The normal period of gestation may be placed at three hundred and forty days, though it varies in horses as it does in all other species of mammals. Veterinary writers usually place the minimum period at three hundred, and the maximum at four hundred days, for mares. Some breeders believe that if the normal period of gestation is exceeded it indicates the probability of a male colt.
If there is more than one mare to be bred, the stinting of them as near together as possible will diminish the work of the care-taker at foaling time. As the time of parturition approaches, an attendant should be close at hand, both day and night; and several foals and mares can thus be cared for with the minimum of extra attention.
The period of gestation being variable, the mare should be closely watched as her normal time of bringing forth young approaches. There are signs of the near approach of parturition which, though not infallible, give indication of near delivery. The udder may become greatly distended, especially in the morning, but exercise usually reduces it. The teats seldom become large and plump more than two or three days before the foal is dropped. A large udder does not necessarily imply near approach to delivery. The waxy substance which closes the ends of the teats usually loosens and allows the milk to escape about one day prior to the birth of the foal. Sometimes the foal is born before there is sufficient flow of milk to sustain it, in which case resort must be had to the nursing-bottle. About one week before parturition occurs, a shrinking and falling away of the muscles of the buttock near the root of the tail takes place.
The mare's milk is relatively poor in fat and protein and rich in sugar. If cow's milk must, for a time, be substituted for the mare's, in part or in whole, that of a fresh young cow should be used. It may be modified by adding a little water to reduce the per cent of fat and protein, and a little sugar that the modified milk may be similar in constituents to the dam's. The temperature of the milk, when fed, should be 98° to 100° Fahr. In cold weather there is danger that the milk, while being used, will fall below the proper temperature. To obviate this, wrap thick, hot, woollen cloths around the bottle. About one-fourth to one-third of a pint of the modified milk may be given every two hours, gradually reducing it as the mother's milk becomes available.
The colostrum, or first milk after parturition, as already shown, tends to move the foal's bowels, which is beneficial. The modified milk, on the other hand, tends toward constipation; therefore the bottle-fed foal should be given a mild physic.
The bowels of foals which nurse their mothers may be moved by administering to them two to four ounces of unboiled linseed oil or the same quantity of castor oil, or by an injection of water at a temperature of 100° F.; or administer to the dam one pint of either of the above-named oils. The feeding of succulent foods tends to hasten the flow of milk after parturition; dry, carbonaceous foods, to delay the milk flow. (For teething, see Chapter XV (Judging Horses).)
The foal should not be petted, but kindness and firmness should be used in handling it. Sometimes the attempt is made to educate the foal beyond its ability to receive instruction. It is a mistake to attempt to educate either boys or foals above their capacity. The colt trained to all the ways of mature horses is sure to be put to horse-work too young. Let the boy be a boy, and the colt a colt. While the foal is yet with its dam, it should be taught to lead and to allow its feet to be handled. The paramount object in all kindergarten work with the foal is to teach it prompt obedience and to inspire it with courage and confidence. It should be taught to follow unhesitatingly when it is led. It should not be allowed to get its legs entangled in stable floors, bridges or fences, and it should never be purposely frightened. The colt and the filly, as well as mature animals, discern quickly a timid, hesitating or incompetent attendant or driver. As the attendant is, so is the future mature animal likely to be. Teach the foal but little; but what little education it does receive should be so thorough that it will be retained through life. Young colts are nervous; endeavor to strengthen their nerves by implanting confidence, which tends to allay nervousness.
Much space has been given to the brood-mare and her offspring, because these are the foundations upon which success or failure rests. But it will be necessary to add something by way of suggestion as to the business of breeding horses, selecting breeds to suit environment and use, and how to dovetail the breeding and rearing of a few colts with the manifold activities of a diversified agriculture, carried on in a diversified climate on radically different soils.