Davies Morel M C G, Newcombe J R, Holland S J
Welsh Institute of Rural Studies, University of Wales, Aberystwyth, Ceredigion, SY23 3AL, UK.
Anim Reprod Sci. 2002 Dec 16;74(3-4):175-85. doi: 10.1016/s0378-4320(02)00171-9.
In order to assist in the accurate prediction of the timing of parturition in the mare true gestation length, along with the potential effect of a number of factors, was investigated. Data from 433 Thoroughbred foal pregnancies were used. Sequential ultrasonic scanning allowed the true gestation length (fertilisation-parturition) to be ascertained, as apposed to previous work, which used the mating-parturition interval. An average gestation length of 344.1 +/- 0.49 days was evident. Colt foal pregnancies were significantly (P < 0.001) longer (346.2 +/- 0.72) than fillies (342.4 +/- 0.65). Month of birth had a significant effect on gestation length in all foals (P < 0.001). With foals born in January having the shortest gestation lengths and those born in April the longest. Mare age, year of birth, stallion age, stud farm and the interval between ovulation and mating had no significant effect. It is concluded that (i) the gestation length range (315-388 days), all resulting in viable foals is noteworthy and of clinical importance when considering the classification of dysmaturity in foals, (ii) mares carrying colt foals due to be born in the middle of the breeding season (April) are likely to have the longer gestation lengths.
为了协助准确预测母马的分娩时间，对真正的妊娠期长度以及一些因素的潜在影响进行了调查。使用了433匹纯种马驹妊娠的数据。与之前使用交配至分娩间隔的研究不同，连续超声扫描使得能够确定真正的妊娠期长度（受精至分娩）。明显的平均妊娠期长度为344.1±0.49天。公马驹妊娠（346.2±0.72天）明显比母马驹妊娠（342.4±0.65天）长（P<0.001）。出生月份对所有马驹的妊娠期长度有显著影响（P<0.001）。1月份出生的马驹妊娠期最短，4月份出生的马驹妊娠期最长。母马年龄、出生年份、种公马年龄、种马场以及排卵至交配的间隔没有显著影响。得出的结论是：（i）妊娠期长度范围（315 - 388天），所有这些都能产下存活的马驹，在考虑马驹发育不全的分类时是值得注意的且具有临床重要性；（ii）怀有预计在繁殖季节中期（4月）出生的公马驹的母马可能具有更长的妊娠期。
