Exploring the genetic control of sweat gland characteristics in beef cattle for enhanced heat tolerance

Authors: HERNANDEZ, AAKILAH - University Of Florida; ZAYAS, GABRIEL - University Of Florida; RODRIGUEZ, EDUARDO - University Of Florida; Sarlo Davila, Kaitlyn; RAFIQ, FAHAD - University Of Florida; NUNEZ ANDRADE, ANDREA - University Of Florida; GONÇALVES TITTO, CRISTIANE - Federal University Of Sao Paulo; MATEESCU, RALUCA - University Of Florida

Submitted to: Journal of Animal Science and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/11/2024
Publication Date: 5/8/2024
Citation: Hernandez, A.S., Zayas, G.A., Rodriguez, E.E., Sarlo Davila, K.M., Rafiq, F., Nunez Andrade, A., Gonçalves Titto, C., Mateescu, R.G. 2024. Exploring the genetic control of sweat gland characteristics in beef cattle for enhanced heat tolerance. Journal of Animal Science and Biotechnology. 15. Article 66. https://doi.org/10.1186/s40104-024-01025-4.
DOI: https://doi.org/10.1186/s40104-024-01025-4

Interpretive Summary: This study identified genetic variants responsible for difference in sweat gland characteristics in Brahman and Angus crossbred cattle. Sweating a key part of how cattle regulate their body temperature during hot conditions and understanding and utilizing genetic traits that confer better heat tolerance is a proactive approach to managing the impacts of climate change on livestock farming. This study identified that sweat gland characteristics are under a moderate amount of genetic control, allowing producers the ability to select for favorable sweat gland properties. Genetic variants in two genes, ADGRV1 and CCDC168, were found to impact sweat gland characteristics. Ancestral DNA from both Brahman and Angus was found to have a positive impact on sweat gland characteristics.

Technical Abstract: Thermal stress in subtropical regions is a major limiting factor in beef cattle production systems with around $370 million being lost annually due to reduced performance. Heat stress causes numerous physiological and behavioral disturbances including reduced feed intake and decreased production levels. Realization of climate change predictions with increased environmental temperatures will increase the risk of heat stress in cattle. Cattle utilize various physiological mechanisms such as sweating to regulate internal heat. Variation in these traits can help identify genetic variants that control sweat gland properties and subsequently allow for genetic selection of cattle with greater thermotolerance. This study utilized 2,401 Brangus cattle from two commercial ranches in Florida. Precise phenotypes that contribute to an animal’s ability to manage heat stress were calculated from skin biopsies and included sweat gland area, sweat gland depth, and sweat gland length. All animals were genotyped with the Bovine GGP F250k chip and BLUPF90 software was used for genetic parameters and GWAS. Sweat gland phenotypes heritability ranged from 0.17 to 0.45 indicating a moderate amount of the phenotypic variation is due to genetics, allowing producers the ability to select for favorable sweat gland properties. A weighted single-step GWAS using sliding 10kb windows identified multiple QTLs explaining a significant amount of genetic variation. QTLs located on BTA7 and BTA12 explained over 1.0% of genetic variance. These SNP were located in genes ADGRV1 and CCDC168, respectively. The variants identified in this study are implicated in processes related to immune function and cellular proliferation which could be relevant to heat management. Breed of Origin Alleles (BOA) were predicted using local ancestry in admixed populations (LAMP-LD), allowing for identification of markers’ origin from either Brahman or Angus ancestry. A BOA GWAS was performed to identify regions inherited from particular ancestral breeds that might have a significant impact on sweat gland phenotypes. The results of the BOA GWAS indicate that both Brahman and Angus alleles contribute positively to sweat gland traits, as evidenced by favorable marker effects observed from both genetic backgrounds. Understanding and utilizing genetic traits that confer better heat tolerance is a proactive approach to managing the impacts of climate change on livestock farming.