Endophyte-free tall fescue cultivars grazed by sheep: forage and quality and sward characteristics.
1995
Vecellio L.C. | Jung G.A. | Harpster H.W. | Shaffer J.A. | Engle C.E. | Everhart J.R.
Although much work has focused on the performance of endophyte-infected (E+), Acremonium coenophialum Morgan-Jones and Gams, tall fescue, Festuca arundinacea Schreb.; little information is available comparing performance attributes of endophyte-free (E-) cultivars in the northeastern USA. Five paddocks of four cultivars ['Festorina', 'Johnstone', 'Roa' and 'Kentucky 31' (KY 31)] of E- tall fescue were rotationally stocked with ewes (Ovis aries) for 2 yr. Tall fescue and weed dry matter (DM) mass, leaf-to-stem ratio, and tiller density were determined both pre- and post-grazing and sward height was measured pre-grazing. Forage crude protein (CP), acid-detergent fiber (ADF), neutral-detergent fiber (NDF), and in vitro dry matter disappearance (IVDMD) were determined by near infrared reflectance spectroscopy (NIRS). Total dry mass was higher for Festorina and KY 31 than for the other cultivars. Leaf-to-stem ratios were similar among cultivars. Forage height was greatest for Festorina and least for Johnstone. Fescue proportion of herbage biomass was greater and weed biomass lower for Festorina and KY 31 than for Roa and Johnstone. Tall fescue proportion of herbage biomass at the end of the trial was lowest for Johnstone. Mean tiller densities were similar for all cultivars and ranged from 2060 m-2 in spring to 1260 m-2 under stockpiling in fall. Pre grazed herbage CP of 204 g kg-1 was similar among cultivars. Roa tended to be low and Festorina high in both ADF and NDF, and IVDMD of Johnstone was higher than Festorina. Across seasons and years, ewe liveweight gain was higher for Johnstone than for the remaining cultivars, which were similar. Gains for Group 2 (late-weaned) lambs were lower for KY 31 and were similar for the remaining cultivars. In light of this information, cultivar as well as endophyte status should be considered in designing experiments or planning grazing systems with tall fescue.
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