Open pasture, silvopasture, and sward herbage maturity effects on nutritive value and fermentation characteristics of cool-season pasture

Authors: Neel, James; FELTON, EUGENE - West Virginia University; SINGH, SMITA - West Virginia University; SEXSTONE, ALLAN - West Virginia University; BELESKY, DAVID - West Virginia University

Submitted to: Grass and Forage Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/2/2015
Publication Date: 4/30/2015
Citation: Neel, J.P., Felton, E.E., Singh, S., Sexstone, A.J., Belesky, D.P. 2015. Open pasture, silvopasture, and sward herbage maturity effects on nutritive value and fermentation characteristics of cool-season pasture. Grass and Forage Science. doi: 10.1111/gfs.12172.

Interpretive Summary: The Appalachian region contains numerous small farms comprised of open pasture and woodlots. There are approximately 16.4 million hectares of farmland, of which an estimated 40% is woodland. Growing forages within woodlots offers promise of increased farm production and income. These benefits would be a direct result of increased available land area, and possible beneficial plant responses to growing conditions within a wooded site. Some research has reported benefits of silvopastoral systems by an extension of the grazing season via protection of plants from environmental extremes and overall increased forage production. Some research has shown that shade improved nutritive value, while other research has indicated the opposite effect. Some researchers have proposed that morphological changes in forages grown in reduced light (e.g., under a tree canopy or in areas with prolonged cloudiness) would very likely result in greater nutritive value. Based on conflicting reports, a synchronized temporal understanding of open and silvopasture nutritive characteristics is essential for grazing system development. We examined pasture type (open versus silvopasture) nutritive value relationships when herbage was harvested at equivalent morphological maturity rather than calendar date. At equivalent morphological stages of maturity, both pasture types have similar nutritive value but there is a 4-6 d delay in silvopasture reaching the same maturity stage. These attributes make SP within a grazing system very advantageous by increasing management flexibility. The delay in morphological development for silvopasture is an important finding in that it allows for delay in grazing date without sacrificing nutritive value. This information provides livestock producers the ability to better manage pasture systems and improve farm productivity.

Technical Abstract: In Appalachian USA, growing forages within woodlots offers promise of increased farm productivity. A synchronized, temporal understanding of open (OP) and silvopasture (SP) nutritive characteristics is essential for grazing system development. We examined pasture type nutritive value relationships when herbage was harvested at equivalent morphological maturity rather than calendar date. Neutral and acid detergent fibre (ADF, NDF) content were greater in silvopasture while organic matter (OM) was lower (P < .05). Digestibility of SP herbage dry matter (DM) and OM tended (P=0.10) to be lower (418 vs 471 and 437 vs 491 g/kg respectively). Neutral detergent fibre digestibility was greater (P < 0.05) for OP than SP forage (538 vs. 480 g/kg), and ADF tended to be greater (P=0.10; 551 vs. 501). Open pasture forage fermentation effluent exhibited slightly higher microbial richness and Shannon diversity than SP. However, overall community composition of both bacteria and archaea did not differ between pasture types or sampling times. At equivalent morphological maturity, pasture types show proximate analyses differences, though both have similar overall nutritive value. In addition, SP exhibited a 4-6 d delay in reaching equivalent maturity. Having SP within a grazing system would be advantageous by increasing herbage production and management flexibility.