Nano-selenium supplementation improves reproductive performance by alleviating physiological and molecular alterations in repeat-breeding crossbred Jersey cattle

Repeat breeding (RB) compromises reproductive efficiency and farm profitability by necessitating repeated inseminations, delaying conception and extending the calving interval in cows. The present study was undertaken to elucidate the haemato-biochemical, endocrine and gene expression alterations associated with RB in crossbred Jersey cows. The study also evaluated the therapeutic efficacy of nano-selenium supplementation in the management of RB through its modulatory effects on haemato-biochemical, endocrine and gene expression profiles. Crossbred Jersey cattle were included in the study owing to their widespread rearing and economic importance. Healthy cyclic cows (n=6) served as controls, whereas cows diagnosed with RB based on history of failed inseminations and gynaeco-clinical findings were included in the affected cohort. The RB animals were treated with either the Ovsynch protocol alone or the Ovsynch protocol in combination with oral supplementation of nano-selenium (30 days). Haemato-biochemical, endocrine and serum selenium parameters were subsequently evaluated. The relative expression of IGF-1 and PRLR mRNA was determined by quantitative real-time PCR. A second Ovsynch protocol was followed with fixed time Artificial Insemination (AI) and pregnancy rates were recorded 60 days post AI. The results indicated significantly increased hemoglobin concentration, packed cell volume and monocytes, along with reduced eosinophils and bile acid levels in RB cows with respect to control (P