48 - Genomic Studies of Feed Efficiency and Component Traits in American Mink

Feed costs are the largest expense in mink production systems. Therefore, improvement of feed efficiency (FE) is the best way to use limited resources efficiently and increase the mink industry's sustainability. The objectives of this project are to 1) identify the genetic relationships among different FE measures and their component traits, and 2) discover the genetic architecture of FE and implement genomic selection for FE traits to increase the genetic gain in American mink. Final body weight (FBW), final body length (FBL), daily feed intake (DFI), average daily gain (ADG), feed conversion ratio (FCR), residual feed intake (RFI), residual gain (RG), residual intake and gain (RIG) and Kleiber ratio (KR) traits were measured based on the phenotypic records on 1,088 American mink from the Canadian Center for Fur Animal Research (Nova Scotia, Canada). Univariate models were applied to test the significance of sex, color type, age, and nested Row(Year) as fixed effects and random maternal effect. Genetic parameters were estimated via bivariate models using ASReml-R 4. Estimated heritabilities (±SE) were 0.38±0.10, 0.36±0.10, 0.25±0.10, 0.34±0.09, 0.38±0.08, 0.37±0.07, 0.29±0.10, 0.32±0.10 and 0.34±0.10 for FBW, FBL, DFI, ADG, FCR, RFI, RG, RIG and KR, respectively. RFI showed non-significant (P >0.05) genetic correlations with component traits such as FBW (0.00±0.17) and FBL (0.30±0.16) but significant (P < 0.05) high genetic correlation with DFI (0.74±0.09), indicating that selection based on RFI will reduce the feed intake without any negative effects on the size and growth. The estimated genetic parameters for FE traits suggested the possibility to implement genetic/genomic selection to improve the FE in American mink. Consequently, the ongoing project on genetic mapping and genomic selection will enhance the knowledge of FE and improve the efficacy of selection for more feed-efficient mink.