on,iron sulfate,selenium,bentonite, The University of Arkansas has also been active Tate ions.antibiotics and owth implants for ltingcn liveto e,Laf ette.IN) ArkPlus is derived from the HiMag tall fescue Endophyte-Free Tall Fescue reached commercial stages. Endophyte-free Although F-tall fes Friendly Tall Fescue performance over toxic tall fescue,endophyte Research Results removal results in reduced see ing vigor and lower Plant Persistence plant pers fescue pastures relative to toxic tall fescue pastures. Unlike toxic E+tall fescue,E-tall fescue can be easily overgrazed and will not tolerate poor st and of Je managemen E+tall fescue to be nearly twice that of Jesup E tall fescue.Three years into a grazing tolerance Research at the University of Tennessee h a mix of E.and study cond by the Univ ue rates have and exceeded Jesun E.tall fescue moderate to high stocking rates increase the These res pr e aplant pants in the pasture.In other sare however ong-term Arkansas needs further evaluation.The d which friendly endophytes improve stand persis- "Friendly"Endophyte-Infected Tall Fescue med or Until rec Preliminary data from south Arkansas suggest tha made between either good plant persistence and friendly endophytes enhance drought tolerance of poor animal performance(toxic E+tall fescue)or tall fescue in pastures. ood d poor plant persis Cow-Calf Performance E+tall fescue hit the market.Friendly E+tall fes cue is also referred to as"novel"or"non-toxic"E+ Two factors that dramatically impact the tall fe tall fesc ergot a the plant wea ing ill i f that tages of toxic E+tall fescue with the animal perfor. be marketed within a given calving season or vear mance advantages of E-tall fescue. Lower pregnancy rates,calving rates and calf wean infected with the MaxQTM endophyte ng we ights have b ers grazing versu in both the jesun and ge ia-5 varieties E-tall fescue Madi on,GA)was the first Cows and heifers must be in proper body den ondition mance.In a competition with bermudagrass and under heavy trials were assigned to either toxic E+or MaxQTME+tall astern as tle studies have been consistent and promising. pasturesover themeactivated carbon, iron sulfate, selenium, bentonite, fat, zeolite, hydrated sodium calcium aluminosili￾cate, drugs, toxin binders, modified yeast cell wall preparations, antibiotics and growth implants for alleviating fescue toxicosis in livestock. None of these products have been found to eliminate all fescue toxicosis problems without adverse side effects. Endophyte-Free Tall Fescue Endophyte-free (E-) tall fescue was initially tapped as a “silver bullet” for fescue toxicosis. Although E- tall fescue improves animal performance over toxic tall fescue, endophyte removal results in reduced seedling vigor and lower plant persistence. Many researchers and producers have observed accelerated stand losses in E- tall fescue pastures relative to toxic tall fescue pastures. Unlike toxic E+ tall fescue, E- tall fescue can be easily overgrazed and will not tolerate poor management. Research at the University of Tennessee indicated that in pastures with a mix of E- and toxic E+ tall fescue, low stocking rates have little or no effect on pasture endophyte infection rate, yet moderate to high stocking rates increase the percentage of E+ plants in the pasture. In other words, E- plants did not stand up to grazing pressure as well as E+ tall fescue plants. “Friendly” Endophyte-Infected Tall Fescue Until recently, producing and utilizing tall fescue was a double-edged sword. A choice had to be made between either good plant persistence and poor animal performance (toxic E+ tall fescue) or good animal performance and poor plant persis￾tence (E- tall fescue). This changed when “friendly” E+ tall fescue hit the market. Friendly E+ tall fes￾cue is also referred to as “novel” or “non-toxic” E+ tall fescue. It contains endophytes that do not pro￾duce the ergot alkaloid livestock toxins. Friendly E+ tall fescue combines the plant persistence advan￾tages of toxic E+ tall fescue with the animal perfor￾mance advantages of E- tall fescue. Tall fescue infected with the MaxQ™ endophyte in both the Jesup and Georgia-5 varieties (Pennington Seed, Inc., Madison, GA) was the first commercially available friendly E+ tall fescue. MaxQ™ E+ tall fescue has been evaluated under demanding management conditions (i.e., in competition with bermudagrass and under heavy stocking rates) in multiple university research trials across the southeastern United States. Both plant persistence and livestock (beef cattle, dairy cattle, sheep and horse) performance results from these studies have been consistent and promising. The University of Arkansas has also been active in friendly E+ tall fescue research, and seed from the Arkansas program is marketed as ArkPlus brand tall fescue (FFR Cooperative, Lafayette, IN). ArkPlus is derived from the HiMag tall fescue variety. Research trials are ongoing across the region examining livestock and plant performance of MaxQ™ and ArkPlus E+ tall fescue as well as other friendly E+ tall fescues that have not yet reached commercial stages. Friendly Tall Fescue Research Results Plant Persistence Extensive testing in Georgia over five years (including some of the hottest and driest years on record) has shown stand survival of Jesup MaxQ™ E+ tall fescue to be nearly twice that of Jesup E￾tall fescue. Three years into a grazing tolerance study conducted by the University of Kentucky, stand survival of Jesup MaxQ™ E+ tall fescue was statistically similar to Jesup toxic E+ tall fescue and exceeded Jesup E- tall fescue. These results are promising; however, long-term stand survival of friendly E+ tall fescue pastures in Arkansas needs further evaluation. The degree to which friendly endophytes improve stand persis￾tence during drought is yet unknown. Arkansas research trials in Fayetteville were performed on deep, moist soil very suitable for tall fescue. Preliminary data from south Arkansas suggest that friendly endophytes enhance drought tolerance of tall fescue in pastures. Cow-Calf Performance Two factors that dramatically impact the profitability of a cow-calf operation are calving rate and weaning weight. Improvement to these produc￾tion factors will increase the pounds of calf that can be marketed within a given calving season or year. Lower pregnancy rates, calving rates and calf wean￾ing weights have been observed in many research efforts in cows and heifers grazing toxic E+ versus E- tall fescue. Cows and heifers must be in proper body condition for optimal reproductive performance. In a trial at the University of Georgia, Angus and Angus x Hereford cows of similar body condition were assigned to either toxic E+ or MaxQ™ E+ tall fescue pastures at calving. Cows grazing toxic E+ tall fescue gained only half as much body condition from calving to weaning as cattle grazing MaxQ™ E+ tall fescue in adjacent pastures over the same