A method for analysis of ergovaline in seed and vegetative tissue of endophyte-infested tall fescue by high-performance liquid chromatography with fluorescence detection was developed. Freeze-dried samples were extracted with alkaline chloroform, filtered, and applied to disposable HL silica gel columns. Following elution of plant pigments with acetone/chloroform, ergopeptine alkaloids were eluted with methanol under vacuum. Column eluant was evaporated to near dryness and the residue redissolved in methanol/water and analyzed by high-performance liquid chromatography; ergotamine was the internal standard. Average recoveries of ergovaline and ergotamine were 85 and 88%, respectively, with a relative standard deviation of 7.5%. The detection limit of ergovaline in fescue seed and vegetative tissue was 50 pg/kg. Replicate samples, collected each week during two growing seasons from experimental plots of KY-31 tall fescue (85-100'3 endophyte-infested), were separated into stems with leaf sheaths, leaf blades, and developing seed heads. Ergovaline levels in all plant tissues were 300-

Hereford yearling steers (N= 144) were alloted to one of three pasture systems: tall fescue, smooth bromegrass-red clover or orchardgrassred clover. After the grazing period, steers were finished in drylot and then serially slaughtered at 0, 56, 84 and 112 days. Carcass quality grades and yield grade numbers increased when steers were fed grain up to 112 days. Tenderness of loin steaks increased up to 84 days, after which no improvements were observed. Sensory panel scores for grassy flavor of steaks and ground beef decreased up to 112 days. Fifty-three compounds were identified in the volatiles of melted subcutaneous fat by direct sampling-gas chromatography/mass spectrometry. The major differences between volatiles from fat of forage-fed compared to grain-fed steers were the higher concentrations of 2,3-octanedione and various diterpenoids present in the samples of the forage-fed animals.

No abstract

Two 120-d trials (May to September, 1988 and 1989) determined the effects of grazing tall fescue (two varieties) or orchardgrass on forage intake and performance by beef cows. Each summer, 48 cow-calf pairs grazed endophyte-infected Kentucky-31 tall fescue (KY-31), endophyte-free Mozark tall fescue (MOZARK), or Hallmark orchardgrass (OG) pastures (16 pairs/treatment). Forage OM intakes and digestibilities were determined during June and August each year. Cow and calf BW and milk production were determined every 28 d. During June of both years, OM intakes did not differ (P greater than .10) among treatments. During August of 1988, intakes were 18% lower (P less than .05) by KY-31 cows (1.6% of BW) than by MOZARK or OG cows (average 1.95% of BW); however, no differences (P greater than .10) were measured in August of 1989. Estimates of ergovaline consumption during June from KY-31 were between 4.2 (1988) and 6.0 mg/d (1989), whereas August estimates were between 1.1 (1988) and 2.8 mg/d (1989). Ergovaline in MOZARK estrusa was below detection limits, except in August of 1989. Cows that grazed KY-31 lost three times (P less than .01) more BW than cows that grazed MOZARK or OG (42 vs 9 and 13 kg, respectively). Milk production by KY-31 cows was 25% lower (P less than .01) than that by cows that grazed MOZARK or OG (6.0 vs average of 8.0 kg/d). Similarly, slower (P less than .01) calf gains were noted for KY-31 than for MOZARK or OG (.72 vs .89 and .88 kg/d, respectively). Cows grazing KY-31 experienced accelerated BW loss and reduced milk production and weaned lighter calves than did cows grazing MOZARK or OG. Decreased performance was not explained by consistently reduced forage intakes; hence, altered nutrient utilization was suspected.

No abstract