It is the predominant cool-season perennial forage in much of the southern U.S. with 8.5 million cattle grazing 32 million acres of wild-type endophyte-infected fescue.
While cultivars of nontoxic tall fescue have been developed and are becoming more widely used, most forage systems in the southeastern U.S. are still based on toxic tall fescue. The plant is a hardy, widely adapted forage applicable in both hay production and grazing situations with multiple different species of livestock. It is a very versatile cool-season forage that allows livestock producers the ability to utilize stockpiled forage to decrease the amount of stored forage needed during the winter months.
Stockpiled fescue retains its quality during the winter months, eliminating the need for haying fescue in the fall. Utilization of a rotational grazing system can allow producers to utilize limited quantities of forage at key times during the winter months.
According to our research, grazing toxic tall fescue prior to and during the breeding season decreases final pregnancy rates (approximately 30%). When you begin to calculate the annual financial loss of a 30% decrease in pregnancy rate coupled with lower weaning weights due to fescue toxicosis, it is obvious that grazing toxic fescue is a major hurdle for cattle producers in the Fescue Belt.
So with all of that said, what can we do to help with this problem? Removing cattle from toxic tall fescue prior to or during the breeding season can modulate these negative effects. Specific mechanisms that lower pregnancy rates remain to be identified, as well as the exact timing of strategic grazing of toxic tall fescue around the breeding season to maximize forage utilization while maintaining pregnancy rates.
The other factor not addressed by this study is the effect of heat stress and its compounding effect on fescue toxicosis. Breeding cows during cool-weather seasons when endophyte levels in fescue are typically low may also help alleviate negative impacts of toxic tall fescue. We certainly realize that wild-type tall fescue is a valuable asset for cattle producers in the Southeast with respect to grazing systems. However, as we begin to answer more of these questions, strategies will be developed to help us manage this tall fescue in a way that decreases the negative impacts on production and profit. 
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Matthew Burns
- Extension Beef Specialist
- Clemson University
- Email Matthew Burns
