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Freitas PHF, Johnson JS, Chen S, Oliveira HR, Tiezzi F, Lázaro SF, Huang Y, Gu Y, Schinckel AP, Brito LF. Definition of Environmental Variables and Critical Periods to Evaluate Heat Tolerance in Large White Pigs Based on Single-Step Genomic Reaction Norms. Front Genet 2021; 12:717409. [PMID: 34887897 PMCID: PMC8650309 DOI: 10.3389/fgene.2021.717409] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 10/15/2021] [Indexed: 12/18/2022] Open
Abstract
Properly quantifying environmental heat stress (HS) is still a major challenge in livestock breeding programs, especially as adverse climatic events become more common. The definition of critical periods and climatic variables to be used as the environmental gradient is a key step for genetically evaluating heat tolerance (HTol). Therefore, the main objectives of this study were to define the best critical periods and environmental variables (ENV) to evaluate HT and estimate variance components for HT in Large White pigs. The traits included in this study were ultrasound backfat thickness (BFT), ultrasound muscle depth (MDP), piglet weaning weight (WW), off-test weight (OTW), interval between farrowing (IBF), total number of piglets born (TNB), number of piglets born alive (NBA), number of piglets born dead (NBD), number of piglets weaned (WN), and weaning to estrus interval (IWE). Seven climatic variables based on public weather station data were compared based on three criteria, including the following: (1) strongest G×E estimate as measured by the slope term, (2) ENV yielding the highest theoretical accuracy of the genomic estimated breeding values (GEBV), and (3) variable yielding the highest distribution of GEBV per ENV. Relative humidity (for BFT, MDP, NBD, WN, and WW) and maximum temperature (for OTW, TNB, NBA, IBF, and IWE) are the recommended ENV based on the analyzed criteria. The acute HS (average of 30 days before the measurement date) is the critical period recommended for OTW, BFT, and MDP in the studied population. For WN, WW, IBF, and IWE, a period ranging from 34 days prior to farrowing up to weaning is recommended. For TNB, NBA, and NBD, the critical period from 20 days prior to breeding up to 30 days into gestation is recommended. The genetic correlation values indicate that the traits were largely (WN, WW, IBF, and IWE), moderately (OTW, TNB, and NBA), or weakly (MDP, BFT, and NBD) affected by G×E interactions. This study provides relevant recommendations of critical periods and climatic gradients for several traits in order to evaluate HS in Large White pigs. These observations demonstrate that HT in Large White pigs is heritable, and genetic progress can be achieved through genetic and genomic selection.
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Affiliation(s)
- P. H. F. Freitas
- Department of Animal Sciences, Purdue University, West Lafayette, IN, United States
| | - J. S. Johnson
- USDA-ARS Livestock Behavior Research Unit, West Lafayette, IN, United States
| | - S. Chen
- Department of Animal Sciences, Purdue University, West Lafayette, IN, United States
- Farm Animal Genetic Resources Exploration and Innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, China
| | - H. R. Oliveira
- Department of Animal Sciences, Purdue University, West Lafayette, IN, United States
- Centre for Genetic Improvement of Livestock, Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada
| | - F. Tiezzi
- Department of Animal Science, North Carolina State University, Raleigh, NC, United States
| | - S. F. Lázaro
- Department of Animal Sciences, Purdue University, West Lafayette, IN, United States
- Department of Animal Science, College of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal, Brazil
| | - Y. Huang
- Smithfield Premium Genetics, Rose Hill, NC, United States
| | - Y. Gu
- Smithfield Premium Genetics, Rose Hill, NC, United States
| | - A. P. Schinckel
- Department of Animal Sciences, Purdue University, West Lafayette, IN, United States
| | - L. F. Brito
- Department of Animal Sciences, Purdue University, West Lafayette, IN, United States
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