Quantifying Cattle Surface Water Use In Response To Fescue Toxicosis

Commodities

Practices

Tall fescue (Schedonorus arundinaceous (Schreb.) Dumort) toxicosis causes significant financial losses and animal welfare concerns for livestock producers in the upper South. Fescue toxicosis is driven by the consumption of ergot alkaloids produced by a wildtype fungus (Epichloe coenophiala), that lives within the plant (endo=within; phyte = plant) in a mutualistic symbiosis. Alkaloids produced by the fungal endophyte cause severe heat stress, with reduced gains and reproductive performance costing the beef industry more than $2B in annual losses. Heat stress induced by the endophyte also costs significant but unaccounted environmental damage to streambanks and surface waters as animals seek water for cooling. In turn, the primary water quality mitigation strategy - stream fencing - is expensive and does not address the root cause of cattle surface water use.

Although many scientists and producers understand this behavioral response (i.e., surface water use when consuming toxic fescue alkaloids), the direct effects have surprisingly not been quantified. Moreover, many state fencing regulations are based solely on removing livestock from streams without understanding the basis for the surface water use. Thus, this project will determine the degree to which consuming toxic fescue drives surface water use. Field trials will assess animal behavior, stress responses, (hair cortisol), and gain in response to consuming toxic fescue or non-toxic alternatives (including novel fescue and native warm season grasses) with or without access to surface waters for cooling. Findings will be used to inform producers and guide conservation policy beyond reactive fencing strategies.

• Quantify cattle surface water use as a function of consuming toxic fescue in comparison with non-toxic forages (novel fescue and native warm-season grasses).

• Test these behavioral responses by season, comparing animal behavior on toxic with non-toxic fescue (in spring, summer, and fall) and by comparing toxic fescue with native grasses (summer only).

• Generate appropriate extension and outreach materials (publications and videos) of cattle surface water use in response to toxic and non-toxic fescues