THE EFFECTS OF COTTONSEED CAKE WITH OR WITHOUT MOLASSES ON FEED-UTILIZATION, PURINE EXCRETION, AND MILK-PRODUCTION OF BORAN (BOS-INDICUS) COWS FED A MIXTURE OF WHEAT AND OAT STRAW

The effects of 1.35, 1.80, or 2.25 kg dry matter (DM) of cottonseed ca ke, with (1.85 kg DM) or without molasses, on straw intake, diet diges tibility, live-weight change, excretion of purine derivatives (PD), an d milk production of Boran (Bos indicus) cows were studied. There were no significant (P > 0.05) interactions. Straw intake was 0.47 kg DM l ower (P < 0.001) showing a substitution effect of 254 g kg(-1) with mo lasses. Straw intake tended also to decrease from 5.18 to 4.94 kg DM ( P < 0.15) with a daily substitution of 107 g kg(-1) with increasing le vels of cottonseed cake. Molasses increased DM and organic matter (OM; P < 0.01) but decreased crude protein (CP; P < 0.001) and neutral-det ergent fibre (NDF; P < 0.01) digestibilities. Molasses (P < 0.05) and increasing levels of cottonseed cake (P < 0.01) increased daily milk y ield from 3.06 to 3.26 and from 2.96 to 3.32 kg, respectively. Molasse s increased live-weight by 300 g day(-1) (P < 0.05). Increasing levels of cottonseed cake caused a live-weight change of 69 g to 467 g day(- 1) (P < 0.05). A supply of microbial-N increased (P < 0.001) in molass es diets but microbial-N production kg(-1) digestible OM was not affec ted by treatments (P > 0.05).