Muscle genetic diseases in quarter horse horses

Abstract

The equestrian industry is a strong segment of Brazilian agribusiness. The Quarter Horse (QH) stands out as one of the main breeds of sport horses in Brazil and may have its athletic performance affected by genetic muscle diseases, such as: hyperkalaemic periodic paralysis (HYPP), type 1 polysaccharide storage myopathy (PSSM1), malignant hyperthermia (MH), and myosin heavy chain myopathy (MYHM). The frequencies of these mutations have been evaluated in QH horses of different sports disciplines, e.g., cutting, halter, racing, reining, and barrel racing. However, little has been investigated in vaquejada QH discipline. Although the vaquejada is an equestrian sport widely practiced in Brazil, especially in Brazilian Northeastern, and accounts for 13% of sport horses, the gap with the lack of information on the occurrence of these mutations in the vaquejada QH lineage is evident. The data published in Brazil using QH of other disciplines and from studs in the Southeast and South regions of the country have certain similarities with the frequencies observed in the United States of America and in this sense, it may be that with the vaquejada QH is not so different, however, as in other sports disciplines, it is speculated that some of these diseases may be more prevalent in the vaquejada QH. Therefore, in order to provide information on the occurrence of mutations responsible for the main muscle genetic disorders in the vaquejada QH, this study will evaluate the frequency of these mutations in registered QH with a history of competitor of vaquejada. Blood or hair samples will be randomly collected from 100 QH, specially, from farms in the Northeast of Brazil. The DNA will be purified and genotyped by Sanger sequencing for the four mutations (HyPP, PSSM1, MH, and MYHM) and consequently the referred allele frequencies will be calculated and known. (AU)