Abstract

The aspects of Black-and-White holsteinized cow’s productive lifespan were the objectives of the survey carried out with 9270 Black-and-White cows and their crosses with Holstein bulls that were culled in 1990–2020 for different reasons at the end of their productive lifespan. The survey was performed based on pedigree and commercial cattle farms in Smolensk oblast with the grouping method. Phenotypic correlations between the analyzed production traits were estimated. Holsteinization of the Black-and-White breed in the Smolensk oblast resulted in its absorption through crossing the cows with Holstein sires to have a Holstein blood percentage of 90.0%. The survey outcomes have revealed a regularity indicating that the higher the percentage of Holstein blood is, the shorter longevity of cows is observed. The difference in lifespan of cows with Holstein blood percentage from 17.6 to 87.1% comprised 4.36 lactation cycles. The productive lifespan of cows can reach 12–13 lactation cycles. However, 50.9% of these animals are culled between the second and fourth lactation cycles. The ratio of days in milk to days dry in dairy cows tends to change with aging. Thus, the longer the productive lifespan in cows is, the higher the number of days in milk per each year of life, on average, is recorded. The major proportion of cows is productive within the ratio of days in milk to lifetime days, varying in the range of 50.1 to 75.0%. Their lifespan is measured by 4.3 lactation cycles. The lifetime milk yield usually varies from 10 000 to 30 000 kg (for 56.7% of the analyzed livestock). The parameter for lifetime daily yield is reasonable to use as an indicator of cow productive lifespan due to its strong positive correlations (r = 0.44–0.90) relative to age-related and productivity performance. The Black-and-White cattle inventory in the Smolensk oblast has proven that it is reasonable to replace this breed with the Holstein breed for its subsequent pure breeding.

中文翻译：

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荷斯坦饲养对斯摩棱斯克州黑白奶牛生产寿命的影响

摘要

黑白荷斯坦奶牛的生产寿命方面是对 9270 头黑白荷斯坦奶牛及其与 1990 年至 2020 年因不同原因被淘汰的荷斯坦公牛杂交进行的调查的目标。寿命。本次调查以斯摩棱斯克州的纯种牛场和商品牛场为对象，采用分组的方法进行。估计了所分析的生产性状之间的表型相关性。斯摩棱斯克州黑白品种的荷斯坦化通过将奶牛与荷斯坦公牛杂交而吸收，其荷斯坦血统比例达到 90.0%。调查结果揭示了一个规律，即荷斯坦血的比例越高，奶牛的寿命越短。荷斯坦血百分比从 17.6% 到 87.1% 的奶牛寿命差异包括 4.36 个泌乳周期。奶牛的生产寿命可达12-13个泌乳周期。然而，50.9% 的动物在第二个和第四个哺乳周期之间被宰杀。奶牛的产奶天数与干奶天数的比例往往会随着年龄的增长而变化。因此，奶牛的生产寿命越长，平均每年记录的产奶天数就越多。大部分奶牛的产奶天数与终生天数之比在 50.1% 至 75.0% 之间变化。它们的寿命是通过 4.3 个哺乳周期来衡量的。终生产奶量通常为 10 000 至 30 000 公斤（占所分析牲畜的 56.7%）。终生日产量参数可以合理地用作奶牛生产寿命的指标，因为它与年龄相关和生产力表现具有很强的正相关性（ r = 0.44-0.90）。斯摩棱斯克州黑白牛存栏证明，将该品种替换为荷斯坦品种进行后续纯种繁育是合理的。