ABSTRACT The objective of this research was to determine the influence of heat stress, using the temperature-humidity index (THI), on the production and quality of native sperm of bulls. The effect of heat stress on the quantity of semen (mL), density of ejaculate (number of spermatozoa, 106/mL), gross sperm motility (1-5), number of frozen doses, and motility after freezing was analysed in 1,017 sperm samples taken from 32 Holstein-Friesian bulls, in the 2017-2019 period, at the Centre for Reproduction and […]

The objective of this study was to evaluate the efficacy of cleaning and decontamination procedures in liquid nitrogen tanks. We evaluated 151 canisters and 133 bottoms from 133 nitrogen tanks of companies or farms for the presence of bacteria and fungi. Samples were collected from the canisters and the bottom of tanks containing liquid nitrogen. Tanks were divided into Group 1 (G1): tanks decontaminated with 2% glutaraldehyde – Glutaron® II (n = 16 canisters in 8 tanks); Group 2 (G2): […]

Two semen extenders were compared for their ability to maintain viability of horse semen during 24 hours of cold preservation, and for the pregnancy rate after artificial insemination. In the experiment 1, five ejaculates from three stallions were split-diluted in either a skimmed milk-based extender (Kenney extender) or a glycine egg yolk-based extender (Foote extender) and cooled at 6-8 ºC for 24 hours. Semen samples stored in Kenney extender for 24 hours had higher motility and spermatic vigor compared with […]

The objective of this study was to verify the effects of GnRH on ovulation and pregnancy of ewes subjected to a short-term synchronization of estrus. Santa Inês and crossbred Santa Inês/Dorper ewes received 60 mg MAP sponges during 6 days plus 300 IU eCG and 30 µg d-cloprostenol 24 h prior to sponge withdrawal (SW). Ewes were assigned to receive 0.9% NaCl solution (Tcontrol; n = 32) or 25 µg GnRH (licerelin, TGnRH; n = 34) 24 hours after SW. […]

The objective of this study was to evaluate the effect of adding different doses of insulin to swine semen processed and stored at 15 ºC. The experiment used sixteen ejaculates from four commercial breeding pigs, distributed in a randomized block design (ejaculate) with split plot along time (0, 24, 48 and 72 hours of storage) with four treatments (insulin levels – 0.0 4.0 8.0 and 12.0 IU per dose) and 16 repetitions. The experimental unit was made of two insemination […]

O objetivo nesta revisão é mostrar os principais avanços científicos obtidos na área da reprodução animal e como estes podem afetar a eficiência reprodutiva e produtiva do rebanho bovino brasileiro. Com o conhecimento dos mecanismos envolvidos no controle da fisiologia reprodutiva, em níveis endócrino, celular e molecular, foi possível o desenvolvimento das biotécnicas reprodutivas, destacando-se a IATF, que tem sido utilizada em larga escala, por permitir a multiplicação de animais superiores geneticamente, aumentar a taxa de natalidade e ser eficaz […]