The duration of pregnancy in the mare is usually about eleven months, though it may vary between ten and twelve months, or even more. The normal duration is, however, between 330 and 350 days. Some foals may be born alive from the 300th to the 310th day, but this is rare.
Breed and feeding have some influence on the duration of pregnancy. In high-bred and well-fed mares it is generally shorter than in under-bred, badly-cared-for, and hard-worked animals.
Allusion has already been made to the signs which indicate that this period is drawing to a close, and it is necessary that these should be noted and acted upon, so as to be prepared for the birth of the foal; and when the event is imminent, a visit should be paid to the mare frequently by night and by day.
Birth of the foal, when all things are favourable, takes place very rapidly, and in the great majority of cases the mare requires no assistance. When the labour pains come on, and she begins to strain energetically, the foal is propelled backwards, with the fore-legs leading, and the head between them. These soon appear externally, usually surrounded by the membranes and the fluid contained in them. A few more strains and the membranes are ruptured, when the foal glides gently down over the mare's hocks, if she is standing - which is generally the case - and falls softly on to the ground; the navel-string (umbilical cord) is nearly always torn through during this descent of the foal.
Fig. 545. - Natural Presentation.
The mare, soon after its birth, cleans the foal by licking it all over, and when this is done it is well to offer her a bucket of warm oatmeal or linseed gruel, and some bran mash, but otherwise she ought to be interfered with as little as possible. In some instances the mare refuses to have anything to do with the foal, and even becomes aggressive towards it: In such cases it has been recommended to sprinkle the foal's back with flour, as an inducement for the dam to lick this off, and so to become attached to her progeny.
The expulsion of the membranes, or " after-birth", sometimes takes place with the birth of the foal, but it is generally subsequent to that event within a few hours. If they are retained until they begin to putrefy, serious consequences may ensue; it is necessary to remove them in a day or so. If they are apparent, or readily accessible to the hand, they may be gently twisted round like a rope and slightly pulled upon until they are brought away. If this procedure is not successful, then the hand and arm, well soaped or oiled, must be introduced into the uterus, and the membranes seized, disengaged from their attachments, and completely removed from the mare. This attempt is all the more urgently necessary when there is a foul odour from the membranes and a bad-smelling discharge from the vagina, the mare at the same time making attempts to strain, and looking feverish. Then not only must every portion of these membranes be removed from the uterine cavity, but this must be thoroughly cleansed by copious injections of warm water, to which a small proportion of carbolic acid has been added, and scrupulous cleanliness should be observed with the mare's hind-quarters and her surroundings.
Sometimes the mare, from debility or other cause, foals while lying-down, and unless she gets up immediately the foal is born, the navel-string is not torn, so that the young creature may remain attached to its parent through this medium unless some accident release it, either the cord being ruptured or the membranes dragged from the uterus. If an attendant is at hand, however, the foal can be readily disengaged if he ties the cord firmly round with a piece of string in two places, about 6 or 8 inches from the foal, and cuts in through between the ties; this prevents bleeding from the mother and from the foal.