Diferenças entre grupo genético e regime alimentar sobre características qualitativas da carcaça e da carne e composição corporal de bovinos de corte

• Autor(a) principal: Oliveira, Ivanna Moraes de
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5632
• topic: Dietas de alta energia; Maciez; Cruzamento; High energy diets; Softness; Crossing; CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::PRODUCAO ANIMAL

The productive section of meat should implement technologies that produce younger animals, with racial characteristics that promote quality meat. The manipulation of the diet and use of industrial crossing are technologies of easy access to the producer. Sixty cattle castrated with 18 moths of age, being 20 Nellore (NE), F1 Simmental x Nellore, F1 Angus x Nellore with average body weight of 265.6±6.4, 325.3±4.7 kg and 324.6±6.0 kg, respectively. The experiment was in completely randomized experimental design, in factorial 3 x 3, being 3 genetics groups (Nellore, F1 Simmental x Nellore, F1 Angus x Nellore) and 3 alimentary regimes (feeding to the maintenance level and ad libitum with 1% and 2% of the corporal weight (CW) at concentrated in natural matter of the diet), composing, therefore, 9 treatments, with 6 repetitions in each genetic group in the feeding levels ad libitum (1% and 2%) and four repetitions for the restricted feeding level (maintenance). After period of initial adaptation, the animals designated to received 2% of CW at concentrated one week passed receiving 1.5% CW in concentrated and one more week receiving 2% CW in concentrated for adaptation on the diet. The animals designated to receive 1% CW in concentrated and the treatment in maintenance started your diet immediately after the initial adaptation. At the end of that second week, call of second adaptation, all the animals were heavy, in fast of 16 hours, for beginning of the first experimental period. The animals in maintenance regime received the same diet supplied for the animals fed with 1% of CW at concentrated, in the equivalent amount to 1% of CW. The roughage was supplied at ease, being constituted of corn silage. The concentrate, in restricted amount, was formulated at base of ground corn, soybean meal, whole cottonseed, soybean hulls, urea/ammonium sulfate (9:1), sodium bicarbonate, magnesium oxide, common salt and mineral premix. The concentrate were formulated for that the same ration was offered the both treatments, changing only relationship corn/urea + ammonium sulfate allowing the diets to keep isonitrogenous (12.5% CP in the DM). The animals were maintained in individual stalls, with floor, concrete feeder and drinker, with total area of 30 m2, with 8 m2 of covered area. The experiment had total duration of 136 days, being 30 days of adaptation to the experimental conditions, 14 days of adaptation to the diet (2nd adaptation) and 84 days of experimental period. Were intermediate weighs, in fast of 16 hours, to the 28 and 56 days of performance. After the period of evaluation performance, started the slaughter of the animals. Like this, was evaluated the effect of genetic group and alimentary regime on quantitative and qualitative characteristics, physical and chemical composition of the gain, of the carcass and of the empty body and standard of deposition of tissues. Animals fed with larger concentrate level had larger (P<0.05) cold carcass weight (CCW), cold carcass dressing (CCD) and rib eye area/100 Kg of cold carcass (REA/100 kg) in relation to the small concentrate level. Except for cut of the top sirloin butt, there was not difference (P>0.05) in the feeding ad libitum for the yield of cuts. Crossbred animals presented larger (P <0.05) CCW that animals NE. The animals NA had larger (P<0.05) fat thickness (FT) and smaller REA/100 kg in relation to the animals NS. The trade cuts was not influenced (P>0.05) for the genetic group, except for the cut of the shoulder clod that had smaller (P<0.05) yield in the crossbred animals. The final pH was not influenced (P<0.05) for the treatments and it was inside of the appropriate patterns for export, below 6.0. The measures of REA and FT taken along the development of the animals detected the growth stage in that met. Crossbred animals and fed with larger concentrate level possess carcasses with more appropriate characteristics to the requirements of the import market, in a general way. Animals in maintenance presented larger (P<0.05) proportion of bones and muscle in the carcass and animals NE had larger muscle proportion and smaller (P<0.05) proportion of total fatty in the carcass that crossbreds animals. Animals NE and in maintenance present smaller (P<0.05) amount of total fat that crossbreds and fed ad libitum, respectively. The fat was deposited in larger proportion in the intermuscle fatty tissue, followed by the fatty of mesentery. The rate of deposition of tissues in the carcass was smaller in the animals NE and fed with 1% of concentrated (except for subcutaneous fatty tissue), in relation to the crossbreds animals and fed with 2% of concentrated, respectively. The rate of fat deposition in the adipose tissue of mesentery it was larger (P<0.05) in the animals NA and fed with 2% of concentrated in relation to NS and animals fed with 1% of concentrated respectively. Animals NS and NA presented more tender meat than the animals NE. The meat of animals fed with 1% and 2% of concentrated it lost more water (P<0.05) that the meat of the animals in maintenance during the thawing and in the total losses. During the cooking, there was difference (P<0.05) in the losses for drip loss for all the regimes, being the larger losses in that order: 1% of concentrated, 2% of concentrated and maintenance. The genetic group Nellore presented larger proportion of intermediate fibers (P<0.05) and lower proportion of oxidative fibers (P<0.05), the opposite was observed for the crossbred animals. There were difference (P<0.05), in the proportion of separated fibers in agreement with contractile characteristics, inside of genetic group. The animals Nellore had larger proportion of fibers of fast contraction and smaller proportion of fibers of slow contraction (P<0.05) in relation to the crossbred animals. Crossbred animals have more tender meat than the animals Nellore; however, all were inside of the pattern for the meat to be considered tender. Animals in restriction lost less water than animals fed ad libitum and the animals Nellore lost more water than the crossbred animals.