October 06, 2019

Interpretive Summary: Genotype by environment interactions

Interpretive Summary: Genotype by environment interactions for performance and thermoregulation responses in growing pigs.

By: Anne Wallace

Heat stress (HS) is detrimental to the health and reproduction of pigs, especially in tropical (TROP) and temperate (TEMP) climates. With climate change, the effects of increased temperatures are further amplified. Therefore, finding ways to mitigate HS is necessary to prevent substantial losses in the profits and production of commercial pig farms. 

Selecting for pigs with heat-tolerant genotypes may be one way to mitigate losses. In this study published in the September 2019 issue of the Journal of Animal Science, researchers looked at two pig populations (heat-sensitive “Large White” and heat-tolerant “Creole”) in both TROP and TEMP climates. Their goal was to determine the spectrum of genetic traits for thermoregulation and production and identify any potential interactions between genetics and environment. Parameters used to measure productivity included the following: body weight, average daily feed intake (ADFI), average daily gain (ADG), backfat thickness, cutaneous and rectal temperature, feed conversion ratio (FCR) and residual feed intake (RFI). 

Heritability estimates for heat-tolerant genotypes were found to be moderate to low in the two populations of pigs studied, but heritability for production traits was found to be moderate to high. The authors noted an interaction between genotype and environment for all production traits measured, except FCR. Additionally, a higher rectal temperature was negatively associated with ADFI and ADG but positively associated with increased feed efficiency and leanness. 

More extensive cohort studies are needed to validate and confirm the findings of this study. Genetic analysis to identify genes specific to heat tolerance may also be helpful when selecting for future study populations of pigs adaptable to HS conditions.  

To view the article, visit theJournal of Animal Science.