Abstract The objective of this study was to evaluate the effect of different levels of concentrate supplementation on carcass characteristics of heifers finished on Tifton 85 pasture. Thirty-two cross-breed heifers (Charolais and Nellore) on average aged 25.51 months and weighing 298 kg were used in a completely randomized experiment. The animals were distributed uniformly to receive four different levels of concentrates based on the body weight: 0.0; 0.4; 0.8 and 1.2%. Animals were slaughtered at 29 months of age. There was increasing linear effect of levels energy supplementation on: slaughter weight, hot and cold carcass weights,hot and cold dressing percentage, thigh thickness, carcass compactness, and L* and b* color values. It was observed quadratic effect of levels of energy supplementation on the percentage of fat in the carcass. Different levels of energy supplementation did not modify the accumulation of vital organs and visceral fat or the sensory attributes of the meat. Higher levels of energy supplementation promote increases in carcass traits of heifers when finished on Tifton 85 pasture.

Abstract The objective of this study was to evaluate the effect of live weight and body condition score, measured at different growth stages, on the rebreeding of first-calf heifers. A total of 120 Nellore and Charolais crossbred heifers born between 2004 and 2008 were assessed. Their average age was 26±1 months, they were all from the same herd, and they received the same management from birth. To conduct this study, pre- and postpartum measurements of first-calf heifers were taken. The data were submitted to analysis of variance, and the means were compared using Student’s t-test at a significance level of α=0.05. A higher live weight of the heifer at 24 months enabled early calving within the first calving season (r=-0.30). First-calf heifers that rebred had a higher live weight at weaning (361 kg vs. 333 kg) than those that did not, although their live weights at calving were similar (344 kg vs. 332 kg). The rebreeding of first-calf heifers that gave birth with the same body condition score as in the first calving was dependent on positive live weight gain until the end of the following breeding season, especially during the calving-weaning period.

Resumen El objetivo de este estudio fue evaluar el efecto del peso vivo y la puntuación de condición corporal, medido en diferentes fases de crecimiento, sobre la repetición de la cría en primíparas. Se evaluaron 120 novillas cruzadas Nellore con Charoles nacidas entre los años 2004 y 2008, con edad media de 26±1 meses siendo todas oriundas del mismo rebaño y que reciben idéntico manejo desde el nacimiento. Para la realización de este estudio se utilizaron de la base de datos a las mediciones de la primípara en el pre y post-partos. Los datos fueron sometidos al análisis de varianza y las medias comparadas a través del test “t” de Student, a α=0,05 de probabilidad. El mayor del peso vivo de la novilla a los 24 meses proporciona que el parto ocurra por adelantado dentro de la primera estación de parición (r=-0,30). Primíparas que repetían crea presentaron mayor peso vivo al destete (361 kg vs. 333 kg) de las que no repitieron crea, aunque hubiera peso vivo al parto semejante entre sí (344 kg vs. 332 kg). La repetición de la cría de primíparas que paren con la misma puntuación de condición corporal, en el primer parto, es dependiente de la ganancia de peso vivo positivo hasta el final de la estación de montaje siguiente, principalmente en el período parto-destete.