ABSTRACT This study aimed to evaluate the effects of backgrounding supplementation, by increasing the levels of energy-protein supplements during the growing phase on the performance and rumen morphometrics of Nellore bulls intensively finished on pasture. Ninety-six Nellore bulls were blocked according to initial body weight (BW) of 385.6 ± 7.3 kg and randomly assigned to one of 24 paddocks of Urochloa brizantha cv. ‘Piata’ (four animals/paddock). The animals were supplemented during the growing phase as follows: (1) energy-protein supplementation at […]

ABSTRACT This study aimed to evaluate genotype × environment (G×E) interactions in Guzerá breed animals for 305-day first-lactation cumulative yields (kg) of milk (MY305), fat (FY305), and protein (PY305). We used 6823 records of MY305, 2466 records of FY305, and 1870 records of PY305. The contemporary groups (CG) were created considering herd and year of calving. The analyses were performed in two steps. In the first step, environmental effects on phenotypes were estimated by using a multi-trait model ignoring G×E […]

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 […]

ABSTRACT The objective of this study was to evaluate the performance of Nellore bulls finished in the feedlot and fed high-energy diets containing sodium monensin associated or not with tannins and saponins. Ninety-six Nellore bulls were used with an average initial body weight of 350.6±17.9 kg. The bulls were weight-blocked and randomly allocated to 12 pens, which were considered the experimental units. The treatments were assigned to the pens according to the blocks, as follows: sodium monensin (25 ppm; SM) […]

ABSTRACT The objective of this study was to evaluate the relationships between preovulatory follicle (POF) and corpus luteum (CL) diameters, and POF and CL vascular perfusion with progesterone production, ovulation, and pregnancy in Nellore cows subjected to timed artificial insemination (TAI). Nellore cows (n = 201) were subjected to ovulation synchronization and later to ultrasound evaluation of POF and CL at the time of insemination (D0) and seven days later (D7), respectively. Females were divided into three categories according to […]

Abstract The objective with this study was to analyze the body measurements of Girolando cattle, as well as measurements extracted from their images, to generate a model to understand which measures further explain the cattle body weight. Therefore, the experiment physically measured 34 Girolando cattle (two males and 32 females), for the following traits: heart girth (HGP), circumference of the abdomen, body length, occipito-ischial length, wither height, and hip height. In addition, images of the dorsum and the body lateral […]

ABSTRACT The objective was to evaluate the addition of antibiotic growth promoters to free-choice mineral supplement on ingestive behavior, mineral intake, and growth performance of grazing bulls. Sixty Nellore bulls [initial body weight (BW) of 219±17.8 kg and 15±2 months of age] were divided in 12 marandu grass paddocks. The treatments were: mineral supplement (control), mineral supplement + virginiamycin (VIRG), mineral supplement + lasalocid sodium (LASA) and mineral supplement + salinomycin sodium (SALI). Mineral supplements were formulated with target intake […]

ABSTRACT The objectives of the study were to evaluate allelic frequencies and test the association between STAT1, OLR1, CSN1S1, CSN1S2 , and DGAT1 gene polymorphisms and milk production traits including lactation milk yield, 305 days milk yield, days before peak milk production, and peak milk yield. In addition, samples of milk were analysed for fat, protein, lactose, and total solid contents. A total of 168 purebred Holstein-Fresian cows were genotyped using polymerase chain reaction and restriction fragment length polymorphism methods. […]

ABSTRACT The objective of this study was to evaluate the effect of high or low energy intake on carcass composition and expression of hypothalamic genes related to the onset of puberty. Twenty-four prepubertal Nellore heifers, 18-20- months-old, with 275.3±18.0 kg body weight (BW), and 4.9±0.2 (1-9 scale) body condition score (BCS) were randomly assigned to two treatments: high-energy diet (HE) and low-energy diet (LE). Heifers were housed in two collective pens and fed diets formulated to promote average daily gain […]

ABSTRACT Herbivores face the dilemma that the level of feed intake is negatively related to factors that determine digestive efficiency, such as thoroughness of ingesta comminution by chewing, and retention of digesta in the digestive tract. Ruminants have evolved particular adaptations to solve this dilemma. Most ruminants share the characteristic of “digesta washing”: fluid moves through their digestive tract faster than particles, thus effectively washing very fine particles, such as bacteria, out of the digesta plug. As the forestomach is […]