Influências da glândula paracloacal sobre características comportamentais e fertilidade em machos de codorna de corte

Abstract

Intense selection for weight gain in birds results in depreciation of the reproductive capacity of the animals. However, reproductive efficiency measures are often expensive or complex to collect, requiring simple characteristics for breeding selection. Cloacal gland area is considered a good indicator of fertility as it can be measured earlier and without incubation, making it less expensive. This study aimed to evaluate methods for measuring the cloacal gland area, to quantify the influence of this area on sexual behavior and fertility and to evaluate genetic parameters of the cloacal gland area, fertility and aggressiveness of fertile males, and to obtain estimates of correlations between them. features We used 116 male breeders, in which the cloacal area in the field was measured, by image index or image contour. fertile or not, aggressiveness, attempted mounts, incomplete mounts and complete mounts were measured in the field. For the analysis between gland measurements, Pearson and Spearman correlation test was performed and for association between gland contour area and fertility, logistic regression was used and Poisson regression with the other behavioral variables. The cloacal gland measurement in the field was highly correlated with the contour measurement (r> 0.90), being an alternative to image phenotyping. Heritabilities and genetic and environmental correlations between traits were estimated using Gibbs sampling. The genetic correlations (standard error) were 0.492 (0.471), 0.23 (0.496) and 0.339 (0.632) between cloacal gland area and aggressiveness, cloacal gland area and fertility, and aggressiveness and fertility, respectively. Heritability estimates (credibility range) were 0.39 (0.029-0.79), 0.35 (0.076-0.762) and 0.08 (0.008-0.219) for cloacal gland area, aggressiveness and fertility, respectively. The cloacal gland area was an adequate predictor for regression using variables related to breeding behavior, but with low adjustment when considering aggressiveness and fertility prediction. The results showed that there is no significantly nonzero correlation between fertility and cloacal gland area and between fertility and aggressiveness, but the gland area is positively correlated with aggressiveness.