Beef quality traits of Nellore, F1 Simmental × Nellore and F1 Angus × Nellore steers fed at the maintenance level or ad libitum with two concentrate levels in the diet

This trial was conducted to evaluate some beef quality attributes of Nellore, F1 Simmental × Nellore and F1 Angus × Nellore steers finished on feedlot. The effects of feeding regime and genetic group on shear force, thawing losses, cooking (leak + evaporation) losses, total losses and muscle fiber type, as well as carcass pH and temperature during 24 h of chilling were evaluated. There was a genetic group effect on shear force, where the beef from F1 Simmental × Nellore and F1 Angus × Nellore animals had lower values than Nellore animals. Beef of the animals fed the diets with 1% and 2% of body weight on concentrated lost more liquid than the meat of the animals fed at maintenance during thawing and when considering total losses. During cooking there was a difference among the feeding regimes for drip losses which were greater on the animals fed the diet of 1% of body weight on concentrate, followed by the 2% diet and, finally, by the animals fed at maintenance. The muscle of the Nellore steers had larger proportion of intermediate fibers and lower proportion of oxidative fibers than the crossbred animals. The proportion of glycolytic fibers was not influenced by genetic group. The Nellore animals had larger proportion of fibers of fast contraction and smaller proportion of fibers of slow contraction when compared with the crossbred animals. Feeding regime did not influence the proportion of muscular fibers or shear force. Nellore cattle produce tougher beef than crossbred Simmental × Nellore or Angus × Nellore, although all of them have the potential to produce an acceptable beef when slaughtered at young age. Feed restriction up to 90 days is not enough to cause modification on muscle fiber frequencies, then not affecting beef quality

Performance and carcass quality of feedlot- or pasture-finished Nellore heifers according to feeding managements in the postweaning phase

The objective of this study was to evaluate the postweaning history of heifers kept on marandu grass pastures with three canopy heights, in a continuous-grazing system, during the rainy period, on feedlot-or pasture finishing. The effects of three canopy heights (15, 25 and 35 cm) associated with two supplements (mineral salt and protein-energy supplement) and two finishing systems in the dry period (feedlot and open pasture) were studied in the postweaning period during the rainy season. The adopted design was completely randomized, with seven replications (animals) in a 2 x 2 factorial arrangement. The animals which received protein-energy supplement reached the finishing period with greater body weight in relation to those fed mineral salt. In both feedlot and pasture finishing systems, compensatory gain effect was observed in the animals that remained on the low pastures during postweaning compared with the high pastures. This compensatory gain was not verified in the animals that received protein-energy supplement in relation to the mineral salt, and thus the animals were slaughtered beforehand. The heifers on pastures with 25 or 35 cm in height were slaughtered in the same period, and those kept on the low pastures were slaughtered afterwards. The studied factors in the postweaning phase did not affect the carcass characteristics. Animals finished in feedlot slaughtered with the same body weight as those finished on pasture show greater carcass yield, subcutaneous fat deposition and renal pelvic and inguinal fat and greater losses with trimmings for cleaning the main hindquarter meat cuts; however, they provide cuts with the same weight but greater fat cover.Univ Fed Lavras, Dept Zootecnia, Lavras, MG, BrazilUniv Estadual Paulista, Dept Zootecnia, Jaboticabal, SP, BrazilAgencia Paulista Tecnol Agronegocios, Colina, SP, BrazilUniv Estadual Paulista, Dept Zootecnia, Jaboticabal, SP, Brazi