Miguel Alejandro Silva Rua

Evaluation of the breeding behavior of Brazilian Pony stallions

The aim of this study was to evaluate the breeding behavior of Brazilian Pony stallions during semen collection to examine the effect of age category (AC) and month of evaluation on the characteristics of breeding behavior. Nine stallions were evaluated during the breeding and non-breeding season, 5-8 (AC1) and 9-13 years (AC2) of age. The variables evaluated were reaction time (RT), mount time one (MT1) and two (MT2), mount and ejaculation time (MEjT), mounting without erection (MWEr), mounting without ejaculation (MWEj), flehmen, kicks, bites, smells, vocalizations and serum testosterone concentration. Analyses of variance and correlation were performed. The average scores were RT: 56.2±92.9s, MT1: 115.0±122.4s, MT2: 196.4±160.7s, MEjT: 21.8±3.2s, MWEr: 0.8±1.3s, MWEj: 2.1±3.5s, flehmen: 3.8±3.0s, kicks: 0.3±1.2s, bites: 1.0±2.0s, smells: 5.7±3.5s, vocalizations: 6.4±6.3s and testosterone: 0.89±0.52ng/mL. The AC affected the RT (P<0.05) but not the other traits. Month of evaluation did not affect most variables (P>0.05). The correlations between age and RT and between age and MT1 and MT2 were significant. The correlation between testosterone and MEjT was moderate and negative. The breeding behavior of Brazilian Pony stallions was similar across different months of evaluation and different age categories. The month of evaluation and age category also did not affect testosterone concentrations, meaning that semen collection is feasible throughout the year.

Diagnostic methods to detect uterus illnesses in mares

Uterine illnesses are the major problem in horse reproductive programs. The diagnosis of these pathologies is often neglected or does not provide enough information about the cause. The aim of this study was to evaluate different diagnoses to provide more accurate information about endometritis and the real endometrial profile at the beginning of a breeding season. Fifty-one mares with reproductive failure were evaluated. Two different uterine cytology diagnoses, culture of uterine flush material and biopsy assay, were performed. The data were analyzed by the Chi-squared test to compare different diagnostic methods for the same sample from each mare, and sensitivity and specificity tests were performed. Most of evaluations showed no association between cytology and other diagnostic methods, except with bacterial culture. The most common bacterium found was Escherichia colli, but it was not associated with neutrophil presence in cytology. The presence of β-hemolitic streptococcus was well characterized by positive cytology and cloudy lavage fluid aspect. Endometrial profile was affected by age and whether the mare was a donor or recipient. The most sensitive diagnostic method was gross aspect of lavage fluid. Endometritis should be diagnosed by at least two methods to increase accuracy. Endometritis is not the only uterine disease that causes embryo loss, since endometrial fibrosis can also be a cause.

Variants in the CYP19A1 gene can affect in vitro embryo production traits in cattle

PurposeThis study aimed to associate DNA variants in promoter and exon flanking regions of the CYP19A1 gene with in vitro embryo production traits in cattle. The role of transcription factor binding sites created or lost due to DNA sequence variation and their possible effect on gene expression was also evaluated.MethodsWe collected date from Gyr dairy oocyte donor cows (Bos taurus indicus) at a commercial in vitro embryo production farm and analyzed the genotype–phenotype association with in vitro production traits. Using Sanger sequencing and web-based software, we assessed important CYP19A1 gene regions in oocyte donor cows and analyzed the effects of variants on the transcription factor binding sites.ResultsTwo SNP mutations significantly associated with oocyte production, oocyte viability, embryo development, and pregnancies were found (T > C in the untranslated exon 1 flanking region ([GenBank: AJ250379.1]: rs718446508 T > C), and a T > C in the 5′-upstream region (1.1 promoter) ([GenBank: AC_000167.1]: rs41651668 T > C). Six new transcription factor binding sites were created. A binding site for transcription factors associated with the development of the placenta and embryo implantation was eliminated due to variations in the DNA sequence identified.ConclusionsThe CYP19A1 gene contributes to genetic variation of in vitro embryo production traits in cattle. The complexity of the physiological phenomena related to estrogen pathways and their influence on reproduction in cattle allow indication of the mutations evaluated here as possible genetic markers for embryo production traits, which should be validated in the next steps of marker-assisted selection.

