High Frequencies of the αS1-Casein Zero Variant in Milk from Swedish Dairy Goats

A high concentration of caseins in milk is a prerequisite for a high cheese yield. Over 70 percent of Norwegian Landrace goats have been shown to have a mutation that reduces or removes the ability to produce αS1-casein (αS1-CN), with a subsequent lower cheese yield as a consequence. Swedish Landrace goats are closely related to Norwegian goats, so it is very likely that Swedish goats carry the gene for zero-synthesis of αS1-CN. The objective of this study was to survey the Swedish goat population in order to estimate the frequency of Swedish goats producing low amounts of αS1-CN. By use of capillary zone electrophoresis, milk samples from 283 goats from ten different geographical regions of Sweden were analysed. Sixty-five percent of goats were found to produce low or no concentrations of αS1-CN. Only 12 percent of the dairy goats showed a high expression of this protein.