Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506.
Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan 66506.
J Dairy Sci. 2021 Apr;104(4):4303-4316. doi: 10.3168/jds.2020-19364. Epub 2021 Feb 13.
Research investigating the effects of feeding raw or pasteurized nonsaleable milk (NSM) on heifers' performance beyond the period of supplementation is limited. This study aimed to examine the effects of type of milk [NSM or milk replacer (MR)] and pasteurization of NSM on preweaning and first-lactation performance of heifers born with low (<36.3 kg) or normal birth weight (≥36.3 kg). Holstein heifers (n = 154) were sequentially assigned to 1 of 3 treatments: MR, pasteurized NSM, or raw NSM. Heifers assigned to raw NSM were fed raw colostrum, whereas heifers assigned to MR and pasteurized NSM were fed pasteurized colostrum. The low birth weight heifers were fed 1.4 L at each feeding until they reached 36.3 kg body weight, whereas normal birth weight heifers were fed 1.9 L at each feeding. A grain mix starter was offered throughout the study. Heifers were weaned ≥42 d old if consuming at least 0.9 kg/d of starter for 3 consecutive days. Data were analyzed with the MIXED procedure of SAS (SAS Institute Inc., Cary, NC), and the basic model included milk treatments, birth weight group, and treatment × birth weight group. The low birth weight heifers fed raw colostrum and NSM versus pasteurized colostrum and NSM had lower serum protein concentrations. Heifers fed MR versus NSM had or tended to have greater concentrations of hematocrit, red blood cells, and eosinophils but lesser concentrations of platelets, although some of those responses were temporary. Pasteurization tended to increase blood lymphocyte concentrations. Heifers with normal birth weight had greater concentrations of blood neutrophils, lymphocytes, and monocytes, compared with low birth weight heifers. For the first 42 d of life, low birth weight heifers fed pasteurized versus raw NSM had greater weight gain, grain intake, and feed efficiency and were weaned earlier (hazard ratio for weaning by 56 d: 2.90). These pasteurization effects for low birth weight heifers tended to be sustained through 24 wk of age, indicated by greater weight gain and hip height growth. In their first lactation, low birth weight heifers produced less mature-equivalent (MEq) protein and tended to produce less MEq milk and fat than normal birth weight heifers. However, the negative effects of low birth weight on MEq milk and fat yield was only evident in heifers fed raw NSM, whereas the performance of low birth weight heifers was similar to that of normal birth weight when fed MR or pasteurized NSM. These findings confirm that calf management practices influence future performance; in this case, failing to pasteurize milk and colostrum for low birth weight heifers had effects that remained apparent for more than 2 years.
研究调查了在补充期之外，给小母牛喂食生的或巴氏消毒的非销售牛奶（NSM）对其性能的影响是有限的。本研究旨在检验牛奶类型[NSM 或代乳粉（MR）]和 NSM 巴氏消毒对出生体重低（<36.3 公斤）或正常（≥36.3 公斤）的小母牛的断奶前和泌乳期性能的影响。荷斯坦小母牛（n=154）按 3 种处理方式之一顺序分配：MR、巴氏消毒的 NSM 或生 NSM。分配给生 NSM 的小母牛喂食生初乳，而分配给 MR 和巴氏消毒的 NSM 的小母牛喂食巴氏消毒的初乳。低出生体重的小母牛每次喂食 1.4 L，直到它们达到 36.3 公斤体重，而正常出生体重的小母牛每次喂食 1.9 L。在整个研究过程中提供了一种谷物混合起动器。如果连续 3 天每天至少消耗 0.9 公斤/天的起动器，小母牛将在≥42 天大时断奶。数据采用 SAS（SAS Institute Inc.，Cary，NC）的 MIXED 程序进行分析，基本模型包括牛奶处理、出生体重组和处理×出生体重组。与巴氏消毒的 NSM 和 colostrum 相比，喂食生 colostrum 和 NSM 的低出生体重小母牛的血清蛋白浓度较低。与 NSM 相比，喂食 MR 的小母牛的红细胞压积、红细胞和嗜酸性粒细胞浓度更高，但血小板浓度较低，尽管有些反应是暂时的。巴氏消毒会增加血液淋巴细胞浓度。与低出生体重小母牛相比，正常出生体重小母牛的血液中性粒细胞、淋巴细胞和单核细胞浓度更高。在生命的前 42 天，与低出生体重小母牛相比，喂食巴氏消毒的 NSM 的小母牛的体重增加、谷物摄入量和饲料效率更高，断奶更早（通过 56 天断奶的危险比：2.90）。这些低出生体重小母牛的巴氏消毒效果在 24 周龄时仍持续存在，表现为体重增加和臀部高度生长。在其第一次泌乳期间，低出生体重小母牛产生的成熟当量（MEq）蛋白质较少，并且 MEq 牛奶和脂肪的产量往往低于正常出生体重小母牛。然而，低出生体重对 MEq 牛奶和脂肪产量的负面影响仅在喂食生 NSM 的小母牛中明显，而喂食 MR 或巴氏消毒的 NSM 的低出生体重小母牛的性能与正常出生体重小母牛相似。这些发现证实了小牛管理实践会影响其未来的性能；在这种情况下，未能对低出生体重小母牛的牛奶和初乳进行巴氏消毒，其影响在 2 年以上仍很明显。
