Lamb Production on Wheatgrasses and Wheatgrass-Sainfoin Mixtures
- T. P. Karnezos and
- A. G. Matches
Previous research indicates that wheatgrasses (Agropyron and Thinopyron spp.) and sainfoin (Onobrychis spp.) produce high quality forage from early spring to summer on the Southern Great Plains. Little information is available on their potential for lamb (Ovis aries L.) production under grazing. Our objective was to determine levels of spring lamb production from three irrigated wheatgrasses, ‘Hycrest’ [A. cristatum (L.) Gaertner ✕ A. desertorum (Fischer ex Link) Shutters], ‘Luna’ [T. intermedium subsp. barbulatum (Schur) Barkw. and D.R. Dewey], and ‘Jose’ [T. ponticum (Podp.) Barkw. and D.R. Dewey], grown alone and with ‘Renumex’ sainfoin (O. viciifolia Scop.). Replicated pastures grown on a Pullman clay loam (fine, mixed thermic Torrertic Paleustoll) were rotationally grazed (herbage allowance of 6.5% of body wt. d−1) by weaned Rambouillet ✕ Suffolk wether Iambs for an average of 77 d in spring of 1987 and 1988. Seasonal average daily gain (ADG) ranged between 45 and 69 g d−1 for monocultures and between 80 and 104 g d−1 for mixtures. Lamb production per hectare (PROD) for all mixtures was similar (463 kg ha−1), but higher than for monocultures (238 kg ha−1). Mixtures compared to monocultures had greater ADG (63%), feed conversion (55%), and intake (23%). For Jose and Jose-sainfoin, poor ADG after Week 7 was associated with low herbage crude protein (92-135 g kg−1) and organic matter digestibility (550-570 g kg−1). Jose (12.2 Mg ha−1) had the highest herbage accumulation and Hycrest (7.31 Mg ha−1) the lowest. Wheatgrasses, particularly when grown with sainfoin, provide good PROD during spring and early summer.
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