Terminação de novilhas em semiconfinamento com grão milho ou sorgo, inteiro ou moído

Abstract

This study aimed to assess two different forms of corn and sorghum (whole or ground) in supplementation in Mombaça grass pasture (Panicum maximum) on productive performance, blood parameters, carcass characteristics and meat of crossbred heifers Angus x Nellore finished in semi-confinement system in the dry season. The experimental design was completely randomized in a factorial arrangement 2 x 2 (two kinds of grain and two different of presentation of the grains) with three repetitions (each repetition represented by a paddocks with three heifers) for performance variables and nine repetitions (each repetition represented by a heifer) for blood variables and carcass and meat characteristics. The concentrates were formulated with corn or sorghum, whole or ground, and protein supplement (pellet) (Engordim®) in a ratio grain:pellet of 850:150 g/kg dry matter (DM). Thirty-six heifers, with average initial age of 13 months and initial weight of 277 kg were used. The animals were fed for 77 days, 14 days for adaptation and three periods of 21 days for data collection. At the beginning of the trial was provided 220 g/kg of concentrate in relation to the live weight of the animals, and adjusted according to the orts, which were kept in paddocks, with average availability of 5586 kg DM/ha at the time of entry animals in the paddock. With the exception of body condition score, and lightness (L *) and color evaluated subjectively, there was no interaction (P> 0.05) of the type of grain and processing for variable consumption, blood parameters and carcass characteristics and meat. Greater nutrient intake (P> 0.05) was observed for animals that received sorghum in the concentrate, with the exception of ether extract (EE), which was higher for corn, explained by nutrient fact be at a higher concentration in the sorghum. Regarding the form of presentation, animals fed grain in the whole form had higher consumption (P> 0.05) of DM, NDF, NFC and EE in g / kgPC, but this difference did not promote better performance with higher average daily gain (ADG) and feed efficiency (EA) for the animals that consumed the corn in the ground form (1.70 vs 1.22 kg/day) and (0.23 vs 0.16 kg/kg), respectively. The muscularity score (MS) and final body condition (ECCF), followed the same behavior of GMD. The muscularity score (MS) and final body condition (ECCF), followed the same GMD behavior. There was no influence of treatments on blood parameters (P> 0.05) despite the glucose and alkaline phosphatase levels are above normal values to bovine species. The quantitative variables differ (P <0.05) in function of the form of presentation of the grains, with higher values for animals fed concentrate with ground grain, except for subcutaneous fat thickness (SFT) which was higher to the animals fed whole grain. There was no influence of the type of grain and processing (P> 0.05) on the relative weight of 100 kg of cold carcass (CC) for primary cuts. The treatments did not affect (P> 0.05) the characteristics that express bone development. For the carcass composition was influence of type of grain (P> 0.05) to the bone percentage in the carcass from animals fed whole grain, reflecting lower ratio of edible portion: bone (EP/B) and muscle:bone (M/B), regardless of the form of presentation. The lightness (L *) and color evaluated subjectively had interaction, but the other characteristics evaluated in meat were not affected by treatments. The corn is indicated for use in concentrate with high participation of grain compared to sorghum, for giving greater weight gain. However, the use of sorghum does not change carcass characteristics and meat, except for the thickness of subcutaneous fat. When using corn or sorghum, they maybe be provided ground for providing better feed efficiency, performance, carcass characteristics and meat.