Genetic analysis of persistency in the israeli holstein population by the multitrait animal model.
Persistency was defined as the predicted milk production 180 d after peak divided by peak production (in %). Heritability of persistency in a multitrait analysis including parities 1 through 5 increased from 0.16 to 0.27 from first through third parity, and then declined through fifth parity. Genetic correlations for persistency between consecutive parities were all > 0.8. First-parity genetic correlations of the traits included in the Israeli selection index with persistency were all < 0.1, except for fertility and herdlife, which were 0.20 and 0.25; whereas second-parity genetic correlations of persistency with the 3 milk production traits were all > 0.34, and the genetic correlation with fertility was only 0.10. The genetic correlation between second-parity persistency and herdlife was 0.58. Persistency in the Israeli Holstein population was analyzed by the multitrait animal model. The genetic trend since 1985 for the multiparity index was 0.22% persistency/yr, even though there was no direct selection on persistency.
Weller
J I
JI
Institute of Animal Sciences, ARO, The Volcani Center, Bet Dagan 50250, Israel. weller@agri.huji.ac.il
Ezra
E
E
Leitner
G
G
D000818:Animals; D001947:Breeding; D002417:Cattle / Q000235:genetics*; D002452:Cell Count; D004777:Environment; D005223:Fats / Q000032:analysis; D005260:Female; D007557:Israel; D007774:Lactation / Q000235:genetics*; D008297:Male; D008892:Milk / Q000737:chemistry / Q000166:cytology; D008894:Milk Proteins / Q000032:analysis; D008957:Models, Genetic; D010298:Parity; D010641:Phenotype; D011247:Pregnancy; D019655:Quantitative Trait, Heritable; D013997:Time Factors
D005223:Fats; D008894:Milk Proteins