Evaluation of environmental effects on reproductive characteristics of Mangalarga Marchador mares in a commercial embryo transfer program

The objective of this study was to evaluate the environmental effects on embryo recovery rate and pregnancy rate of Mangalarga Marchador mares. The reproductive characteristics of donor and recipient mares were evaluated during five years in Brazilian tropical environment. The mares were used throughout the year and seasons were classified as: October to April (breeding season - BS); May (autumn transition out of the breeding season - ATBS); June to August (non-breeding season - nBS); and September (vernal transition into the breeding season - VTBS). Daily temperature rainfall and hours of daylight (photoperiod) were measured during all months and years of evaluation. The embryo recovery rate (ERR) and the pregnancy rate (PR) were observed and frequencies were calculated. The effect of environmental variables, day of flushing, and hormonal treatments (estradiol benzoate and progesterone) were determined for the reproductive measures using the Chi-square and Kruskal-Wallis tests. Significant effects were noted of the year, season and temperature on ERR (P < 0.05), but no significant effects were observed of the environmental parameters (year, season, hormone treatment, rainfall and photoperiod) on PR (P > 0.05). The day of uterine flush affected ERR (P < 0.05) but did not affect PR (P > 0.05). In addition, hormone treatment also supported favorable results of PR in recipient mares during nBS. The conclusion is that mares of this breed can be used in reproduction all year long, with good pregnancy rates, in Brazils tropical environment. The hormone treatment also supported favorable pregnancy rates in recipient mares during the non-breeding season. It seems that mares can have good pregnancy rates throughout the year in Brazil´s tropical environment.

Alterações nos parâmetros hematológico durante a gestação e no pós-parto de cabras da raça Saanen criadas no sul do Espírito Santo

The aim of this study was to evaluate the hematological profile of Saanen goats at different stage of pregnancy and postpartum. For this study were uses 24 pregnant goats and 10 non-pregnant Saanen raised in intensive conditions in the Alegre city, Espirito Santo state. Samples were collected from 60 to 135 days of gestation, with intervals of 15 days between collections. After parturition were performed two more collections, also with intervals of 15 days. The blood samples were refrigerated until arrival at the laboratory. It was possible to perform the red blood cell (RBC) count, packed cell volume (PCV), hemoglobin, mean cell volume (MCV), mean corpuscular hemoglobin concentration (MCHC) and the white blood cell (WBC) count, on an automatic analyzer and the blood smears were stained whit panoptic stain for differential WBC counts. After analyzing results it can be seen that in goats assessed no influence of gestation, delivery and postpartum on the order of the values of the erythrocyte. All evaluated parameters except MCV, decreased with advancing gestation until fifteen days after birth, with the largest changes occurred in late pregnancy. The WBC and differential also showed significant differences according to the physiological stage of the females. The average values of WBC were 10579 e 15836 leukocytes/mm3. Non pregnant females showed higher WBC, with decreasing gestation until 15 days of postpartum. Thirty days postpartum increased the value of WBC, resembling the values of non-pregnant goats. The absolute values of segmented neutrophils followed the same trend of WBC. the number of lymphocytes showed decrease a 120 days of pregnancy, increasing from thirty days postpartum. The number of eosinophil was not changed according to the physiological state and the number of basophils was higher in non-pregnant females. For monocytes results were generally higher in non-pregnant goats and 120-135 days of gestation. With respect to parity other was observed that females with more than four birth a lower values of PVC, there were no differences in the other parameters of the erythrocyte. WBC was higher in goats with four deliveries, mainly due the increase of neutrophils, whereas the number of lymphocytes was lower in these goats. Already the number of lymphocytes was lower in goats with four birth. The results showed the influence of pregnancy, postpartum and the order of birth of the Saanen females studied on the hematological parameters and the need for studies to determine references values of blood cell counts for each type of goats breed.