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'Carostan' flaccidgrass (Pennisetum flaccidum Griseb.) is a perennial, warm-season grass with potential in forage systems for the mid-Atlantic region. Using established flaccidgrass pastures, we estimated steer (Bos taurus) average daily gain (ADG), stocking rate, and pasture productivity in a 4-yr experiment. Pastures were continuously and variably stocked at a forage mass (FM) of 1895 (Short), 4186 (Medium), and 5297 (Tall) kg ha-1 (linear; P < 0.01). Steer ADG was similar among FM (mean = 0.65 kg d-1). The Short was stocked at 8.3 steers ha-1 and numbers decreased linearly (P < 0.01) to 7.2 steers ha-1 for Tall. Animal days ha-1 decreased linearly (P < 0.01) from 963 (Short) to 756 (Tall). Weight gain ha-1 did not vary significantly (P = 0.14). Effective feed units (kg ha-1) declined linearly (P = 0.02) from 3756 for the Short to 2842 for Tall. Analysis of digesta kinetics revealed no differences among FM in rate of passage, retention time of liquid or solid phases, fill, or fecal output. Diets selected by steers among FM were similar in concentration of in vitro dry matter disappearance (mean = 690 g kg-1); however, CP declined linearly (P = 0.03) while NDF increased (P = 0.01) with increasing FM. Steer ADG was greater (P = 0.03) in Period 1 (0.77 kg d-1 up to early July) compared with Period 2 (0.53 kg d-1 after early July) and attributed to greater forage quality in Period 1. Flaccidgrass is a productive, perennial forage that can provide quality pasture during the summer. [ABSTRACT FROM AUTHOR]

'Carostan' flaccidgrass (Pennisotum flaccidum Griseb.) has potential as a perennial, warm-season grass for pastures. This 2-yr study examined digesta kinetics, dry matter intake (DM1), and diet of steers as related to canopy charactéristics. Steers (Bos taurus L.) were continuo~usly and variably stocked at canopy heights of Short (15 to 20 cm), Medium (30 to 40 cm), and Tall (45 to 55 cm) with forage mass (FM) of 1245, 2600, and 3585 kg ha-1, respectively (linear; p <0.01). Neither mean retention time nor p~assage rate of either liquid or digesta phases were altered by FM. Fecal output increased linearly (p = 0.04) from Short to Tall (0.643 to 0.739 kg 100 1 kg body weight [BW]) indicating a possible variation in DM1. However, DM1 and digestible DM1 (based on leaf in vitro dry matter disappearance [IVDMD]) were similar among FM (mean = 1.99 and 1.29 kg 100-1 kg BW). Leaf imposed 24.3% of the three canopies and was not altered by FM. Stem increased linearly (p = 0.01) from 40.1 to 53.1% with height whereas dead tissue declined linearly (p = 0.06) from 34.8 to 23.4%. Steers selected diets (1 yr data), regardless of FM, similar in IVDMD (mean = 713 g kg-1) and neutral detergent fiber (NDF) (mean 486 g kg-1). In general, steer digesta kibetics were not influenced by FM as animals adjusted grazing behavior to result in similar responses. Flaccidgrass canopies were flexible aipd no particular optimum FM was detecting for an optimum diet. The influence of FM on pasture productivity (regrowth after defoliation) requires additional study. [ABSTRACT FROM AUTHOR]

Tall fescue (Festuca arundinacea Schreb.) is a well-adapted perennial pasture species utilized across the north-south transition zone of the United States. This 3-yr trial evaluated the influence of three forage masses (FM) on steer and pasture responses for spring (April to July) and fall (October) growths. Spring FM averaged 1450 kg ha-1 (Short), 3032 kg ha-1 (Medium), and 3812 kg ha-1 (Tall) for the three treatments. Canopy in vitro true organic matter disappearance (ITOD) decreased linearly from Short (797 g kg-1) to Tall (771 g kg-1). Steer daily gains (0.88 kg) and gains per hectare (392 kg ha-1 yr-1) were not altered by FM, but the mean number of steers per hectare decreased linearly from Short (8.2 steers ha-1) to Tall (6.1 steers ha-1) as did effective feed units per hectare (2256 to 1712 kg ha-1 yr-1). Canopies were predominately leaf (53%) and averaged 847 g kg-1 ITOD with estimates similar among FM treatments. Diet ITOD declined linearly from Short (870 g kg-1) to Tall (839 g kg-1) as did crude protein (CP) (from 235 to 192 g kg-1). In the fall, FM averaged 1556, 3228, and 3494 kg ha-1 for the three FM treatments. Canopy ITOD averaged 774 g kg and was not altered by FM. Canopy leaves averaged 60% with an ITOD of 864 g kg-1 and were similar among FM treatments. Diets selected averaged 834 g kg-1 ITOD and 233 g kg-1 CP and were not altered by FM. Tall fescue pasture free of toxic endophyte needs to be effectively utilized to enhance production and can be managed flexibly in grazing systems. [ABSTRACT FROM AUTHOR]

Management strategies to accommodate switchgrass (Panicum virgatum L.) in production systems have been reported but impact of variation in forage mass (FM) on animal responses and pasture stands are lacking. This 4-yr study assessed canopy and stand characteristic and steer (Bos taurus) responses when 'Kanlow' switchgrass was continuously and variably stocked to produce Short (S) (10-16 cm), Medium (M) (20-26 cm), and Tall (T) (35-41 cm) canopy heights. From April to mid-July (Period 1) FM for S, M, and T average 818, 2164, and 3294 kg ha-1, respectively. Canopies had similar in vitro organic matter disappearance (IVOMD) (626 g kg-1), but increased in neutral detergent fiber (NDF) from S (645 g kg-1) to T (665 g kg-1). Diets decreased in IVOMD from S (744 g kg-1) to T (706 g kg-1). Digesta kinetics data were not altered and average daily gain was similar among FM (1.11 kg d-1). From mid-July to late September (Period 2), FM averaged 465, 1282, and 2388 kg ha-1, respectively, for 5, M, and T. Whole canopy IVOMD increased from S (484 g kg-1) to T (538 g kg-1), whereas NDF was not altered (696 g kg-1). Steers selected a diet similar in IVOMD (685 g kg-1) and NDF (667 g kg-1) among FM. Estimates of dry matter intake (kg 100-1 kg body weight) increased from S (1.75) to T (2.54). Tiller density decreased from T to S. Continuously stocked switchgrass at 20 to 40 cm remained vegetative with 1279 tillers m-2 after 3 yr of grazing. [ABSTRACT FROM AUTHOR]