Estimation of test-day model (co)variance components across breeds using New Zealand dairy cattle data
نویسندگان
چکیده
منابع مشابه
Genetic evaluation of dairy cattle with test-day models with autoregressive covariance structures and with a 305-d model.
This study compared genetic evaluations from 3 test-day (TD) models with different assumptions about the environmental covariance structure for TD records and genetic evaluations from 305-d lactation records for dairy cows. Estimates of genetic values of 12,071 first-lactation Holstein cows were obtained with the 3 TD models using 106,472 TD records. The compound symmetry (CS) model was a simpl...
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The purpose of this study was to monitor current and predict future rates of inbreeding in the Danish dairy breeds. Calves born from 1999 until 2003 and registered as Danish Holstein (1,883,983), Danish Jersey (336,966), or Danish Red (261,047) were reference populations. Average complete generation equivalent was approximately 7. For calves born in 2003, average inbreeding was 3.9, 3.4, and 1....
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genetic parameters were estimated for somatic cell score (scs) in dairy cattle of iran using test day records. the records of first lactation were extracted from the database of national animal breeding center for cows calved between 2001 and 2010. data included 222923 test-day records, obtained from 29668 animals distributed in 100 different herds. estimates were carried out through gibbs samp...
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Over 18% of cows returning to service within 49 days of first insemination were remated within the first 17 days. A distinct peak representing 31.4% of all short return intervals occurred from 8 to 10 days after first insemination. Because nonreturn rates to second insemination following these service intervals were equal to nonreturn rates for first inseminations, it is probable that some cows...
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Using monthly test day records the genetic parameters of Iranian Holstein cattle in first lactation were studied. Data of 277400 test-day milk records from 65320 cows and 2210 sires were analyzed by an animal random regression model using restricted maximum likelihood methodology. The model included herd-test-date, interaction between year-season of calving, days in milk (linear and quadratic) ...
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ژورنال
عنوان ژورنال: Journal of Dairy Science
سال: 2009
ISSN: 0022-0302
DOI: 10.3168/jds.2007-0794