STOCKPILED PRAIRIEGRASS PROVIDES HIGH-QUALITY FALL GRAZING FOR LAMBS

Authors: Cassida, Kimberly; Neel, James; Belesky, David

Submitted to: Forage and Grazinglands
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/20/2009
Publication Date: 3/18/2009
Citation: Cassida, K.A., Neel, J.P., Belesky, D.P. 2009. STOCKPILED PRAIRIEGRASS PROVIDES HIGH-QUALITY FALL GRAZING FOR LAMBS. Forage and Grazinglands. doi:10.1094/FG-2009-0318-01-RS.

Interpretive Summary: Prairiegrass attracted renewed attention for grazing in the USA with the introduction of ‘Grasslands Matua’ in the 1980’s. It is a high yielding, high quality, palatable forage, but unfortunately Matua proved highly susceptible to winter-kill and powdery mildew under growing conditions in the USA. Two varieties were recently released (‘Dixon’ and ‘Lakota’) which may be able to overcome these obstacles and also have been shown to be highly productive in the fall within Appalachia. High fall productivity would be especially desirable as most cool season forages drop in productivity during this time, but spring born lambs being finished on pasture have their greatest nutritive demand. We conducted a two-year grazing trial using stockpiled ‘Dixon’ prairiegrass in order to evaluate 1) the gain potential of this forage for pasture-finished lambs, and 2) the effect of fall grazing intensity on persistence of the stand over winter. Prairiegrass was cut for hay in mid-May and late July each year, and was then allowed to grow for approximately eight weeks after the July harvest to prepare for autumn grazing. Grazing treatments were designated to achieve target forage removal of 50% (“take half, leave half”) or 75% of the available forage. Powdery mildew was almost always present in isolated patches within the prairiegrass stand, but grass was able to outgrow the mildew without application of fungicide. Stockpiled Dixon prairiegrass produced good forage yields of excellent nutritive value and supported very high lamb gains when grazed in early fall in West Virginia. Individual lamb performance was greatest at 50% forage utilization while gain per unit of area was greatest at 75%. Grazing stockpiled prairiegrass through mid-October at up to 75% forage utilization was not detrimental to stand performance in the following spring. This grass deserves further research attention and serious consideration for inclusion in small ruminant production systems.

Technical Abstract: New varieties of prairiegrass (Bromus catharticus Vahl. = B. willdenowii Kunth.) exhibit improved persistence over ‘Matua’ under USA growing conditions, but animal performance data is lacking. We evaluated performance of lambs grazing stockpiled ‘Dixon’ prairiegrass on West Virginia hill pasture in autumn. In 2006 and 2007, a three-year-old stand of Dixon was cut for hay in late July, fertilized with 56 kg/ha of N, and stockpiled for eight weeks. Three pasture replicates of stockpiled forage were grazed by ewe lambs under a put-and-take grazing system for a total of 24 d (Sept. 25 to Oct. 19) with target forage utilization rates of 50 (U50) or 75 (U75) % of total available forage. At the end of the grazing period, lambs were heavier (42.3 vs. 41.3 kg), and had greater ADG (264 vs. 216 g/d) on the U50 vs. U75 treatment, respectively, but gain per ha was greater on the U75 treatment (193 vs. 253 kg/ha). Grazing treatments did not affect forage yield, botanical composition, tiller density, or nutritive value of stands harvested for hay in the following May. Good forage yields and excellent lamb gains on stockpiled prairiegrass indicate this grass deserves serious consideration for fall-finishing of lambs.