Comparative study of water elimination by enteric route in taurine and zebuine heifers fed fresh grass

Abstract

Eight clinically healthy heifers, 18 to 24 months old, four of which were pure Bos taurus (crosses of Danish and Flemish breeds) and the other four were pure Bos indicus (Nelore breed) were put in individual partitions of a stable, where each received water and freshly cut “Elephant Grass” (Pennisetum purpureum Schum)‘‘ad libitum” . The experiment was conducted at the “Centro Intraunidade de Zootecnia e Indústrias Pecuárias Fernando Costa” (University of São Paulo), in Pirassununga, State o f São Paulo. For 10 consecutive days, during which ambient temperature varied from 8°C to 24°C, daily foecal water determinations were made following the AOAC Method and the results were expressed in ml permetabolic weight unit (W_kg0,75). The variations among samples from one to the other of the taurine heifers (15.90%) were statistically significant, while they were not significant from one to the other of the zebuine heifers (5.18%). On the other hand variations from day to day were slightly smaller in taurine (9.26% to 21.62%)than in zebuine animals (14.87% to 25.21%). In what concerns the average global daily water elimination by the enteric route it was consistently superior in the taurine heifers, since the smallest individual average for an animal in this group (129.07 ± 5.11), animal no.1, was conspicuously higher than the largest individual average in the zebuine group (117.06 ± 6.61), animal no.5. Obviously the average difference from group was statistically significant.