A prospective study involving 18 pregnant ewes of Baloochi breed were conducted to measure the effect of monensin administered 40 days pre-lambing on metabolic function preparturition and post-parturition. The pregnant ewes were randomly assigned to one of the 4 treatments: 1) were received monensin and fed an ordinary ration, 2) received monensin and fed restricted ration, 3) fed restricted ration without monensin and 4) control group which fed an ordinary ration without monensin administration. Blood was sampled from each sheep at days 60, 45, 30, 20, 15, 10, 5, 1 prior to parturition, and hour 12 and days 1, 2, 3, 4, 7, 13, 19 and 21 postpartum. The BHB concentrations significantly decreased in animals which received monensin and fed a restricted or an ordinary ration in comparison to the group which not received monensin and fed a restricted ration at prepartum period. The sheep which received monensin showed lower concentrations of NEFA in comparison to animals which were not received monensin. There was no significant effect of monensin on energy, protein indicators and electrolytes in postpartum period. However, feed restriction significantly decreased the concentrations of cholesterol, urea, albumin and Mg at post-parturition period. The results of this study indicate that administration of monensin to pregnant ewes during prepartum period had a markedly positive influence on energy indicators in late pregnancy.

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