Teagasc, Animal and Grassland Research and Innovation Centre, Moorepark, Fermoy, Co. Cork, P61 C996, Ireland; Institute of Global Food Security, Queen's University Belfast, Belfast, BT9 5DL, Northern Ireland.
INRAE, AgroCampus Ouest, Physiologie, Environnement et Génétique pour l'Animal et les Systèmes d'Elevage, St. Gilles, 35590, France.
J Dairy Sci. 2020 Jun;103(6):5200-5214. doi: 10.3168/jds.2019-17476. Epub 2020 Apr 3.
Pasture-based production systems typically require highly fertile, healthy, and robust genetics, with greater emphasis on milk solids (MSo; kg of fat + protein) production as opposed to milk yield. This study assessed milk production, production efficiency, reproductive performance, body weight (BW), body condition score, and functional traits in 3 different dairy cow genotypes: Holstein-Friesian (HF), Jersey × Holstein-Friesian (JEX), and Norwegian Red × (Jersey × Holstein-Friesian) (3-way). The 3 genotypes were rotationally grazed on 4 different grazing treatments after calving in spring and were stocked at a rate of 2.75 cows/ha. Holstein-Friesian cows produced higher daily and total milk yields compared with JEX and 3-way cows (5,718 vs. 5,476 and 5,365 kg/cow, respectively). However, JEX and 3-way cows had higher milk fat and protein contents (4.86 and 4.75%, respectively, for JEX and 3.87 and 3.88%, respectively, for 3-way) compared with HF (4.52 and 3.72%), resulting in similar MSo yield for JEX and HF (469 and 460 kg/cow) and slightly lower MSo yield for 3-way (453 kg/cow) compared with JEX. As parity increased, milk and MSo yield per cow increased. Reproductive performance was not significantly different between the 3 genotypes, which had similar 24-d submission rates, 6-wk pregnancy rates, and overall pregnancy rates over the 4-yr period. No difference in calving difficulty, incidence of mastitis, or incidence of lameness was observed among the 3 genotypes. Body weight was significantly different among all 3 genotypes, with HF being the heaviest followed by 3-way and JEX (530, 499, and 478 kg, respectively), and 3-way cows had a higher body condition score throughout lactation compared with HF and JEX cows. The differences in BW coupled with similar MSo production resulted in JEX cows having the highest production efficiency (4.58 kg of MSo/kg of metabolic BW), 3-way cows being intermediate (4.30 kg of MSo/kg of metabolic BW), and HF cows having the lowest (4.16 kg of MSo/kg of metabolic BW). In conclusion, HF herds with poor reproductive performance and low milk fat and protein contents are likely to benefit considerably from crossbreeding with Jersey, and all herds are likely to benefit in terms of production efficiency. However, where herd performance, particularly in relation to reproductive performance, is comparable with HF in the current study, crossbreeding with Jersey or Norwegian Red is unlikely to lead to significant improvements in overall herd performance.
基于牧草的生产系统通常需要高度肥沃、健康和强壮的遗传基因，更注重乳固体（MSo；脂肪+蛋白质千克数）的生产，而不是产奶量。本研究评估了 3 种不同奶牛基因型的产奶量、生产效率、繁殖性能、体重（BW）、体况评分和功能特性：荷斯坦-弗里生（HF）、泽西牛×荷斯坦-弗里生（JEX）和挪威红牛×（泽西牛×荷斯坦-弗里生）（3 向）。3 种基因型在春季产后分别进行 4 种不同放牧处理的轮牧，每公顷载畜量为 2.75 头奶牛。与 JEX 和 3 向奶牛相比，荷斯坦-弗里生奶牛的日和总产奶量更高（分别为 5718、5476 和 5365 千克/头）。然而，JEX 和 3 向奶牛的乳脂和乳蛋白含量较高（分别为 4.86%和 4.75%，JEX 和 3.87%和 3.88%，3 向），与 HF（4.52%和 3.72%）相比，结果是 JEX 和 HF 的 MSo 产量相似（每头 469 千克），3 向的 MSo 产量略低（每头 453 千克）。随着胎次的增加，每头奶牛的产奶量和 MSo 产量增加。3 种基因型之间的繁殖性能没有显著差异，它们在 4 年期间具有相似的 24 天提交率、6 周妊娠率和总妊娠率。3 种基因型之间没有产犊困难、乳腺炎发生率或跛行发生率的差异。所有 3 种基因型的体重均有显著差异，HF 最重，其次是 3 向和 JEX（分别为 530、499 和 478 千克），3 向奶牛在整个泌乳期的体况评分均高于 HF 和 JEX 奶牛。体重的差异加上相似的 MSo 产量，导致 JEX 奶牛的生产效率最高（每代谢 BW 4.58 千克 MSo），3 向奶牛居中（每代谢 BW 4.30 千克 MSo），HF 奶牛最低（每代谢 BW 4.16 千克 MSo）。总之，繁殖性能差、乳脂和乳蛋白含量低的 HF 牛群可能会从与泽西牛的杂交中获得巨大收益，所有牛群在生产效率方面都可能受益。然而，在当前研究中，如果牛群的表现，特别是繁殖性能与 HF 相当，那么与泽西牛或挪威红牛的杂交不太可能导致整体牛群性能的显著提高。
