Kern Jessica, Jorgensen Matt W, Boerman Jacquelyn P, Erasmus Marisa, Johnson Jay S, Pempek Jessica A
Department of Animal Sciences, Purdue University, West Lafayette, IN, 47907, USA.
USDA-ARS, Livestock Behavior Research Unit, West Lafayette, IN, 47907, USA.
Transl Anim Sci. 2025 Jun 14;9:txaf062. doi: 10.1093/tas/txaf062. eCollection 2025.
The use of beef genetics in dairy herds is becoming increasingly popular due to higher value for dairy × beef crossbred compared to purebred dairy calves. While previous research has documented higher-quality neonatal care for female compared to male dairy calves, few studies have investigated colostrum management between purebred dairy and dairy × beef crossbred calves. The aims of this cross-sectional study were to 1) compare transfer of passive immunity between purebred dairy and dairy × beef crossbred calves and 2) investigate colostrum management practices associated with TPI on farms rearing both calf breeds. A blood sample was collected from the jugular vein of 12 purebred dairy and 12 dairy × beef crossbred calves (1 to 7 d of age) across 15 dairy farms to measure serum total protein concentration using serum refractometry. Sex, age, and breed were recorded for each calf. A 29-question survey was also administered to dairy farm managers that included questions on colostrum management, calf sale, and farm demographics. Descriptive statistics were computed for survey-based questions, and mixed effects ordinal regression models were created to evaluate factors at the calf and farm-level that were associated with TPI, categorized according to Lombard et al. (2020). Consensus recommendations on calf- and herd-level passive immunity in dairy calves in the United States. J. Dairy Sci. 103:7611-7624. doi:https://doi.org/10.3168/jds.2019-17955) as excellent TPI (STP ≥ 6.2 g/dL), good TPI (STP 5.8 to 6.1 g/dL), fair TPI (STP 5.1 to 5.7 g/dL), and poor TPI (STP < 5.1 g/dL). All farms reported similar colostrum management practices between purebred dairy and dairy × beef crossbred calves. Most farms (60%, 9/15) fed 2 colostrum feedings, 33% (5/15) of farms fed 1 colostrum feeding, and 7% (1/15) fed 3 or more colostrum feedings. Serum total protein concentration ranged from 3.2 to 8.0 g/dL, and the distribution of calves within each TPI category was: 20.8% (74/355) excellent, 25.4% (90/355) good, 26.5% (94/355) fair, and 27.3% (97/355) poor. There was no evidence to suggest differences in TPI between breeds. The reported timing of the first colostrum feeding influenced TPI; calves born on farms that reported feeding colostrum within 1 h after birth had reduced odds of being within a lower TPI category (OR: 0.48, 95% CI: 0.30 to 0.77; = 0.002). The results of this study indicate that colostrum management practices and TPI did not differ between purebred dairy and dairy × beef crossbred calves. Future research should continue to explore strategies to improve TPI for dairy calves regardless of breed.
由于奶牛与肉牛杂交犊牛相比纯种奶牛犊具有更高的价值，肉牛基因在奶牛群中的应用越来越普遍。虽然先前的研究记录了雌性奶牛犊比雄性奶牛犊能得到更高质量的新生护理，但很少有研究调查纯种奶牛犊和奶牛×肉牛杂交犊牛之间的初乳管理情况。这项横断面研究的目的是：1）比较纯种奶牛犊和奶牛×肉牛杂交犊牛之间的被动免疫转移情况；2）调查在饲养这两种犊牛品种的农场中与总蛋白指数（TPI）相关的初乳管理实践。从15个奶牛场的12头纯种奶牛犊和12头奶牛×肉牛杂交犊牛（1至7日龄）的颈静脉采集血样，使用血清折射仪测量血清总蛋白浓度。记录每头犊牛的性别、年龄和品种。还对奶牛场管理人员进行了一项包含29个问题的调查，问题涉及初乳管理、犊牛销售和农场人口统计学。对基于调查的问题进行描述性统计，并创建混合效应有序回归模型，以评估犊牛和农场层面与TPI相关的因素，这些因素根据Lombard等人（2020年）的分类进行分类。美国奶牛犊牛在犊牛和牛群层面被动免疫的共识性建议。《乳品科学杂志》103:7611 - 7624。doi:https://doi.org/10.3168/jds.2019 - 17955）将TPI分为优秀（血清总蛋白≥6.2 g/dL）、良好（血清总蛋白5.8至6.1 g/dL）、中等（血清总蛋白5.1至5.7 g/dL）和较差（血清总蛋白<5.1 g/dL）。所有农场报告的纯种奶牛犊和奶牛×肉牛杂交犊牛的初乳管理实践相似。大多数农场（60%，9/15）喂2次初乳，33%（5/15）的农场喂1次初乳，7%（1/15）喂3次或更多次初乳。血清总蛋白浓度范围为3.2至8.0 g/dL，每个TPI类别内犊牛的分布情况为：优秀20.8%（74/355）、良好25.4%（90/355）、中等26.5%（94/355）、较差27.3%（97/355）。没有证据表明品种之间的TPI存在差异。报告的首次初乳喂养时间影响TPI；出生在报告在出生后1小时内喂初乳的农场的犊牛处于较低TPI类别的几率降低（比值比：0.48，95%置信区间：0.30至0.77；P = 0.002）。本研究结果表明，纯种奶牛犊和奶牛×肉牛杂交犊牛之间的初乳管理实践和TPI没有差异。未来的研究应继续探索提高奶牛犊牛TPI的策略，无论其品种如何。
