The influence of cows stresses resistance on cheese yield and quality
The study of the influence of types of stress resistance of Ukrainian red dairy cows on milk safety indicators, technological properties of milk associated with the production of rennet cheese, and the organoleptic qualities of cheese and its yield are presented. The experimental animals were divided into three groups according to the standard deviation value of 0.67 from the average concentration of cortisol in the studied group of animals of the same age during the calving. Blood for the study of cortisol concentration in cows was taken in the morning hours before feeding after a stress load. The stress load was a complex of technological factors associated with blood sampling, fixation of animals for one hour, and the presence of veterinary specialists and support personnel. Among 117 experimental cows, groups of 12 animals were formed to study the cheese suitability of milk and cheese quality. The method of balanced analog groups was applied. The animals were of the same breed, peers in age, average body condition, gentle-dense constitution type, and the intergroup difference in body weight were not reliable. The need for these studies arose due to the constant technological stresses that animals experience in the conditions of their operation, and the effect of the type of stress resistance on the cheese suitability of milk and the quality of rennet cheese produced from it remains an insufficiently studied issue, which determined their scientific novelty and relevance. It was found that milk, which was obtained from cows with high and medium resistance to stress, meets the requirements for raw materials for cheese preparation and has high technological properties, in contrast to peers with low-stress resistance, in which milk according to the fermentation test was attributed to the third class and found unsuitable for the production of rennet cheese. This is evidenced by the twice lengthened phases of milk coagulation under milk-clotting enzyme and double quality of rennet fermenter for its coagulation, which led to a decrease in the quality of the finished product - rennet cheese "Lyubitelskiy", which, according to the results of the examination, had a bitter taste and a rubbery consistency. However, the yield of finished products did not depend on the group of cows differing in stress resistance. It is concluded that milk obtained from cows of the first two groups can be used for the production of cheese according to a reduced technological process, as a result of which the energy costs for the production of finished products will be reduced and the cost of cheese will decrease.