Zobrazeno 1 - 10
of 15
pro vyhledávání: '"J.R. Wright"'
Publikováno v:
Journal of Dairy Science. 88:3337-3345
If genetic evaluations are calculated with a single-trait repeatability model, evaluation changes may be attributed in part to bulls that have daughters that deviate considerably from the typical response to aging. Differences in maturity rate of bul
Publikováno v:
Journal of Dairy Science. 87:2299-2306
To determine the relationship of test-day (TD) somatic cell score (SCS) to TD and lactation milk yields, 1,320,590 records from Holstein first and second calvings from 1995 through 2002 were examined. All lactations had recorded yield and SCS for at
Publikováno v:
Journal of Dairy Science. 86:1513-1525
Progeny-test (PT) programs of US artificial-insemination (AI) organizations were examined to determine timeliness of sampling, PT daughter distribution, rate of return of PT bulls to widespread service, and genetic merit of PT bulls compared with AI-
Publikováno v:
Journal of Dairy Science. 80:2563-2571
A multitrait animal model was used to calculate predicted transmitting ability and reliabilities for final score and 15 linear type traits of 225,632 US Jersey cows. Records were adjusted for age and stage of lactation before analysis. The model cont
Publikováno v:
Journal of dairy science. 96(4)
Genetic parameters were estimated for mobility score and 16 linear type traits of Brown Swiss dairy cattle. Mobility is an overall assessment trait that measures a cow's ability to move, as well as the structure of her feet, pasterns, and legs. Score
Publikováno v:
Journal of dairy science. 92(5)
Genetic and environmental factors that might affect gestation length (GL) were investigated. Data included information from >11million parturitions from 1999 through 2006 for 7 US dairy breeds. Effects examined were year, herd-year, month, and age wi
Publikováno v:
Journal of dairy science. 91(9)
Factors that affect frequency of death of lactating cows were studied for cows with records that terminated from 1995 through 2005. Analyses included effects of herd, year, month, parity, and lactation stage at lactation termination as well as cow br
Publikováno v:
Journal of dairy science. 90(8)
Differences among bulls in maturity rate of their daughters for milk yield were investigated. Milk records for US Holsteins with first-parity calving dates between 1960 and 1998 were used to calculate 3 evaluations for bulls based on daughter records
Publikováno v:
Journal of dairy science. 90(2)
Emphasis by dairy producers on various yield and fitness traits when culling cows was documented for US Holstein calvings since 1982. Least squares differences between cows retained for additional parities and those culled were estimated for milk, fa
Publikováno v:
Journal of dairy science. 89(9)
Survival rates and productive herd life were examined for 13.8 million US dairy cows that calved from January 1, 1980, through March 2, 2005. Cows that left the herd for dairy purposes or were from herds that discontinued Dairy Herd Improvement testi