Rotational vs. Continuous Stocking of Beef Cows and Calves on Mixed Endophyte-Free Tall Fescue-Bermudagrass Pasture

Endophyte-free tall fescue (Festuca arundinacea Schreb.) furnishes better animal performance than endophyte-infected grass but is less persistent under grazing, especially in mixture with common bermudagrass [Cynodon dactylon (L.) Pers]. Rotational (RS), compared with continuous (CS), stocking of endophyte-free tall fescue may improve persistence when grown with an aggressive warm season perennial grass. Four 40-acre bermudagrass pastures no-till seeded with endophyte-free ‘AU Triumph’ tall fescue were used, allowing two replications to compare CS and RS methods. Rotationally stocked pastures were divided into 12 paddocks to allow 2 d of grazing and 22 d of rest. Twenty Hereford (Bos taurus)× Brangus (B. indieus × B. taurus) beef cows/40-acre pasture were maintained year around for 3 yr with additional cows added in spring and summer to maintain similar forage availability. Grazing method had no effect on cow weight change, pregnancy rate, or calf weaning weight. Pasture stocking rate and calf weaning weight per acre were 38 and 37% higher (P < 0.10), respectively, and winter hay consumption was 31% lower from rotationally stocked pastures because of better tall fescue persistence and forage availability. Crude protein (CP) and in vitro dry matter digestibility of available forage generally exceeded 8 and 50%, respectively, throughout the year. Rotational stocking appears to be useful in maintaining stands of endophyte-free tall fescue in bermudagrass pastures. Research QuestionEndophyte-free tall fescue furnishes better animal performance than grass infected with the fungal endophyte, Neotyphodium coenophialium. However, endophyte-free tall fescue is less tolerant than infected grass to stresses such as drought, pests, overgrazing, and competition from vigorous pasture species such as bermudagrass. If rotational instead of continuous stocking were used, it should favor persistence of endophyte-free tall fescue in mixture with common bermudagrass and result in a highly productive pasture over much of the year. The present study compared the performance of beef cows and calves with year around rotational vs continuous stocking of mixed endophyte-free tall fescue-bermudagrass pastures in central Georgia over 3 yr. Literature SummaryMost beef cow-calf pastures in the transition zone of the southeastern USA are mixtures oftall fescue and bermudagrass, providing grazing over most of the year. Under normal management practices of continuous stocking and periods of overgrazing, endophyte-infected tall fescue persists well in the mixture but generally results in reduced animal performance because of fescue toxicosis. Cattle producers' experiences with endophyte-free tall fescue have generally been unsatisfactory so it has gained a reputation for poor persistence in pastures. Small plot clipping trials have shown that allowing rest periods between defoliation during summer will maintain stands and productivity of endophyte-free tall fescue. This suggests that rotational stocking with cattle may favor persistence of endophyte-free tall fescue in association with common bermudagrass, an aggressive warm season perennial grass. Study DescriptionFour 40-acre bermudagrass pastures overseeded with endophyte-fiee ‘AU Triumph’ tall fescue were used, with two replications, to compare rotational stocking (12 paddocks with 2 d grazing and 22 d rest) with continuous stocking for 3 yr at the Central Georgia Branch Station in Eatonton. Twenty beef cows per pasture were maintained year around with cows added to rotationally stocked pastures fiom April to November to use surplus growth and maintain similar grazing pressure. Cow weight and pregnancy rate, calf weaning weight, and supplemental winter hay fed were recorded. Applied QuestionsWhat was the effect of stocking method on endophyte-free tall fescue? Continuous stocking resulted in reduced persistence and productivity oftall fescue in association with bermudagrass over the 3 yr. In contrast, rotational stocking resulted in more total forage available, more than twice the production of tall fescue from October through April and July through September of the third year. What was the effect on forage nutritive quality? Crude protein and in vitro dry matter disappearance (IVDMD) was similar with both continuous and rotational stocking. Crude protein levels of available forage at all seasons exceeded 8%, which is adequate for beef cows. The IVDMD values were generally adequate throughout the year. No energy or protein supplements were fed. Was there an effect on hay consumption in winter? More Coastal bermudagrass hay was consumed each year with continuous than rotational stocking, the difference increasing each year until the third winter when 39% less hay was fed with rotational stocking. How was animal performance affected? Rotational stocking increased stocking rate 38% and calf weaning weight per acre 37%. Grazing method had no effect on cow weight change, pregnancy rate, or individual calf weaning weight (488 lb). RecommendationRotational stocking using a 12-paddock method was effective in maintaining endophyte-free tall fescue in common bermudagrass pastures when grazed year around with beef cows and calves. This eliminated the fescue toxicosis problem, resulting in good animal performance with no supplemental protein or energy feeding. Although additional costs are encountered with electric fencing and waterers, the higher potential stocking rate and lower winter hay feeding suggest that rotational stocking of endophyte-fiee tall fescuehermudagrass pastures offer an attractive option for beef producers in the Southeastern transition zone.