Energy and protein requirements for maintenance of Texel lambs.

It can be hypothesized that the body composition characteristics of different sheep breeds affect their nutritional requirements. However, no study has yet been carried out to determine the nutritional requirements for maintenance of Texel purebred lambs, despite their growing importance in sheep meat production globally. Our objective was therefore to determine the energy and protein requirements for maintenance of Texel lambs. Thirty-four Texel lambs were used, all intact males that were weaned at 50 days old, and confined in individual pens. Two experiments were conducted, as follows. In Experiment 1, a digestibility assay was performed to determine the dietary energy value, in a 3×3 double Latin square design, in which lambs were submitted to three levels of feed restriction (0%, 55% and 70% of ad libitum feed intake). In Experiment 2, the energy and protein requirements for maintenance of Texel lambs from 21 to 40 kg BW were determined using a randomized block design, in which lambs were also submitted to three levels of feed restriction (0%, 55% and 70% of ad libitum feed intake). The requirements for net energy for maintenance (NEm), metabolizable energy for maintenance (MEm), net protein for maintenance (NPm) and metabolizable protein for maintenance (MPm) were determined. The digestibility of dry matter, energy, protein and metabolizability were similar between food restriction levels, averaging 74.4%, 75.5%, 80.3% and 0.636, respectively. The NEm determined for growing Texel lambs was 263 kJ/kg of the metabolic fasting BW (FBW), the MEm was 417 kJ/kg0.75 FBW and the efficiency of use of MEm was 0.63. In addition, the NPm was 1.24 g/day per kg0.75 FBW and the MPm was 2.98 g/day per kg0.75 FBW. The energy requirements of Texel lambs are different from those reported in the literature, possibly due to differences between breeds, diets and environmental effects, whereas the protein requirements are different from literature mainly due to methodological differences; further studies are need to address these aspects that affects the nutritional requirements for raising sheep from different breeds in different environments.

Consumo, desempenho e análise econômica da alimentação de cordeiros terminados em confinamento com o uso de dietas de alto grão / Consumption, performance and economic analysis of the feeding of lambs finished in feedlot as the use of high-grain diets

O presente experimento, conduzido no Laboratório de Ovinocultura da Universidade Federal de Santa Maria, teve como objetivo avaliar o efeito do uso de diferentes dietas de alto grão sobre o consumo de nutrientes e o desempenho de cordeiros terminados em confinamento, bem como realizar uma análise econômica da alimentação utilizada para terminação dos animais. Foram utilizados 32 cordeiros machos, castrados, da raça Texel, nascidos de parto simples e desmamados com aproximadamente 50 dias de idade. Os tratamentos foram constituídos por diferentes tipos de grãos, não processados, sendo: grão de milho, grão de aveia branca, grão de aveia preta ou grão de arroz com casca. Os animais foram abatidos quando atingiram o peso vivo de abate pré-estabelecido de 32kg, que corresponde a 60% do peso adulto de suas mães. Cordeiros alimentados com dietas de alto grão de milho apresentam maiores consumos de matéria seca, matéria orgânica, proteína bruta, carboidratos totais e de nutrientes digestíveis totais, menor consumo de fibra em detergente neutro, melhor escore de condição corporal, ganho de peso e conversão alimentar, o que leva à redução do número de dias no confinamento necessários para atingir o peso de abate. Além disso, cordeiros terminados com o uso de dieta de alto grão à base de grão de milho proporcionam melhor resultado econômico quando comparados com cordeiros terminados com as demais dietas de alto grão utilizadas neste experimento. O uso de dietas de alto grão de milho, aveia branca, aveia preta ou arroz com casca para terminação de cordeiros em sistema de confinamento é uma alternativa viável do ponto de vista produtivo. Porém, o uso de grão de milho proporciona melhores resultados produtivos e econômicos.

This experiment was conducted at the Laboratory of Sheep, Federal University of Santa Maria, and aimed to evaluate the effect of using different high-grain diets on nutrient intake and performance of lambs in a feedlot, as well as conduct an economic analysis of feeding used for termination of the animals. A total of 32 Texel breed castrated male lambs, born from a simple birth and weaned at approximately 50 days of age were used. The treatments consisted of different types of grains, unprocessed, as follows: corn grain, white oat grain, black oat grain or grain of rice in the husk. The animals were slaughtered when they reached a pre-established body weight of 32kg for slaughter, which corresponds to 60% of the mature weight of their mothers. Lambs fed diets with high corn grain have higher intakes of dry matter, organic matter, crude protein, total digestible nutrients and total carbohydrate, lower consumption of neutral detergent fiber and better body condition score, weight gain and feed conversion, which leads to reduction in the number of days in confinement needed to reach slaughter weight. In addition, lambs using high-grain diet based grain corn provide better economic results when compared with lambs with other high-grain diets used in this experiment. The use of diets high in grain corn, white oat grain, black oat grain or grain of rice in the husk for finishing lambs in feedlot is a viable alternative from a productive point of view. However, the use of corn grain provides better performance and economic results.