Two experiments were conducted to determine the effects of endophyte fungus (Acremonium coenophialum) ingestion in tall fescue diets and environmental temperature on heat dissipation and diet utilization by cattle. In Exp. 1, 12 Angus heifers (average weight 244 kg) were allotted by weight to either an endophyte-free (E-) or endophyte-infected (E+; 381 ppb of ergovaline) diet. Environmental temperature varied between 22 and 32 degrees C. Voluntary DM and water intakes were similar (P > .10) among treatments. Rectal temperatures and concentrations of prolactin in plasma were lower (P < .05) after ingestion of the E+ diet. Plasma triiodothyronine, thyroxine, and cortisol concentrations were not affected by diet. In Exp. 2, 24 Holstein steers (average weight 114 kg) were allotted by weight to either E- or E+ (285 ppb of ergovaline) and one of two environmental temperatures (22 or 32 degrees C). At 32 degrees C, feed intake was reduced by 22%, and water consumption was increased by 62% compared with steers housed at 22 degrees C. Consumption of E+ reduced feed intake by 10% but did not influence water consumption. Plasma concentration of prolactin was decreased (P < .05) within 48 h after consumption of E+. Rectal temperatures increased in response to both environmental temperature (P < .05) and E+ consumption (P = .06). Digestibilities of DM and OM for E+ were 9% lower (P < .05) than for E-.(ABSTRACT TRUNCATED AT 250 WORDS)

Fall application of anhydrous ammonia for corn production is a common practice for Illinois farmers, but if applications are made too early, rapid nitrification can lead to increased risk of nutrient loss and water quality concerns. In 2001, educational materials and soil thermometers were sent to over 1000 producers in Illinois to encourage them to closely monitor soil temperatures before applying nitrogen fertilizer in the fall. A follow‐up survey of producers in two watersheds indicated that over 70% of all respondents used the soil thermometers, and the median date of fall application occurred during the first week of November for both watersheds.