DEPENDING OF RUMINATION DYNAMICS IN MILK COWS ON AGE IN LACTATION

Abstract

Rumination (duration of cud in cows per day) becomes an effective and reliable test that characterizes the general state of metabolism in their body, the process of digestion and the predicted level of productivity. In an experiment on an array of dairy cows at Petrodolinsky LLC, using a remote electronic control system with a SCR Heatime HR-IR feeding behavior monitoring function, the nature of rumination was observed depending on age in lactations. Studies have found that the average duration of rumination in cows in the herd changes during the lactation period depending on the age in lactations. The array of cows of the first lactation at the time of calving has the lowest rumination value, and its maximum is recorded in cows of the third lactation. By the 30th day of calving, the indicator of rumination activity in cows of all ages levels off, however, it remains the highest in animals of the second lactation. Only by 200 days of the lactation period, the difference in rumination of cows of all ages practically disappears. By the time of lactation cessation before calving, the intensity of rumination in cows of the first lactation again becomes lower than in older animals. It has been established that the first 30 days after calving in cows there is a close correlation between the increase in the amount of rumination and the level of milk yield. At the same time, the correlation coefficient for cows of the first lactation was 0.78, the second - 0.65 and the third - 0.63. When the maximum milk yield is reached (100–120 days of lactation), the correlation coefficient between the nature of rumination and the level of milk yield drops sharply, however, it remains the highest in cows of the first lactation (0.57) versus 0.48 and 0.42 in animals of the second and third lactations . However, in the phase of the second third of lactation, the corresponding indicator remains significant for characterizing the relationship between rumination and milk yield. The connection is significant and direct. After 200 days of lactation, the dependence of milk yield on the nature of rumination decreases even more and the correlation coefficient that determines this indicator is at the level of 0.28 (first lactation), 0.24 - second lactation and 0.23 - third lactation. The results of the research are of significant scientific and practical interest for determining changes in the nature of rumination in cows depending on age in lactation, assessing the age dynamics of the digestion process and establishing the relationship between the nature of rumination and the duration of economic use of animals and productivity. Keywords: cows, rumination, rumination activity, lactation, milk yield.