منابع مشابه
Genetic parameters for growth traits for a composite terminal sire breed of sheep.
Records of 9,055 lambs from a composite population originating from crossing Columbia rams to Hampshire x Suffolk ewes at the U.S. Meat Animal Research Center were used to estimate genetic parameters among growth traits. Traits analyzed were weights at birth (BWT), weaning (7 wk, WWT), 19 mo (W19), and 31 mo (W31) and postweaning ADG from 9 to 18 or 19 wk of age. The ADG was also divided into d...
متن کاملStillbirth (co)variance components for a sire-maternal grandsire threshold model and development of a calving ability index for sire selection.
(Co)variance components for stillbirth in US Holsteins were estimated under a sire-maternal grandsire threshold model using subsets of data from the national calving ease database, which includes over 6 million calving records with associated stillbirth scores. Stillbirth was coded as a binomial trait indicating whether the calf was alive 48 h postpartum. Records were selected for calves whose ...
متن کاملCompeting risks analysis of lamb mortality in a terminal sire composite population.
Mortality records from birth to weaning of 8,301 lambs from a composite population at the U.S. Meat Animal Research Center were analyzed using a competing risks model. The advantage of the competing risks model over traditional survival analyses is that different hazards of mortality can be assigned to different causes, such as disease, dystocia, and starvation. In this study, specific causes o...
متن کاملIndex selection in terminal sires improves lamb performance at finishing.
Lamb meat is often perceived by consumers as fatty, and consumption has decreased in recent decades. A lean growth index was developed in the UK for terminal sire breeds to increase carcass lean content and constrain fat content at a constant age end point. The purposes of this study were 1) to evaluate the effects of index selection of terminal sires on their crossbred offspring at finishing a...
متن کاملThe influence of breeding intensity on above- and below-average sexual performance rams in single- and multiple-sire breeding environments.
Two studies were conducted to evaluate the relationship between serving capacity scores and breeding performance of rams. The first study was conducted to determine whether rams with above or below mean serving capacity scores could perform equally in greater and lesser breeding intensity, single-sire mating schemes. The second study was conducted to determine whether rams with above and below ...
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ژورنال
عنوان ژورنال: Canadian Journal of Animal Science
سال: 2002
ISSN: 0008-3984,1918-1825
DOI: 10.4141/a02-024