Identification of quantitative trait loci affecting wet carcass syndrome in sheep using high density snp genotypes

English: Wet carcass syndrome (WCS) is a condition predominantly found in sheep, which negatively affects the quality of their carcasses. The Northern Cape Province in South Africa and the southern part of Namibia have been identified as geographic regions with a high occurrence rate of WCS. During the pre-slaughter period, the animal appears to be clinically normal, showing no symptoms of an abnormality. However, after the removal of the skin during the slaughter process the carcass appears to be “wet”. The condition is phenotypically described as a subcutaneous accumulation of watery fluid. The areas on the carcass most affected are the brisket, flanks, hindquarters, sides, and back. The watery fluid is also found in the intramuscular connective tissue layers of both the flank and subscapular area. Unfortunately, WCS results in sheep carcasses that are deemed to be unacceptable by the end consumer from both an appearance point of view and an apparent reduced shelf life. When the description and results of previous research are considered, no physiological-, environmental- or management system was conclusively identified as a causative agent of WCS. However, stress experienced by the animals during the pre-slaughter period was identified as a possible cause and is continuously discussed throughout the current research to date. The tentative breed-specificity, i.e. Dorper sheep breed, of the condition lends some credence to a potential genetic basis for it. However, previous research has not considered a genetic variant as a causal agent of WCS. The current study employed the Ovine Infinium® HD SNP BeadChip and a genome-wide association analysis (GWAS) approach to scan the genomes of both afflicted- and unafflicted sheep in search of putative quantitative trait loci associated with the WCS phenotype. This study was not only one of the first in Southern Africa to make use of this specific BeadChip but also the first to investigate the role of genetics as a causative
Afrikaans: Natkarkassindroom (NKS) is ‘n toestand wat hoofsaaklik onder skape voorkom en wat die gehalte van hul karkasse negatief beïnvloed. Die Noord-Kaap-provinsie in Suid-Afrika asook die suidelike deel van Namibië is geïdentifiseer as geografiese gebiede met ’n hoë voorkoms van NKS. Gedurende die tydperk voor die skape geslag word, kom die dier klinies normaal voor en toon geen simptome van abnormaliteit nie. Nadat die vel egter gedurende die slagproses verwyder word, kom die karkas as “nat” voor. Die toestand word fenotipies beskryf as die onderhuidse aansameling van ‘n waterige vloeistof. Die dele van die karkas wat die meeste geaffekteer word is die borsstuk, lies, agterkwart, sye en rug. Die waterige vloeistof word ook aangetref in die binnespierse bindweefsel-lae van beide die lies- en die bladbeen-area. Ongelukkig is NKS skaapkarkasse nie aanvaarbaar vir die eindverbruiker, nie slegs omdat dit ’n onaanvaarbare voorkoms het nie, maar ook omdat dit ’n korter rakleeftyd het. Wanneer die beskrywings en resultate van vorige navorsing in ag geneem word, kon geen fisiologiese-, omgewings-, of bestuurstelsel oortuigend geïdentifiseer wat NKS veroorsaak nie. Die stres wat die diere gedurende die tydperk voor die slagproses ervaar, is egter geïdentifiseer as ’n moontlike oorsaak en word deurlopend in die navorsing tot nou toe bespreek. Die tentatiewe ras-spesifieke geneigdheid dat die toestand meer onder Dorperskape voorkom dui daarop dat daar ’n moontlike genetiese basis daarvoor is. Vorige navorsing het egter nie ’n genetiese variant as ’n veroorsakende faktor van NKS ondersoek nie. Die huidige studie het gebruik gemaak van die ‘Ovine Infinium® HD SNP’ skyfie en ’n genoomwye assossiasie-analise (GWA) om die genome van beide aangetaste- en onaangetaste skape te skandeer in die soeke na vermeende kwantitatiewe-eienskap-loki (KEL) wat geassosieer kan word met die NKS-fenotipe. Hierdie studie is nie net slegs een van die enigste studies in Suider-Afrika om hierdie sp
Red Meat Research and Development SA (RMRD SA)
Technology Human Resources for Industry Programme (THRIP)