Phosphorus Management to Improve Profit and Ensure Environmental Sustainability

Transcription

1 Phosphorus Management to Improve Profit and Ensure Environmental Sustainability Dave Beede Department of Animal Science Michigan State University - East Lansing World Dairy Expo October 4, 2005

2 Who is responsible for P management on the dairy farm? What is your Organizational Chart for P Management???

3 Who is responsible for P management on the dairy farm? Nutritionist/ Feed sales Veterinarian Employees Dairy Producer

4 Who is responsible for P management on the dairy farm? Dairy Producer Nutritionist/ Feed sales Veterinarian Employees

5 Example: P Excretion: 300-cow herd Feeding: High group Medium group Low group 0.44% P 0.43% P 0.42% P

6 Example: P Excretion: 300-cow herd Feeding: what if? High group 0.44% P 0.34% P Medium group 0.43%P 0.33% P Low group 0.42%P 0.32% crop removal rate = 50 lb P 2 O 5 /acre: Reduces cropland needed by 250 acres/yr for 300-cow dairy

7 Take Home Messages Feeding Management Strategies: 1. Formulate rations knowing that true bioavailability of P is high.

8 Take Home Messages Feeding Management Strategies: 1. Formulate rations knowing that true bioavailability of P is high. 2. Formulate rations to meet the animals P requirements as accurately as possible.

9 Take Home Messages Feeding Management Strategies: 1. Formulate rations knowing that true bioavailability of P is high. 2. Formulate rations to meet the animals P requirements as accurately as possible. 3. Routinely analyze feeds for P content.

10 Take Home Messages Feeding Management Strategies: 1. Formulate rations knowing that true bioavailability of P is high. 2. Formulate rations to meet the animals P requirements as accurately as possible. 3. Routinely analyze feeds for P content. 4. Stop P supplementation in many dairy rations.

11 Take Home Messages Feeding Management Strategies: 5. Consider alternative, lower-p feeds for rations.

12 Take Home Messages Feeding Management Strategies: 5. Consider alternative, lower-p feeds for rations. 6. Formulate specific rations to meet P requirements of cows in specific management groups.

13 Take Home Messages Feeding Management Strategies: 5. Consider alternative, lower-p feeds for rations. 6. Formulate specific rations to meet P requirements of cows in specific management groups. 7. Optimize animal performance (intake, productivity, and efficiency).

14 Environmental Sustainability Phosphorus as a pollutant: in the farm system; in neighboring ecosystems; in surface water, stimulates algae and plant growth; causing oxygen debt, and, fish kills.

15 Environmental Sustainability Whole Farm P Mass Balance: = imported P exported P = P inputs P outputs Of the whole farm system: Of the whole farm system: (all acreage, all animal facilities, all feed and manure storage, everything)

16 Whole-Farm P Mass Balance P Inputs = 1. P in purchased feeds 2. P in purchased fertilizer P Outputs P in: calves/ cattle sold milk sold crops sold Manure P (to someone else)

17 Whole-Farm P Mass Balance P Inputs = 1. Phosphorus in purchased feeds 2. P in purchased fertilizer P Outputs P in: calves/ cattle sold milk sold crops sold Manure P (to someone else)

18 Environmental Sustainability, Whole Farm P Mass Balance Management objective: to be in zero P balance P inputs = P outputs New objective for some dairy producers and their nutritionists?

19 Six Topics Topic 1. Introduction Topic 2. Formulation Strategies and Feed Sources of P Topic 3. P Requirements for Dairy Cattle Topic 4. Benefits to Over-Feeding P? Topic 5. Measuring and Predicting P Excretion Topic 6. P Excretion in a 300-Cow Herd

20 Topic 1 Introduction

21 P in Dairy Systems 1. P = 2 nd most expensive nutrient supplemented in rations 2. Purchased feeds: a major source of imported P on dairy farms 45 to 80% of total P inputs (Klausner, 1993) 3. Only 20 to 30% of feed P is exported in milk and marketed animals to 80% of feed P is excreted in manure!

