Submitted to: Professional Animal Scientist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/21/1995
Publication Date: N/A
Interpretive Summary: Bermudagrass is a productive, warm-season perennial grass that is widely grown in the southeastern United States. Although forage quality of the grass can be moderately high in the early part of the growing season, it typically will decline during the middle- to late-summer months. A two- year grazing study was conducted to determine if steer weight gain on bermudagrass is improved if individual steers are fed .45 kg/da soybean-cottonseed meal mixture, and if there is additional benefit to adding a specialized antibiotic, lasalocid, to the supplement at a concentration of 330 mg/kg of feed. The protein supplement showed to increase steer average daily gain, but feeding lasalocid did not result in any further improvement. Increases in average daily gain were not high enough to result in any detectable increases in gain per acre. Crude protein of the bermudagrass stayed at or above marginally deficient levels; however, digestibility values indicated that energy may have been more of a limiting factor to animal performance than protein. Cost analysis further indicated that the increase in average daily gain was not high enough to make feeding the supplement a cost effective practice. Thus, less costly energy supplementation should be examined as a possible means of improving steer performance on bermudagrass.
Technical Abstract: Bermudagrass [Cynodon dactylon (L.) Pers.] is a productive warm-season, perennial grass that usually declines in forage quality during the summer. A two-year grazing study was conducted to determine the influence of protein supplementation or protein supplementation plus lasalocid on steer weight gain. Performance of steers on continuously stocked common bermudagrass was compared between treatments of: 1) Daily consumption of a supplement, containing soybean meal and cotton seed meal, to provide individual steers in each group with .2 kg of protein/d, 2) Daily consumption of the quantity of supplement plus 150 mg/d of lasalocid, and 3) pasture only (control). Average daily gain (ADG) for the supplements were higher (P < .1) than for the control, but ADG did not differ (P > .1) between the two supplements. Crude protein of bermudagrass was above 9.0% for most of the study, indicating it was not deficient, but low digestibility over most of the study period indicated that energy content of the grass was low, as anticipated. Gain per hectare did not differ (P > .1) between the three treatments. Cost/benefit analysis further indicated that the cost of the increase in individual animal gain may be too high to have any positive economic benefit. Results of this study indicated that soybean and cottonseed meal protein supplemented to steers on bermudagrass may be utilized for energy rather than protein and will likely not provide any apparent economic benefit.