SOME FACTORS INFLUENCING MILK PRODUCTION TRAITS OF PURE AND CROSSBRED COWS IN THE TROPICS

Abstract

10 year record of 879 lactation yield of three breeds of cows comprising Brown Swiss (pure), White Fulani (indigenous) and Brown Swiss x N’Dama (crossbred) raised and maintained at the teaching and Research farm of the University of Ibadan was used to investigate effect of some factors on milk  production traits. Breed exerted significant (P<0.01) effect on all the production traits. Lactation  milk yield,  milk yield per day and lactation length was significantly (P<0.05) affected by calving interval while the age at first calving had significant (P<0.05) effect on production years and lifetime yield indicating that where calving interval had significant effect, age at first calving had no significant effect and vice versal.  The seasonal effect (P>0.05) had no influence on the production traits except on the lactation milk yield. Calving interval and age at first calving did not follow any trend of effect, however on the average 16-18 months calving interval, 23-32 month age at first calving was best for most of the       production traits. The phenotypic and genetic correlation coefficients amongst the milk production traits revealed a high genetic association between the genes controlling these traits with exception of productive years.