Iñiguez L, Hilali M, Thomas D L, Jesry G
International Center for Agricultural Research in the Dry Areas (ICARDA), Aleppo, Syria.
J Dairy Sci. 2009 Sep;92(9):4613-20. doi: 10.3168/jds.2008-1950.
To improve the effectiveness of community-based breeding programs for increased milk production, the values of different udder measurements for predicting milk production traits during the milking period were assessed over 3 yr on 273 Awassi ewes. Machine milking of ewes began after weaning, 56 d after parturition, and continued until the milk yield of the ewes was <200 mL/d. Milk yield obtained by hand milking and milk composition were measured weekly, and days in milk, total milk yield, and total yields of protein, fat, and nonfat solids in milk were calculated for each ewe. On d 70 of milking, morphological traits of the whole udder (circumference, width, height, and length), udder cistern (height), and teats (length, width, and position score) were measured. On the same day, the milk yield of ewes was recorded by hand milking. Positive and moderate to strong correlations (r = 0.36 to 0.76) between udder circumference and width, teat width, and milk production traits of total milk yield, and total yields of protein, fat, and nonfat solids were found. However, a more accurate predictor of milk production traits was milk yield on d 70, as higher positive correlations between this variable and the milk production traits were found (r = 0.63 to 0.89). Nine farmers were invited to independently estimate the hand-milked milk yield performance of a sample of 169 ewes (d 15 to 45 of milking) by visually observing each ewe and making a subjective linear score (1 to 5). Their assessments were significantly correlated with milk yield on the day of the observation (r = 0.52), total milk yield (r = 0.50), and days in milk (r = 0.45). Considering the perception details provided by farmers concerning each of the subjective linear scores, it was found that most predictive linear udder measurements of udder circumference and width and teat width identified in this study were implicit in these scores. The predictive ability of the measurements studied have practical implications for community-based breeding programs involving improvement of milk production-not just in Syria, but in other countries in dry areas as well-because it is possible for experienced farmers to visually assess milk production of dairy ewes or take simple udder measurements with predictive value.
为提高基于社区的繁殖计划在提高产奶量方面的有效性,在3年时间里对273只阿瓦西母羊的不同乳房测量值在挤奶期预测产奶性状的价值进行了评估。母羊在断奶后(分娩后56天)开始机械挤奶,并持续到母羊产奶量低于200毫升/天。每周测量手工挤奶获得的产奶量和奶成分,并计算每只母羊的泌乳天数、总产奶量以及奶中蛋白质、脂肪和非脂固形物的总产量。在挤奶第70天,测量整个乳房的形态特征(周长、宽度、高度和长度)、乳房储乳池(高度)和乳头(长度、宽度和位置评分)。同一天,通过手工挤奶记录母羊的产奶量。发现乳房周长与宽度、乳头宽度以及总产奶量、蛋白质、脂肪和非脂固形物总产量等产奶性状之间存在正相关且中等至强相关(r = 0.36至0.76)。然而,产奶性状的更准确预测指标是第70天的产奶量,因为该变量与产奶性状之间发现了更高的正相关(r = 0.63至0.89)。邀请了9位农民通过目视观察169只母羊样本(挤奶第15至45天)并给出主观线性评分(1至5分),来独立估计其手工挤奶的产奶性能。他们的评估与观察当天的产奶量(r = 0.52)、总产奶量(r = 0.50)和泌乳天数(r = 0.45)显著相关。考虑到农民提供的关于每个主观线性评分的感知细节,发现本研究中确定的乳房周长、宽度和乳头宽度的大多数预测性线性乳房测量值都隐含在这些评分中。所研究测量值的预测能力对涉及提高产奶量的基于社区的繁殖计划具有实际意义——不仅在叙利亚,在其他干旱地区国家也是如此——因为经验丰富的农民能够目视评估奶用母羊的产奶量或进行具有预测价值的简单乳房测量。