Disturbances of early embryogenesis in high-productive dairy cows

The article presents research materials to identify signs of the manifestation of early embryogenesis-developmental delay syndrome and intrauterine flexibility in dairy cows. The syndrome of delayed development of the embryo and fetus is recorded in 33.0% of fertilized cows, and intrauterine flexibility in 16.5%, including with productivity of 4, 000-5, 000 kg, respectively, at 26.9% and 11.9%, with productivity of 6, 000-7, 000 kg at 33.2% and 16.8%, and with productivity of 8, 000-9, 000 kg at 38.9% and 20.0%. Developmental syndrome and prenatal flexibility are most often diagnosed in first-lactation cows (45.5% and 25.4%) and have a tendency to lower the age of animals, as well as in animals fertilized after four or more insemination-47.6% and 30.8%, which is, respectively, 1.96 and 3.58 times more compared to cows which were pregnant after the first insemination. There is a tendency to reduce the size of the corpus luteum in the first 3 weeks of pregnancy, even during the physiological course, including within 5-6 days-by 14.7%-23.7%, 10-12 days-by 6.7%-11.6%, and 1923 days - by 4.8-7.7%. Factors indicating malnutrition of the developing embryo and fetus. During the physiological course of pregnancy, in 38-45 days, the embryo’s length is longer compared to cows with delay syndrome and prenatal flexibility, respectively, 1.66 and 3.19 times, body diameter - 1.53 and 3.18 times, 60-65 days, it was, respectively, 1.85 and 1.4 times. The size of the fetus in highly productive cows is smaller than in animals with lower milk productivity-by 4.6%-7.7% and 9.4%-23.0%. Compared with animals suffering from the embryo and fetal growth retardation, progesterone levels increase by 8.5%-33.8%. Pregnancy in highly productive cows occurs against the background of low progesterone levels, which is a risk. In high-yielding cows, progesterone levels, even with the physiological course of pregnancy, are lower than those of low-producing animals by 16.9%-25.3%. © 2020, Advanced Scientific Research. All rights reserved.