Abstract
Background: The allelic and genotypic frequencies of ESR1 in Landrace and Large White boars, and the effect of breed and genotype on reproductive traits of boars were investigated. Methods: Landrace (n=12) and Large White boars (n=15) were genotyped for ESR1, and the data was subjected to Fisher’s exact test. Testes length and width, semen volume, and sperm concentration of boars, and litter records (n=988) of their mates were analyzed using different statistical models which include breed and genotype effects. Results: Majority (83%) of the Landrace boars were AA, while Large White boars were mostly AB (67%) genotypes. No BB genotype was detected. Distribution of genotypes were different between breeds (p<0.05). Testes length and width, semen volume and sperm concentration were neither different between breeds nor genotypes. Litter size and average birth weight of progenies sired by these boars were comparable between breeds and genotypes. Conclusion: The proportion of boars with AA and AB genotypes differ between breeds. Landrace and Large White are both dam breeds, which may explain their consistent similarities in the traits measured. No significant associations between boar traits and ESR1 were detected under the conditions and limitations of the study. Further investigation using a population of boars with a more balanced number ESR1 genotypes is warranted.
Keywords
Swine, ESR1, Estrogen receptor, Boar, Litter size