The confinement reactivity (CR) has been used as a measure of temperament in Brazil and it is defined as the animal reaction when contained in the scale. It is quantified through the animal reactivity test – REATEST®. This test consists of an electronic device coupled to the scale and of specific software. The device captures the movement that the animal provokes in the scale, during 20 seconds and sends it for the software that processes this movement and determines the […]

This manuscript reports on the main problems decreasing productivity of dairy cows (e.g. fatty liver syndrome and poor fertility) and how antioxidants could enhance it. High producing dairy cows are prone to oxidative stress, and the situation can be exacerbated under certain environmental, physiological, and dietary conditions. Antioxidants have important effects on the expression of genes involved in the antioxidant status, which may enhance animal health and reproduction. Moreover, antioxidants may contribute to decrease the incidence of spontaneous oxidized flavour […]

This review summarizes recent developments on the utilization of specific fatty acids to modulate bovine energy metabolism, with emphasis on the periparturient dairy cow. A number of experiments have assessed the effects of polyunsaturated fatty acids on bovine hepatic energy metabolism using in vitro and in vivo models. Treatment of hepatocytes with specific fatty acids altered energy metabolism in vitro. For example, linolenic acid seemed to decrease hepatocyte triacylglycerol accumulation. This effect was confirmed in vivo, using parenteral infusions of […]

Oocytes in cattle are formed during embryogenesis and develop within individual follicles in the cortex of the ovary. Dormant primordial follicles become active and undergo progressive development at regular intervals commencing during the late fetal stage and continuing throughout adulthood. Once activated, follicles and oocytes in a cohort either grow to maturation and ovulation or undergo atresia, ultimately depleting the ovaries of germ cells. It takes an estimated 100 days for a follicle and its oocyte to reach the mature […]

This study aimed to evaluate the effects of temporary calf removal (TCR) or eCG administration on pregnancy rates of milking Nelore cows treated with a intravaginal progesterone releasing device (IPRD). In the first experiment 83 Nelore and 102 Nelore vs. Red Angus crossbred cows were randomly allocated to 3 groups. Animals in Group 1 (CON) received estradiol benzoate (EB; 2.5 mg, i.m., Estrogin®) and an IPRD (1g progesterone, DIB®) in a random stage of the estrous cycle (D0). At D9 […]

In order to evaluate the influence of tropical grass sward structure on the intake of grazing cattle, five sward heights (60, 80, 100, 120, and 140 cm) of Panicum maximum Jacq. were established, in a completely randomized design with two replications. Four black-and-white coat Holstein heifers, carrying feces and urine bags, were used in grazing tests of 45 minutes each. Number of bites and feeding time were registered by counters and chronometers. Total herbage mass consumed was obtained by double […]

The last twenty years have been characterized by some remarkable technological advances in the field of genomics which were essential to unveil the genome of varies species. Furthermore, these genomic advances contributed to pinpoint particularities in genome sequences which might be associated with phenotypic variations, therefore, it became possible to study functions associated with specific sequences in a more holistic context within biological systems. More importantly, the blossoming in genomics contributed to a better understanding on the mechanisms that control […]

The market demands, since the end of the 1920s the market demands a technology for spermatozoa sexing that can be inserted in the industry to production of frozen semen and that has the following features: a) does not change sperm viability; b) it be compatible with freezing of spermatozoa after treatment for sexing; c) it allows the spermatozoa sexing after their thawing; d) it allows the production of various doses of sexed frozen semen per day at a compatible cost […]

The development of in vitro embryo production (IVP) methodology to maximize genetic gain and animal production at lower cost is a challenge of the research and it has been studied for many years. The possibility to produce, in commercial scale, embryos from ovum pick up methodology may increase the benefits of the use of artificial insemination (AI) for its decisive role to maximize the genetic progress between generations, according to the requirements of each genetic improvement program and livestock capacity. […]

The objective of this trial was to study the effect of forage defoliation intensity and energy or protein supplementation on chewing activity of beef cattle. Eight Nellore steers fitted with ruminal cannula were used in a rotational grazing system of tanzaniagrass (Panicum maximum Jacq.) with 33 days of resting and three days of grazing. Additional steers were allowed to access the pasture before those with ruminal cannula to maintain the green dry matter (GDM) residue at 1,000 or 4,000 kg/ha […]