DENTITION OF ANIMALS.

Northern Advocate, 18 May 1914, Page 11

DENTITION OF ANIMALS.

THE HORSE.

A foal at birth has two temporary incisors, while three temporary molars above and below are cutting the gums. At six weeks the two lateral incisors appear, and about nine months the two corner incisors. At twelve months the fourth molar is cut, and at two years the fifth molar,-and at two years and six months the two central permanent incisors appear, and are in wear at three years. At the same time the first and second temporary molars fall off, and are replaced by permanent ones.

At three years and six months the two lateral permanent incisors are out, and come into wear at four years. At this time the third temporary molar is shed, to be replaced by a permanent tooth; also the sixth molar is cut. At four and six months the lateral temporary irfcisors are replaced by permanent teeth, which come into wear at three years, and about this time the tushes appear. The horse has then a full mouth of 40 .teeth, namely, 12 incisors, 4 tushes, and 24 molars. At this age, upon examination, it will be seen that the incisor teeth contain a hollow cavity on their cutting edges, which disappear as the animal advances in years. lAt six years the cavity has disappeared from the central incisors, at seven years from the lateral, and at 8 years from the corner incisors, after which the age of the animal is somewhat difficult to tell. As age advances the teeth become rounder, until in ola age they have resumed a triangular appearance; the gums also recede from the teeth as the animal advances jn age. • Little devices are often practised by horse dealers and others, which often deceive the purchaser in the age of the animal he is buying. This consists in cutting small cavities: in the teeth, of aged horses, so as to make them rosemble the teeth of younger animals. Only the inexperienced are taken in by such devices, as the length and shape of the teeth give a true indica.tion to the animal's age.

Another trick that is sometimes practised is pulling the corner temporary incisor a year before it is realy to come off. By doing so the permanent teeth are allowed to come up, and the aniirial shows a five-year-old mouth when :it is only four years. Th'.rJ, however, can again be detected, as there is always a space left between the corner and lateral incisors when the teeth have been pulled 'before they are ready to leave the gum. , THE OX.

A calf at birth has two, four, six, eight temporary incisors, also three temporary molars above and below, or each side.

The first change takes place' :it six months when the fourth molar (permanent) is cut, and comes into wear at nine months. ' , ' •

Next change, the fifth molar (permanent)! is cut at twelve months, aud comes into wear at fifteen months. Ast one year' nine months the sixth molar (permanent) is cut, and comes into .wear at two years. At the sarna time the two central incisors (p3 lnariym) are cut, and come into wea:. Between two years and two years a'r.d three months, the first, seoor.d, and thiid temporary molars are cast, and Immanent ones take their place.

At two years and three montas the seccnd pair of permanent mo'avo are 1 ciit. and come into wear at two year? anl six months.

At two years and nine months the three pair of peramnent are cut. and come into wear at three years. 'At three years and three months'the '."ninth pair of permanent incisor &. ire cut, and come into wear at years and six months, when the an'mial has pot its full mouth of teeth, numbering t-2. At this age the incisor tei>h will be found flat and sharp; as th*-; animal geif, older the edges begin to wear off, and the teeth become rdinjei until "l-.mately, in old age, only stumps are loft The above table van's slightly 'n the case of pedigree stoci on in animals that are well fed. In suc]i cases

thy teeth are frequently a little c irlier. SHEEP. A lamb at birth may ha-, four, six. •>r light temporary incisor;; if they are rot all through the gum they make t'leir appearance by the time the animal is a month old; also by to.is time the first, second, and third tampoany mo'igrs are in wear. 'A', three months .he fourth mj'.rirs a>' cut, and at nine trie 'h';h.A 15 months the central pair ol pe>- - n pr-ent incisors are cv", a:ul in wear a. 18 months. At 18 months the first, second, and third temporary molars are shed, and replaced by permanent at the same time the sixth molar is cut. These are all up and in wear when the animal is two years. At one year and nine months the second pair of permanent inciso 3 are cut, and in wear at two years. At two years and six months, the third pair of permanent incisors are cut, and in wear at three years. At three years and six monlns the fourth pair of permanent incisoj s are cut, and in wear at four years, when ■■he animal has a full mouth. At this stage the teeth are very sharp; as the animal gets older the teeth become worn at their cutting edges, and have tables formed upon them. The neck also becomes and in very old animals only small stumps are left.

In judging the'age of sheep it must not be forgotten that the age at which the animals cast their temporary teeth, to be replaced by permanent ones, is subject to variation, in some cases to the extent .of several months. , The writer has often seen lambs getting their central pair of permanent teeth at a little over a year old, and the others at a corresponding early date. In other instances they have been well over the 15 months before any permanent teeth made their appearance.