Resumen

ESPINOZA, Freddy et al. Strategic use of sugar cane (Saccharum officinarum) in dual purpose pregnant heifers. Zootecnia Trop. [online]. 2006, vol.24, n.2, pp.95-107. ISSN 0798-7269.

It was carried out a trial in the experimental unit of the National Center of Agricultural Research to evaluate the effects of sugar cane supplementation  in the last third period of gestation of dual purpose crossbred heifers on live weight of before and after parturition, calving interval, calving weight, and milk production. Animals (14), with a mean initial body weight of 495 kg, were randomly placed in two treatments: T1: grazing + 1.5 kg of concentrated feed/head/day and T2: grazing + 1.5 kg of concentrated feed/head/day + 4 kg of sugar cane with urea/head/day, as the animals approached to the seventh month of pregnancy. Grazing was on bermuda grass (Cynodon dactylon) with a carrying capacity of 2 animal units/ha/year. A complete randomly design was used, where each animal represented an experimental unit (seven per treatment), with a mean comparison through Tukey test. The results did not show significant differences (P>0.05) on calving weight and heifer live weights, before and after parturition. However, there was a significant difference (P<0.01) on heifer average daily gain. Calving interval was lower in T2 (P<0.05), but a higher milk production, with a mean of  1269 L/head/lactation, when it was compared to treatment T2 with a mean of 1634 L/head/lactation. Milk cost was higher for T2, but net income in T1 was lower with a mean of 516 and 619 US$, for T1 and T2, respectively. It can be concluded that sugar cane as energetic source in dual purpose crossbred heifers previous to parturition significantly affected animal response, such as higher milk production/lactation, lower calving interval, and improved body weight gain.

Palabras clave : Crossbred heifers; calving interval; milk production; bodyweight; sugar cane; parturition.