Steers grazing warm- (bermuda and bluestem) and cool-season (fescue and wheatgrass) grasses produced adequate gains within seasons (spring, summer, fall) and year-long; however gains in the spring were generally greater than in the fall. The best seasonal rotational system was grazing Jose tall wheatgrass in the spring and fall and Hardie bermudagrass in the summer. Grasses must be maintained in an actively growing, vegetative stage for maximum animal production
The primary use of irrigated cropland in New Mexico is producing forages for livestock grazing. Many pro-ducers use irrigated pastures in conjunction with native rangeland
Pasture management can be more effective when cool- and warm-season perennial grasses are grown separately and growth habits of each species are ex-ploited to obtain full-season grazing (Krueger and Curtis, 1979). Gross et al. (1966) reported seasonal grazing of cool- and warm-season perennial grasses has been suc-cessful for stabilizing seasonal stocking rates and in-creasing animal gains per ha. Krueger et al. (1974) reported pasture systems composed of separate pastures of cool- and warm-season species had the greatest carrying capacity and beef production per ha, when compared to either a cool-season native grass rangeland or an alfalfa and cool-season grass mixture
Grasses used in Experiments 2 and 3 (1990, 1991) included two cool-season perennial grasses Jose tallwheatgrass (Agropyron elongatum) and Johnstone tall fescue (Festuca arundinacea), and two warm-season perennial grasses - Hardie bermudagrass (Cynodon dactylon), and Ironmaster oldworld bluestem (Bothriochloa ischaemum)
Furrow irrigation was used in all pastures
annual herbicide application of Weedmaster® or 2,4-D at labeled rates
bindweed (Convoluvlus arvensisL.), bermudagrass (Cynodon dactylon (L) Pers.). Annual grasses, sandbur (Cenchrus longispinus(Hack.) Rem.), and rescuegrass (Bromus catharticusBahl) were present in pastures but were not treated.
blue grama (Bouteloua gracilis), sideoats grama (Bouteloua curti-pendula), and sand dropseed (Sporobous cryptandrus). Sub-dominant grasses consisted of yellow bluestem (Bothriochloa ischaemum), threeawns (Aristidaspp.), lovegrass (Eragrostis spp.), vine mesquite (Panicum obtusum), and silver bluestem (Bothriochloa saccha-roides)
(Good quality refers to species relatively low in fiber components and high in protein and digestibility.)
Table 5. Dry matter yield of Jose tall wheatgrass and Johnstone tall fescue pastures for spring 1989. [pdf 8]
tall fescue pastures in the fall had slightly greater gains. Wheatgrass pastures produced more forage than tall fescue in the spring and fall.
Year-long animal management strategies utilizing cool- and warm-season grasses can result in greater animal gains and beef production per ha over continu-ous year-long grazing of rangeland pastures. Wheat-grass has an inherent ability to produce greater amounts of forage than fescue in the spring, as well as fall. This greater forage production allows for increased beef production per ha, while maintaining individual animal gains at an acceptable level.
Johnstone tall fescue did not yield an acceptable level of forage and therefore would not be recommended for grazing pur-poses. Hardie bermudagrass was superior to Ironmaster oldworld bluestem in terms of forage yield. Both warm-season grasses have the potential to produce an accept-able amount of forage. Imposed management practices should provide enough animals to maintain grasses in an actively growing, vegetative stage to maintain maxi-mum animal production
This implies that rangeland pastures can be used in conjunction with introduced species to pro-vide quality grazing, i.e., introduced pasture grasses can be used to reduce pressure on native range. Manage-ment systems that can utilize existing rangeland pas-tures when quality is high, and use introduced pasture when rangeland quality is low (winter, fall), could prove to be an economical alternative, especially with regard to cow/calf performance