Dynamics of Selected Trace Minerals during Estrus Induction in Anestrus Sahiwal Cattle

Abstract

The present study evaluated the effect of circulatory trace mineral profiles on fertility response during estrus induction by progesterone based therapy in acyclic Sahiwal cattle. Sahiwal cows and post-pubertal heifers (n=25 each) with true anestrus condition (acyclicity confirmed ultrasonographically) were subjected to CIDR-based protocol (intravaginal CIDR application for 7 days, 500 IU eCG at CIDR removal, followed by estrus observation and AI). In heifers, additionally an injection of 5.0 mg estradiol valerate at CIDR insertion was given. Blood samples on days 0 (before CIDR application), 3, 5, 7 and 9 were collected. Almost similar estrus induction (68% vs. 64%) and subsequent conception rates (41.2% vs. 50%) during the first induced estrus were recorded in cows and heifers, respectively. During the course of treatment, significant (P<0.05) variation in plasma copper and zinc concentrations was recorded both in cows and heifers. Contrarily, manganese concentrations varied significantly (P<0.05) in cows only. However, iron profiles remained uniform during the course of treatment. Significantly (P<0.05) higher pre-treatment plasma concentrations of copper, zinc and manganese was recorded in those cows and heifers in which estrus was induced, compared to those in which estrus induction failed to occur. No significant difference (P>0.05) was recorded for iron concentration vis-à-vis estrus induction response. Hence, it is indicated that circulatory copper, zinc and manganese profiles influence the reproductives energy in acyclic animals and their suboptimal profiles may reduce the efficacy of estrus induction protocols in Sahiwal cattle.