Genetic Evaluation of Holstein Friesian Cattle Using Milk Flow Rate (Research Note)

Kais H. Juma, Jalal E. Alkass, Mahfouz A. Al-Hered

الملخص


At Al-Nasr Animal Breeding Station 201 Holstein cows and 41 bulls were genetically evaluated for Milk Flow Rate (MFR) using the Animal Model. Random variances were estimated by REML method with account of the fixed effects.

MFR was measured 60 days post- partum and repeated 2.5 months later. The overall mean of MFR was 1.58 kg/min. MFR increased with parity (P< 0.01). highest and lowest  MFR were among cows having dish-and pendulous-shaped udders (p< 0.01). The effects of milk production, California Mastitis Test score, shape of teat and udder texture on MFR were not significant.

Heritability and repeatability of MFR were 0.09 and 0.13, respectively. The overall mean predicted breeding values of MFR for bulls and dams was 0.013 and 0.040 kg/min, respectively. Average real producing ability of cows was 0.003 kg/min. Genetic and phenotypic trends for MFR over the birth years of cows were significant  (p< 0.01) being 0.042 and 0.126 kg,/min/ year, respectively.


الكلمات المفتاحية


Genetic evaluation, Holstein Friesian, Milk flow rate

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