Effect of selenium application on pregnancy and hematological values in older-age heifers

In this study, The effect of long-acting selenium administered intramuscularly on the pregnancy rate of older heifers, which were not pregnant despite the use of 3 or more artificial inseminations or bulls, was investigated. For research purposes, 60 Holstein heifers that did not become pregnant were divided into three groups. A synchronization program was applied to the heifers in the control group for artificial insemination. A single dose of barium selenate was applied to the heifers in the 2nd group. A synchronization program was implemented for the purpose of artificial insemination on the same day. Heifers in the 3rd group were administered 2 doses of barium selenate with an interval of 20 days. On the first day of the application, a synchronization program was applied for artificial insemination. For the purpose of the synchronization program, prostaglandin was applied every 11 days. Pregnancy examination was performed on the heifers on the 35th day of artificial insemination. Blood samples were taken into anticoagulant and gel tubes on the first, 20th and 35th days of the application in each group. In blood samples taken into anticoagulant tubes, hemogram values were determined. Blood collected in gel tubes was centrifuged in the laboratory and serum samples were taken. Selenium levels in serum were examined. There was a significant difference in RBC, MCH, Se values between the groups (P<0.01). The difference between the groups in HB value was found to be significant (P<0.05). It was observed that there was no significant difference in WBC, HCT, MCV, MCHC, Platelet, RDW, PCT, PDW, LYM and MON values between the groups (P>0.05). As a result of the research, a statistically significant higher pregnancy rate (85%) was obtained after single-dose long-acting selenium application compared to control and double-dose long-acting selenium application (P<0.01). In double dose long-acting selenium application, a very low pregnancy rate was achieved compared to the control group (35%). The pregnancy rate in the control group was 65%. It is likely that the administration of excessive amounts of selenium may have caused toxicity to the reproductive organs. It is important to investigate the effect of selenium on reproduction through further research.