Effects of ionizing radiation and feeding restriction on physiological, clinical, biochemical parameters and fertility of heifers (experimental research)

Chernobyl accident, its effects on human health, environment, agriculture and farm livestock set up a problem of preparedness and response to radiation emergency for veterinarians. To identify measures for preparedness and mitigating adverse effects of radiation on livestock we should know response of animals to external and internal radiation, as well as effects of confounding factors. The article presents results of the experiment aimed to describe combined effect of external g-radiation and feeding level on health status, physiological and biochemical parameters and fertility in heifers. Twenty two heifers of black-and-white breed (age 14-18 months) were exposed to sublethal doses of external gamma-radiation (2.5 и 3.25 Gy), in postradiation period the scenario modelling the worst post-emergency housing and maintenance was applied: 4-day hunger, 1 month - feed restrictions. Health and physiological status as well as the dynamic of the biochemical parameters of blood and reproductive capacity were estimated. On the 3rd day after radiation exposure and hunger the body weight of the heifers decreased by 22-28 kg, prd day following irradiation. On the 7th day after exposure of the animals experiencing feed restrictions to 3.25 Gy the WBC count decreased by 5 times. Changes in such biochemical parameters as total protein content, alkaline phosphatase activity and alpha-amylase activity in the blood plasma were of wave-like nature due to severity of postradiation health disorder, different phases of radiation damage, restricted feeding regime and maintenance. During the follow-up period we observed the largest changes in biochemical parameters in the group of heifers experienced feed restrictions and exposed to 3.25 Gy. In the animals exposed to 2.5 Gy and experienced feed restrictions biochemical parameters were close to the parameters in the heifers exposed to 3.25 Gy and fed standard diet. Exposure to external gamma-radiation to 2.5 and 3.25 Gy and temporary diet restrictions did not cause any changes in the regularity and manifestation of sexual cycles. All animals exposed to radiation dose of 3.25 Gy and fed standard diet gave birth to their calves, 60% of animals exposed to 3.25 Gy and experienced feeding restrictions gave birth to calves. Health status of calves in both groups calves of both group, similar. Investigations with animals were carried out in accordance with the basic requirements of the Russian national standard GOST 33215-2014.