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Title: BLOOD UREA NITROGEN FROM LAMBS GRAZING OPEN AND SILVO PASTURE

Author
item Neel, James - Jim
item Belesky, David

Submitted to: American Forage and Grassland Council Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 1/11/2006
Publication Date: 3/10/2006
Citation: Neel, J.P., Belesky, D.P. 2006. Blood urea nitrogen from lambs grazing open and silvo pasture. American Forage and Grassland Council Conference Proceedings. 15:82-86.

Interpretive Summary:

Technical Abstract: The Appalachian region contains numerous small farms comprising open pasture and woodlots. Growing forages within woodlots offers promise of improved forage availability, higher forage quality and increased farm income. Research shows herbage grown under restricted light conditions has greater crude protein (CP) content and excessive N relative to energy. We evaluate source of pasture forage on blood urea nitrogen (BUN) and its relationship to herbage CP and energy content. Lambs were assigned to one of three treatments: 100% time grazing open pasture (OP), 67% OP and 33% hardwood forest pasture (HW), or 67% OP and 33% hardwood forest pasture with initial grazing delayed 10 days (HWD) after the HW treatment. Herbage from silvopasture had greater CP except for HW in spring versus OP. Open pasture herbage had greater TDN:CP values versus HW and HWD except in spring. Open pasture herbage had greater TNC content during mid-season compared to HW and HWD. During all sampling times except initial, BUN concentrations were greater in HW and HWD treatments versus OP. Our results show that greater N content found in silvopasture resulted in increased BUN. Higher BUN concentrations within HW and HWD treatments indicate N is not being captured by rumen microbes or grazers but is most likely being returned to the environment via urinary excretion.