ABSTRACT The objective was to evaluate factors that influence calving probability in the first and second reproductive years of beef heifers that reached the minimum recommended body weight (BW) in the first breeding season. Two hundred twenty-seven 24-month-old Charolais × Nellore heifers that mated between 2003 and 2012 were analyzed. The parameters evaluated were: year effect; individual and maternal heterozygosis; percentage of Charolais genotype; average daily gain (ADG) from weaning to the end of the first breeding season; BW at […]

ABSTRACT Fifty-seven multiparous Awassi ewes in the breeding season were used to compare the effects of controlled internal drug release (CIDR) reuse on hormone profiles, reproductive performance, and economic production. Ewes were randomly allotted to one of three CIDR treatments: new (control), once-used, and twice-used; treatment lasted 12 days. Blood samples were collected from all groups at the time of CIDR insertion, three and six days following insertion, at withdrawal time, and at insemination. Serum estradiol (E2) and progesterone (P4) […]

ABSTRACT This study analyzed the adenosine concentration on quality of ram semen in different refrigerated storage times at 5 °C. The design was in blocks with repeated-measures factorial design. Five levels of adenosine and four refrigeration times were considered as fixed effects and the animal as random effect (block). Ram semen was diluted with Andromed® diluent (control) and increasing adenosine levels (0.5, 0.75, 1, and 1.5%). The samples were taken from refrigeration after 4, 8, 12, and 16 h and […]

ABSTRACT The objective of this study was to evaluate the effect of environment on follicular diameter and repeatability of the size of preovulatory follicles of mares. Temperature, rainfall, and photoperiod were measured, and their effects were evaluated on follicular dynamics. Data were studied by analysis of variance of follicular size and environment traits. During the five years, 7% double ovulations and 159 anovulatory follicles were recorded. Mean preovulatory follicle diameters of left and right ovaries were 39.3±3.8 and 39.2±3.5 mm […]

ABSTRACT Since few studies have addressed the embryonic development of Guinea fowl (Numida meleagris), the objective of the present study was to evaluate its embryonic development in the Cerrado region of Brazil and compare the results to published descriptions of the embryonic development of other domestic bird species. The commercialized weight for Guinea fowl eggs used in the experiment was found to be 37.57 g, while egg fertility was 92%. Embryo growth rate (%) was higher on the sixth day […]

ABSTRACT The objective of this study was to evaluate the reproductive performance of ewes subjected to a short-term protocol for estrus induction using 1 mg of Norgestomet during the non-breeding season in Brazil. A total of 84 ewes were randomly divided into two equal groups (n = 42 per group). Controlled Internal Drug Release (CIDR) containing 330 mg progesterone was inserted into the vagina in the first 42 ewes, and for the other 42 ewes in the second group, 1 […]

ABSTRACT This study evaluated the effect of the addition of conjugated linoleic acid (CLA) to in vitro culture on viability, lipid content, and cryoresistance of bovine embryos at different in vitro culture times. Cumulus oocyte complexes (N = 974) were maturated in vitro for 22 h. In vitro fecundation ensued for 18 h. Viable zygotes were cultivated in vitro in medium supplemented with CLA (100 mM) in the first 72 h (CLA-F), last 72 h (CLA-L), or throughout the culture […]

ABSTRACT The objective of this research was to study the effect of immunocastration on the morphometric characteristics of sex glands in male Swallow-bellied Mangalitsa pigs. The study included 24 animals (13 entire and 11 immunocastrated males). The research focused on the following traits: age at slaughter (days), live weight at slaughter (kg), growth rate (kg day−1), and morphometric testicle traits (volume, cm3; weight, g; length, width, thickness, and circumference, mm). The efficacy of immunocastration was determined based on androstenone and […]

ABSTRACT We evaluated the effect of some environmental factors on age at first lambing (AFL) and lambing to conception interval (LCI) of Pelibuey ewes under the humid tropical conditions of Mexico. Ewes grazed on Tanzania (Panicum maximum), Bermuda (Cynodon dactylon), and Brachiaria grass (Brachiaria humidicola) and received hay in the corral in the months of grass scarcity. Reproduction was continuous during the year. Data of 839 lambings from 334 ewes registered from 2009 to 2017 were analyzed using survival analysis […]

The industry has made available in the market a series of substances (nutraceuticals) which intent would be to optimize the use of nutrients in some metabolic paths, influencing positively reproductive performance in animals. However, the response to the use of nutraceuticals varies according to the animal. As the organism is highly complex and in order to achieve a perfect activity of the hypothalamic-pituitary-gonadal axis, an ideal interaction in molecular basis is needed, where the nutraceuticals can have their direct action. […]