This study was carried out to estimate efficiencies of the utilization of metabolizable energy for maintenance (k m) and weight gain (k g) and to evaluate the Small Ruminant Nutrition System (SRNS) model in predicting dry matter intake and average daily gain of growing Santa Ines sheep. Twenty-four non-castrated Santa Ines sheep, at 50 days of age and with average body weight of 13.00 ± 0.56 kg, respectively, were used. After a 10-day adaptation period, four animals were slaughtered to be used as reference for estimating initial empty body weight and body composition of the other animals. The remaining animals were distributed in a random block design, with the treatments consisting of diets containing different levels of metabolizable energy (2.08, 2.28, 2.47 and 2.69 Mcal/kg of DM), with five replicates. The metabolizable energy use efficiencies for maintenance and for weight gain were calculated from the relationship between the dietary net energy for maintenance and gain and ME concentration in the diets. Evaluation of the SRNS model was performed by adjustment of simple linear regression model between the predicted (independent variable) and observed (dependent variable) values. The estimated energy use efficiency for maintenance (k m) was 0.70; and for gain weight (kg) it showed to be inversely proportional to the increase of metabolizable energy concentration in the diet. The dry matter intake predicted by the SRNS model did not statistically differ from that observed, but the model overestimated the average daily gain by 5.18%. Those results can contribute to the construction of a database, which could be condensed into several others in a predictive model of performance and feed planning for sheep reared in Brazil.

This study aimed at estimating the kinetic parameters of ruminal degradation of neutral detergent fiber from agroindustrial byproducts of cashew (pulp and cashew nut), passion fruit, melon, pineapple, West Indian cherry, grape, annatto and coconut through the gravimetric technique of nylon bag, and to evaluate the prediction equation of indigestible fraction of neutral detergent fiber suggested by the Cornell Net Carbohydrate and Protein System. Samples of feed crushed to 2 mm were placed in 7 × 14 cm nylon bags with porosity of 50 µm in a ratio of 20 g DM/cm² and incubated in duplicate in the rumen of a heifer at 0, 3, 6, 9, 12, 16, 24, 36, 48, 72, 96 and 144 hours. The incubation residues were analyzed for NDF content and evaluated by a non-linear logistic model. The evaluation process of predicting the indigestible fraction of NDF was carried out through adjustment of linear regression models between predicted and observed values. There was a wide variation in the degradation parameters of NDF among byproducts. The degradation rate of NDF ranged from 0.0267 h-1 to 0.0971 h-1 for grape and West Indian cherry, respectively. The potentially digestible fraction of NDF ranged from 4.17 to 90.67%, respectively, for melon and coconut byproducts. The CNCPS equation was sensitive to predict the indigestible fraction of neutral detergent fiber of the byproducts. However, due to the high value of the mean squared error of prediction, such estimates are very variable; hence the most suitable would be estimation by biological methods.

Avaliou-se o efeito de diferentes níveis de energia metabolizável na dieta sobre a composição corporal e as exigências de proteína líquida de 24 ovinos Santa Inês em crescimento, não-castrados, com idade e peso corporal médio de 50 dias e 13,00 ± 0,56 kg. Após um período de adaptação de 10 dias, quatro animais foram abatidos para serem utilizados como referência para as estimativas do peso do corpo vazio (PCVZ) e da composição corporal inicial dos demais. Os animais remanescentes foram distribuídos em um delineamento em blocos casualizados com rações contendo diferentes níveis de energia metabolizável (2,08; 2,28; 2,47 e 2,69 Mcal/kg MS) e proteína bruta (12,74; 14,36; 15,97 e 17,65% PB na MS) com cinco repetições. A excreção diária de N foi estimada extrapolando-se a equação de regressão de consumo de N (g/kg PC0,75/dia) em função da retenção de N (g/kg PC0,75/dia) para o consumo zero. A derivada da equação de regressão do logaritmo do conteúdo de proteína em função do logaritmo do PCVZ dos animais permitiu a estimativa da exigência proteica líquida para ganho de peso de corpo vazio (GPCVZ). A excreção diária de N foi estimada em 277 ± 0.05 mg/kg PC0,75/dia e a exigência de proteína líquida para mantença em 1,73 g/kg PC0,75/dia. O conteúdo de proteína no PCVZ dos animais diminui de 157,83 para 144,33 g/kg PCVZ quando o peso corporal aumentou de 15 para 30 kg, respectivamente. A quantidade de proteína depositada no ganho diminuiu de 137,47 para 125,71 g/kg GPCVZ com o aumento do peso corporal de 15 para 30 kg, respectivamente. A excreção fecal de nitrogênio e exigência líquida de proteína para mantença de ovinos Santa Inês em crescimento foi inferior ao preconizado pelos principais sistemas de avaliação de alimentos e exigências nutricionais para pequenos ruminantes.

