forage quality and utilization of kentucky bluegrass residue john holman plant, soil and...

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