1. Feeding Strategies to Lower P in Manure Dr. Mireille Chahine, Extension Dairy Specialist Dr. Rick Norell, Extension Dairy Specialist

2. Measuring Nutrient Excretion Source: Weiss, 2006

3. 1. Formulate Rations to Meet the 2001 NRC Guidelines Avoid the “safety margin” principle P fed in excess of a cow’s requirements  Reduce or eliminate the supplemental P Free-choice P should not be used on dairies

4. Current Phosphorus Requirements Milk (lbs)DMI (lbs)P intake (g)P (% DM) 4441550.31 6648730.33 8856910.36 110631100.38 132701280.40 Source: 2001 NRC

5. Example of Reductions in Phosphorus Intake and Excretion Dietary P (%DM) P Intake (g/cow/day) P Excretion (g/cow/day) 0.5%113.584.7 0.38%86.369.5 Reduction27.215.2 (Assumes average DMI = 50 lbs/cow/day)

6. Impact of Reducing Phosphorus 15.2 gram decrease on a 1000 cow dairy equates to an annual reduction of 12,220 pounds of phosphorus! Benefits ▫Reduced total number of acres required for land application ▫Higher manure application rates possible per acre ▫Improved N:P ratio in manure

7. Feed Savings 27 g reduction in P equates to 0.34 lbs of 17% P mineral per day at $0.10/cow/day Elevated P may be due to other high P feeds in the diet rather than solely due to the mineral supplement

8. Accuracy in Feeding Cows Source: Dou, J Dairy Sci 86:3787

9. Source: J Dairy Science 88:3721

10. Source: J Dairy Sci. 99:3721)

11. 2. Group and feed cows according to their stage of lactation and repro status Avoid the one ration for all scenario  Cows eating approximately 7% more P than requirements Grouping cows according to milk production and repro status  Decreased feeding costs and less nutrient excretions

12. 3. Wisely use byproducts and concentrates in dairy cow rations Nutritionists should be encouraged to utilize ingredients with lower P concentrations General rule: Byproduct ingredients and oilseed meals  higher in P relative to cereal grains and forages

13. Average protein and phosphorus content of common protein supplements SourceCP%P%Ratio CP:P Blood meal95.50.30318:1 Soybean meal49.90.7170:1 Cottonseed meal44.91.1539:1 Canola meal37.81.1034:1 Fish meal68.53.0522:1 Source: 2001 Dairy NRC

14. Ethanol Production in the US  Ethanol price   availability of wet distillers grains with solubles (WDGS) and dried distillers grains with solubles (DDGS)

17. Corn: 1 bushelEthanol: 2.7 gal CO2CO2 ++ DDGS: 18 lbsCO 2 : 18 lbs

18. Conversion from Corn to Distiller’s grains NRC, 2001

19. 4. Routinely analyze the ingredients used in the ration The level of P in the feed ingredients used in dairy cow rations is variable This variability needs to be addressed when formulating rations

20. Plant 1 n=9 Plant 2 n=11 Plant 3 n=31 Entire Populatio n P0.80.9 Min0.50.6 0.5 Max1.01.21.11.2 SD0.2 0.10.2 Source: Robert M. Kaiser, 2005 Variation in composition of WDGS

21. 5. Maximize the use of forages in the ration Maximizing the amount and quality of forages in dairy cow rations  Improves cow health, reduces the need for imported feed, and reduces the need to use imported by-products

22. Wu and Ishler, 2002

24. Source: Weiss, 2007

25. Feeding strategies to lower P in manure: Formulate rations to meet the 2001 NRC guidelines Group and feed cows according to their stage of lactation and reproduction status Routinely analyze the ingredients used in the ration Wisely use byproducts and concentrates in dairy cow rations Maximize the use of forages in the ration