THE GROWTH OF ANIMALS.

Lyttelton Times, Volume CXV, Issue 16606, 18 July 1914, Page 5

THE GROWTH OF ANIMALS.

AN INTERESTING MATTER. The subject of the growth of animals is one which must always be of interest to breeders. As Weismann ("Essays on Heredity," 1891, p. 31) has explained, the growth of an individual depends chiefly upon the multiplication of cells. This multiplication nr growth is strictly limited both as regards the number of cells produced and the rate at which they are formed. Every species of animal grows to a different size, and at a different rate, such size and rate being more or less fixed in wild animals by natural selection or adaptation to a given environment. As many practical breeders can testify, it is not possible by feeding to increase the size of a creature which has a natural tendency to be small, I thus proving that size is controlled by heredity, and not, as many have supposed, mainly by nutriment. Although the detailed information procurable is naturally sketchy and imperfect, it may be of interest to set out for comparison all the particulars obtainable on the subject of the_ raw of growth of common domestic animals. Uy duing this perhaps some idea can be gained of how animals grow; or at least the breeder can obtain .an insight into what is a correct periodical increase in the class of stock in which ho is interested. HORSES. It is rather unfortunate that such particulars as are available on the subject of the growth of the horse should be measurements and not weights, for in the case of the other animals dealt with the rate of growth ~ls indicated by the increase of weight as shown by a machine at more or less frequent intervals. ' Professor Cossar Ewart made an exhaustive inquiry' into the " Rate and Growth of the Horse," which was published in the "Live Stock Journal Almanac," 1901, and we may perhaps Se allowed to extract some of the details in respect of a 14 hands pony;—

In 1909 a correspondent signing himself "J.R." gave soma particulars in the "Field" of the measurements he had taken of a foal 'from 14-hand stock, which corresponded very closely with Professor Ewart'e figures. "J.R.'s" foal was 36Jin high at the withers at birth, 40in at the end of the first month and 47§in at the end of five months. . » , . It appears that an increase of about 12in in height in the first six months is a fair average rate of growth tor horses of 14 hands high; this is not brought about by steady development at the rate of 2in each month, but takes place in leaps of 3in or 4m in a tronth; followed by a resting stage when an increase of only about an inch is to be recorded in the same period of time.

CATTLE. No particular interest seems to be as a rule attached to the growth of ordinary farm animals, except :n the case of fat beasts exhibited at the leading fat stock shows, about which plenty of statistics are available. It is usually considered that a fairly good calf of the larger breeds weighs about 601 b at birth. According to French authorities, ordinary calves from medium-sized stocK may bo expected to increase about 2Jlb in weight on an average daily during the first eight weeks of lite. Specially bred cross-breds may add nearly 31b to their weight daily, while in the case of the calves of particularly small varieties only 111 b to l«b per week is expected. When more than eight weeks old growth is said to be much slower. Compare these figures with the following table selected from M'Connell s " Agricultural Notebook " : Live weight gain in pounds per day since birth of cattle at the Smithfield Club Show (Average, four years).

Kerry . '• •' i-W 0.89 0.79 ' 0.85 In every case it appears that the older the animal is the slower it grows, which bears out and supplements the French observations on young calves.

Height at Withers. Girth In. In. At birth . . 36$ 80 End of one month . 41 38$ End of two months • . 42$ 42 End of three months . . 45) 46 End of four . . 46* 48 End of five months .. 48 49$ End of six months . 48$ 52$" End of seven months . . 49J H 53$ End of eight months . . 50$ 54 End of nine months . • ; 60g 66 End of ten months . eii 56J Knd of eleven months . . 62$ 571 End of twelve months . . 53 59 End of twenty-four monthi . 661 61 End of thirty-six montis . 57 68

8 •9 A Is si a a 0 ri S a °* >>» M ►. go E O C 1! W33 IS t03 5W Shorthorn . X.93 1.67 1.53 1.58 Sussex • . 1.95 1.68 1.38 1.57 Aberdeen Angus . 1.91 1.67 '1.43 1.55 Wo'oh . 1.76 1.54 1.35 1.5)