Nothing is more important to the success of the breeding-stud than a good sire, and to prolong and maintain his fertility can only be effected by scrupulous care and rational treatment, in which the aim should be to keep up the balance of health and render his sexual work fruitful.
It must, however, be remembered that the fertility or power to beget stock will differ in different animals, and in the same animal at different periods of life. The recognition of this fact suggests the desirability of regulating the work of a sire to his powers of service and reproduction, so that abuse may be avoided, his use at the stud prolonged, and the number and value of his produce enhanced.
Rightly or wrongly it is the common practice to allow a horse to commence his stud career at two years old, and, although no apparent ill consequences may follow when sexual work is judiciously apportioned, we cannot help thinking that at this critical period of growth some benefit would be derived by allowing another year to pass over, before calling upon him to exercise his reproductive function.
This precaution is especially needed where condition and growth are backward, or where the latter is in excess of what it should be at that age, when in consequence the system is wanting in strength and vigour. Big colts should be allowed ample time to develop before being put to the stud, and little ones to grow.
When it is decided to use a two-year-old colt, the natural question arises as to how many mares he should be allowed to have. " The number of mares sometimes allowed to horses at this age is almost incredible, and the view seems to find favour with many that what a colt can do should be the measure of what he should do, and it is no rare occurrence for forty, fifty, or even sixty mares to receive service from these baby sires during their first season. That they may be fairly fruitful under such a strain there are examples to show; but the general result of such a practice is not only to check growth and physical development, but to lay the foundation for sexual weakness and disappointment in the following season, and, it may be, to produce an abiding weakness of the reproductive function, or even permanent incapacity to get stock. Moreover, the offspring of horses so overtaxed are at the best but doubtful blessings to the breeder, and many a farmer can tell how his money and the stud services of a good mare have been thrown away by the incautious use of those overworked youngsters. . . . Having regard to health interests, to quality of produce, and endurance at the stud, a horse at the age in question should not be allowed more than ten to fifteen mares, and it would be much to his advantage, as it would to that of all young sires, if the season were allowed to set well advanced before commencing service. At this time, grass will be plentiful and good, mares will 'come keen' to the horse, the chance of returning will be materially diminished, and the horse's services correspondingly lightened. As to older stallions, the same want of care obtains with them as with the more juvenile section, and many a good horse is prematurely used up or falls a victim to disease as the outcome of unbridled abuse. The number of mares a horse should receive from three years old upwards allows of no fixed rule being laid down. Very much will depend upon growth and development, and even more on natural vigour of constitution and sexual capacity, which latter can only be known by experience. Some horses almost complete their upward growth at two years old, while others at that age have made but little progress."
In settling the work of young sires, every consideration should be given to their fitness in respect of the points referred to above, and lack in one respect or the other should be deemed sufficient to withhold them from stud service until, by time and good living, they have acquired the necessary growth and vigour of constitution to enable them to exercise the reproductive function without prejudice to their full development and maturation as sires.
There is a very wide difference in the desire and the capacity of horses for stud work. Some, although young and fairly fruitful, display a vexatious indifference towards their mares, and can only be induced to consummate the act by the greatest care, or some special device on the part of the groom. Many of these horses become more and still more indisposed for sexual connection, and ultimately refuse service altogether and become prematurely impotent. In some the desire may be maintained by good living, plenty of walking exercise, iron tonics, and by keeping the horse away from mares for such a period as will bring back the sexual impulse. How long this may be, the attendant must find out for himself, and, having done so, exercise his discretion in directing the services of the horses under his care. On the other hand, there are stallions which with a remarkable capacity for service unite an extraordinary fertility and endurance. A notable instance of this was afforded by a well-known Shire stallion, which, on completing a heavy season in Lancashire, was let for further work in the south. On reaching his destination, at three o'clock in the day, twenty-three mares were waiting for service. Of these, nineteen were found to be in season, and were served the same day, and thirteen proved to be in foal.
"Many sires, and some of great celebrity, have been known to serve from 200 to 260 mares in one season, and to leave a fair proportion of foals." Of course, it cannot be expected that such an amount of sexual work as is here implied can be continued for any number of years without inducing sterility or premature impotence, and owners of stallions, in their own interest, no less than that of their stock, should guard against dangerous abuse of their stock-horses by judicious restriction of their services at the stud.
It is impossible to lay down any hard-and-fast rule by which the work of horses at different ages should be governed, but the following scale may be accepted as a fair average allowance for the season: -
Number of Mares.
" and upwards