Impact of Shade on Nutritive Value and ergot Alkaloid Concentrations in Forage

Mixtures for Silvopastures

Kelly Mercier, Chris Teutsch, John Fike, and John Munsell

How does shade affect forage nutritive characteristics?

Tall Fescue

– Endophytic mutualism benefits plant but hurts livestock

–U.S. cattle industry loses >$1 billion annually (Lacefield, 2016)

Do shaded conditions affect alkaloid concentration?

Objectives

To evaluate the impact of shade on: – nutritive value– ergot alkaloid concentration– yield– botanical composition– soil temperature & moisture– ground cover

of cool-season forage mixtures for silvopastures

Randomized Complete Block with2 Factor Factorial (4 reps)

α = 0.053 Forage Mixtures 4 Shade Levels

Simple Intermediate Complex Full Sun (control)

Tall Fescue Tall Fescue Tall Fescue F. arundinacea 30% shade

White Clover White Clover White Clover T. repens 50% shade

Red Clover Red Clover T. Pratense 70% shade

Orchardgrass Orchardgrass D. Glomerata

Kentucky Bluegrass

P. pratensis

Alfalfa M. sativa

Birdsfoot Trefoil

L. corniculatus

30% Shade 50% Shade

70% Shade

Harvest ProceduresCut at 15” to 3-4” residual heights

Collect subsamples for:yield & nutritive valuebotanical composition

ergot alkaloid concentration

Photo courtesy of wintersteiger.com

Total Ergot Alkaloids per Plot

mix x shade interaction

mix x shade interaction

June 2016 Alkaloid Interactions

Total Ergot Alkaloids per % Tall Fescue in Plot

Shade Effects on NDF (2015)

Shade Effects on CP (2015)

Shade Effects on TDN (2015)

Why the difference in

forage quality?

Shade Effects on NDF (2016)

Shade and Mixture Interaction on CP (2016)

Shade Effects on TDN (2016)

Summary

• Mixture affects alkaloid concentration

– Botanical diversity is important

• Nutritive value varied throughout the year

– Full sun better in spring

– Shaded better in summer

• Microclimate moderation may improve forage quality during summer

Thank you!Contact: Kelly Mercier, kmerc094@vt.eu