appeared in the dissertations of Coleman (2020) and Martín (2021) , that will be available online through the university repository at Massey Research Online ( https://mro.massey.ac.nz/ ).…”