Forage Quality And Utilization Of Kentucky Bluegrass Residue
John HolmanPlant, Soil and Entomological Sciences
Carl HuntAnimal and Veterinary Science
Larry Van TassellAgricultural Economics and Rural Sociology
Kentucky Bluegrass Forage Quality
• Post-seed harvest forage valueBaleGrazeBale and graze
• Pre-seed harvest forage value (during fallowyear)
•Bale•Graze•Graze and bale
Bluegrass Forage Quality - Analogy
• I need to come to this meeting in Spokane but my department head only gave me funds for gas (energy) to make 85% of the trip. Does that mean his offer is of no value to me?
• Of course not, it just means that I have to find funds for gas (energy) for the rest of the trip
Nutritive value of bluegrass straw needs to be enhanced to support a productive beef
cow
Nutrient Bluegrass straw
Cow requirement*
ME, Mcal/lb .77 .91
Protein, % ~4.0 9.0
* NRC (1996) requirements for a late pregnancy, 1200 lb beef cow
Methods to Enhance Straw Quality
Energy and protein supplementation
Chemical modification: Ammoniation
Physical modification Grinding Pelleting
Energy and protein supplementation
1200 lb cow, late gestationConventional program
19.3 lbs grass hay ($75/ton)7.5 lbs alfalfa ($96/ton)$1.08/cow/day
Grass straw program
14.0 lbs grass straw ($40/ton)9.5 lbs alfalfa ($96/ton)3.4 lbs barley ($102/ton)$0.91/cow/day
Energy and protein supplementation
What happens with a 10% improvement in straw quality? Grass straw program
14.0 lbs grass straw ($40/ton) 9.5 lbs alfalfa ($96/ton) 3.4 lbs barley ($102/ton) $0.91/cow/day
Improved straw program 14.0 lbs grass straw ($40/ton) 8.1 lbs alfalfa ($96/ton) 3.2 lbs barley ($102/ton) $0.83/cow/day
Or, straw is worth $51.50!
Ammoniation!!
How does ammoniation work in the “real world” – Study with WSU beef herd
Lbs of ration intake per cow per day
No difference in performance: cow weight, body condition, calf weight (45 day), rebreeding
Ration ingredient
Ammoniated Non-ammoniated
Alfalfa hay 10.1 13.6
Bluegrass straw
20.8 19.6
Rumen digestibility: 36-h ISDMD
Same as Control (P > 0.10)
Pre-seed harvest forage value:
We don’t know yet
Seasonal quality and quantity of grazable forage
Kentucky Bluegrass (KBG) Forage Study Background
• Baling is an integral component of many reduced and non-thermal KBG residue management alternatives-Baling removes 75-80% of the post-harvest residue
▪ Proprietary types produce ~ 1 ton/ac
▪ Common types produce ~ 2 ton/ac
• Baled residue needs to be utilized for alternative methods of residue removal to be economically viable
Kentucky Bluegrass Forage Study Objectives
• Determine if KBG can be hayed or grazed in an alternate year production system while maintaining system profitability and sustainability • Quantify the decline of KBG quality post combine• Determine if variety impacts forage quality
- Quantify stem/leaf ratio, C/N ratio, and elemental nutrient content
• Quantify the amount and type of nutrients removed with the baled residue
Kentucky Bluegrass Forage Study Methods
• RCB design with 3 replications-For 2 years under non-irrigated conditions at the WSU
Turfgrass Research Site- Varieties: Kenblue, Touchdown, Ascot, and Limousine
• Collect KBG forage samples at boot, flowering, swathing, combining, and 0-21 days post combining• Measure the collected samples for fiber (ADF & NDF),
crude protein, in-vitro digestibility, lignin content, C/N ratio, and elemental nutrient content
Kentucky Bluegrass Forage Study Outcomes
• Identify the optimum time to bale post-harvest residue
• Identify the type and amount of nutrients removed with the baled residue
• Calculate the optimum time of grazing or baling KBG in the fallow year of the alternate year cropping system to maximize profitability
• Determine KBG forage quality and energy value
• Determine if KBG variety impacts forage quality
• Disseminate information to KBG growers and public