In the 1st trial, 3 lactating Hereford cows with calves 4-7 months of age were gavaged with lithium chloride at 100, 150 and 200 mg/kg liveweight. Milk yield and lithium concentration in blood serum and milk were measured at intervals up to 96 h after treatment. Milk yield decreased by 20% the first day following dosing, but increased to pre-treatment levels by 96 h after treatment. Lithium concentration in blood and milk peaked 10 h after dosing and decreased to pre-treatment levels by 96 h. Peak blood serum level for the 200 mg LiCl/kg dose was 19.3 p.p.m., compared with 13.8 and 11.5 p.p.m. for the 150 and 100 mg/kg doses. The peak Li level in milk was 4 p.p.m. for the 200 mg/kg dose, and a total of 16.8 mg Li was excreted in milk during the first 24 h. The calculated minimum Li required to create an aversion in a 100 kg calf was 1400 mg. The behavioural responses of 5 calves to Li in their dams' milk was observed in trial 2. Milk intake decreased by 10% after dams were dosed with 200 mg/kg LiCl (from 3.2 to 2.9 kg/suckling; P = 0.003), it is presumed that this was due to the reduction in milk yield observed in trial 1. However, there was no difference in suckling time before or after treatment (15.9 and 17.8 min/suckling). Lithium was not detected in the blood of 3 calves; average Li concentration in the blood of the other 2 calves was 0.9 and 0.7 p.p.m.. It is suggested there is no threat of averting calves to their dams' milk when using LiCl to avert the cows to poisonous plants.
|Publication Title||Applied Animal Behaviour Science|
|Author Address||USDA/ARS Poisonous Plant Laboratory, 1150 E 1400 N, Logan, UT 84341, USA.|
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