Estimation of genetic parameters of semen characteristics and reproductive traits in AI boars

Exploring the genetics of the efficiency of fertile AI dose production in rabbits

“…Results of the two studies also agreed in the negative genetic correlation between total number of sperm and litter size whereas the genetic correlation between sperm abnormalities and litter size seemed to be breed specific. The genetic correlation between litter size and sperm motility was positive and negative in Smital et al (2005) and Wolf (2010), respectively. In addition, Smital et al (2005) obtained a negative genetic correlation between semen volume and litter size whereas the same figure was estimated to be positive in the first parity of one of the two breeds analysed by Wolf (2010).…”

“…In general, there is a wide range of values of heritability and repeatability of Vol and Conc in different species varying from extremely low to high values (Robinson and Buhr, 2005) and it is clear that the variation in with that in the current study, their negative correlation between permanent environmental effects of the male did (-0.47 ± 0.14 and PM:-0.51, HPD95%: [-0.78, 0.18] in and in our work, respectively). In boars, Smital et al (2005) also estimated the rg between Conc and Prod (0.21) and between Vol and Prod (0.63), respectively. They obtained a similar rg between Conc and Vol to that in the current study (-0.61) indicating that a higher ejaculate volume does not seem to be associated with a higher number of sperm in the ejaculate that could remain constant or even decrease.…”

“…Several studies in different livestock species have estimated the genetic correlation (rg) between ejaculate volume and sperm concentration indicating the existence of a genetic antagonism: in pigs (-0.60 on average; Smital et al, 2005;Wolft, 2009), bulls (-0.31 on average; Karoui et al, 2011;, sheep (-0.36 on average in adult males; Rege et al, 2000;David et al, 2007b) and goats (-0.33 on average; . In rabbits, the only reported estimate of the rg between sperm concentration and ejaculate volume was very imprecise and cannot be considered to be different from zero (0.38 ± 0.45; Low h 2 values have been obtained for sperm motility traits when they have been evaluated in a subjective manner.…”

“…In addition, Smital et al (2005) obtained a negative genetic correlation between semen volume and litter size whereas the same figure was estimated to be positive in the first parity of one of the two breeds analysed by Wolf (2010). Finally, among several seminal traits analysed, conception rate was only positively correlated with sperm motility (Smital et al, 2005).…”

“…This makes the precision of the estimate very dependent on the relationship structure of the data (commonly sire-daughter). Genetic correlations between semen characteristics and sow litter traits have been analysed in two studies where some of the obtained results seemed to depend on the breeds and on the parity order (Smital et al, 2005;Wolf, 2010). Both studies showed a non relevant genetic correlation between sperm concentration and female contribution to litter size.…”