Farm live-stock, as the term is usually understood, includes the mammals that produce edible products or perform agricultural labor, as the cow, the horse, the sheep, the goat, the swine. Strictly speaking, it should also comprise poultry (Chapter XX), but this large group usually is treated by itself. Many kinds of pets and of fancy stock — cats, dogs, cavies, canaries — form another group.

Determining the Age of Farm Animals (Wing) Cattle.

The teeth of the ox serve to help in the determination of its age, although not so accurately nor to so great an extent as in the horse. Under ordinary circumstances, the incisors are the only teeth that are used in the determination of age. Of these, the ox has eight, or four pairs, and on the lower jaw only. There are two sets, the temporary or milk teeth, and the permanent teeth, the latter differing from the former mainly in their greater size and width.

Months

First, or middle pair...................18

Second, or first intermediate pair..............27

Third, or second intermediate pair..............36

Fourth, or outer pair...................45

If there is any variation from the foregoing, the animal is likely to be older rather than younger than the teeth indicate. After the teeth are up and in full wear, there is comparatively little change in their appearance for several years. The teeth are broad, flat, and white in color, and their edges should almost or quite meet. They are never firmly fixed in the jaw, as in the case of the horse, but rather loosely imbedded in a thick, cartilaginous pad or gums. The looseness of the teeth should not therefore be taken by the novice as an indication of unsoundness or of advancing age.

After the animal has reached an age of eight or nine years, the teeth become narrower through wear. They shrink away from each other and often become more or less discolored and finally drop out one by one. A vigorous old cow will often do very well, especially if fed liberally on grain and succulent food, after the last incisor tooth has disappeared. And so long as the teeth are all present and reasonably close together, the animal is said to have a good mouth. This condition may remain up to ten or twelve years of age, and occasionally even longer.

The horns also afford a means for estimating the age of cattle, especially of cows. During the first two years, the horns grow rapidly and the greater part of the total growth is made in this time. Afterward, the growth is slow from year to year, and each year's growth is marked by a more or less distinct ring. The first ring appears when the animal is about three years old, and the age may be reckoned by adding two to the number of rings present.

Sheep.

Sheep have two sets of incisor teeth, on the lower jaw only. The first or middle pair of temporary teeth is replaced by permanent ones when the lamb is thirteen to fifteen months old, and thereafter the succeeding pairs of permanent teeth appear at intervals of a little less than a year. Most shepherds reckon a year for each pair, so that when the last pair is fully up and in wear, the sheep is four years old.

As age advances, the teeth grow narrower and slimmer until advanced age, eight or nine years, when they often shorten rapidly from wear, and finally disappear. So long as the teeth remain strong and fairly firm, the sheep may be said to be in good working condition.

Swine.

While swine have two sets of teeth, temporary and permanent, as in the other domestic animals, the dentition is so irregular as to be of little service in determining the age of the animal. Moreover, the difficulty of catching, holding, and examining the animal is so great that the teeth are seldom, if ever, used to determine the age of swine. In market stock, the age does not play an important part, as the value depends entirely on the weight and condition of the animal, except in the case of old sows and stags (castrated mature males). The former are easily distinguished by evidence of having suckled pigs, and the latter by the tusks and the development of the " shield " — a coarse heavy fold of muscle under the skin on the shoulder. In breeding animals, the age is always indicated on the certificate of registry of pure-bred stock.

Horse's teeth at different ages (Roberts).

1-2 weeks old.

4-6 weeks old.

8-10 mos. old.

Milk tooth.

1 he lower nippers at two years old.

Lower nippers at three years of age.

Side view of the teeth of a four-year-old.

Lower nippers at four years of age.

Lower nippers of a five-year-old.

Side view of the teeth of a five-year-old.

Side view of the teeth of a six-year-old horse.

Lower nippers of a six-year-old.

Lower nippers of a seven-year-old.

Side view of the nippers of a seven-year-old.

The lower incisor, or nipper, teeth of an eight-year-old.

Side view of the teeth of an eight-year-old.

Cross section to show shape of incisor tooth at 4, 9, 14, and 20 years.

The lower incisor teeth of an old horse.

A side view of the nippers of an old horse.

Showing, at the upper end, the wearing away of the cusps at 3,4,5,6,9, and 20 years.