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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Ruminant Diseases and Immunology Research » Research » Publications at this Location » Publication #424293
Research Project: Genomic and Mitigation Strategies to Control Mastitis

Location: Ruminant Diseases and Immunology Research

Title: Genetic architecture of thermotolerance traits in beef cattle: a novel integration of SNP and breed-of-origin effects

Author
item ZAYAS, GABRIEL - University Of Florida
item SANTOS ROJAS, CAMILA - University Of Florida
item RODRIGUEZ, EDUARDO - University Of Florida
item HERNANDEZ, AAKILAH - North Carolina State University
item BEARD, ASHLEY - University Of Florida
item RAFIQ, FAHAD - University Of Florida
item Sarlo Davila, Kaitlyn
item MATEESCU, RALUCA - University Of Florida

Submitted to: Frontiers in Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/22/2025
Publication Date: 4/29/2025
Citation: Zayas, G.A., Santos Rojas, C., Rodriguez, E.E., Hernandez, A.S., Beard, A.M., Rafiq, F., Sarlo Davila, K.M., Mateescu, R.G. 2025. Genetic architecture of thermotolerance traits in beef cattle: a novel integration of SNP and breed-of-origin effects. Frontiers in Genetics. https://doi.org/10.3389/fgene.2025.1576966.
DOI: https://doi.org/10.3389/fgene.2025.1576966

Interpretive Summary: This study identified alleles regulating hair length and sweat gland area in Brahman and Angus crossbred cattle. Hair length and sweating are key to cattle regulating 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 alleles regulating these traits and found that the breed of origin (Brahman or Angus) of the allele also impacted these traits.

Technical Abstract: Background: Rising temperatures increasingly expose beef cattle to heat stress, reducing productivity and welfare, especially in tropical climates. Crossbreeding Bos t. taurus and Bos t. indicus has emerged as a critical strategy to balance the production efficiency of taurine breeds with the superior thermotolerance of indicine breed. Understanding the genetic architecture of thermotolerance traits is essential for improving heat resilience in beef cattle populations. Methods: Phenotypes for short hair length (SHL), long hair length (LHL), sweat gland area (SWA) and thermal stress slope (TSS) were collected from 3,962 crossbred Angus and Brahman heifers. They cattle where genotyped and breed-of-origin (BOA) for each marker was determined using LAMP-LD. Genome-wide association studies were conducted using SNP-only, BOA-only, and integrated SNP + BOA models to identify quantitative trait loci (QTLs) associated with thermotolerance traits. Results: Significant QTLs for SHL and LHL were identified on BTA20, overlapping the PRLR gene. A QTL on BTA19, driven solely by BOA effects, was also identified for SHL and LHL. For SWA, six suggestive QTLs were detected, predominantly linked to Angus-derived alleles associated with reduced sweat gland area. For TSS, a significant QTL on BTA1 exhibited a strong BOA effect, with Angus BOA associated with higher TSS values, indicative of reduced thermoregulatory efficiency. Integrated SNP + BOA models provided greater resolution and revealed novel QTLs compared to single-effect models. Conclusions: This study demonstrates the value of integrating BOA with SNP-based models to uncover the genetic architecture of thermotolerance traits in beef cattle. By better capturing breed-specific contributions, these findings enhance our understanding of thermoregulation and provide actionable insights for improving heat resilience in cattle.