Nano-selenium supplementation ameliorates physiological and molecular alterations in Binjharpuri and crossbred Jersey cattle with postpartum silent estrus

A missed estrus in a dairy cow can substantially reduce farm profitability by prolonging the calving interval. Postpartum silent estrus is a multifactorial reproductive disorder involving alterations in metabolic, endocrine and ovarian functions, while the potential role of selenium in modulating these physiological pathways remains insufficiently explored. Considering the need to generate information on Binjharpuri cattle, a registered indigenous breed with limited scientific documentation, and the economic importance of widely reared crossbred Jersey cattle, both populations were included in the study. The present study was undertaken to elucidate the haemato-biochemical, endocrine and gene expression alterations associated with postpartum silent estrus. The study also evaluated the therapeutic efficacy of nano-selenium supplementation in the management of postpartum silent estrus through its modulatory effects on haemato-biochemical, endocrine and gene expression profiles. Healthy cyclic cows served as controls, whereas cows diagnosed with silent estrus based on gynaeco-clinical findings and serum progesterone concentrations were included in the affected cohort. Silent estrus 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, PRLR and IL-8 mRNAs 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. In Binjharpuri cattle, lymphocyte percentage decreased, while cortisol levels were elevated in silent estrus (P < 0.05). Nano-selenium supplementation restored lymphocyte as well as cortisol levels, increased AMH concentration and IGF-1 mRNA expression (P < 0.05). Pregnancy rates were higher in nano-selenium supplemented groups. In crossbred Jersey cattle, nano-selenium supplementation improved TEC, restored bile acid concentration and increased kisspeptin-1 levels (P < 0.05). IL-8 mRNA expression was elevated in silent estrus but declined following treatment (P < 0.05). PRLR expression remained non-significant across groups. Nano-selenium supplemented groups showed improved pregnancy rates. The findings indicate that nano-selenium may be a promising adjunct therapeutic agent for the management of silent estrus under field conditions.