Enhancing the Nutritive Value of Grass Seed Straw for Beef Cattle

1. Enhancing the Nutritive Value of Grass Seed Straw for Beef Cattle • Carl Hunt • Department of Animal and Veterinary Science • University of Idaho • Kristen Johnson • Department of Animal Sciences • Washington State University

2. “I am almost 11 years old, and I was born with cystic fibrosis and asthma. Because of the grass burning, there are many things I can't do…I can't go outside during recess…I can't be a kid.” —Letter from Derek published in the Spokesman Review (October 5, 1997)

3. Standardized Performance Analysis (SPA) for the Western States • What characterizes a profitable cow/calf producer? • High weaning weight? • High calving percentage? • Low cost of production; low unit cost of production ($/cwt)? YES!! • Feed cost represent the largest cost of production • Winter feed cost is the major feed cost

4. Can grass seed straw help reduce wintering cost? • Low quality roughages, have same potential energy as contained in grains • Need to make that energy available to the animal – bioavailable • We believe grass seed straw is prime for enhancing energy value

5. Nutritive value of bluegrass straw needs to be enhanced to support a productive beef cow * NRC (1996) requirements for a late pregnancy, 1000 lb beef cow

6. Need a Way to Improve Straw! • Ammoniation increases the nutritive value of straw • Increased DM digestion by 8-15 % units • Increased DMI 15-20 % units • Increased CP 5 – 6 % units Momont et al, 1992 and Sundstol et al., 1984

7. Research on Ammoniation % DM Digested

8. Swells “cracks” fiber to provide better ruminal microbial attack Provides a source of nitrogen for microbes to convert to protein Agents for ammoniation: *** Anhydrous ammonia Aqueous ammonia Urea Principles of Ammoniation

9. Tested Methods of Ammoniation

10. Past Success Ammoniating Cereal Straw • Treated barley straw with • 1, 2, or 3% ammonia

11. Grass Seed Straw Ammoniation • 18 bales (400 lbs) of bluegrass straw • Treatments: • Control • 3% Ammoniation • 5% Ammoniation • Core sampled before and after treatment to measure composition and laboratory digestibility

12. Composition of grass seed straw treatments

13. Ruminally Fistulated Cow

14. Removing bags

15. In situ (laboratory) Digestibility of Grass Seed Straw

16. Cattle digestion trial • Dietary treatments: Control =Untreated straw Positive Control =Untreated straw + CP A3 =3% ammoniated straw A5 =5% ammoniated straw

17. Effect of Ammoniation on Dry Matter Intake kg/d

18. Effect of Ammoniation on In Situ DM Degradation † * * * % Disappearance †A5 was > others *A5 and A0+DIP were > A0 SE < 3.61 8 16 24 36 48 96 Hours of Ruminal Incubation

19. Effect of Ammoniation on Total Tract DM Digestibility a,b,cMeans lacking a common letter differ b* *A5 differed from A0+DIP at the P = 0.06 level % Digested a,b a a

20. Effect of Ammoniation on Total Tract Fiber Digestibility a,b,cMeans lacking a common letter differ b b % Digested a a a a a a

21. Implications • Digestibility of bluegrass straw was substantially enhanced by ammoniation; however, intake was still low (1.3% of BW) for winter feeding of beef cows • Ammoniation ($18/ton) was cost beneficial when compared against the cost of barley ($105/ton) and alfalfa hay ($85/ton) that would be required to supplement untreated straw

22. Untreated bluegrass straw Straw = 15.4 lb Barley = 7.5 lb Alfalfa hay = 5.1 lb $/day = $.89 Ammoniated bluegrass straw Straw = 8.6 kg Barley = 1.2 kg $/day = $.61, or Instead of $18, could afford $47/ton) treatment cost Daily feed cost for 1000 lb, late gestation cow Rations formulated using “Balancer”

23. Any Questions?