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Wayamba Journal of Animal Science

REPEATABILITY ESTIMATES OF MILK YIELD BY PARITY AND AGE IN FRIESIAN- BUNAJI CROSSBRED COWS

J. Aliyu., U. M. Kolo., M. I. Jibrilla and G. A. Mohammed
WJAS ID 1480516069 Date : 2017-12-06 Volume : 9

This study was conducted to determine the repeatability estimates of milk yield by parity and age in 390 Friesian - Bunaji crossbred (25% Friesian and 75% Bunaji) cows that had 7 lactation records. Data collected on each animal include age, parity and weekly milk yield for 20 weeks. The results revealed that milk yield per week were between 9.41±00.79 - 14.07±1.03 litres. The cows within the ages of 1-10 years had consistently similar yield throughout the 140 day lactation period. Significant effect (p<0.05) had been observed on milk yield by parities. The yield in parities 4 and 8 were significantly highest. The yield increases irregularly with age of the cows and the highest values were observed in cows of 7 and 10 years while the lowest were in ages 1 to 8. Repeatability estimates was low (0.208) in parity 5, medium (0.416 and 0.357) in parities 4 and 7, high (0.704, 0.790 and 0.722)in parities 1, 3 and 6. In this study, high repeatability estimates of milk yield in Friesian -Bunaji suggests that culling low producing heifers or cows will improve average milk yield in the herd. The low repeatability estimates for parity 5 (0.208)indicates that the parity was highly influenced by environmental factors and evaluation should be made when more records are available.

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