The effects of plane of nutrition and slaughter weight on the performance and carcass composition of continental beef bulls given high forage diets

Abstract

Bulls (V 2 Blonde d'Aquitaine % Charolais) were used in a 2 X 3 factorial design experiment with two planes of nutrition in the finishing period and three slaughter weights. High and low planes of nutrition were based on diets with similar forage to concentrate ratio (040 of dry matter (DM)) offered ad libitum or at 0-78 of ad libitum DM intake at equal live weight respectively. The target slaughter live weights were 550, 625 and 700 kg. Twelve bulls were taken to each slaughter point and an additional five animals were killed as a pre-experimental slaughter group. Mean initial live weight was 412 (s.e. 5-3) kg at a mean age of 342 (s.e. 2-5) days. No significant interactions were found between the main factors. For the high and low planes, live-weight and estimated carcass gains were 1251 and 989 (s.e. 47-7), and 816 and 668 (s.e. 35-3) g/day respectively, the reduction in gains being similar to the proportional degree of nutritional restriction. Plane of nutrition had no effect on live-weight or carcass gain per unit of energy intake. The low plane of nutrition produced significant decreases in body cavity fat depots, subcutaneous fat in the sample joint and increased the proportions of both saleable beef and high-priced joints in the carcass. With increase in slaughter weight, energy intake per unit of live weight 073 and rates of both live-weight and carcass gain tended to decline. The dressing proportions were 583,579 and 609 (s.e. 9-1) g/kg for the slaughter live weights of 550, 625 and 700 kg. Carcass conformation improved while fat depots in the body cavity and estimated concentration of separable fat in the carcass increased with increase in slaughter weight, and both estimated lean and bone concentrations decreased. Forequarter as a proportion of total side tended to increase with increase in slaughter weight. Slaughter weight had no effect on concentration of saleable meat or ultimate pH of carcass muscle. It is concluded that bulls of this genotype can be taken to high slaughter weights on diets having a relatively high proportion of forage as grass silage, with high rates of growth and acceptable carcass leanness.

Animal performance and carcass characteristics of Nellore young bulls fed coated or uncoated urea slaughtered at different weights

“…The rib eye area expressed in 100 kg cold carcass decreased with increase in body weight, agreeing with the results observed in the literature, demonstrating linear decrease from 27 to 24 and from 26.2 to 23.2 cm 2 /100 kg carcass, with increase in slaughter weight from 550 to 700, in crossbred Blonde D'Aquitaine × Charolais (Patterson et al, 1994) and from 440 to 507 kg in crossbred Aberdeen Angus × Brahman (Huffman et al, 1990). According to Restle et al (1997), the decrease is a consequence of the reduction in the level of muscle development as the weight of animals increases.…”

Beef production potential of Norwegian Red and Holstein-Friesian bulls slaughtered at two ages

“…These differences largely reflect the greater maintenance requirements (115%; Dawson and Steen, 1998) of bulls slaughtered at the higher live weight, and the major differences in the energy content of the gain with increasing slaughter weight, as reflected by the higher measures of carcass fatness and fat in the internal depots. A deterioration in efficiency of food conversion with increasing slaughter weight has been observed in many studies with continental breed (Patterson et al, 1994), Friesian-type (Andersen and Ingvartsen, 1984a;Bailey et al, 1985) and HF bulls (Kirkland et al, 2006).…”

“…However, the marginal rate of growth of bulls between the E and L slaughter ages, 0.88 kg/day, was 30% lower than the growth rate of the bulls recorded between the start of the study and slaughter at 485 days (1.14 kg/day). A reduction in rate of gain with increasing weight has been observed in many studies involving serial slaughter (Andersen and Ingvartsen, 1984a;Bailey et al, 1985;Patterson et al, 1994), reflecting the stage of maturity of the animals in these studies and their relative position on the established animal growth curve, which is known to be sigmoidal until mature body weight is reached (Brody, 1945). Hence, the reduced rate of gain of L compared with E bulls reflects the higher maintenance costs and increased fat deposition of L bulls.…”

Peso de abate de machos não-castrados para produção do bovino jovem. 1. Desempenho em confinamento e custos de produção

“…Levy et al (1975) também observaram aumento do ganho de peso vivo, com bovinos da raça Holandesa não-castrados, com os incrementos nos pesos de abate de 400 para 450 e 500 kg. Patterson et al (1994) verificaram tendência para redução do ganho de peso vivo com o aumento do peso de abate de 550 para 625 e 700 kg para animais não-castrados (7/8 de raças continentais) e afirmaram que o peso vivo de 550 kg já estava acima do ponto de inflexão da curva de ganho de peso, embora tenham utilizado grupos genéticos de maturação tardia.…”

“…Estudos de pesos de abate, visando melhor desempenho em confinamento e características desejáveis de carcaça foram efetuados, entre outros, com machos não-castrados da raça Holandesa (Bailey et al, 1985), cruzados Blonde d'Aquitaine x Charolês (Patterson et al, 1994), Nelore e cruzados Limousin x Nelore e Marchigiana x Nelore (Galvão et al, 1991), Nelore e cruzados Holandês x Nelore e bimestiços FleckviehAngus x Nelore (Jorge et al, 1997), e machos castrados Angus e cruzados Angus x Brahman (Huffman et al, 1990).…”