GENERAL PRINCIPLES OF BREEDING.
Some few suggestions upon the general principles to be observed in breeding may not be superfluous here, referring the reader, who is disposed to investigate this subject in detail, to its full discussion in the author’s treatise upon “Cattle and their Diseases.”
As illustrative of the importance of breeding only from the best, taking care to avoid structural defects, and especially to secure freedom from hereditary diseases, since both defects and diseases appear to be more easily transmissible than desirable qualities, it may be remarked that scrofula is not uncommon among sheep, and presents itself in various forms. Sometimes it is connected with consumption; sometimes it affects the viscera of the abdomen, and particularly the mesenteric glands, in a manner similar to consumption in the lungs. The scrofulous taint has been known to be so strong as to affect the fœtus, and lambs have occasionally been dropped with it; but much oftener they show it at an early age, and any affected in this way are liable to fall an easy prey to any ordinary or prevalent disease, which develops in such with unusual severity. Sheep are also liable to several diseases of the brain, and of the respiratory and digestive organs. Epilepsy, or “fits,” and rheumatism sometimes occur.
The breeder’s aim should be to grasp and render permanent, and increase so far as practicable, every variation for the better, and to reject for breeding purposes such as show a downward tendency. A remarkable instance of the success which has often attended the well-directed efforts of intelligent breeders, is furnished in the new Mauchamp-Merino sheep, which originated in a single animal—a product of the law of variation—and which, by skilful breeding and selection, has become an established breed of a peculiar type, and possessing valuable properties. Samples of the wool of these sheep were shown at the great exhibition in London, in 1851, as well as at the subsequent great agricultural exhibition at Paris, and attracted much attention.
This breed was originated by Mons. J. L. Graux. In 1828, a Merino ewe produced a peculiar ram lamb, having a different shape from the ordinary Merino, and possessing wool singularly long, straight, and silky. Two years afterward, Mr. Graux obtained by this ram one ram and one ewe, having the silky character of wool. Among the produce of the ensuing year were four rams and one ewe with similar fleeces; and in 1833, there were rams enough of the new sort to serve the whole flock of ewes. In each subsequent year, the lambs were of two kinds; one possessing the curled, elastic wool of the old Merinos, only a little longer and finer, and the other like the new breed. At last, the skilful breeder obtained a flock containing the fine, silky fleece with a smaller breed, broader flanks, and more capacious chest; and several flocks being crossed with the Mauchamp variety, the Mauchamp-Merino breed is the result.
The pure Mauchamp wool is remarkable for its qualities as a combing-wool, owing to the strength, as well as the length and fineness of the fibre. It is found of great value by the manufacturers of Cashmere shawls, and similar goods, being second only to the true Cashmere fleece, in the fine, flexible delicacy of the fibre; and when in combination with Cashmere wool, imparting strength and consistency. The quantity of this wool has since become as great as that from ordinary Merinos, or greater, while its quality commands twenty-five per cent. higher price in the French market. Breeders, certainly, cannot watch too closely any accidental peculiarity of conformation or characteristic in their flocks.
The apparent influence of the male first having fruitful intercourse with a female, upon her subsequent offspring by other males, has been noticed by various writers. The following well-authenticated instances are in point:
A small flock of ewes, belonging to Dr. W. Wells, in the island of Granada, was served by a ram procured for the purpose. The ewes were all white and woolly; the ram was quite different, being of a chocolate color, and hairy like a goat. The progeny were, of course, crosses, but bore a strong resemblance to the male parent. The next season, Dr. Wells obtained a ram of precisely the same breed as the ewes; but the progeny showed distinct marks of resemblance to the former ram, in color and covering. The same thing occurred on neighboring estates, under like circumstances.
Six very superior pure-bred black-faced horned ewes, belonging to Mr. H. Shaw, of Leochel, Cushnie, were served by a white-faced hornless Leicester ram. The lambs were crosses. The next year they were served by a ram of exactly the same breed as the ewes themselves, and their lambs were, without an exception, hornless and brownish in the face, instead of being black and horned. The third year they were again served by a superior ram of their own breed; and again the lambs were mongrels, but showed less of the Leicester characteristics than before; and Mr. Shaw at last parted from these fine ewes without obtaining a single pure-bred lamb.
To account for this result—seemingly regarded by most physiologists as inexplicable—Mr. James McGillivray, V. S., of Huntley, has offered an explanation, which has received the sanction of a number of competent writers. His theory is, that when a pure animal of any breed has been pregnant by an animal of a different breed, such pregnant animal is a cross ever after, the purity of her blood being lost, in consequence of her connection with the foreign animal, and herself becoming a cross forever, incapable of producing a pure calf of any breed.
To cross, merely for the sake of crossing, to do so without that care and vigilance which are highly essential, is a practice which cannot be too much condemned, being, in fact, a national evil, if pushed to such an extent as to do away with a useful breed of animals, and establish a generation of mongrels in their place—a result which has followed in numerous instances amongst every breed of animals.
The principal use of crossing is to raise animals for the butcher. The male, being generally an animal of a superior breed, and of a vigorous nature, almost invariably stamps his external form, size, and muscular development on the offspring, which thus bear a strong resemblance to him; while their internal nature, derived from the dam, well adapts them to the locality, as well as to the treatment to which their dams have been accustomed.
With sheep, where the peculiarities of the soil, as regards the goodness of feed, and exposure to the severities of the weather, often prevent the introduction of an improved breed, the value of using a new and superior ram is often very considerable; and the weight of mutton is thereby materially increased, without its quality being impaired, while earlier maturity is at the same time obtained. It involves, however, more systematic attention than most farmers usually like to bestow, for it is necessary to employ a different ram for each purpose; that is, a native ram, for a portion of the ewes to keep up the purity of the breed, and a foreign ram, to raise the improved cross-bred animals for felting, either as lambs or sheep. This plan is adopted by many breeders of Leicester sheep, who thus employ South-Down rams to improve the quality of the mutton.
One inconvenience attending this plan is the necessity of fattening the maiden ewes as well as the wethers. They may, however, be disposed of as fat lambs, or the practice of spaying (fully explained in “Cattle and their Diseases”) might be adopted, so as to increase the felting disposition of the animal. Crossing, therefore, should be adopted with the greatest caution and skill, where the object is to improve the breed of animals. It should never be practised carelessly or capriciously, but it may be advantageously pursued, with a view to raising superior and profitable animals for the butcher. For the latter purpose, it is generally advisable to use males of a larger breed, provided they possess a disposition to fatten; yet, in such cases, it is of importance that the pelvis of the female should be wide and capacious, so that no injury may arise in lambing, in consequence of the increased size of the heads of the lambs. The shape of the ram’s head should be studied for the same reason.
In crossing, however, for the purpose of establishing a new breed, the size of the male must give way to other more important considerations; although it will still be desirable to use a large female of the breed which is sought to be improved. Thus, the South-Downs have vastly improved the larger Hampshires, and the Leicester, the huge Lincolns and the Cotswolds.