Abstract

Factors affecting plasma carotene concentration were investigated in New Zealand dairy heifers. Blood samples were collected from 4000 dairy heifers in spring in November 1992. Significant (P<0.001) variation was found in plasma carotene concentrations due to region, breed and farm. Values for individual cows ranged from 1.7 to 56.2 ug/ml. Purebred Jersey heifers had the highest plasma carotene levels (18.2 ± 0.4 ug/ml), purebred Friesians the lowest (14.4 ± 0.2 ug/ml), crossbreds were intermediate with 50% Jersey and 50% Friesian significantly different from the purebreds (16.9 ± 0.6 and 15.4 ± 0.4 ug/ml respectively).

S-AN, Newman, TW Knight, KT O'Neill, AF Death, and M Ridland

Proceedings of the New Zealand Society of Animal Production, Volume 54, , 119-120, 1994