Estimation of milk producing ability of Holstein friesian cattle in a commercial herd in Egypt
2000
Khattab, A.S. (Tanta Univ., (Egypt). Faculty of Agriculture) | El- Ariain, M.N. | Atil, H.
A total of 3236 lactation records of 929 Holstein Friesian cattle sired by 290 bulls kept at a commercial herd in Egypt (Dalla Farm) were used. Cows transmitting abilities (CTA) were estimated by best linear unbiased prediction (BLUP). All cows whose at least two records up to six were used. Means of 90 day milk yield (90 dMY) and 305 day milk yield (305 dMY) are 1673+-25 and 5076+-64 kg, respectively. Least squares analysis of variance showed a significant effect of month of calving, year of calving and parity as fixed effects and sire and cow within sire as random effects on 90 dMY and 305 dMY. Heritability, repeatability, genetic and phenotypic correlations were estimated by paternal half sibs correlations. Heritability estimates were 0.31+-0.06 and 0.15+-0.05 for 90 dMY and 305 dMY, respectively. Repeatability estimates were 0.25+-0.02 and 0.34+-0.02 for 90 dMY and 305 dMY, respectively. Genetic and phenotypic correlations between the two traits studied were 0.47+-0.12 and 0.53, respectively. Estimates of CTA for 90 dMY ranged from -513 to 556 kg and from -989 to 1754 kg for 305 dMY with the range being 1069 and 2743 kg, respectively. Product moment correlations between 90 dMY and 305 dMY was 0.92. The present results indicated that CTA for 90 dMY was good predictor of CTA for 305 dMY.
اظهر المزيد [+] اقل [-]الكلمات المفتاحية الخاصة بالمكنز الزراعي (أجروفوك)
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