Department of Animal Science, University of Minnesota, St. Paul, MN 55108.
Department of Animal Science, University of Minnesota, St. Paul, MN 55108.
J Dairy Sci. 2024 Nov;107(11):9656-9665. doi: 10.3168/jds.2024-24652. Epub 2024 Jul 14.
Cull cows from dairy farms in the United States account for 10% of the beef market; however, few studies have evaluated the effects of crossbreeding on reasons for disposal and cull value of dairy cows. The objective of the study was to compare reasons for disposal and cull cow value of Holstein and crossbred cows (n = 1,292) in an experimental dairy herd at the University of Minnesota West Central Research and Outreach Center (Morris, MN). Cows were Holstein (n = 272), 1964 genetic control Holstein (n = 161), 3-breed crossbred cows (n = 538) composed of the Montbéliarde, Viking Red, and Holstein (MVH) breeds, and 3-breed crossbred cows (n = 321) composed of the Normande, Jersey, and Viking Red (NJV) breeds. The 1964 genetic control Holstein cows originated from a design initiated at the University of Minnesota for comparison of the 1964 Holstein and contemporary Holstein cows selected for production across time. Records spanned from January 2010 to December 2023. Reasons for disposal were recorded in PCDart Herd Management Software, and cull value and body weight were obtained from receipts from livestock cull markets. For all cows, the primary reasons for disposal were as follows: reproduction (44.4%), mastitis (18%), other reasons (14.6%), death (10.3%), dairy purposes (8.4%), and low production (4.3%). Independent variables for statistical analysis of cull value were the fixed effects of body weight at time of culling, DIM at culling (0-49 DIM, 50-99 DIM, 100-149 DIM, 150-199 DIM, 200-249 DIM, 250-299 DIM, 300-350 DIM, and >350 DIM), year (2010-2023), season (spring, summer, autumn, winter), parity (1, 2, 3, 4, 5+), primary reason for culling, breed group, and sire breed group nested within breed group. Least squares means for body weight at culling was 558 kg for Holsteins, 543 kg for 1964 Holsteins, 551 kg for MVH crossbred cows, and 499 kg for NJV crossbred cows. For the analysis across time, 2014 had the highest cull value ($1,126.98), and 2020 had the lowest gross cull value ($515.21). Cows culled at greater than 300 DIM had the highest cull value and cows culled at less than 50 DIM had the lowest cull value. Cows culled during the spring and summer had higher cull value compared with cows culled during the autumn and winter. The Holstein cows ($730.04) had lower gross value compared with 1964 Holsteins ($804.38) cows and MVH ($767.39) cows. The NJV ($771.39) cows were not different from crossbreds sired by Montbéliarde, Viking Red, and Holstein bulls. Results for comparisons of breed group are from one experimental herd, so inferences to the wider dairy cow population should be undertaken with caution. In summary, dairy producers may receive greater cull value from crossbred cows compared with Holstein cows.
美国从奶牛场淘汰的奶牛占牛肉市场的 10%；然而，很少有研究评估杂交对淘汰和淘汰奶牛价值的原因。本研究的目的是比较明尼苏达大学西部研究与推广中心（莫里斯，MN）实验奶牛场荷斯坦和杂交奶牛（n=1292）的淘汰原因和淘汰牛价值。奶牛分为荷斯坦（n=272）、1964 年遗传控制荷斯坦（n=161）、3 品种杂交奶牛（n=538）由蒙贝利亚尔、维京红和荷斯坦（MVH）品种组成，以及 3 品种杂交奶牛（n=321）由诺曼底、泽西和维京红（NJV）品种组成。1964 年遗传控制荷斯坦奶牛源自明尼苏达大学为比较 1964 年荷斯坦和随时间选择生产的当代荷斯坦而发起的一项设计。记录始于 2010 年 1 月，止于 2023 年 12 月。淘汰原因记录在 PCDart herd Management 软件中，淘汰价值和体重从牲畜淘汰市场的收据中获得。对于所有奶牛，淘汰的主要原因如下：繁殖（44.4%）、乳腺炎（18%）、其他原因（14.6%）、死亡（10.3%）、奶牛用途（8.4%）和低产（4.3%）。淘汰价值统计分析的自变量为淘汰时体重的固定效应、淘汰时的 DIM（0-49 DIM、50-99 DIM、100-149 DIM、150-199 DIM、200-249 DIM、250-299 DIM、300-350 DIM 和>350 DIM）、年份（2010-2023）、季节（春季、夏季、秋季、冬季）、胎次（1、2、3、4、5+）、淘汰主要原因、品种组和品种组内嵌套的父本品种组。淘汰时体重的最小二乘均值分别为荷斯坦 558 公斤、1964 年荷斯坦 543 公斤、MVH 杂交奶牛 551 公斤和 NJV 杂交奶牛 499 公斤。对于跨时间分析，2014 年的淘汰价值最高（$1126.98），2020 年的总淘汰价值最低（$515.21）。DIM 大于 300 的奶牛淘汰价值最高，DIM 小于 50 的奶牛淘汰价值最低。春季和夏季淘汰的奶牛淘汰价值高于秋季和冬季淘汰的奶牛。荷斯坦奶牛（$730.04）的总价值低于 1964 年荷斯坦奶牛（$804.38）和 MVH（$767.39）奶牛。NJV（$771.39）奶牛与由蒙贝利亚尔、维京红和荷斯坦公牛配种的杂交牛没有区别。品种组比较的结果来自一个实验性奶牛场，因此对更广泛的奶牛种群的推论应谨慎进行。总之，与荷斯坦奶牛相比，奶牛养殖者可能从杂交奶牛中获得更高的淘汰价值。