22 Examples: P in Dairy Farms - Past Surveys: greater than ½ herds in WI, PA and FL were fed rations with more P than needed to meet requirements; 0.4 to 0.6% ration P common in Wisconsin (Shaver & Howard, 1995); 0.38% typically maximum ration P% needed to meet requirement

23 P on Dairy Farms 2003 a 30 dairy farms: Vermont & northeastern NY Dairy producers willing to reduce dietary P to NRC (2001) recommendations 54% said their nutritionists were balancing for less P 79% of TMRs tested had P% greater than NRC maximum recommendation (0.38%) Why? a Research of K. Cotanch, W.H. Miner Agricultural Research Institute, Chazy, NY, reported in Dairy Herd Management

24 Topic 2 Formulation Strategies and Feed Sources of P for Rations

25 What might be happening in ration formulations? 1. P analysis by wet chemistry vs. NIRS? for forages especially? 2. P analysis of forages lower than actual (by NIRS)? 3. book values for concentrates and byproducts? Many book values low. Therefore, P supplementation in excess of actual necessary to meet requirement results in excess ration P excess manure P

26 What might be happening in ration formulations? Other considerations?

27 Dietary Fat and Ca Supplementation; and, P Supplementation It is common.. Supplemental dietary fat Supplemental dietary Ca 1.0 to 1.2% dietary Ca, dry basis To maintain Ca-to-P ratio of 2-to-1 Dietary P set at 0.5 to 0.6%, dry basis Exceeds P (and Ca) requirements NOT necessary! Evidence?

28 Common P Supplements Source Ammonium phosphates Bone meal, steamed Calcium phosphate Dicalcium phosphate Phosphoric acid Corn & alfalfa silages Corn grain P % P Absorption Coefficients

29 P Content of Feeds - Examples Feed P % CP % CP-to to-p Blood meal Corn gluten meal SBM, 44% Corn silage DDGS Corn grain Corn gluten feed Hominy Wheat bran

30 Excess P in Byproducts & Supplements Byproducts good value CP & energy Many high in P% (DDGS, 0.83%) Use of byproducts more P than needed in rations (even with no P supplementation) Excess ration P increases manure P Extra cost to manage/ dispose of extra manure P? Extra acres? CNMP?

31 Topic 3: P Requirements for Dairy Cattle

32 Factorial Method Phosphorus Requirements: NRC (2001) for Dairy Cattle

33 P Requirement (mature, non-preg Holstein, 80 lb MY) Factors (functions) Maintenance Milk production Growth Pregnancy Required P in blood Coefficient of Absorption Dietary P required grams/cow per day (for 80 lb MY) 0 (4 to 10 g/d if growing) 0 (3 to 5 g/d late preg) 58 (total) 0.72 (as example) ~80 grams ration P (58/.72)

34 Phosphorus Requirements Milking Cow Description: 1540 lb BW mature Holstein; 0 wt loss 3.5 % milk fat, 3.2% milk protein MY varied = 20, 30,.100, 120 lb/d Diet: CS, AH, HMC, gdc, SBM, BM, CaCO 3, Ca 2 PO 4, TM-Vit Prmx ---- Balanced: National Research Council (2001)

35 Total Dietary P Requirement (grams/day) Total Dietary P, g/d NRC (2001); AC = 0.72; AC varies with diet % FCM, lb/d

36 The 1-to to-1 Rule: Milking Dairy Cows 1 gram of ration P for each 1 lb of milk for each cow in each management group

37 Dietary P Recommendation (% of ration DM) Dietary P, % NRC (2001) % FCM, lb/d

38 P Feeding Recommendations (NRC, 2001) MY, lb/day 0 (dry cow) Ration P, % of DM (max)!

39 Topic 5 Any real benefits of over-feeding P vs. NRC requirements?

40 Reasons for Over-feeding P Compare with NRC Requirements? 1. Improved MY & reproductive performance? 2. Hypophosphatemia (low blood P) of fresh cows caused by low ration P before calving?.. some vets say Decrease risk of hypophosphatemia?????

41 Reproductive Performance Any real benefits of over-feeding P vs. NRC requirements?

42 Dietary P and Reproduction Summary: 6 research studies ( ) 1 no evidence that feeding P in excess of requirements improved reproductive performance P ranged from 0.24 to 0.62% among studies (Beede and Davidson,1999; NRC, 2001)

43 Recent Study: P and Reproduction NRC: excess Item 0.37% P 0.57% P P < First blood P 4 surge NS Days to first service NS Concept. rate at d 60, % NS Average days open NS Services/ conception Lopez et al. (2004). J. Dairy Sci. 87:146. Univ. WISCONSIN n = 267 Holstein cows. NS

44 P Nutrition of : Transition performance of close-up, late pregnant, dry cows?

45 Experimental 43 mature pregnant Holstein cows MSU Dairy Research Center (Sept - Feb) Objective: evaluate health, metabolic and lactational performance Dietary P treatments: Trt 1: 0.21% total dietary P Trt 2: 0.31% Trt 3: 0.44% 28 d before calving

