FR 05. Field reproductive potential evaluation of Brahman bulls

Abstract

A total of 838 Brahman bulls were subjected to a breeding soundness evaluation (BSE) just prior to be exposed to cows under natural breeding. The bull population examined had a range of ages between 2 and 15 year-old. Classification of the bulls acording to BSE was as follows: 52 % of the 2-year-old bulls were satisfactory potential breeders while a 31% did result insatisfactory mainly due to either small scrotal circumference (SC) or poor semen characteristics. Bulls between 3 and 6 years of age were satisfactory breeders in a 80 to 87 % range. The percentage of insatisfactory bulls increased (P<.0001) with age. Scrotal circumference was the main factor affecting (P<.0001) the proportion of bulls in each classification; satisfactory, insatisfactory or deferred. There was a clear tendency shown for insatisfactory 20 to 30 month old bulls to have smaller SC measurements. The study indicates that young Brahman bulls do not meet the standard requirements indicated by the Society of Theriogenology and therefore most young Brahman bulls are penalized when using the BSE scoring system which was developed using data collected from European bulls.