Genotype by environment interaction in response to cold stress in a composite beef cattle breed. (31st March 2020)

• Record Type: Journal Article
• Authors: Toghiani, S.; Hay, E.; Fragomeni, B.; Rekaya, R.; Roberts, A. J.
• Is Part Of: Animal. Volume 14:Number 8(2020)
• Page Start: 1576
• Page End: 1587
• Publication Date: 2020-03-31
• Subjects: bovine, -- reaction norm, -- cold load, -- birth weight, -- weaning weight; Animal breeding -- Periodicals; Animal genetics -- Periodicals; Animal nutrition -- Periodicals; Animal physiology -- Periodicals; Environmental sciences -- Periodicals; 636.005
• DOI: 10.1017/S1751731120000531
• Languages: English
• ISSNs: 1751-7311

Abstract

Abstract : Extreme weather conditions such as cold stress influence the productivity and survivability of beef cattle raised on pasture. The objective of this study was to identify and evaluate the extent of the impact of genotype by environment interaction due to cold stress on birth weight (BW ) and weaning weight (WW ) in a composite beef cattle population. The effect of cold stress was modelled as the accumulation of total cold load (TCL ) calculated using the Comprehensive Climate Index units, considering three TCL classes defined based on temperature: less than −5°C (TCL5 ), −15°C (TCL15 ) and −25°C (TCL25 ). A total of 4221 and 4217 records for BW and WW, respectively, were used from a composite beef cattle population (50% Red Angus, 25% Charolais and 25% Tarentaise) between 2002 and 2015. For both BW and WW, a univariate model (ignoring cold stress) and a reaction norm model were implemented. As cold load increased, the direct heritability slightly increased in both BW and WW for TCL5 class; however, this heritability remained consistent across the cold load of TCL25 class. In contrast, the maternal heritability of BW was constant with cold load increase in all TCL classes, although a slight increase of maternal heritability was observed for TCL5 and TCL15. The direct and maternal genetic correlation for BW and maternal genetic correlation for WW across different cold loads between all TCL classes were high ( r > 0.99), whereas the lowest direct genetic correlations observed for WW were 0.88 for TCL5 and 0.85 for TCL15. The Spearman rank correlation between the estimated breeding value of top bulls ( n = 79) using univariate and reaction norm models across TCL classes showed some re-ranking in direct and maternal effects for both BW and WW particularly for TCL5 and TCL15. In general, cold stress did not have a big impact on direct and maternal genetic effects of BW and WW.