Genetic characterization of 24 Angus × Hereford cows from the Jornada Experimental Range, Las Cruces, NM, USA

The southwestern US is increasingly facing dry and variable climate
conditions, requiring beef operations to adopt novel strategies to
meet these emerging challenges. One potential approach is the use of
locally adapted cattle breeds or biotypes. A distinctive Angus x
Hereford (AH) research herd at the USDA Agricultural Research
Service Jornada Experimental Range provides an opportunity to
explore the genetic makeup of a desert-adapted cattle herd bred for
over four decades under the extreme and harsh conditions of New
Mexico’s Chihuahuan Desert. The objective of this study was to
analyze the population structure, genetic diversity and signatures
of selection of the AH research herd (n = 24). All cows were
genotyped using a 64K SNP chip. Principal component and admixture
analyses confirmed the mixed genetic background of the AH cows,
predominantly of Angus ancestry. The heterozygosity level, effective
population size, and inbreeding coefficient indicated that the AH
cows maintain moderate genetic diversity and inbreeding levels.
Genomic regions under positive selection revealed genes and
Quantitative Trait Loci associated with beneficial carcass traits,
milk composition, fertility, body homeostasis, antioxidant activity,
immune response, and terrain utilization. This research herd could
potentially serve as a valuable genetic resource for improving the
adaptability and productivity of commercial beef cattle in harsh
semi-arid and arid environments, balancing hardiness and
performance.