Alexandre Menezes Dias

Consumo, desempenho e parâmetros econômicos de novilhos Nelore e F1 Brangus x Nelore terminados em pastagens, suplementados com mistura mineral e sal nitrogenado com uréia ou amiréia

The effects of protein supplementation of finishing grazing steers by feeding nitrogenous salts (40% CP, urea or starea) or mineralized salt only on supplement intake, growing performance and profitability were evaluated. One hundred and twenty steers (60 Nellore and 60 Brangus x Nellore, 19-month old, 358kg BW) were divided in 12 equal groups which were allotted to one of 12 Brachiaria brizantha pastures (10-ha each) performing two pastures for each breeding group and nutritional treatment. Groups were allowed to graze each pasture for 42 days when they were randomly moved into a new one. Nutritional treatments were as follow: MS - mineralized salt only; ST -mineralized salt plus starea - 150S; and UR - mineralized salt plus urea, corn and sulphur. UR supplement was prepared mixing the same ingredient contents of ST. Crossbred steers consumed 206.1; 145.9 and 73.1g/day whereas Nellore steers consumed 236.0; 205.11 and 94.29g/day of ST, UR and MS; respectively. For Nellore steers, UR increased slaughter weight (518.8kg) compared to ST and MS (491.9 and 485.2kg, respectively). Protein supplementation also increased slaughter weight for crossbred steers (P<0.05) in comparison to animals fed mineralized salt as sole supplementation (515.9 and 520.2kg for the UR and ST, respectively). Protein supplementation enhances growing performance of crossbred steers during periods of forage abundance. Urea supplementation yields a higher profitability in grazing systems for cattle finishing.

Avaliação da produção de bezerros em confinamento ou em suplementação exclusiva

Performances of cows and calves weaned at 90 (D90) and 210 days of age (D210) were evaluated, using 36 Beefalo-Nelore multiparus cows and their calves, in a randomized block experimental design, with 18 replicates of nine animals of each sex. Calves were allotted to treatments using as criteria to form blocks, the weight and sex of the animal. Calves (D210) were raised in 48ha pasture of Brachiaria decumbens e B. humidicula. Calves (D90) were raised in feedlot condition, in an area of 7.95m 2 /animal, and were fed chopped elephant grass and concentrate. The average concentrate dry matter intake, weaned body weight and weight gain were, respectively, 0.56 and 1.69kg/day; 208.68 and 185.67kg; 0.75 and 0.52kg/day respectively for D210 e D90 calves. Cows from D90 treatment showed higher body weight (448.86kg) at 210 days post partum. Creep-feeding is suggested for weaning heavier calves.Performances of cows and calves weaned at 90 (D90) and 210 days of age (D210) were evaluated, using 36 Beefalo-Nelore multiparus cows and their calves, in a randomized block experimental design, with 18 replicates of nine animals of each sex. Calves were allotted to treatments using as criteria to form blocks, the weight and sex of the animal. Calves (D210) were raised in 48ha pasture of Brachiaria decumbens e B. humidicula. Calves (D90) were raised in feedlot condition, in an area of 7.95m2 /animal, and were fed chopped elephant grass and concentrate. The average concentrate dry matter intake, weaned body weight and weight gain were, respectively, 0.56 and 1.69kg/day; 208.68 and 185.67kg; 0.75 and 0.52kg/day respectively for D210 e D90 calves. Cows from D90 treatment showed higher body weight (448.86kg) at 210 days post partum. Creep-feeding is suggested for weaning heavier calves.

Effect of breed and corpus luteum on pregnancy rate of bovine embryo recipients

The objective of this study was to evaluate pregnancy rates of recipients of different breed groups (Nellore and crossbreed), as well as the effects of size and type of the corpus luteum (CL) on plasmatic concentrations of progesterone and pregnancy rates of embryo recipients. A total of 152 heifers were synchronized with progesterone implants and on the day of embryo transfer, previously obtained by superovulation and frozen in ethylene glycol, the diameter and type of the corpus luteum (cavitary and compact) was measured and blood was collected for progesterone measurement. The pregnancy rate was 44.1%, with a diameter of corpus luteum higher in recipients that became pregnant (2.03±0.41) compared with non-pregnant ones (1.86±0.34 cm). Plasmatic concentrations of progesterone did not differ between pregnant (1.50±1.05) and non-pregnant (1.31±0.91 ng/mL) animals. The type of corpus luteum did not influence the pregnancy rates. Only Angus and crossbred Marchigiana differ among themselves in pregnancy rates (33.3 and 59.2%, respectively). The pregnancy probability was affected only by CL diameter, but not by P4 plasmatic concentration. Selection of the corpus luteum size at the time of embryo transfer is an important factor to increase pregnancy rates in recipients, and compact and cavitary corpora lutea do not influence the pregnancy rates of bovine embryo recipients. Nellore recipients have pregnancy rates that are satisfactory and comparable to crossbred (Bos taurus × Bos indicus) recipients.

Follicular dynamics and production of oocytes in young Nellore heifers with energetic supplementation

To verify the effects of energy supplementation and fat on follicular dynamics, metabolic profile and the production of oocytes, 15 young heifers (Bos taurus indicus) with an average age of 14 months and with an initial weight of 256.35 kg were assigned to two treatments according to weight and follicular population as evaluated by ultrasonography: in T1 (1.0 × M), animals received 100% of the energy requirements for maintenance; in T2 (1.7 × M), animals received 170% of the energy requirements for maintenance, achieved by the addition of 200 g of Megalac®. After a period of adaptation to the diet, the treatments, blood collection and follicular aspirations were started using a randomized design. The dry matter intake and weight gain were lower in the 1.0 × M group than in the 1.7 × M group. No differences were found in the plasma progesterone concentrations, albumin, glucose, urea or gonadotropin (FSH and LH) levels between the groups. The mean concentrations of cholesterol were higher in the 1.7 × M group. The total number of small (<4 mm) and medium follicles (4-8 mm) was not altered by the treatments, but the number of small follicles increased on days 1 and 2 of the estrous cycle, with higher values found in the 1.7 × M group. The average of the oocytes also increased (9.50±2.1 and 12.5±4.4 for the 1.0 × M and 1.7 × M groups, respectively). The rapid increase in the amount of energy offered in the diet changes the amount of follicles and oocytes available for follicular aspiration (OPU) in young heifers without changing their metabolic profile.