In the matter of size, some persons, with the view to produce increased height in the foal, recommend the stallion being larger than the mare, while others advocate the contrary. No rule, it would seem, can be laid down for this, as circumstances of which we know as yet but little operate in this direction. Reynolds says that three of the best cart geldings he ever saw - all exceeding 16 1/2 hands high - were bred from a little Welsh mare barely 15 1/4 hands in height; and he truthfully remarks that, as a rule, it will be found that a well-proportioned stallion, of commanding size, begets from low, wide mares, a better class of foals than when the relative proportions are reversed.
As before noted, the qualities desired in the progeny should be possessed by the parents, but if they are present only in one, then that should be the one which will most probably transmit them.
With regard to the age of the parents, it may be remarked that, while they can produce both when young and old, yet the best time is when they have arrived at mature age, or are fully developed and in the zenith of their vigour. Immature, or old animals, as well as those which have undergone severe toil and privation, often beget weakly stock. The stallion has more durability for procreation than the mare, some commencing at two years old and continuing until advanced age; instances are known of stallions being prolific for thirty years, and twenty years is not at all uncommon. But young stallions have to be carefully limited in their vocation, as excessive use checks their development and injures their hind legs; while the stimulating diet they require to keep them vigorous is hurtful to their constitution, and predisposes to disease. On this subject, Reynolds (who is treating specially of heavy draught stallions, but his remarks are applicable to other kinds) states: Entire horses, which have not been forced by strong food, and have been but moderately used up to five years old, remain sound and vigorous to a good old age; and to a sound, hardy stallion of from seven to fifteen, or even more, years, possessing suitable qualifications, let me commend those breeders who desire good, strong, and healthy foals.
Mares breed from two years old up to twenty-five, sometimes; but after they are fifteen or sixteen years old their stock is not so good or strong. Though fillies will breed at two years old, yet this is rather early. Three or four is better, as they are then more developed and robust.
When mares have not been tried until they are advanced in years, and especially if they have been accustomed to high feeding, they often prove sterile; or if they do breed, parturition is frequently difficult.
Next to age, as favouring breeding, is the condition of the parents, and particularly the mare. Obesity is unfavourable, as well as emaciation. Robust health, ensured by good food and exercise or moderate labour, is conducive to this end. Mares doing regular work or at pasture, are much more likely to prove in foal, than those which are kept in stables, pampered, and little worked. The stallion should also be in good hard condition.
The number of mares a stallion should serve in the course of a season will much depend upon circumstances, but it is often controlled by his age and value. In many cases he is overdone and prematurely worn-out. A fair proportion of mares per season is given as from fifty to seventy.
During the season, the stallion must be well fed, but not fattened; the amount of food will depend on circumstances, but it should be good. Oats and hay are the best articles, and for horses over five years of age a small proportion of split beans is advantageous. A small quantity of grass, clover, or tares, may be mixed with the hay. Above all things, recourse should not be had to physic (unless absolutely necessary), nor to drugs and hurtful substances supposed to stimulate the procreative faculty. Food is the natural and the best stimulant.
It is better to put the stallion to the mare twice within a very short period - twice in one or two days even - when possible, than oftener at longer intervals. The mare, of course, should be in a fit state, which is recognised by signs familiar to horsemen and horse-keepers, or by "trying" the stallion with her.
For a mare which has recently had a foal, the best time to show her to the stallion is about the ninth day after foaling. To make certain that she is impregnated, she is again shown in about twenty days after the first contact, or "service" as it is termed.
Sterility or "barrenness" may be due to various causes, some of which may be remedied by the veterinary surgeon, others are not removable. If it is owing to over-feeding and obesity, the remedy is obvious - less food and more work or exercise.
Mares may be bred from every year, or less frequently, according to circumstances; but when convenience will permit, annual breeding is generally recognised as most certain and profitable. Though there may be certain indications that a mare has conceived, yet these are not invariably present - even being in "heat" occasionally is not incompatible with pregnancy; in certain cases, when her condition must, if possible, be ascertained before the fifth or sixth month, a manual examination of the uterus by an expert may decide the question, but there may be danger in this. After the sixth month, the foetus may be seen moving at the right flank, especially after the mare has drunk a quantity of cold water.
During pregnancy mares can perform a certain amount of work, so long as it is not very heavy and is steady; indeed, slow and continuous work is advantageous to them until near, or even up to within a day or two of foaling, and if they cannot be worked they should at least have exercise - either voluntary, as in a paddock, or in hand. But towards the end of pregnancy, if not throughout the whole period - which is from 330 to 360 days - severe or straining work should be avoided, and a week or so before foaling it ought to be very light, if allowed at all. And for some time, if not during all the interval, the animal should be stabled in a loose box or roomy shed, apart from other horses, and with the view to prevent accidents, such as kicks, getting "cast," etc.
The feeding of a pregnant mare is of much importance with regard to her own health and that of the foetus, and requires a good deal of judgment, if justice is to be done to both. Gross condition must be guarded against to prevent abortion, as well as under-feeding, which leads to debility of the mare, and bad development and feeble health of the foal. No fixed rule can be prescribed, as individual cases must be dealt with on their requirements. If the mare is working, then a little more food than is allowed to non-pregnant animals must be given. It is needless, of course, to insist that it should be of good quality. Grass alone may suffice for non-working mares, if it be sweet and nutritious, but towards the ninth or tenth month, an allowance of grain may advantageously be added. For heavy draught-mares doing no work, unless they are very young or old, or it is in the depth of winter, green and chopped forage, with pulped roots, will suffice. Reynolds recommends mashes or bruised oats or barley, associated with pulped roots and chopped hay or straw, moistened with linseed-cake water, for draught pregnant mares at work; as these articles form a substantial and at the same time a non-exciting and easily-digested diet. He also adds that maize is not a suitable food for such mares, as when it constitutes a chief part of their grain allowance the foals always exhibit general weakness of muscle, and abnormal relaxation of the ligaments of the joints.
Food should be given at frequent intervals, as long fasts are injurious, especially when they are succeeded by over-repletion.
If possible, clean fresh water should be provided; and if at pasture, provision ought to be made to shelter brood mares from extremes of heat and cold. Care ought also to be taken that the animals be not frightened or chased when near foaling; and young horses or cattle should not be pastured with them, lest injury be inflicted and abortion produced. This accident is due to a number of causes, but in the mare it is generally injury which brings it on, though in some animals there is a predisposition to it from malformation or disease. Improper diet, illness, over-exertion, exposure to bad weather, fright, drinking too much cold water, poisonous plants, frosted food, etc., may all operate in causing such an accident.
When abortion occurs early in pregnancy, it is often unobserved, and causes but little apparent disturbance in the mare; but when it takes place later it is very noticeable, and sometimes serious in its results. It usually takes place suddenly, and without any of the usual premonitory signs of parturition, though there may be a good deal of distress preceding and accompanying the expulsive effort. When the foetus dies and is not expelled, there may be no immediate indications of its death, but in a short time a foul-smelling discharge will take place from the external genital parts, showing that putrefaction has set in, and the dead creature will come away, or require removal; the mare will also be dull and feverish, or uneasy and restless. Veterinary assistance should in all these cases be sought, particularly if the dead foetus or its membranes are retained. If there are other pregnant mares, they should be removed from the immediate neighbourhood of that which has miscarried, and cleansing and deodorising of the box ought to be carried out as speedily as possible.