the effect of size and type upon the efficiency of milk and beef production in cattle尺寸和类型的影响在牛牛奶和牛肉生产的效率.pdf

THE EFFECT OF SIZE AND TYPE UPON THE EFFICIENCY OF MILK AND BEEF PRODUCTION IN CATTLE* A. HORN, S. BOZÓ A. DUNAY Chair of Animal-Husbandry, Research Institute for Animal Breeding, Cattle-Breeding Department, Z7nivevsity of Veterinary Science, Rottenbilleyu. 23-25 Budapest VII Hungary SUMMARY Partly on the basis of their investigation and of synthetising data of the professional literature the authors have analyzed the correlation and effects of the body size and of some other grading characters of cattle in relation to the production of products by whole populations. According to their examinations the efficiency of size of the individual production is not always characteristic for the trend in the productivity of the total population. Thus e.g. the selection aiming at a larger daily gain, which is advantageous for the feed conversion of the individual, may lead to the development of a cow stock of a large body weight, which may decrease the quantity of beef (calfs) and of milk which can be produced on the identic quantity of nutrients. Examining the relation of body size and milk-yield in populations producing under the same environmental conditions -in contradiction with most earlier examinationsmdash; within the breed there is no conspicuous correlation between the two characters according to the more recent results of researches. Similarly a substantial reciprocity -within the breedmdash; between the body size of parents and beef-production of their progenies cannot be demonstrated either. The probable cause of this is that within the breed the different live weights are not separated genetically. On