Performance by yearling Katahdin ewes grazing toxic tall fescue using either continuous or rotational grazing schemes in late spring through summer.

Rotational grazing has increased in popularity; however, this management practice has not been evaluated thoroughly with Katahdin hair sheep. Our objective was to evaluate the effects of continuous or rotational grazing on performance by yearling Katahdin ewes grazing endophyte-infected, tall fescue [Lolium arundinaceum (Schreb.) Darbysh; E+] in late spring through summer. Over two consecutive years, a total of 50 yearling Katahdin ewes were stratified by BW and BCS and allocated randomly to one of five, 0.4-ha E+ pastures on May 5, 2011 and May 7, 2012. Treatments consisted of: 1) continuous (Cont) or 2) 4cell rotation (4R). Basal cover and forage quality and quantity did not differ (P ≥ 0.19) between treatments. A sampling date effect (P ≤ 0.01) was detected for forage quality and quantity. Grazing d, beginning, end of breeding, and end of the grazing period BW, FAMACHA scores, ADG, total gain, number of lambs/ewe exposed, and lamb birth weight did not differ (P ≥ 0.12) between treatments. Ewe BW and BCS change during the breeding season did not differ (P ≥ 0.17) between treatments. Beginning breeding BCS tended (P = 0.10) to be greater for Cont compared with 4R, but end BCS did not differ (P = 0.45) between treatments. Pregnancy rates and frequency of multiple births were greater (P ≤ 0.04) from 4R compared with Cont. Therefore, utilizing a 4-cell, rotational-grazing system for yearling Katahdin ewes grazing E+ in late spring through summer may improve pregnancy rates and multiple births. However, further studies are warranted.