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 Brazil's 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.

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 ß-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.