title: Genetic parameters for thermoregulation and production traits in lactating sows reared in tropical climate.
abstract: The objective of this study was to estimate the genetic parameters for thermoregulation traits and the relationships with performance of Large White lactating sows reared in a tropical humid climate. The thermoregulation traits were rectal temperature (RT), cutaneous temperature (CT) and respiratory rate (RR) during lactation measured in the afternoon (1200 h) and in the morning (0700 h). The production traits were sow's average daily feed intake (ADFI), litter BW gain (LBWg) and sow's proportion of BW change between farrowing and weaning (BWc). Complete data included 931 lactating performance on 329 Large White sows from the INRA experimental unit in Guadeloupe (French West Indies). Random regression models using linear spline functions were used for longitudinal data (RT, CT, RR and daily feed intake). Results showed that when ignoring values at the beginning and the end of lactation, the traits studied can be treated as the same trait throughout days of lactation, with fairly constant heritability and variance. However, largest heritabilities and genetic variances were estimated in mid-lactation. Heritability estimates on average performance during lactation were low to moderate for thermoregulation traits (0.35±0.09 for RT, 0.34±0.12 for CT and 0.39±0.13 for RR). Heritability estimates for production traits were 0.26±0.08 for ADFI, 0.20±0.07 for BWc and 0.31±0.09 for LBWg. Significant genetic correlations between thermoregulation traits and production traits were only obtained for ADFI and RR (0.35±0.12). From this study it can be concluded that thermoregulation traits are heritable, indicating that there are genetic differences in heat stress tolerance in lactating Large White sows.
authors.affiliation: 1INRA,UR143,Unité de Recherches Zootechniques (URZ),F-97170 Petit-Bourg,Guadeloupe,France.
authors.forename: J-L
authors.initials: JL
authors.lastname: Gourdine
authors.affiliation: 1INRA,UR143,Unité de Recherches Zootechniques (URZ),F-97170 Petit-Bourg,Guadeloupe,France.
authors.forename: N
authors.initials: N
authors.lastname: Mandonnet
authors.affiliation: 2INRA,UE1294,Plateforme Tropicale d'Expérimentation sur l'Animal (PTEA),F-97170 Petit-Bourg,Guadeloupe,France.
authors.forename: M
authors.initials: M
authors.lastname: Giorgi
authors.affiliation: 3INRA,UMR1348,Physiologie, Environnement et Génétique pour l'Animal et les Systèmes d'Élevage (PEGASE),F-35590 St Gilles,France.
authors.forename: D
authors.initials: D
authors.lastname: Renaudeau
mesh_terms: D000818:Animals; D001833:Body Temperature Regulation; D005247:Feeding Behavior; D005260:Female; D019430:Guadeloupe; D007774:Lactation; D010641:Phenotype; D012098:Reproduction; D034421:Sus scrofa / Q000235:genetics / Q000502:physiology*; D014329:Tropical Climate; D015430:Weight Gain
keywords: genetic parameters; heat stress; lactating sow; thermoregulation; tropical climate