1. Diurnal Changes in Forage Quality Affects Animal Preference, Intake, Performance Hank Mayland, Dave Mertens and Bret Taylor USDA-ARS Kimberly, ID; Madison, WI; Dubois, ID Pablo Gregorini, Universidad Nacional de La Plata, Argentina Joe Burns, Dwight Fisher, Tony Ciavarella, Kevin Smith, Glenn Shewmaker, Tom Griggs Dec 2005

2. PM-Cut Hay Is it For Me ?

3. Diurnal Cycling of TNC  1. In forages  2. Animal preference PM-AM cut hay  3. Animal production PM-AM cut hay  4. Animal production: strip grazed pasture  5. Economic response to PM-cut hay  6. Other benefits

4. Photosynthesis = CO 2 + H 2 O chlorophyll O 2 + Sugar Time TNC SunupSundown DayNight

5. Time TNC SunupSundown Variety Differences in TNC.

6. Relative Quality and Intake 3-cuttings alfalfa, Kimberly, ID PMAM NDF, % 39.641.1 ADF, % 30.331.3 CP, % 22.422.3 NO 3 -N, ppm 730 730 810 810 RFV 154 154 148 148 RFQ 157 157 150 150 TNC, % 5.32 5.32 4.19 4.19 DMI g 30002300

7. Cattle Preferences

8. Preference Testing  Forage species Fescue, p/a ryegrass, orchard grass, bromegrass oat hay, etc. Fescue, p/a ryegrass, orchard grass, bromegrass oat hay, etc. Corn, switch grass, sudangrass. Corn, switch grass, sudangrass. Legumes: alfalfa, several clovers Legumes: alfalfa, several clovers  Animal species Ruminants – cattle, sheep, goats Ruminants – cattle, sheep, goats Non Ruminants – horses, rabbits Non Ruminants – horses, rabbits

9. Preference for PM/AM-cut Hay  Cattle, sheep, goats, horses, rabbits sense hays differing by 0.5% sugar concentrations

10. Dairy Cow Lactation

11. Milk Production Hay Source Milk Yield, lbs/d P TMR with PM-cut alfalfa TMR with AM-cut alfalfa IDAHO8883<0.01 WISCONSIN9392 0.28 0.28

12. Sheep Growth

13. Growth Study  Lambs at USSES being conditioned for fall breeding were fed TMRs containing 50% PM- or AM-cut alfalfa.  Lambs adapted more quickly to the PM- than AM- TMR by consuming more of the stem material.  No overall difference in DMI, feed efficiency, or weight gains.

14. Pasture – Strip Grazing

15. Heifer Weight Gains (lbs/d) in 24 h Strip Graze System Season Season Time on Pasture 7 am to 7 am 3 pm to 3 pm Winter Winter1.41.6 Spring Spring1.22.5

16. Ensiled Materials

17. Protein Degradation & Ensiling  Alfalfa and red clover (Owens et al) TNC increased throughout the day TNC increased throughout the day Silage pH decreased and starch increased with cutting time Silage pH decreased and starch increased with cutting time Success in ensiling forages like alfalfa Success in ensiling forages like alfalfa

18. Time TNC SunupSundown When Do I Cut?

19. Impact on ½ of Crop on Western US Alfalfa and Dairy Industry  5% increased forage value = $100,000,000+  Reducted NDF: $2.40-3.40/ton for each 1% = $44 to 62 m annually.  Increased RFQ: $0.90/ton for each 1% = $127 m annually.  Increased milk production 5% at $13/cwt = $276 m annually.

20. Benefits of Feeding Afternoon vs. Morning Cut Forage  > Rate of passage  > DM intake and digestibility  > Efficiency of forage utilization  > Efficiency of protein utilization  > Increased energy intake for production --------------------------------------------------------- < Ammonia excreted < Ammonia excreted < Manure excreted < Manure excreted

21. Summary  Sugars increase during day in plants  Herbivores can detect sweeter forage  Expect 5%+ increased milk production in western U.S.

23. Isn’t it astonishing that all these secrets have been preserved for so many years just so that we could discover them. Orville Wright, 17 Dec. 1903