BREEDING OF CATTLE.

New Zealand Herald, Volume LXVI, Issue 20162, 24 January 1929, Page 5

BREEDING OF CATTLE.

SIRES AND DAUGHTERS.

THE INDEX OF VALUE

A qreat dairy sire is one whose daughters have a high average yield ot milk and butler-fat. :i high average increase in milk and butter-fat yield over that of their dams, and a high percentage of their.number better than their dams, says R. R. Graves of the Bureau of Dairying, United States Department of Agriculture.

In a study of 23 Kriesian sires, each having six or more tested daughters from tested dams, some conclusions were arrived at concerning the hereditary transmission of production, says Mr. Graves. Sonic of the sires in the list raised both the milk yield and the percentage of but-ter-fat of their daughters as compared to the production of their dams. Some raised one and lowered the other. Some lowered both. But no one siro raised both the milk and butter-fat percentage of all his daughters, nor d'.d any 0110 sire lower these records of all his daughters.

The fact that the percentage of butterfat and tlio milk yield are inherited independently, at least within limits, ami that bolh the sire and the dam contribute to tho inheritance of their daughters, governing both milk yield and percentage of butter-fat, indicates that improvement in yield of butter-fat can lie brought hy selection for both milk yield and percentage ot butter-fat. Tho big problem seerns to be to locate the siro that has inherited only the factors determining .1 high producing capacity. Tho degree to which he has inherited these factors can be determined only by testing a large number of his daughters and comparing their records with those of their flams.

The increasing number of records of daughters and their dams becoming available through the cow-testing associations furnishes a means of calculating the comparative worth of a great number of sires than has been possible in the past. The 23 sires in this stucly were given comparative rankings in a new method devised by Mr. Graves.

For instance, sire E ranked first in average milk yield of daughters, third in average butter-fat yield, fifth in average increase of milk, fifth in average increase of butter-fat, first in percentage of daughters making increase in milk, and first in percentage of daughters making increase in butter-fat. The sum of these rankings is 16, which, being the smallest ranking number, places him at the head of the list. On the other hand, sire V, at the bottom of the list of sires, ranked 19th, 20th, 23rd, 22ud, 17th and 16ih respectively in these same classes, giving him a total ranking of 117, or more than any other sire in the list.