Resumen

ESPINOZA, Freddy et al. Productivity response of dual purpose cows grazing sorghum straw (Sorghum bicolour) and supplemented with liquid diet at cují (Acacia macracantha) and ureaphosphate. Zootecnia Trop. [online]. 2009, vol.27, n.3, pp.233-238. ISSN 0798-7269.

The experiment was carried out in a farm at the north of Guárico state, Venezuela, with the objective to evaluate the effect of a liquid diet with molasses, cují leaves (Acacia macracantha) and ureaphosphate in dual purpose cows grazing sorghum straw (Sorghum bicolor) on the production of milk and weight gain in the dry period, and a simple analysis of income vs. supplement cost. The duration of the experiment was 75 days, including 15 days of adaptation during the dry period of year 2006. Thirty two cows Bos taurus x Bos indicus were used with an initial weight average of 422.5 ± 30.4 kg, grazing a pasture of 80 ha of sorghum straw (PSS). The design was a completely random where each animal represented a repetition. Two treatments were used, T1: PSS and T2: PSS supplemented with liquid diet molasses, cují leaves, urea phosphate, and water at the rate of 70, 15, 6, 9%, respectively. The variables studied were milk production (MP), weight gain (WG), dry matter (DM) offer of sorghum straw, and chemical composition. The initial dry matter was 3044 kg DM/ha and residual herbage was 1702 kg DM/ha, which represented 44% of efficiency of grazing of sorghum straw (P<0.01). MP was higher in T2 (6.4 vs. 5.7 L/animal/d) (P<0.01). WG was higher in T2 (P>0.05) with values of 991 g/animal/day. The content of crude protein, calcium, and phosphorus in supplement was 14, 0.78, and 1.18%, respectively (P<0.01). The income was higher in T2 with a difference near to US $ 887. It is concluded that the supplementation with liquid diet molasses-cují-urea phosphate in dual purpose cows improved the bioproductive indicators.

Palabras clave : dual purpose cows; milk production; weight gain; dry matter; sorghum straw.

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