The influence of breed characteristics and the level of milk productivity on the quality of colostrum of cows

At the “Pchany-Denkovych” farm of the Stryi district of the Lviv region, the content of immunoglobulins in the colostrum of experimental cows was studied during the entire lactation period, according to lactations, depending on the level of productivity. We also studied the biochemical indicators of colostrum of cows of the Ukrainian black-spotted dairy, Simmental, and Ukrainian red-spotted dairy breeds. The dynamics of the content of immunoglobulins in the colostrum of the cows of the experimental groups and their content depending on the age and level of productivity were established. On the first day, the colostrum of experimental cows of the first, second, and third groups contained 67.4; 86.8; 69.5 g/l of immunoglobulins. On the third, fifth, eighth, and tenth days, its content in the colostrum of cows decreased in the experimental groups, respectively – on the third day, it was 3.6; 4.0; 3.7 times, the fifth – 6.3; 3.4; 5.7; 5.8 times, the eighth – 10.5; 7.9; 8.4 times and the tenth – 25.0; 24.1; 21.7 times. It has been proven that the colostrum of firstborns does not meet the physiological norm. In the dynamics of the content of immunoglobulins by lactation in all cows of the experimental breeds, there is an increase in their content by lactation. At the same time, its maximum rate in different breeds is manifested in different lactations. In cows of the Ukrainian black-spotted dairy breed of the first group and the Ukrainian red-spotted dairy breed of the third group, the entire content was found in the fourth lactation (68.4; 98.9 g/l), and in the Simmental breed of the second – in the fifth lactation (112.5 g/l). According to the maximum index of immunoglobulins, the advantage belongs to cows of the Simmental breed of the second group, which is 44.1 g/l (Р < 0.001) and 13.6 g/l (Р < 0.001) more than the index of cows of the Ukrainian black and red-spotted dairy breeds of the first and the third group. Among cows of different productivity levels, the highest content of immunoglobulins was in the colostrum of Simmental cows (87.83 g/l), with a productivity of up to 4,000 kg of milk per lactation. It was correspondingly low in animals of the Ukrainian black-spotted dairy breed (53.91 g/l) with a productivity of 5001–6000 kg of milk. In the colostrum of Simmental cows belonging to the second group, the maximum absolute content of fat (5.89 %), protein (7.25 %), and dry skimmed milk residue (10.70 %) were determined, and the minimum indicators were found (respectively – 5.42; 6.81 and 10.24 %) in analogs of the Ukrainian black and spotted dairy breed from the first group.