Frequency of the Rendement Napole RN− allele in a population of American Hampshire pigs

Abstract

The U.S. swine industry has shown an increasing interest in the Rendement Napole (RN) gene, which has been shown to cause detrimental effects on waterholding capacity and processing yields (Enfa¨ lt et al., 1994; Lundstro¨m et al., 1996; Sutton, 1997). Evidence suggests that this is a single dominant gene (LeRoy et al., 1990; Fernandez et al., 1992) and that animals carrying the detrimental allele (RN−) have increased glycogen within the muscle, which is converted into lactate postmortem, resulting in a lower than normal ultimate pH. This so-called acid meat has paler muscle color and increased drip loss (LeRoy et al., 1996; Enfa¨ lt et al., 1997a,b; Sutton, 1997). Currently, the acid-meat condition has been found only within Hampshire populations or populations with Hampshire ancestry. The Hampshire is widely used within terminal sire lines in the United States. However, there are no published estimates of the frequency of the RN−allele in U.S. populations. Such an estimate is needed to indicate the potential magnitude of any detrimental effects of the gene within the industry. The objective of this study was to estimate the frequency in a broadly based sample of Hampshires.