Allen W R, Wilsher Sandra, Tiplady Clare, Butterfield R M
University of Cambridge, Department of Clinical Veterinary Medicine Equine Fertility Unit, Mertoun Paddocks, Woodditton Road, Newmarket, Suffolk CB8 9BH, UK.
Reproduction. 2004 Jan;127(1):67-77. doi: 10.1530/rep.1.00024.
The growth parameters exhibited by seven Thoroughbred (Tb) foals that had experienced a 'restricted' in utero existence following transfer as embryos to the uteri of smaller Pony (P) mares (Tb-in-P) and, conversely, six P foals that experienced a 'luxurious' in utero existence after transfer to larger Tb mares (P-in-Tb), were compared from birth to 3 years of age with those exhibited by six normal Tb-in-Tb and six P-in-P foals conceived by within-breed artificial insemination. Bodyweight, height at the withers, girth, poll-to-nose length, crown-rump length and three foreleg longbone measurements were made at regular intervals. At birth, an approximate 15% reduction or increase in parameters was observed in the Tb-in-P and P-in-Tb respectively, which declined to 5% by 3 years of age. Growth post partum was affected by restricted or enhanced growth in utero. In the first 6 months post partum, growth rate was enhanced in the previously restricted Tb-in-P foals and curbed in the previously enhanced P-in-Tb foals compared with their respective controls. Overall, the similarity of the responses of the offspring to both 'restriction' and 'luxury' in utero ensured that no major changes to conformation resulted from either treatment. Thus, the Thoroughbreds carried by the Pony mares were merely scaled down versions of the Tb-in-Tb controls while the Ponies carried by the Thoroughbred mares were scaled up versions of the P-in-P controls.
将7匹纯种马（Tb）驹作为胚胎移植到体型较小的矮种马（P）母马子宫内，使其在子宫内经历“受限”的生长环境（Tb-in-P）；反之，将6匹矮种马驹移植到体型较大的纯种马母马子宫内，使其在子宫内经历“优越”的生长环境（P-in-Tb）。将这两组马驹从出生到3岁的生长参数，与通过同种内人工授精受孕的6匹正常的纯种马（Tb-in-Tb）和6匹矮种马（P-in-P）驹的生长参数进行比较。定期测量体重、肩高、胸围、鼻尖长度、顶臀长度以及三条前腿长骨的尺寸。出生时，Tb-in-P组和P-in-Tb组的参数分别出现了约15%的降低或增加，到3岁时降至5%。产后生长受到子宫内生长受限或增强的影响。在产后的前6个月，与各自的对照组相比，之前生长受限的Tb-in-P驹的生长速度加快，而之前生长优越的P-in-Tb驹的生长速度减慢。总体而言，后代对子宫内“受限”和“优越”环境的反应相似，确保了两种处理方式都不会导致体型发生重大变化。因此，由矮种马母马所怀的纯种马驹只是Tb-in-Tb对照组的缩小版，而由纯种马母马所怀的矮种马驹则是P-in-P对照组的放大版。
