Departamento de Producción Animal, Universidad de Córdoba, Córdoba 14071, Spain.
Departamento de Producción Animal, Universidad de Córdoba, Córdoba 14071, Spain.
J Dairy Sci. 2018 May;101(5):3878-3886. doi: 10.3168/jds.2017-13816. Epub 2018 Mar 1.
Milk coagulation, especially in small ruminant species, is often hard to evaluate, as coagulation traits are normally considered individually and several factors related to udder health might distort yield calculation. Due to the lack of studies about these factors, our objective was to determine milk coagulation efficiency (CE) and its determinants using a deterministic technical efficiency approach, an ordinary least square regression model, and ANOVA. Milk from 300 Manchega ewes was collected and analyzed for composition, milk coagulation properties, and hygienic quality. The study results indicate that the estimated CE in Manchega ewes was 0.69, implying an important proportion of the animals produce poorly coagulating milk. The results of the ordinary least square regression model and ANOVA revealed that the main factor causing inefficiency was the initial pH of milk. Crude protein, casein and plasmin activity had moderate effects on CE, and, finally, other factors such as freezing point depression, somatic cell count, colony-forming units, and fat concentration had minor effects.
乳的凝固，特别是在小型反刍动物中，通常难以评估，因为凝固特性通常被单独考虑，并且与乳房健康有关的几个因素可能会扭曲产奶量的计算。由于缺乏关于这些因素的研究，我们的目标是使用确定性技术效率方法、普通最小二乘回归模型和方差分析来确定乳的凝固效率（CE）及其决定因素。收集并分析了 300 只曼彻格绵羊的乳样，以评估其组成、乳的凝固特性和卫生质量。研究结果表明，曼彻格绵羊的估计 CE 为 0.69，这意味着相当一部分动物产的乳凝固不良。普通最小二乘回归模型和方差分析的结果表明，造成效率低下的主要因素是乳的初始 pH 值。粗蛋白、酪蛋白和纤溶酶活性对 CE 有中等影响，最后，其他因素如冰点降低、体细胞计数、菌落形成单位和脂肪浓度的影响较小。
