Submitted to: Professional Animal Scientist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/15/2005
Publication Date: 12/20/2005
Citation: Burns, J.C. 2005. Utilization by cattle, sheep and goats of forage harvested from long-term bermudagrass spray fields receiving swine-lagoon effluent. Professional Animal Scientist. 21:352-360. Interpretive Summary: Forages frequently serve as receivers of animal waste across the Southeastern and Southern USA. Forage produced from fields of bermudagrass serving as receivers of swine lagoon effluent is a potential feed source for ruminants. However, the hog producer is not interested in the forage produced and potential users of hay are not anxious to feed waste-treated forage. Results from this study showed that forages direct chopped, dehydrated and pelleted were readily consumed (> 2.8 kg/100 kg BW) by steers, sheep, and goats, regardless of forage maturity. Immature forage was consumed at over 2 kg/100 kg BW when dehydrated and fed chopped. Nitrate N status of the forage needs to be monitored. Regrowth forage not receiving effluent at the onset of growth could be safely fed as a sole diet. Forages receiving effluent at initiation of regrowth poses risk of nitrate toxicity and should be fed as only a portion of the daily diet. Timely harvesting of spray fields and packaging of the forage, such as pelleting and bagging to add convenience for handling and transportation, will enhance its use for off-site feeding. Such innovation will make spray fields a ready source of nutrients for ruminants and a method of redistributing excess nutrients over the landscape and away from nutrient-rich sites. These forages could contribute at least 50% and up to 100% of a herbivores diet providing they are fed based on knowledge of their composition.
Technical Abstract: Bermudagrasses frequently serve as receivers of swine-lagoon effluent in swine-production confinement systems in the southeast. This study evaluated DMI and digestion of field chopped, dehydrated regrowth forage cut from mature Coastal bermudagrass spray fields following a late-July harvest. Four treatments were evaluated in separate experiments each with cattle, sheep, and goats. The treatments consisted of forage harvested at 2 wk of regrowth and either fed chopped (2-WC) or pelleted (2-WP), and harvested and pelleted at 3 wk (3-WP) and at 4 wk (4-WP) of regrowth. The long-time established spray fields varied in the proportions of bermudagrass but averaged 45% for the 2-wk regrowth and 50% for the 4-wk regrowth with the balance composed of annual grasses and broadleaved weeds. All three pelleted forages were readily consumed with DMI (kg/100 kg BW) averaging 2.99 for steers, 4.35 for sheep, and 3.21 for goats. Steers and goats consumed all pelleted treatments similarly, whereas sheep consumed 2-WP and 3-WP similarly (4.41) but less of 4-WP (4.23) compared with 2-WP (4.49). Pelleting increased (P ' 0.01) DMI compared with chopping (3.01 vs. 2.16 ± 0.087 for steers, 3.29 vs. 2.37 ± 0.071 for goats and 4.49 vs. 2.54 ± 0.072 for sheep). Steers and sheep digested 2-WP and 4-WP similarly and both greater (P ' 0.05) compared with 3-WP, whereas goats digested all similarly (P = 0.11). These short-term responses indicate that forages from mature bermudagrass fields sprayed with swine effluent have potential as a feed in ruminant production systems. (Key words: Swine-Lagoon Effluent, Bermudagrass, Steers, Sheep, Goats)