Out on First Record?

How accurately can one decide on the basis of a heifer\u27s first record whether she is good enough to keep

Genetic aspects of the Danish system of progeny-testing swine

1. The history of the Danish system of progeny testing swine is traced briefly. 2. Changes in the average characteristics of the Danish swine since this system began in 1907 are shown in graphs. 3. The variance of six of these characteristics is analyzed, largely by means of correlations between litter mates, between half-sibs and between progeny tests of sire and of son, to find the extent to which individual variance in each characteristic can be attributed to the additive effects of genes. 4. A little less than half the individual variance in body length, thickness of back fat and thickness of belly can be thus ascribed to additive gene effects. Differences in rate of gain, yield of export bacon and in economy of gain are less highly hereditary, yet there seems to be in them enough additive gene variance to permit selection still to make distinct changes in the population for at least a few more generations. (Summary in table 11.) 5. Although the actual basis of the selections which the Danish farmers practice is not completely demonstrated, the figures from these progeny tests must have played a considerable part. 6. The Danish plan of progeny testing has been developed in such close connection with the economic peculiarities of Danish cooperative organizations that its operating principles might need much revision before it could be used in other countries. The biological principles involved, however, are the same everywhere and any people wishing seriously to improve the real economic productivity of their livestock, especially in characteristics which cannot be seen or measured until the animals are slaughtered, will find useful suggestions in this Danish model

Linebreeding

Linebreeding is a form of inbreeding (usually mild) directed toward keeping the offspring closely related to one ancestor (usually a much admired one). All inbreeding not necessary for holding this relationship high is avoided as far as possible. It is practiced to conserve, among the descendants, the good traits of an outstanding sire or dam, increasing those descendants in numbers without lessening their resemblance to this ancestor even for many generations after that ancestor’s death. The more superior a breeder’s herd or flock is to the average merit of its breed, the more reason he has to practice linebreeding to his very best animals or to the very best of their recent ancestors. Breeders of grades cannot often afford to do much linebreeding

Application of Genetics to Animal Breeding - Paper Presented at the Fifty-Fifth Annual Meeting

Animal breeding is is an old art, which long ago developed far beyond the scientific knowledge of the subject. By actual experience men built up certain rules as to what practices were or were not good procedure for a given set of conditions. Man naturally devised philosophical explanations which more or less satisfied his intellect as he went along. But it would be a far stretch of the imagination to call those explanations scientific

Changes in Body Measurements of Steers During Intensive Fattening.

59 p

Normal Growth of Range Cattle.

34 p

Rice Bran as a Feed for Dairy Cows.

22 p

The Influence of Individuality, Age, and Season Upon the Weights of Fleeces Produced by Angora Goats Under Range Conditions.

54 p

The Inheritance of Cryptorchidism in Goats.

23 p

Karakul Sheep.

20 p