Consumo de nutrientes e comportamento ingestivo de cordeiros da raça Santa Inês alimentados com rações com diferentes níveis de energia metabolizável

Objetivou-se avaliar o consumo de nutrientes e o comportamento ingestivo de cordeiros da raça Santa Inês na fase de cria alimentados com diferentes níveis de energia metabolizável (EM). Foram utilizados 20 cordeiros não-castrados, com idade e peso corporal médio de 50 dias e 13,00 ± 0,56 kg, respectivamente, distribuídos em quatro tratamentos experimentais com diferentes níveis de energia metabolizável (2,08; 2,28; 2,47 e 2,69 Mcal de EM/kg de matéria seca), em delineamento em blocos casualizados, com cinco repetições. Como volumoso utilizou-se feno de capim-tifton adicionado à ração concentrada. Os níveis de energia metabolizável (EM) tiveram efeito linear sobre os consumos de matéria seca, matéria orgânica, proteína bruta, extrato etéreo, carboidratos não-fibrosos e nutrientes digestíveis totais, expressos em g/dia. O consumo de FDN, expresso em %PV e kg/PV0,75, decresceu linearmente com o aumento dos níveis de energia nas rações, devido à redução no teor de FDN na matéria seca total das rações. Os tempos de alimentação e mastigação total, expressos em hora/dia, diminuíram linearmente com os níveis energéticos das rações experimentais. Em compensação, o tempo de ócio aumentou linearmente e o de ruminação não foi influenciado pelos níveis energéticos das rações. O número de bolos ruminais, de mastigações merícicas e de mastigações merícicas por bolo ruminal e o tempo de mastigações merícicas por bolo ruminal não foram influenciados pelos níveis de energia metabolizável nas rações. O aumento dos níveis de energia metabolizável das rações influencia o consumo de nutrientes e o comportamento ingestivo de cordeiros da raça Santa Inês na fase de cria.The objective of this work was to evaluate the nutrient intake and ingestive behavior of growing Santa Inês lambs fed different levels of metabolizable energy (ME). It was used 20 non-castrated lambs at 50 days of age and with 13.00 ± 0.56 kg of body weight. The animals were distributed into four experimental treatments with different levels of metabolizable energy (2.08, 2.28, 2.47 and 2.69 Mcal/kg of dry matter) in a randomized block design with five replications. It was used as roughage tifton hay added to concentrate diet. Levels of metabolizable energy (ME) linearly affected intakes of dry matter, organic matter, crude protein, ether extract, no-fiber carbohydrates, and total digestible nutrients, expressed in g/day. The NDF intake, expressed as % BW and kg/BW0.75, decreased linearly with the increase of levels of energy in the diet due to the reduction in NDF content in the total dietary dry matter. Feeding and total chewing time, expressed in hour/day, decreased linearly with the energy levels of the experimental diets. However, idle time increased linearly, whereas rumination was not influenced by energy levels of the diets. Number of ruminate boli, of ruminating chews, of ruminating chews per bolus and time of chewing per bolus were not influenced by levels of metabolizable energy in the diets. Increase in metabolizable energy levels of diets affects intake of nutrients and ingestive behavior of growing Santa Inês lambs

Growth performance of native goats fed diets containing different levels of energy

Castrated male goats (n = 40) of the Moxotó (n = 20) and Canindé (n = 20) breeds with an average weight of 15.3 kg were studied to determine intake, nutrient digestibility and weight gain for two diets with different energy levels. The experiment utilized a 2 × 2 factorial arrangement (two breeds and two diets), in which goats were randomly allocated. A diet of low energy density and a forage:concentrate ratio of 70:30 was utilized along with a diet of high energy density and a forage:concentrate ratio of 35:64. To determine the nutrient intake and digestibility, at the end of the experiment, goats were kept in metabolism cages for a period of 15 days. Weighing of the goats was conducted weekly over a period of 90 days. The goats that were fed a diet of high energy density displayed significantly increased consumption of metabolic fractions, with the exception of dry matter and neutral detergent fiber, when compared with those fed a diet of low energy density. The lack of difference in dry matter and neutral detergent fiber intake indicated that goats have a high digestive capacity for the diet containing a greater quantity of Maniçoba hay. Weight gain was significantly greater for those on the diet of greater energy density. Among the breeds, Canindé goats recorded the highest average consumption and weight gain. Coefficients of digestibility were significantly greater for the more energy dense diet, with no difference between breeds. Regardless of diet, the Canindé breed shows greater weight gain than the Moxotó breed