Correlation between hypoosmotic swelling test and breeding soundness evaluation of adult Nelore bulls

Abstract

This study aimed at evaluating the relationship between physical and morphological semen features with the hypoosmotic swelling (HOS) test in raw semen of adult Nelore bulls classified as sound and unsound for breeding. Two hundred and six Nelore bulls aging from 3 to 10 years of age were subjected to breeding soundness examination. After physical and morphological semen examination, HOS test was done. After the breeding soundness examination, 94.2% of the bulls were classified as sound for breeding. There was no difference between the average scrotal circumference of bulls classified as sound and unsound for breeding (P>0.05), but there was difference between all semen physical and morphological aspects of bulls classified as sound and unsound for breeding (P>0.05), and no difference resulted in the mean percentage of reactive spermatozoa to HOS test results both for sound (38.4±17.9) and unsound animals (39.5±16.4; P>0.05), with no Pearson correlation between the HOS test and variables. According to these results HOS test can not be used alone to predict the reproductive potential of adult Nelore bulls.