Impact of exposure of farm dairy animals to radiation of different parameters on severity of adverse health effects and milk production

Radiation emergency is a matter of great public concern. There are a variety of radiation exposure scenarios, among them accidents at nuclear facilities, release of radioactive facilities and many other radiation incidents. Dairy animals make great contribution to people healthy diet providing milk, meat and other products for human use. Therefore, it is important to be aware about effects of radiation exposure on dairy animal health, milk production and reasonability of their economic use. The article presents results of evaluating impact of exposure of farm dairy animals to radiation of different parameters on their physical condition and milk production. The research was based on analysis of experimental data on exposure of lactating animals to doses that cause radiation sickness of different severity. According to obtained results milk production depends on radiation sickness severity. In case of mild radiation sickness, milk yield and the quality of milk, practically did not change. Among animals with radiation-induced abnormalities of average severity mortality was 10-15%, milk yield reduced by 8-20%. Some animals developed subclinical and haemorrhagic mastitis, which might cause reduction of milk production as well. In animals experienced the disease of high severity (100% mortality) the milk yield reduced on the first day following radiation exposure and the milk production was stopped in the disease course. The milk quality could not be used as food. The results of analysis allow making the following conclusion: in order for the loss of milk production to be minimum, it is necessary to estimate the parameters of radiation exposure that cause 15% mortality among animals. Since the calculated LD15 for sheep and goats with a live weight of 40-45 kg are close in value, we propose to use the relationship between a sheep death and dose rate that previously was estimated for animals with the same live weight and exposed to radiation with dose rate ranged between 0.02 and 6.6 Gy/h. It is important to stress that parameters of radiation exposure, namely dose rate, affecting mortality of irradiated sheep, can be registered in radioactively contaminated areas.