The Fertilisation of Rabbit Ova in Relation to Time: A Method of Controlling the Litter Size, the Duration of Pregnancy and the Weight of the Young at Birth
The Fertilisation of Rabbit Ova in Relation to Time: A Method of Controlling the Litter Size, the Duration of Pregnancy and the Weight of the Young at Birth
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兔卵受精与时间的关系：控制产仔数、妊娠持续时间和幼仔出生体重的方法
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发表时间：
1934
期刊：
影响因子：
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通讯作者：
J. Hammond
中科院分区：
文献类型：
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作者：
J. Hammond
1.在与输精管切除的雄鹿交配（以诱导排卵）后，通过在不同的时间间隔与能生育的巴克斯交配，兔子的授精时间可以连续地移动到更接近排卵的时间、排卵时和排卵后。2.从排卵前5小时到排卵后2小时的授精过程中，可育的配种率、平均产仔数和平均配种幼仔数以恒定的速度逐渐下降，直至完全不育。正常交配时（排卵前10小时）产下大窝仔的母犬，可在排卵前或排卵后不久交配，以产下小窝仔。3.卵子只有在它们处于或离开输卵管顶部的塞子时才能受精，即排卵后约6小时。当它们开始沿着试管向下移动并在周围获得一层蛋白时，它们就无法受精。4.由于在排卵时进行交配，“精子群”的顶点及时到达试管的顶部，只使那些仍然留在塞子中的卵子受精。精子群的顶端含有相对较少的精子，因此产生的窝仔较小。5.通过显性和隐性有色雄鹿与隐性有色雄鹿的“双交配”，它们之间有一个时间间隔，可以在交配后的不同时间间隔测量管顶部“精子群”的相对大小。6.“精子群”的大小，以及由于交配比正常排卵时间晚而可能获得受精的时间间隔，在不同的雄性中有很大的差异。7.精子在雌性通道中上升的速度显然不受其中存在的雄性和雌性性别决定因素的影响。8.通过减少窝仔的数量来延长妊娠期。随着怀孕时间的延长，新生儿死亡的比例也在增加。这些事实的各种可能的原因进行了讨论。9.虽然由于妊娠期从31天延长到34天，个体幼仔的体重几乎没有持续增加，但由于窝仔数量减少，个体体重大幅增加。10.个体幼仔的大小很可能受到母体某些内分泌物或代谢产物数量的限制。
1. By matings with fertile bucks at different intervals of time after a mating with a vasectomised buck (to induce ovulation) the time of insemination in the rabbit can be moved successively nearer to, at, and after the time of ovulation. 2. From inseminations 5 hours before to 2 hours after ovulation the percentage of matings which are fertile, the average litter size, and average number of young permating fall gradually and at a constant rate until absolute sterility is obtained. Does which produce large litters when mated normally (10 hours before ovulation) may be made to produce small litters by mating shortly before or after the time of ovulation. 3. The ova are only capable of fertilisation while they are in, or as they leave, the plug at the top of the Fallopian tubes, i.e. up to about 6 hours after ovulation. They are incapable of fertilisation as they begin to move down the tube and acquire a layer of albumen around them. 4. As a result of a mating made about the time of ovulation the apex of the "sperm swarm" arrives at the top of the tube in time to fertilise only those ova which still remain in the plug. The apex of the "sperm swarm" contains relatively few spermatozoa, and so small litters are produced. 5. By "double matings," of dominant and recessive coloured bucks on recessive coloured does, with a time interval between them, it is possible to measure the relative sizes of the "sperm swarms" at the tops of the tubes at different intervals of time after mating. 6. The size of the "sperm swarm," and so the interval of time over which it is possible to obtain fertilisation as a result of mating later than normal in relation to the time of ovulation, varies considerably in different males. 7. The speed at which the sperms ascend the female tract is apparently not affected by the presence in them of male and female sex-determining elements. 8. The duration of pregnancy is prolonged by reducing the size of the litter. With the prolongation of pregnancy the proportion of young born dead increases. Various possible causes for these facts are discussed. 9. While there is but little constant increase in the weight of the individual young due to the prolongation of pregnancy from 31 to 34 days, there is a large increase in the individual weight due to reduction in the number of young in the litter. 10. It is probable that the size of individual young is limited by the amount of some internal secretion or metabolic product of the mother.