Brenner, J., Department of Immunology, Kimron Veterinary Institute, POB 12, Bet Dagan, 50250, Israel
Rosenthal, I., Department of Food Science, The Volcani Center, Bet Dagan, 50250, Israel
Bernstein, S., Department of Food Science, The Volcani Center, Bet Dagan, 50250, Israel
Trainin, Z., Department of Immunology, Kimron Veterinary Institute, POB 12, Bet Dagan, 50250, Israel, Department of Cancer Biology, Harvard School of Public Health, Boston, 02115, MA, United States

Two groups of cows infected with the bovine leukosis virus (BLV) were kept on two different diets and the fat content of their milk was assayed. The results were compared with those obtained from two comparable groups of BLV-free cows. The cows in each group were of similar ages, those in the groups on the poorer diet being 1-4 months post partum, while those on the richer diet were 5-7 months post partum. The mean percentage of fat in the milk from uninfected cows on the poorer diet was 2.94 while that from the similar infected cattle was 3.06. Uninfected cows on the richer diet produced milk containing 3.39% fat, while those that were infected produced milk containing 3.30% fat. No statistical differences in milk fat production were observed between the BLV seropositive and seronegative cows. © 1990 Kluwer Academic Publishers.