Genetic and Phenotypic Parameters for Semen Characteristics and Their Relationship with Scrotal Circumference in Black Bengal Bucks

Abstract

Black Bengal goat is the heritage and one of the potential genetic resources of Bangladesh. Genetic and phenotypic parameters for semen characteristics and their relationships with scrotal circumference in Black Bengal bucks were estimated in this experiment. Genetic parameters were estimated by residual maximum likelihood procedure, fitting an animal model ignoring maternal genetic or permanent environmental effects. The least-squares means of semen volume (mL/ejaculate), sperm concentration (10⁹cells/mL), mass motility (%), sperm livability (%) and normal spermatozoa (%) were 0.56, 2.55, 79.7, 86.8 and 90.5, respectively. Season of collection and scrotal circumference significantly affected all semen characteristics studied. Age of bucks affected all the semen characteristics, except mass motility. Body weight had a significant effect on semen volume and mass motility. Heritability estimates were moderate for sperm concentration (0.38) and low for semen volume, mass motility, sperm livability and normal spermatozoa (0.05 to 0.18). Phenotypic correlations ranged from slightly negative (-0.001) to moderately positive (0.42) and the genetic correlations ranged from moderately negative (-0.37) to strongly positive (0.99). Sperm concentration was the only semen trait of Black Bengal goat where reasonable genetic progress may be possible through selection. Selection for increased scrotal circumference should have favorable correlated response in semen characteristics.