This study evaluated the effect of different dietary levels of metabolizable energy on the body composition and net protein requirements of 24 Santa Inês non-castrated growing sheep at average age of 50 days and average body weight of 13.00 ± 0.56 kg. After a ten-day adaptation period, four animals were slaughtered to be used as a reference for estimates of empty body weight (EBW) and initial body composition of the other animals. The remaining animals were assigned into a randomized block design with diets containg different levels of metabolizable energy (2.08; 2.28; 2.47 and 2.69 Mcal/kg of DM) and crude protein (12.74; 14.36, 15.97 and 17.65% CP of DM) with five replicates. The N daily excretion was estimated by extrapolating regression equations of N intake (g/kg BW0.75/day) in function of retention (g/kg BW0.75/day) for zero intake. The derivative regression of the logarithm of protein content in function of the logarithm of EBW enabled the estimation of net protein requirement for empty body weight gain (EBWG). Daily nitrogen excretion was 277 ± 0.05 mg/kg BW0.75/day and net protein requirement for maintenance was 1.73 g/kg BW0.75/day. Protein content of EBW of animals decreased from 157.83 to 144.33 g/kg of EBW when the BW of the animals increased from 15 to 30 kg, respectively. The amount of protein deposited in the gain decreased from 137.47 to 125.71 g/kg of EBWG with the increase of body weight of the animals from 15 to 30 kg, respectively. Nitrogen fecal excretion and protein net requirement for maintenance of Santa Inês growing lambs was lower than the values commonly cited by the main systems of feed evaluation and nutrient requirements for small ruminants.

Objetivou-se avaliar o consumo, a digestibilidade aparente dos nutrientes e o comportamento ingestivo de ovinos alimentados com rações contendo farelo de castanha de caju (FCC) nos níveis de 0; 10; 20 e 30% na ração concentrada. O delineamento experimental utilizado foi quadrado latino 4 × 4 duplo. Os consumos de matéria seca (MS), matéria orgânica, proteína bruta, matéria mineral, carboidratos não-fibrosos e nutrientes digestíveis totais não foram influenciados pela adição de FCC, contudo o consumo de fibra em detergente neutro (FDN), fibra em detergente ácido e carboidratos totais apresentaram comportamento quadrático com o aumento no teor de lipídeos da ração. A digestibilidade aparente da MS, matéria orgânica, proteína bruta, FDN, fibra em detergente ácido e carboidratos não fibrosos não foi influenciada pela adição de FCC nas rações, contudo as digestibilidades do extrato etéreo e dos carboidratos totais apresentaram comportamentos quadrático e linear, respectivamente. Não foram observadas diferenças significativas no tempo despendido com alimentação e ruminação, no entanto, o tempo de mastigação total foi influenciado, apresentando comportamento linear crescente com os níveis de FCC. As eficiências de alimentação e ruminação não foram influenciadas pelo aumento no teor de lipídeos das rações, no que se refere aos consumos de MS e FDN por hora. O tempo de mastigação merícica por bolo ruminal, o número de bolos ruminados e o número de mastigações merícicas por dia não foram influenciados pelas rações experimentais. No manejo alimentar de ovinos, caso haja disponibilidade, recomenda-se como alternativa alimentar a utilização de no máximo 30% de FCC na ração concentrada.

The objective of this work was to evaluate intake, nutrient apparent digestibility and ingestive behavior of sheep fed rations with cashew nut meal (CNM) at the levels of 0; 10; 20 and 30% in the concentrate ration. It was used a double 4 × 4 Latin square experimental design. Intakes of dry matter (DM), organic matter, crude protein, mineral matter, non-fibrous carbohydrates and total digestible nutrients were not influenced by the addition of CNM, however, intake of neutral detergent fiber (NDF), acid detergent fiber and total carbohydrates presented a quadratic behavior with the increase of content of lipids in the ration. Apparent digestibility of DM, organic matter, crude protein, NDF, acid detergent fiber and non-fibrous carbohydrates was not influenced by the addition of CNM in the rations; however digestibility of ether extract and total carbohydrates presented quadratic and linear behavior, respectively. It was not observed any significant differences in time spent with feeding and rumination, however, total chewing time was influenced, presenting increasing linear behavior with the levels of CNM. Concerning to intakes of dry matter and NDF per hour, feed efficiency and rumination were not affected by increase on lipid content in the rations. Ruminating chews time per rumen bolus, number of ruminated boli and the number of ruminating chews per day were not influenced by experimental rations. In sheep feeding management, it is suggested as a feeding alternative the use of up to 30% of CNM in the concentrate ration if it is available.