PSXIII-15 Thyroid and biochemical profiles during the prepartum and postpartum periods in the blood of primiparous dairy cows with various reproductive abilities

摘要

The metabolic status of dairy cows prior to and after calving can be of great importance for their subsequent reproductive performance. The current research was aimed to compare prepartum and postpartum biochemical and thyroid profiles in dairy cows with different reproductive abilities during the first lactation. Blood samples from 44 Russian Black Pied cows were collected 8, 6, 4, and 2 weeks before calving and 2 and 7 weeks after calving. The cows were divided into three groups: (1) animals with short open days period (< 125 days; SOP, n = 12), (2) animals with long open days period (>125 days; LOP, n = 21), and (3) animals remaining non-pregnant for 1 year after calving (NPR, n = 11). Serum components were measured using a biochemical analyzer and hormonal levels were determined by ELISA. Specific differences between the compared groups in alterations of some biochemical indices, especially the activity of alanine transaminase (ALT) and the content of triglycerides (TG), were found. The ALT activity reduced 1.3–1.5 times (P < 0.05) from the 4th week before calving to the 2nd week after calving in LOP cows and did not change in SOP and NPR cows. In the SOP group, the serum content of TG increased 1.7 fold (P < 0.05) between the 8th and 2nd week prepartum and then declined 1.5 fold (P < 0.05) by the 2nd week postpartum, whereas it was invariable during this period in the LOP and NPR groups. Besides, free thyroxine (T4) and free triiodothyronine (T3) levels four weeks prepartum were 1.2 times lower (P < 0.05) in the blood of LOP cows than SOP cows. Thus, modified prepartum profiles of ALT, triglycerides and free thyroid hormones are associated with the elongation of open days period in primiparous dairy cows. The study was supported by Russian Ministry of Science and Higher Education (0445-2019-0025).