Teagasc, Animal & Grassland Research and Innovation Centre, Moorepark, Fermoy P61 P302, Co. Cork, Ireland.
Teagasc, Animal & Grassland Research and Innovation Centre, Moorepark, Fermoy P61 P302, Co. Cork, Ireland.
J Dairy Sci. 2023 Dec;106(12):9044-9054. doi: 10.3168/jds.2023-23632. Epub 2023 Aug 23.
Gains through breeding can be achieved through a combination of both between-breed and within-breed selection. Two suites of traits of particular interest to dairy producers when selecting beef bulls for mating to dairy females are calving-related attributes and the expected value of the subsequent calf, the latter usually being a function of expected carcass value. Estimated breed effects can be informative, particularly in the absence of across-breed genetic evaluations. The objective of the present study was to use a large national database of the progeny from beef-on-dairy matings to estimate the mean breed effects of the used beef sires. Calving performance (i.e., gestation length, calving difficulty score, and perinatal morality) as well as calf value were investigated; a series of slaughter-related traits (i.e., carcass metrics and age at slaughter) of the prime progeny were also investigated. Phenotypic data on up to 977,037 progeny for calving performance, 79,903 for calf price and 103,175 for carcass traits (including dairy × dairy progeny for comparative purposes) were used; sire breeds represented were Holstein-Friesian, Angus, Aubrac, Belgian Blue, Charolais, Hereford, Limousin, Salers, and Simmental. Large interbreed differences existed. The mean gestation length of male calves from beef sires varied from 282.3 d (Angus) to 287.4 d (Limousin) which were all longer than the mean of 280.9 d for Holstein-Friesian sired male calves. Relative to a Holstein-Friesian sire, the odds of dystocia varied from 1.43 (Angus) to 4.77 (Belgian Blue) but, once adjusted for both the estimated maternal genetic merit of the dam and direct genetic merit of the calf for calving difficulty, the range in odds ratios shrunk. A difference of €125.4 existed in calf sale price between the progeny of the different beef breeds investigated which represented over twice the residual standard deviation in calf price within the day of sale-Angus was the cheapest while Charolais calves were, on average, the most expensive calves. Mean carcass weight of steers, not adjusted for age at slaughter or carcass fat, varied from 327.1 kg (Angus) to 363.2 kg (Belgian Blue) for the beef breeds with the mean carcass weight of Holstein-Friesian steer progeny being 322.4 kg. Belgian Blues had, on average, the best carcass conformation with the Herefords and Angus having the worst of all beef breeds. Angus and Hereford steers were slaughtered the youngest of all beef breeds but just 9 d younger than the average of all other beef breeds yet 24 d younger than Holstein-Friesian sired progeny. Clear breed differences in calving and carcass performance exist among beef breeds mated to dairy females. Those breeds excelling in calving performance were not necessarily the best for carcass merit.
通过杂交和品种内选择相结合,可以实现繁殖带来的增益。在选择用于与奶牛配种的肉牛公牛时,奶农特别关注两类特征:与产犊相关的属性和随后小牛的预期价值,后者通常是预期胴体价值的函数。估计的品种效应可能很有参考价值,特别是在缺乏跨品种遗传评估的情况下。本研究的目的是利用大型全国肉牛与奶牛杂交后代数据库,估计所使用的肉牛父本的平均品种效应。研究了产犊性能(即妊娠长度、产犊难度评分和围产期死亡率)和小牛价值;还研究了主要后代的一系列与屠宰相关的特征(即胴体指标和屠宰年龄)。使用了多达 977037 头与产犊性能相关的后代、79903 头与小牛价格相关的和 103175 头与胴体特征相关的(包括为比较目的的奶牛与奶牛的后代)的表型数据;代表的父本品种有荷斯坦-弗里森、安格斯、奥布拉克、比利时蓝、夏洛来、海福特、利木赞、萨莱、西门塔尔。品种间存在很大差异。来自肉牛父本的公犊的平均妊娠长度从 282.3 天(安格斯)到 287.4 天(利木赞)不等,均长于荷斯坦-弗里森父本公犊的平均妊娠长度 280.9 天。与荷斯坦-弗里森父本相比,难产的几率从 1.43(安格斯)到 4.77(比利时蓝)不等,但在同时考虑到母本的估计遗传优势和犊牛的直接遗传优势后,比值范围缩小了。不同肉牛品种的后代在小牛售价上存在 125.4 欧元的差异,这超过了销售当天小牛价格内的剩余标准差的两倍——安格斯是最便宜的,而夏洛来小牛平均是最昂贵的。未根据屠宰年龄或胴体脂肪调整的阉牛胴体重,从肉牛品种的 327.1 公斤(安格斯)到 363.2 公斤(比利时蓝)不等,而荷斯坦-弗里森阉牛后代的平均胴体重为 322.4 公斤。比利时蓝牛的胴体结构最好,而海福特牛和安格斯牛的胴体结构最差。安格斯和海福特牛是所有肉牛品种中最早屠宰的,但比所有其他肉牛品种的平均屠宰年龄仅小 9 天,比荷斯坦-弗里森父本的后代小 24 天。在与奶牛配种的肉牛品种中,产犊和胴体性能存在明显的品种差异。在产犊性能方面表现出色的品种,不一定在胴体价值方面表现最好。
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