Effect of feeding prebiotic supplement to cows at different fee-ding levels on milk productivity and quality

The aim of research is to investigate the effect of feeding a Chlorella suspension as a prebiotic supplement on the productivity and component composition of milk in cows at different feeding levels. Cows at the beginning of lactation were fed a suspension of microscopic algae of the genus Chlorella in addition to the main ration. In the first stage of the experiment, the concentration of exchange energy in the dry matter of the ration was 11 MJ, crude protein – 16.8 %; in the second stage of the experiment – 10.8 MJ and 16.5 %, respectively. Feeding the prebiotic supplement to cows at a high feeding level had a positive effect on increasing milk productivity and contributed to a change in the chemical and physical properties of the obtained milk. During the first month of the experiment, the differences in average daily milk yield were 2.79 kg of milk in favor of the experimental group. A higher dry matter content was noted in the milk of cows in the experimental group. The low fat and protein content in the milk of both groups of experimental animals in the first month of the study indicates a lack of energy in the diet and replenishment of energy reserves at the expense of the body reserves of fresh cows. With a decrease in the feeding level in the second half of the experiment, the decline in productivity continued. The average daily milk yield decreased: in the control group in the third month – by 2.88 kg, in the fourth – by 0.92 kg; in the experimental group – by 2.21 and 1.29 kg, respectively. At the same time, the component composition of milk of cows in the control group had higher indicators. By the end of the experiment, the productivity of cows receiving the prebiotic supplement was significantly higher compared to animals in the control group – by 4.17 kg. Analysis of the composition of milk showed that the balance of energy and protein was maintained in the diet, while in the control group there was an excess of energy.