title: The effects of subcutaneous injections of sodium selenate on blood composition and milk yield in dairy cows.
abstract: Three groups of four lactating cows received a subcutaneous injection of 0 . 05, 0 . 10 and 0 . 15 mg Se/kg body weighty respectively administered as sodium selenate. A fourth group was injected with saline. In all the cows injected with sodium selenate, the concentration of Se in blood increased rapidly and was significantly higher than in control cows for two days in the group receiving the lowest dose and for 182 days (the duration of the experiment) in the two other groups. The activity of glutathione peroxidase in blood increased slowly in all cows injected with sodium selenate and was significantly greater than in control cows after 15, 22 and 29 days respectively, and remained significantly greater for 63, 91 and 182 days respectively. In a second experiment a single subcutaneous injection of 0 . 15 mg Se/kg body weight had no effect on the mean milk yield of 37 animals (19 . 1 kg/day) compared with the milk yield of a similar group of control animals (19 . 1 kg/day) during 70 days. The concentration of Se in milk was significantly higher on the first (168 microgram/litre) and second (69 microgram/litre) day after injection than in control animals (mean 26 microgram/litre).
mesh_terms: D000818:Animals; D002417:Cattle / Q000097:blood / Q000502:physiology*; D005260:Female; D005979:Glutathione Peroxidase / Q000097:blood; D007279:Injections, Subcutaneous; D007774:Lactation / Q000187:drug effects*; D011247:Pregnancy; D064586:Selenic Acid; D012643:Selenium / Q000097:blood / Q000494:pharmacology*; D018036:Selenium Compounds; D013997:Time Factors
chemical_list: D018036:Selenium Compounds; D005979:Glutathione Peroxidase; D012643:Selenium; D064586:Selenic Acid