King K K, Seidel G E, Elsden R P
J Anim Sci. 1985 Oct;61(4):758-62. doi: 10.2527/jas1985.614758x.
Lengths of gestation were determined from 1,484 pregnancies resulting from embryo transfer procedures. Least-square means of lengths of gestation by breed of embryos (P less than .005) were: Holstein, 278.7; Angus, 281.0; Hereford, 285.7; Simmental, 287.6 and Limousin, 289.7 d. Recipient breed had a small effect on length of gestation (P less than .005). The length of gestation for recipients less than 4 yr old was 2.7 d shorter (P less than .005) than for older recipients. As asynchrony of recipient and donor estrus changed by 1 d, length of gestation changed linearly by .78 d (P less than .005). Male calves were carried 1.4 d longer than females (P less than .005). Embryo age at time of transfer, embryo quality, length of embryo storage between collection and transfer, and donor age did not affect length of gestation significantly. Lengths of gestation of 185 embryo transfer pregnancies were 1.5 d longer (P greater than .1) than those of 305 matched control pregnancies from the same farms. We conclude that length of gestation of embryo transfer calves and length of gestation of non-embryo transfer calves are influenced by similar factors.
从1484例胚胎移植手术所产生的妊娠中确定了妊娠期长度。按胚胎品种划分的妊娠期最小二乘均值（P<0.005）为：荷斯坦牛，278.7天；安格斯牛，281.0天；赫里福德牛，285.7天；西门塔尔牛，287.6天；利木赞牛，289.7天。受体品种对妊娠期长度有较小影响（P<0.005）。4岁以下受体的妊娠期比年长受体短2.7天（P<0.005）。随着受体与供体发情同步性每改变1天，妊娠期长度呈线性变化0.78天（P<0.005）。雄性犊牛的妊娠期比雌性长1.4天（P<0.005）。移植时的胚胎年龄、胚胎质量、采集与移植之间的胚胎储存时间以及供体年龄对妊娠期长度均无显著影响。185例胚胎移植妊娠的妊娠期比来自同一农场的305例匹配对照妊娠长1.5天（P>0.1）。我们得出结论，胚胎移植犊牛的妊娠期长度和非胚胎移植犊牛的妊娠期长度受相似因素影响。
