Sampling procedures on the fat content of milk in Pantaneiras cows

Abstract

This study sought to verify the concentration of lipids in milk during milking and throughout lactation. Pantaneira cows kept on pasture were used. Milking was performed in the morning and afternoon and samples were collected at biweekly intervals. During milking, equal volumes of milk were collected in quadruplicate from the teats at the beginning and at the end of milking, as well as a sample taken at the end of milking, directly into the bucket after complete homogenization. Lactation lasted 180 days and was stratified into beginning, middle and end. Fat content was measured following the Gerber methodology, and the information was collected and subjected to the model identity test, which was Linear Simple. The milk segregated at the beginning of the milking showed a great variability and lower fat concentration (1.7 %), obtaining the highest content in the samples collected at the end of the milking (4.5 %), with the average values coming from the complete milking (3.7 %). It was also observed that the milk from the evening milking contained more fat (4.0 %) than that from the morning milking (3.3 %). In relation to the lactation period, an increase in fat content was observed, with the highest values being obtained in the final third of lactation, with averages of 3.0, 3.7 and 4.3 % for the beginning, middle and end, respectively. It is concluded that milk fat concentration varies with milking time, time of day and lactation stage of the animals.