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ARS Home » Northeast Area » University Park, Pennsylvania » Pasture Systems & Watershed Management Research » Research » Publications at this Location » Publication #336058
Title: Potential of forage brassicas for use in pasture-based livestock systems

Author
item Dillard, Sandra
item ROCA-FERNANDEZ, ANA - Universidad De Chile
item RUBANO, MELISSA - Consultant
item Soder, Kathy

Submitted to: American Forage and Grassland Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 1/25/2017
Publication Date: 1/25/2017
Citation: Dillard, S.L., Roca-Fernandez, A., Rubano, M., Soder, K.J. 2017. Potential of forage brassicas for use in pasture-based livestock systems. American Forage and Grassland Conference,January 22-25,2017,Roanoke,Virgina.P.1.

Interpretive Summary: No Interpretive Summary is required. JLB.

Technical Abstract: Brassicas (Brassica spp.) are gaining popularity as high-quality forage for pasture-based livestock producers due to their use to extend the fall grazing season and during the summer forage slump. However, inclusion of brassicas in the diet can be limited by the presence of glucosinolates (a class of plant compounds that can reduce average daily gains and cause off-flavors in meat and milk). To date, little research has been conducted to evaluate forage yield, nutritive value, and the total and individual glucosinolate concentration of brassicas. The objective of this study was to determine yield, nutritive value, and glucosinolate content of 3 brassicas [Appin’ turnip (B. rapa), ‘Barisca’ rapeseed (B. napus), ‘Inspiration’ canola (B. napus)] and ryegrass [‘KB Supreme’ annual ryegrass (Lolium multiflorum)] grown in central PA. Yield, nutritional composition, and glucosinolate concentration of forage were determined every 2 weeks. Seasonal forage yield was similar among brassica varieties (1,023 kg DM/ha) and lowest in ryegrass (242 kg DM/ha). While crude protein was greater in ryegrass than the brassica varieties (33.1 vs. 29.2%), both degradable and soluble protein fractions were lower in annual ryegrass than all brassicas (76 vs. 84% and 18.7 vs. 14.4%, respectively). While all forages were relatively low in NDF and ADF, ryegrass had greater NDF and ADF than brassicas (35.4% vs. 18.7% and 17.5% vs. 14.1%, respectively). Turnip had the greatest total glucosinolate concentration (27.9 mg/g dry), and rapeseed and canola were 40 and 67% lower, respectively. Annual ryegrass contained no glucosinolates. Inclusion of brassicas in a cool-season pasture rotation has the potential to increase animal productivity and reduce the need for stored feed during periods of perennial cool-season forage shortages, including mid-summer and late fall; however, glucosinolate levels must be considered to reduce potential negative impacts on animal health and off-flavors in milk and meat.