Características seminales de toros Brahman y mestizos (Bos Indicus X Bos Taurus) ubicados en el llano central venezolano

To determine seminal quality of Brahman (Br) and Crossbred (Cbr: Bos indicus x Bos taurus) bulls during the breeding season (December-May), in three localities of Guarico State, Venezuela, 62 bulls were evaluated. Bulls were 5.6 ± 0.3 years old in average (rank = 2-12 years old), handle under pasturing conditions and natural breeding. Breed (R), age (E), body weight (P), body condition (BC), and scrotal circumference (SC) effects on the ejaculate volume (EV), macroscopic aspect, masal motility (MM) and individual motility (IM) were evaluated. Hypothesis test of two average samples was made, based on the “t” Student distribution for independent samples. The average age of bulls was greater (p 0.05) in average body weight (Br=651.9 ± 4.3 Kg; Cbr=620.0 ± 11.8 kg), nor BC (Br=2.7 ± 0.1; Cbr=2.9 ± 0.1). The SC (cm) did not show difference (p>0.05) between Brahman (37.2 ± 0.8 cm) and Crossbred bulls (37.1 ± 0.8 cm), as well as EV (Br= 6.9 ± 0.8 mL; Cbr= 6.3 ± 0.7 mL). Semen from Brahman bulls showed a better aspect (Dense=76.5%; Medium dense=23.5%) than Crossbred bulls (Dense=40.0%; Medium dense =35.6%; Rale=24.4%). Masal motility was similar (p>0.05) between Brahman (2.6 ± 0.2) and Crossbred bulls (2.4 ± 0.2), where: MM: ++++=1; +++=2; ++=3; +=4; 0=5; whereas, IM in Crossbred bulls (71.9 %) was greater (p<0.05) than in Brahman (58.1%). These results allow us to conclude that the breed has influence in some of the evaluated seminal parameters, whereas the age did not affect the seminal quality of bulls between 4 - 6 years old.