Rabbits Pseudo Pregnancy

The small yellow body or corpusluteum left in the cavity of the ovary after the egg is shed produces certain hormones which maintain the rest of thereproductive system in condition for pregnancy. Now if adoe is mated, and the mating is not fertile, then the eggswill have been shed and the corpora lutea formed. Thehormones released by the corpora lutea will stimulate theremainder of the reproductive system and the doe will behaveas though pregnant, although she is not. This condition isknown as pseudo-pregnancy. The mammary glands arestimulated to activity, the uterus increases in size and so on.During proper pregnancy the corpora lutea, after the 16thday of pregnancy are themselves maintained by furtherhormones from the placenta. If there are no placentas,as occurs in pseudo-pregnancy, then the corpora lutea ofpseudo-pregnancy degenerate, the doe acts as though shewere about to give birth to young, i.e. she makes a nest,and the mammary glands may even secrete some milk.Pseudo-pregnancy continues for t6 to 18 days, and afterthis period the doe is highly fertile, and opportunity shouldbe taken to mate her.

It is only when the doe ovulates, but the eggs are notfertilised, that pseudo-pregnancy occurs, thus not everyinfertile mating results in this condition. Nevertheless insome studs the percentage of matings which result in pseudo-pregnancy is high, and as many as one-third may producethis result.

The nest building at the end of pseudo-pregnancy maybe very slight, but any such signs as early as the 16th or 17thday after mating may be taken as a fairly reliable sign thatthe doe has been pseudo-pregnant.
The stimulation which causes the doe to shed eggs andthus produce this condition is usually the behaviour of abuck. It may also be produced however when a doe 'jumps'another, and for this reason does should not be run togetherwithin three weeks of their being mated.

Some cases of pseudo-pregnancy might be prevented by double matings, i.e. a second mating within at most fivehours after the first. A mating later than this would havevery little effect. When the services of a buck are freelyavailable, that is when spare bucks are in use, then a secondmating could be given.