Effect of racial crossing on the seminal parameters of rams submitted to heat stress

Abstract

The aim of this study was to evaluate the effect of racial crossing on seminal parameters of eight Santa Inês and crossbred (Santa Inês x Dorper) rams submitted to heat stress, and to monitor the return of these parameters to previously reported. Before to place the insulation bags, two collects of semen through electroejaculation were performed. The insulation pouches were made with double-layer plastic, internally lined with cotton, and fixed around the spermatic funiculus and scrotum with adhesive tape and bandage remaining on the testes of the animals for seven days. The first collect was performed on the day that the pouches were taken (day 0) and thereafter, every seven days, totalizing 15 measurements. Data were submitted to analysis of variance (ANOVA). The analyzed variables were subjected to Dunnett test at 5% probability to compare the values obtained before treatment with those obtained in the following days. In this study it was found that the animals restored normal seminal parameter after the insulation effects, however, the return rate differed slightly among the studied breeds. The crossbred animals restored the seminal patterns, on average, a week before Santa Inês. It is concluded that the racial crossing influences the semen parameters of rams submitted to heat stress.

Keywords: motility, scrotal insulation, sperm concentration, sperm quality.