Othmane M Houcine, Angel Fuertes J, Gonzalo Carlos, De La Fuente L Fernando, Primitivo Fermín San
Institut National de la Recherche Agronomique de Tunisie, Rue Hédi Karray, 2049 Ariana, Tunisia.
J Dairy Res. 2006 Feb;73(1):109-14. doi: 10.1017/S0022029905001573.
Simplified designs of milk-composition recording, based on information from a single monthly milking, adjusted or not for interval between milkings and for milk yield, were simulated and evaluated for 2553 ewe-test-day records belonging to 155 lactations of Churra dairy ewes. Accuracy of simplified methods was evaluated by comparing estimated trait values (fat, protein, casein and total solid yields) with those observed both in a reference plan, where the two daily milkings were recorded at weekly intervals (A1), and in the official A4 milk recording (monthly records of the two daily milkings). Trait yields per lactation were estimated and adjusted to the only milking period (days in milk 30-120). Estimates of milk component traits were less precise when monthly designs, including the A4 design, were compared with a weekly sampling of both a.m. and p.m. milkings, with fat yield being the most difficult trait to estimate. All options with one daily milking every month were more accurate when the corresponding plan was based on, or began with, the a.m. milking. Adjustment for the preceding interval between milkings or milk yield did not improve sampling accuracy. The design alternating a.m. and p.m. milkings every month, without adjustment, is suggested for recoding milk component traits in dairy ewes.
基于单次月度挤奶信息的简化奶成分记录设计，无论是否针对挤奶间隔和产奶量进行调整，均针对属于155头丘拉奶羊155个泌乳期的2553条母羊测试日记录进行了模拟和评估。通过将估计的性状值（脂肪、蛋白质、酪蛋白和总固体产量）与在参考方案（其中每周记录两次每日挤奶）和官方A4奶记录（两次每日挤奶的月度记录）中观察到的值进行比较，评估了简化方法的准确性。估计每个泌乳期的性状产量，并将其调整到唯一的挤奶期（产奶30 - 120天）。当将包括A4设计在内的月度设计与上午和下午挤奶的每周抽样进行比较时，奶成分性状的估计不太精确，脂肪产量是最难估计的性状。当相应方案基于上午挤奶或以上午挤奶开始时，每月一次每日挤奶的所有选项都更准确。对前一次挤奶间隔或产奶量进行调整并不能提高抽样准确性。建议采用每月交替进行上午和下午挤奶且不进行调整的设计来记录奶羊的奶成分性状。
