Reproductive Performance of Crossbred and Purebred Dairy Cows
نویسندگان
چکیده
منابع مشابه
Reproductive Efficiency of Purebred and Crossbred Dairy Cattle
Nine measures related to breeding efficiency were used for comparisons among purebred Ayrshires, Brown Swiss, Holsteins, and Jerseys and between purebreds and 32 crossbred groups representing 2-breed, 3-breed, 5/8, and backcrosses by purebred sires and progeny of crossbred sires. There were four herds wi th Holsteins common to all, Brown Swiss and Jerseys in three herds and Ayrshires in one her...
متن کاملReproductive performance for four breeds of swine: crossbred females and purebred and crossbred boars.
Matings and litters were studied involving all three-breed crosses (sired by purebred boars) and four-breed crosses (sired by cross-bred boars) from the Duroc, Yorkshire, Landrace and Spotted breeds. There were 764 female mating records and 161 boars used over five sequential breeding seasons. A sample of pregnant gilts was slaughtered each season and the remainder were allowed to carry their l...
متن کاملEpidemiology of reproductive performance in dairy cows.
The objectives of this presentation are to review results of our previous and on-going research with respect to the risk factors and consequences of poor reproductive performance in dairy cows, and to develop an economic framework to optimize decisions related to dairy cow reproductive performance. To make profitable breeding and replacement decisions, the farmer must account for factors includ...
متن کاملEconomic merit of crossbred and purebred US dairy cattle.
Heterosis and breed differences were estimated for milk yield traits, somatic cell score (SCS), and productive life (PL), a measure of longevity. Yield trait data were from 10,442 crossbreds and 140,421 purebreds born since 1990 in 572 herds. Productive life data were from 41,131 crossbred cows and 726,344 purebreds born from 1960 through 1991. The model for test-day yields and SCS included eff...
متن کاملReproductive and testicular characteristics of purebred and crossbred boars.
Purebred Hampshire, Duroc and crossbred (H x D, D x H) boars were studied to evaluate reproductive characteristics. One hundred seventeen boars were castrated at 7Y:! months of age to evaluate testicular weights and sperm numbers. Seventy-eight additional boars were studied to evaluate conception rate and embryo numbers when mated to Yorkshire gilts. Rate of gain and backfat probe were also ava...
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ژورنال
عنوان ژورنال: Journal of Dairy Science
سال: 1986
ISSN: 0022-0302
DOI: 10.3168/jds.s0022-0302(86)80431-3