Previous studies of milk coagulation from individual Swedish Red (SR) cows have shown a high frequency of non-coagulating (NC) milk (18%), and genetic studies have proposed chromosome 6 to be related to the coagulation properties. Genetic analyses also indicated that bovine autosome 18 could be related to the occurrence of NC milk. Further studies to deepen the knowledge of NC milk is now made by comparing milk composition and functional properties in a larger sample of SR cows and these data will be used for genetic parameters as well. Coagulation properties of the recently collected individual milk samples were determined using rennet-induced coagulation measurements with two types of rheometer systems. Milk that had not coagulated within 40 minutes after rennet addition was considered to be NC.

The results indicate that 21% of the milk samples could be categorized as NC, confirming the previously estimated frequency in the new sample of cows. Different chemical components in the milk were also analyzed to determine the cause of NC milk, which in the future could be used together with the genetic data in breeding to remove this undesirable trait of the milk. This would lead to a better cheese yield at dairies and better use of the raw material, thus improving the overall efficiency of milk.