Pool-Anderson K, Raub R H, Warren J A
Kansas State University, Manhattan 66506-0201.
J Anim Sci. 1994 Jul;72(7):1661-6. doi: 10.2527/1994.7271661x.
Six pairs of full-sibling Quarter Horse foals were produced by non-surgical embryo transfer and immediate rebreeding of donor mares. Each pair of donor/recipient mares consisted of one multiparous (donor) and one nulliparous (recipient) mare of similar body type and size. Milk yield was determined within 2 d of 8, 15, 22, 29 d (early lactation); 45, 60 d (midlactation); and 90, 120 d (late lactation) postpartum by the weigh-suckle-weigh method. On the following day, milk samples were collected, and foals were weighed and measured for wither height, heart girth, metacarpal length, metatarsal length, carpus height, tarsus height, and hip height. Mean gestation length was longer (P < .05) in nulliparous mares than multiparous mares (343 vs 333 d). Daily milk production was greater (P < .05) during early lactation (12.1 vs 10.8 kg) and tended to be greater (P = .08) during midlactation (11.7 vs 10.4) in multiparous mares but was similar between groups in late lactation. Milk composition was similar between groups throughout lactation. Foals produced by multiparous mares weighed more (P < .03) throughout early lactation (70.4 vs 63.1 kg), but no differences in weights occurred between foals from multiparous and nulliparous mares through mid- and late lactation. Average daily weight gain (ADG) was similar between foal groups through early and midlactation. During late lactation, ADG tended to be greater (P = .07) in foals from nulliparous mares (1.05 vs .92 kg/d). These data suggest that nulliparous and multiparous mares of the same breed and similar body type and size produce foals with no differences in size and weight by 4 mo of age.
通过非手术胚胎移植和供体母马立即再次配种，培育出了6对同胎 Quarter Horse 马驹。每对供体/受体母马由一匹体型和大小相似的经产母马（供体）和一匹初产母马（受体）组成。在产后第8、15、22、29天（泌乳早期）；45、60天（泌乳中期）；以及90、120天（泌乳晚期）的2天内，采用称重-哺乳-称重法测定产奶量。在接下来的一天，采集牛奶样本，并对马驹进行称重，测量其鬐甲高度、胸围、掌骨长度、跖骨长度、腕关节高度、跗关节高度和臀部高度。初产母马的平均妊娠期比经产母马长（P < 0.05）（343天对333天）。经产母马在泌乳早期的日产奶量更高（P < 0.05）（12.1千克对10.8千克），在泌乳中期也倾向于更高（P = 0.08）（11.7千克对10.4千克），但在泌乳晚期两组之间相似。整个泌乳期内，两组之间的牛奶成分相似。经产母马所产马驹在整个泌乳早期体重更重（P < 0.03）（70.4千克对63.1千克），但在泌乳中期和晚期，经产母马和初产母马所产马驹的体重没有差异。在泌乳早期和中期，马驹组之间的平均日增重（ADG）相似。在泌乳晚期，初产母马所产马驹的ADG倾向于更高（P = 0.07）（1.05千克/天对0.92千克/天）。这些数据表明，相同品种、体型和大小相似的初产母马和经产母马所产马驹在4月龄时，大小和体重没有差异。
