A comparison of the effects of porcine somatotropin, genetic selection and sex on performance, carcase and meat quality traits of pigs fed ad libitum

A comparison was made of the effect of recombinant porcine somatotropin (PST) and genetic selection on performance, carcase and meat quality traits of entire male and female pigs grown from 50 kg to 90 kg liveweight and fed ad libitum. Pigs of each sex were drawn from a selected and an unselected control line of common genetic origin and subjected to daily intramuscular injections of either 90 g PST or saline per kg body weight. The selected line had undergone a period of selection for low backfat (P2) depth and high growth rate. The effects of PST and selection were additive for all traits. For performance traits, growth rate was increased 17% by PST and 22% by selection, food conversion ratio was reduced 20% by PST and 14% by selection. For carcase traits P2 fat depth was reduced 15% by PST and 14% by selection. Both PST and selection caused a 1.3% reduction in killing out. For chemical composition of soft tissue, fat was reduced 9.1% by PST and 2.4% by selection, water was increased 6.9% by PST and 2.2% by selection, and protein was increased 2.1% by PST. For lean quality traits, PST had the slightly adverse effect of increasing paleness, cooking loss and firmness of certain muscles, particularly in males, but selection had no adverse effect. The changes brought about by PST could be accounted for by the repartitioning of metabolisable energy away from fat and toward protein whereas both repartitioning and increased appetite accounted for the effects of selection

Qualidade da carne de novilhos Charolês confinados e abatidos com diferentes pesos Meat quality of Charolais steers slaughtered with different weights

Foi comparada a qualidade da carne de 18 novilhos de corte Charolês, com trinta meses de idade, alimentados durante diferentes períodos e abatidos com diferentes pesos: T1 = 421 kg; T2 = 461 kg; e T3 = 495kg. O marmoreio, a coloração e a textura da carne não diferiram entre os tratamentos. Os animais do T1, apresentaram carne com maior perda ao descongelamento (8,1%) em relação a proveniente dos animais do T2 e T3 (4,8 e 5,1%, respectivamente). No entanto, durante a cocção, a carne do T2, apresentou maior perda em relação à carne do T3. Não verificou-se diferença estatística para maciez da carne, tanto na análise sensorial (painel de degustadores) como na análise instrumental (WB-Shear). Os animais abatidos com maior peso apresentaram carne com maior suculência e palatabilidade.<br>Meat quality of eighteen Charolais steers, 30 months old, feedlot finished with different slaughter weights: T1 = 421 kg; T2 = 461 kg; and T3 = 495kg was evaluated. Meat marbling, color and texture did not differ among treatments. T1 meat showed higher thawing losses (8.1%) than T2 and T3 meat (4.8 and 5.1%, respectively), while cooking losses were higher in T2 meat than for T3. No statistical difference was observed among treatments for meat tenderness (panel or WB-Shear). Meat of higher slaughter weight steers was juicier and had better flavor

Carcass and meat characteristics of crossbred steers submitted to different nutritional strategies at growing and finishing phases Características da carcaça e da carne de novilhos mestiços submetidos a diferentes estratégias nutricionais na recria e terminação

This study was carried out to evaluate the effects of different nutritional strategies at growing and finishing phases on carcass and meat characteristics from 24 crossbred steers predominatly Holstein, slaughtered at 15 months of age and with 395.00kg of body weight. At the growing phase, the animals were maintained on Brachiaria brizantha pasture with two levels of supplementation in amounts equivalent to 0.5 or 1.0% of body weight. Subsequently, the animals were finished in feedlot with diets composed of 50 or 80% of concentrate. The high level of the concentrate at the finishing phase increased significantly (P<0.05) the hot carcass yield (50.16 vs. 48.62%). The lowest level of supplementation at the growing phase resulted in higher (P<0.05) percentage of carcass fat (25.61 vs. 23.39%) but it did not influence the percentage of muscle and bone. The high level of supplementation at the growing phase provided higher (p<0.05) meat tenderness, required less shear force (4.72 vs. 6.66kg cm-3) and lighter red meat (3.88 vs 2.89 points). The high feeding level during the growing phase was more interesting because it affected positively some important carcass and meat characteristics, especially tenderness.<br>Objetivou-se com este estudo avaliar os efeitos de diferentes estratégias nutricionais na recria e terminação sobre as características da carcaça e da carne de 24 bovinos mestiços com predominância Holandês, abatidos com 15 meses de idade e 395,00kg de peso vivo. Na fase de recria, os animais foram mantidos em pastagem de Brachiaria brizantha com dois níveis de suplementação energética em quantidade equivalente a 0,5 ou 1,0% do peso vivo. Posteriormente, os animais foram terminados em confinamento com dietas compostas por 50 ou 80% de concentrado. Constatou-se efeito significativo (P<0,05) do nível de concentrado na terminação sobre o rendimento de carcaça quente em favor do nível alto (50,16 vs 48,62%). O menor nível de suplementação na recria resultou em maior (P<0,05) percentual de gordura na carcaça (25,61 vs 23,39%), mas não influenciou os percentuais de músculos e ossos. O nível alto de suplementação na recria proporcionou carne mais macia, requerendo menor força de cisalhamento (4,72 vs 6,66kg cm-3) e de coloração vermelha mais clara (3,88 vs 2,89 pontos). O nível alimentar alto na recria mostrou-se mais atrativo por ter efeitos positivos sobre algumas características importantes da carcaça e da carne, notadamente a maciez