Accumulated genetic analysis of piglets born alive and litter weights at birth in pigs from a commercial farm

摘要

Inordertoestimatethevariancecomponents(VC)andthegeneticparameters(GP)forprolificacy,measuredascumulativenumberofpigletsbornalive(NPB)andtheaccumulatedlitterweightatbirth(LWB)ofLandraceandLargeWhitesowsfromacommercialfarm,3,419and3,142litterswereanalyzed,respectively.Theanimalswerekeptinintensiveproductionconditions,followingastricthealthandfoodcontrol,appliedbythesameenterprise.Reproductivemanagementincludedartificialinseminationoftheentirefemalepopulation.TheVCandGPwereestimatedusingMTDFREMLsetofprograms.Themodelincludedthefixeffectsofyearandmonthofbirthofthesowandthecovariateageatfirstfarrowing.Therandomeffectsincludedwerethedirectadditivegeneticandpermanentenvironmental.Genetic,environmentalandphenotypictrendswereestimatedbyregressionoftherespectivevaluesontheyearsofbirthofthesows.Averagevalueswere28.8piglets,45.1kgand31.8piglets,59.7kg,forNPB,LWB,forLandraceandLargeWhitesows,respectively.Thedirectheritabilityrangedbetween0.03and0.05,thepermanentenvironmentaleffectsrangedbetween0.13and0.15andrepeatabilitybetween0.17and0.18.Itisexpectedalowresponsetoselectionforthecharactersstudied,duetolowratesofdirectheritabilityfound.