THE INVOLUTION OF THE MAMMARY GLAND IN HOLSTEIN COWS: EVALUATION OF THE MICROBIOLOGICAL CHARACTERISTICS OF THE LACTEAL SECRETION IN THE DRY PERIOD

ABSTRACT

In order to evaluate the microbiological characteristics of the lacteal secretion in the involution of the mammary gland of Holstein cows, examination was made of 44 udders at last milking before the dry period, during the dry period (1, 3, 5, 7, 10, 15, 30 and 45 days of the dry period), as well as the return to lactation. After discarding the first jets of the lacteal secretion, the samples for the microbiological analysis were aseptically collected. The percentage of bacteria isolated from the udders was lower on the return to lactation (46.15%) than during the involution of the mammary gland. There was no statistical difference between the frequency of bacteria isolated from the last milking and from the 45th day of the dry period isolations that oscillated between 72.73% and 84.09%. The rate of cure of the infections in the dry period was 40.63%, while the rate of new infections and reinfection were, respectively, 66.67% and 61.54%.

KEY WORDS
Milk; dry period; microbiological characteristics; bovine; Holstein breed