Estimación de los parámetros genéticos de producción y calidad seminal en una línea paternal de conejos

The objective of this study was to estimate the genetic parameters of seminal characteristics in a paternal rabbit line selected for increased growth rate in the fattening period (GMD). Bucks (412) from line R, selected during 25 generations, in three different insemination stations were used. The males reproductive rhythm was two ejaculates per week, the training period started at five months of age, the semen samples were taken one week after finishing the training period and three months later. The examined traits were: traits involved in total seminal production (volume, concentration, total number of spermatozoa per ejaculate), morphological traits (spermatozoa percentage with normal apical rigde, sperm morphological abnormalities percentage), morphometry traits (length of head spermatozoa, width of sperm head, area of sperm head and perimeter of sperm head), and sperm motility parameters assessed using a computer-assisted sperm analysis (percentage of total motile sperm, average path velocity, curvilinear velocity, straight-line velocity, linearity index, amplitude of lateral head displacement, wobble, and straightness). (Co)variance genetic components of buck semen characteristics and growth traits were estimated using a bivariate animal model. Equal model equations for all semen traits included the artificial insemination station-year season, the age, and order of ejaculate as fixed effects; the animal, the permanent environmental and non-additive genetic effect of the male over all its ejaculates, the common little effect and the residual as random effects. The model of daily gain (GMD), included litter size at birth as covariate, parity order and year-season as fixed effects and the animal, the common litter, the permanent environmental and non-additive genetic effect, and the residual as random effects. Heritability estimates were low for motility traits, and for those involved in semen production, nevertheless, the heritabilities for morphological and morphometry traits were intermediate. Most semen characteristics had unfavorable genetic correlations with GMD, with the exception of volume that showed a favorable genetic correlation with GMD