CATTLE GRAZING PREFERENCE AMONG 8 ENDOPHYTE-FREE TALL FESCUE CULTIVARS

'HiMag' tall fescue (Festuca arundinacea Schreb,) was selected for hig h Mg concentration to reduce grass tetany risk to ruminants, but neith er animal preference nor consumption of HiMag were known, The objectiv es were to evaluate methods of quantifying perference and to determine intake and preference by cattle (Bos taurus L.) of HiMag relative to seven other tall fescues, AU entries were free of a fungal endophyte [ Neotyphodium coenophialum (Morgan Jones & Gams) Glen, Bacon & Hanlin] that reduces cattle performance, The experimental design was a randomi zed complete block with three replications of eight cultivars nested w ithin each of three test pastures, Six heifers grazed the vegetative t o boot-stage pastures for 48 h in May, June, August, and September of 1993 and 1994, The pastures, located at 1200 m elevation, were furrow irrigated, Pre-and postgrazed forage were clipped and weighed to deter mine yield and utilization (48-h utilization < 50%), Preference scorin g of 0 to 10 (0 to 100% of forage eaten) was done by four trained obse rvers at 24, 30, and 48 h, The heifers quickly learned to distinguish between cultivars, and their order of preference was Kenhy > KY 31 > H iMag = Barcel = C1 = Stargrazer > MO96 = Mozark. The cultivar x trial( year) interaction for preference indicated that cultivars responded di fferently to weather conditions, which in turn affected animal prefere nce. Preference scoring had high repeatability and ranked cultivars si milarly to the clip-and-weigh method of measuring utilization, Prefere nce scoring was accomplished with 27% of the experimental error and on ly 6% of the time required for clip-and-weigh. Only 44% of the variati on in preference score (PS) was explained by the model: PS = 8.8 - 1.1 (Mg DM yield ha(-1)), Estimated dry matter (DM) intake of HiMag was 6 .4 kg (animal unit day)(-1). Consumption and preference of HiMag by ca ttle are satisfactory relative to other tall fescue cultivars.