46 Prepartum P Intake P Intake (g/d) Trt 1 Trt 2 Trt Days before Parturition Trt 0.01 Trt*Time 0.01

47 Transition Serum P Serum P (mg/dl) Trt 1 Trt 2 Trt Days around Parturition Trt NS Trt*Time 0.01

48 Transition Serum Ca S e rum C a lc ium (m g/dl) Trt 1 Trt 2 Trt 3 Days around Parturition Trt NS Trt*Time 0.02

49 Lowest Serum P mg/dl Days around Parturition Serum P Serum Ca Cow 3109, Trt 3, Parity 5; no clinical signs

50 Dietary P Recommendation for Close-up Pregnant Cows Sufficient: 30 to 35 g/cow per day (requirement) NRC (2001) = 0.24% P Experimental = 0.21 to 0.31% (recommended ration P%) J. Dairy Sci.. (2005) 88:

51 Reasons for Over-feeding P? Improved MY & reproductive performance? Hypophosphatemia (low blood P) of transition cows caused by low dietary P? Feed phytate-p unavailable to ruminants? These are misconceptions! (NRC, 2001; Beede & Davidson, 1999).

52 Topic 6 Measuring and Predicting P Excretion Use of P Mass Balance for Comprehensive Nutrient Management Planning

53 Concept: P Intake Manure P Manure P, g/d Holstein cow: P requirement for 70 lb MY P intake, g/d

54 P Balance (Intake P - Milk P) Relationship with P Excretion Measured P Excretion (g/d) R 2 = 0.86, P < Measured Intake P - Milk P (g/d)

55 Topic 7 Example: P Excretion from a 300-cow dairy herd

56 Estimate of Manure P P Excretion (lb/d) = P intake (lb/d) - P in milk (lb/d) P% of rations x lb ration consumed 0.09% P in milk x lb milk shipped

57 Calculating P Excretion at NRC (2001) Recommendations Herd of 300 lactating Holsteins: 100/ group (feed P intake) (milk P output) = manure P P intake, lb/ day: Production Group DM Intake (lb/day) NRC (2001) Ration P (%) P intake (lb/ day) High: 80 lb Med: 70 lb Low: 60 lb Total 49.7

58 Calculating P Excretion at NRC (2001) Recommendations Herd of 300 lactating Holsteins: 100/ group (feed P intake) (milk P output) = manure P P intake = 49.7 lb/ day P in milk, lb/ day: 70 lb x 0.09% x 300 cows = 18.9 lb/ day Total P in manure: = 30.8 lb/ day

59 Calculating P Excretion at Greater Than NRC (2001) Recommendations Herd of 300 lactating Holsteins: 100/ group (feed P intake) (milk P output) = manure P P intake, lb/ day: Production Group DMI (lb/day) Greater > NRC P (%) P intake (lb/ day) High: 80 lb {0.34} 24.7 {19.1} Med: 70 lb {0.33} 21.0 {16.1} Low: 60 lb {0.32} 19.0 {14.5} Total 64.7 {49.7}

60 Calculating P Excretion at Greater Than NRC (2001) Recommendations Herd of 300 lactating Holsteins: 100/ group (feed P intake) (milk P output) = manure P P intake = 64.7 lb/ day P in milk, lb/ day: 70 lb x 0.09% x 300 cows = 18.9 lb Total P in manure: = 45.8 lb/ day

61 Comparison of Manure P Excretion for Example 300-Cow Herd Consider: Item At NRC (2001) P fed At > NRC (2001) P fed Difference % Increase In 1 year equal to: Manure P, lb/day % 12,443 lb (P 2 O 5 ) 12,443 lb (

62 @ 50 lb P 2 O 5 /acre: 250 extra acres/year or ~1 additional acre/cow due to over-feeding of P!

63 The 1-to to-1 Rule: Milking Dairy Cows 1 gram of ration P for each 1 lb of milk for each cow in each management group

64 Take Home Messages Feeding Management Strategies: 1. Formulate rations knowing that true bioavailability of P is high. 2. Formulate rations to meet the animals P requirements as accurately as possible. 3. Routinely analyze feeds for P content. 4. Stop P supplementation in many dairy rations.

65 Take Home Messages Feeding Management Strategies: 5. Consider alternative, lower-p feeds for rations. 6. Formulate specific rations to meet P requirements of cows in specific management groups. 7. Optimize animal performance (intake, productivity, and efficiency).

66 Summary and Conclusions Feed to exact P requirements to: 1. Reduce ration costs $ $ 2. Produce less manure P 3. Reduce land needed for manure application! 4. Reduce operating costs $ $! 5. Essential for: Environmental Sustainability and PROFITABLE FUTURE!

67 Thanks! Questions? Discussion