PSXV-10 Targeted Gene Evaluation for Association with Heifer Maturity Grading based upon Skeletal Ossification. (7th December 2018)

• Record Type: Journal Article
• Authors: Colacchio, A; Murdoch, B; Salove, K; Davenport, K; Doumit, M; O'Connell, A; Murdoch, G
• Is Part Of: Journal of animal science. Volume 96(2018)Supplement 3
• Page Start: 237
• Page End: 238
• Publication Date: 2018-12-07
• Subjects: skeletal maturity -- candidate genes -- alkaline phosphatase; Livestock -- Periodicals; Livestock; Electronic journals; Periodicals; 636.005
• DOI: 10.1093/jas/sky404.518
• Languages: English
• ISSNs: 0021-8812

Abstract

Abstract: Over the last several decades, there has been an increase in the number of heifers categorized as B and C-maturity based upon skeletal maturity at harvest in animals that are actually under 30 months of age chronologically. While the losses associated with advanced maturity will be abated through the new USDA approved use of dentition to determine carcass age, in large commercial plants; it is important to examine the biology associated with the advanced skeletal ossification for the US beef industry and smaller plants still utilizing ossification. We hypothesize that selection for early reproductive maturity, along with faster growth rate and increased feed conversion efficiency has increased the propensity for advanced osteogenesis that physiologically mediate endochondral ossification. Specifically, we examined the genetic variation in genes that promote ossification or extracellular matrix mineralization in young heifers resulting in maturity grades more representative of heifers that are over 30 months of age. In this study, we extracted DNA from 90 heifers; 30 A-maturity, 30 B-maturity and 30 C-maturity. Following DNA library preparation we utilized targeted gene pulldown and sequencing to examine candidate genes that play an important role in ossification of cartilage for sequence variation. Sequence variations within our candidate genes, were tested for association with our A, B, and C- carcass maturity. In association with maturity grading, we have identified a significant (p < 0.04) single nucleotide polymorphism (SNP) in the alkaline phosphatase (ALPL) gene on chromosome two. ALPL plays a role in bone development as it is an osteoblast differentiation marker and provides the inorganic phosphate required for extracellular collagen mineralization. This represents the first report identifying sequence variations associated with accelerated skeletal maturation in US beef heifers.