ABSTRACT The objective with this study was to determine the lysine maintenance requirements (LMR) of male and female broilers as animal models. A total of 252 birds were used for nitrogen balance trials during three periods (I: 6-21, II: 22-37, and III: 38-53 days). Six lysine levels were used (2.76, 5.88, 8.99, 12.1, 15.2, and 18.3 g kg−1) with six replications. A control group also included, totalizing seven treatments for males and females for each assay. The experimental period was […]

The objective of this study was to determine the protein requirements for the growth of intact male, female, and castrated male Saanen goats weighing 30 to 45 kg of body weight (BW) and to compare estimates of the protein requirements for maintenance (NPm) by the comparative slaughter and nitrogen balance techniques. To determine the maintenance requirements, 55 goats were assigned in a split-plot design using a 3 × 3 factorial arrangement (three sexes and three dry matter intake (DMI) levels). […]

The objective of this study was to determine the nutritional requirements of energy and protein and estimate the efficiencies of metabolizable energy utilization for fat and protein deposition, as well as for maintenance (km) and growth (kg). An experiment of comparative slaughter was carried out with thirty-seven 14-month-old (±1 month) Nellore bulls with 259±24.9 kg. Animals were divided as follows: five to reference, four to maintenance level and twenty-eight bulls feeding ad libitum. Bulls were also grouped in 4 different […]

The objective of this study was to determine the energy nutritional requirements for females of Nellore, Nellore × Angus and Nellore × Simmental fed on two levels of concentrate. Sixty heifers from three genetic groups were used: 20 Nellore, 20 Nellore × Angus and 20 Nellore × Simmental. Twelve belonged to the reference group (four of each genetic group) and were slaughtered at the beginning of the experiment. Another 12 heifers (four of each genetic group) were fed on the […]

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 […]

The objective of this trial was to estimate the efficiency of utilization of metabolizable energy (MEEU) for maintenance (Km) and weight gain (kg) of feedlot purebred and crossbred Nellore. Seventy-two young bulls averaging 10 to 11 months of age from four genetic groups: Nellore, F1 Nellore x Angus, F1 Nellore x Brown Swiss and F1 Nellore x Simental and initial average body weights of 286, 309, 333 and 310 kg, respectively, were used in this study. A completely randomized design […]

This investigation was carried out to determine body composition of protein, fat, and energy as well as nutritional requirements of protein and energy for maintenance and weight gain of Morada Nova Lambs. Thirty lambs averaging 15 kg of initial body weight (BW) were used in this trial. To determine the body composition using the comparative slaughter approach six lambs were slaughtered at 15 kg (reference animals), six at 20 kg (intermediary slaughter), and the remaining were distributed in one of […]

The intake, digestibility, ruminal pH and ammonia concentrations and passage rate were evaluated in steers fed corn silage (CS) and Tifton 85 bermudagrass hay (T85H)-based diets, at different forage proportions. Four rumen fistulated steers with 523 kg of live weight were used in a 4×4 latin square design, and fed diets containing 60:40 forage:concentrate proportions in dry matter basis. The forage portion consisted of: 100 T85H:0 CS; 67 T85H:33 CS; 33 T85H:67 CS and 0 T85H:100 CS. The dry matter […]

The objective of this study was to determine prediction equations for crude protein (CP) requirements for males and females broilers using the factorial method. In order to determine the crude protein for the maintenance was used the nitrogen balance technique. The crude protein requirements for weight gain were determined based on body nitrogen content and nitrogen utilization efficiency for the diet. Considering the requirements for maintenance and weight gain were elaborated prediction equations for CP requirements (g/bird/day) for males broilers […]

The objective of this experiment was to estimate the dietary phosphorus requirement (P) for maintenance of kid goats in the growth phase by the endogenous loss method and comparative slaughter technique. Twenty-one males, average 18 kg LW, were used. From those, three were slaughtered at the beginning of the experiment, as reference, and the remaining 18 animals were fed isocaloric and isoproteic diets in a completely randomized design with 3×2 factorial arrangement (level of dietary P [0.12, 0.21 and 0.29% […]