Interpretive Summary: Influence of form of selenium supplementation and tall fescue endophyte toxicity on growth performance, serum parameters, and tissue masses of grazing beef steers

By: Kelsie L Webb, Ronald J Trotta, Yang Jia, Phillip J Bridges, James C Matthews

Beef cattle production in the southeastern United States is plagued by two common nutritional problems. Fescue toxicosis, caused by consumption of toxic ergot alkaloids in endophyte-infected tall fescue, is a major detriment to growth performance of grazing cattle and profitability for cow/calf and backgrounding cattle operations. At the same time, Se deficiency is an issue that can lead to decreased growth, poor immune function, and inadequate reproductive function. We characterized the effects of endophyte toxicity (toxic vs. nontoxic endophyte-infected tall fescue) and form of Se supplementation [sodium selenite vs. SELPLEX and sodium selenite (MIX)] on growth, serum parameters, tissue mass, and carcass characteristics. Depressed serum prolactin concentrations and alkaline phosphatase activities are markers of fescue toxicosis. As expected, toxic endophyte decreased serum prolactin and alkaline phosphatase, whereas MIX supplementation ameliorated this decrease. However, MIX supplementation did not improve average daily gain or restore serum prolactin to the level of steers grazing nontoxic fescue. More research is needed to understand if longer supplementation of MIX can fully alleviate symptoms of fescue toxicosis in beef cattle.

Read the full article in Translational Animal Science.