Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853.
Department of Animal Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, NY 14853.
J Dairy Sci. 2023 Jul;106(7):4896-4905. doi: 10.3168/jds.2022-22960. Epub 2023 Jun 7.
Colostrum yield and quality are influenced by prepartum nutrition and the metabolic status of the cow; however, data considering these associations on multiple dairy farms are limited. Our objective was to identify cow-level prepartum metabolic indicators, as well as farm-level nutritional strategies associated with colostrum yield and the indicator of colostrum quality, Brix %. A convenience sample of 19 New York Holstein dairies (median: 1,325 cows; range: 620 to 4,600 cows) were enrolled in this observational study. Records for individual colostrum yield and Brix % were collected by farm personnel between October 2019 and February 2021. Farms were visited 4 times, approximately 3 mo apart, to obtain feed samples of the prepartum diets, collect blood samples from 24 pre- and postpartum cows, respectively, and determine prepartum body condition score. Feed samples were submitted for analysis of chemical composition, and particle size was determined on-farm using a particle separator. Prepartum serum samples (n = 762) were analyzed for glucose and nonesterified fatty acid concentrations. Whole blood from postpartum cows was analyzed for herd prevalence of hyperketonemia (proportion of samples with β-hydroxybutyrate ≥1.2 mmol/L). A cohort of primiparous (PP; n = 1,337) and multiparous (MPS; n = 3,059) cows calving ± 14 d of each farm visit were included in the statistical analysis. Animals calving in this period were assigned results for the close-up diet composition and herd prevalence of hyperketonemia collected from the respective farm visit. Greatest colostrum yield from PP and MPS cows was associated with moderate starch [18.6-22.5% of dry matter (DM)] and a moderate herd prevalence of hyperketonemia (10.1-15.0%). Greatest colostrum yield from MPS cows was associated with moderate crude protein (13.6-15.5% of DM) and a less severe negative dietary cation-anion difference (DCAD; >-8 mEq/100 g), whereas greatest colostrum yield from PP cows was associated with low crude protein (≤13.5% of DM). In addition, a moderate proportion of the diet with particle length ≥19 mm (15.3-19.1%) was associated with lowest colostrum yield from PP and MPS cows. Highest colostrum Brix % was associated with prepartum dietary factors of low neutral detergent fiber (≤39.0% of DM) and high proportion of the diet with particle length ≥19 mm (>19.1%). In addition, low starch (≤18.5% of DM) and low and moderate DCAD level (≥-15.9 mEq/100 g) were associated with greatest Brix % from PP cows, whereas moderate DCAD (-15.9 to -8.0 mEq/100 g) was associated with greatest Brix % from MPS cows. Prepartum serum nonesterified fatty acid concentration ≥290 µEq/L was associated with increased colostrum yield, but prepartum serum glucose concentration and body condition score were not associated with colostrum yield or Brix %. These data provide nutritional and metabolic variables to consider when troubleshooting colostrum production on farms.
初乳的产量和质量受产前营养和奶牛的代谢状况影响；然而，考虑到这些关联在多个奶牛场的数据是有限的。我们的目的是确定与奶牛产前代谢指标以及农场层面的营养策略相关的初乳产量和初乳质量指标（Brix%）。本研究采用方便抽样法，选取了 19 个纽约荷斯坦奶牛场（中位数：1325 头奶牛；范围：620-4600 头奶牛）参与这项观察性研究。2019 年 10 月至 2021 年 2 月期间，农场工作人员分别收集了个体初乳产量和 Brix%的数据。每隔 3 个月左右，农场会进行 4 次访问，以获取产前饮食的饲料样本，分别从 24 头产前和产后奶牛中采集血液样本，并确定产前体况评分。饲料样本被送去进行化学成分分析，并在农场使用颗粒分离器测定颗粒大小。产前血清样本（n=762）被用于分析葡萄糖和非酯化脂肪酸浓度。产后奶牛的全血用于分析 herd prevalence of hyperketonemia（β-羟丁酸浓度≥1.2mmol/L 的样本比例）。我们还纳入了在每个农场访问±14d 产犊的初产（PP；n=1337）和经产（MPS；n=3059）奶牛的队列进行统计分析。在这段时间内产犊的动物被分配了各自农场访问期间收集的近距离饮食组成和 herd prevalence of hyperketonemia 的结果。PP 和 MPS 奶牛的最大初乳产量与中等淀粉（18.6-22.5%干物质）和中等 herd prevalence of hyperketonemia（10.1-15.0%）有关。MPS 奶牛的最大初乳产量与中等粗蛋白（13.6-15.5%干物质）和较低的负阳离子-阴离子差异（DCAD；> -8mEq/100g）有关，而 PP 奶牛的最大初乳产量与低粗蛋白（≤13.5%干物质）有关。此外，与初乳产量较低的 PP 和 MPS 奶牛有关的是，饲料中具有中等长度（15.3-19.1%）的颗粒比例较高。最高的初乳 Brix%与产前饮食因素有关，如低中性洗涤纤维（≤39.0%干物质）和高比例的颗粒长度≥19mm（>19.1%）。此外，低淀粉（≤18.5%干物质）和低至中等 DCAD 水平（≥-15.9mEq/100g）与 PP 奶牛的最大 Brix%有关，而中等 DCAD（-15.9 至-8.0mEq/100g）与 MPS 奶牛的最大 Brix%有关。产前血清非酯化脂肪酸浓度≥290μEq/L 与初乳产量增加有关，但产前血清葡萄糖浓度和体况评分与初乳产量或 Brix%无关。这些数据为解决农场初乳生产问题时提供了营养和代谢方面的变量。
