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Full-Text Articles in Animal Sciences
Prediction Of Breeding Values For Twinning Rate And Ovulation Rate With A Multiple Trait, Repeated Records Animal Model, L. Dale Van Vleck, K. E. Gregory, S. E. Echternkamp
Prediction Of Breeding Values For Twinning Rate And Ovulation Rate With A Multiple Trait, Repeated Records Animal Model, L. Dale Van Vleck, K. E. Gregory, S. E. Echternkamp
Department of Animal Science: Faculty Publications
A genetic correlation near unity between ovulation rate in heifers and later twinning frequency led to consideration of using measures of ovulation rate in heifers for each estrous cycle, beginning at puberty, to increase accuracy of selection for twinning rate. An initial evaluation with a multiple trait animal model for predicting breeding values included six genetic groups: 1) selected Scandinavian bulls, 2) transfers from other populations at the Research Center to a twinning project, 3) early-purchased Holsteins, 4) late-purchased Holsteins, 5) early purchases-other breeds. and 6) late purchases-other breeds. For ovulation and twin measures, heritabilities of .l00 and .070 and …
Ovulation Rate And Twinning Rate In Cattle: Heritabilities And Genetic Correlation, L. Dale Van Vleck, K. E. Gregory, S. E. Echternkamp
Ovulation Rate And Twinning Rate In Cattle: Heritabilities And Genetic Correlation, L. Dale Van Vleck, K. E. Gregory, S. E. Echternkamp
Department of Animal Science: Faculty Publications
Repeated measures of ovulation rate on puberal heifers should be an effective way to select for increased twinning rate. A reliable estimate of the genetic correlation between ovulation and twinning rates is needed to implement such selection and to predict its efficiency. Restricted maximum likelihood was used to estimate genetic correlations from subsets of data collected from the twinning project at the Roman L. Hruska U.S. Meat Animal Research Center. The animal model included numerator relationships among the animals and 6x4 effects of year-season of measurement, age at measurement, and birth group. Genetic correlations between averages of ovulation rates for …