ABSTRACT The objective of this study was to evaluate the effect of castration and days of feed (DOF) on glucose sensitivity and muscle expression of genes related to glucose metabolism, muscle growth, and fat deposition. Thirty-six Nellore bull calves were either surgically castrated or left intact, then harvested at 0, 100, or 200 DOF. Glucose tolerance tests were performed at 100 and 200 DOF. Longissimus dorsi (LD) samples were taken just after stunning for gene expression. Data were analyzed as […]

The objective of this study was to evaluate performance and nutritional traits of beef cattle raised on pastures, castrated at different ages, with and without supplementation. Forty-four crossbred young bulls with predominance of Zebu breed at initial average age of 120±30 days were used in the experiment. Animals were distributed in a completely randomized design in a factorial arrangement with four ages of castration and two supplementation systems. The animals were distributed into four groups and placed on Brachiaria decumbens […]

The objective of this experiment was to estimate the requirements of energy, protein and macrominerals of grazing crossbreds calves, in Brachiaria decumbens Stapf pasture, castrated at different ages, with and without supplementation. Forty-seven young calves at initial age of 120±30.1 days and 115.3±1.97 kg of live weight were used. To estimate net energy requirements for weight gain, a regression equation between energy retained in the gain and empty body weight gain and metabolic empty body weight was obtained. For estimation […]

The objective of this study was to evaluate muscle composition and physical-chemical characteristics of 20 intact and castrated crossbred Ideal male lambs exposed to either a short photoperiod (SP) of 12 h or to a long photoperiod (LP) of 18 h. Animals were randomly assigned to four treatments (T) in a 2 x 2 factorial arrangement with five repetitions as follows: intact lambs exposed to a SP; castrated lambs exposed to a SP; intact lambs exposed to a LP or […]

Groups of crossbred castrated and intact goats were slaughtered at 175, 220, 265 and 310 days of age. The effect of castration and slaughter age on physical-chemical, sensorial and aromatic properties was researched. Calcium content was influenced by castration; however, slaughter age had a significant effect on moisture, protein, iron, calcium and pH. Castration and slaughter age had no significant effect on phospholipids contents, but slaughter age affected the percentage of total cholesterol. Fatty acids were significantly affected by castration. […]

Seventy beef males of three breeding systems (BS), straightbreds Charolais (Ch) and Nellore (Ne), G1 crossbreds: 1/2 Ch + 1/2 Ne (1/2 Ch) and 1/2 Ne + 1/2 Ch (1/2 Ne) and G2 crossbreds: 3/4 Ch + 1/4 Ne (3/4 Ch) and 3/4 Ne + 1/4 Ch (3/4 Ne) were used. The number of animals by genetic group was, respectively, 15, 12, 8, 12, 14 and 9. Thirty-five males were castrated (C) at seven months and 35 were kept intact […]

With the objective to study the carcass and the meat qualitative characteristics of young bulls or castrated males, slaughtered at fourteen months of age, fifteen Hereford males were used, eight castrated at seven months and seven kept entire. From birth to weaning animals were raised on improved native pasture, and after weaning, at seven months, they were confined. Meat measurements were taken from the longissimus muscle, and to determine carcass composition the method of manual dissection of muscle, fat and […]

The carcass characteristics from young bulls or steers from different breed compositions of Charolais x Nellore were the objective of this study. Seventy beef males from three breeding systems: straightbreds (Charolais (Ch) and Nellore (Ne)), G1 crossbreds (1/2 Ch 1/2 Ne and 1/2 Ne 1/2 Ch) and G2 crossbreds (3/4 Ch 1/4 Ne and 3/4 Ne 1/4 Ch) were used. Thirty-five males were castrated (steers) at seven months and 35 were kept entire (young bulls). The animals were confined from […]

The objective of the experiment was to evaluate, during the growth phase, the dry matter intake, weight gain and feed to gain conversion of young bulls and steers, castrated at eight month, from two breeding systems, straightbred (Charolais – C and Nellore – N) and crossbred (1/2 CN, 1/2 NC), as well as to measure the resulting heterosis. The animals were confined from nine to twelve months and fed a 15% crude protein diet and a 70:30 forage to concentrate […]