Phosphorus Management to Improve Profit and Ensure Environmental Sustainability

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

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

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

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

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

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% P @ crop removal rate = 50 lb P 2 O 5 /acre: Reduces cropland needed by 250 acres/yr for 300-cow dairy

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

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.

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

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.

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).

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.

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)

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)

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)

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?

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

Topic 1 Introduction

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 4. 70 to 80% of feed P is excreted in manure!

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

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 2003. Dairy Herd Management

Topic 2 Formulation Strategies and Feed Sources of P for Rations

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

What might be happening in ration formulations? Other considerations?

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?

Common P Supplements Source Ammonium phosphates Bone meal, steamed Calcium phosphate Dicalcium phosphate Phosphoric acid Corn & alfalfa silages Corn grain P % 21 25 13 22 19 32 0.27 0.30 P Absorption Coefficients 0.80 0.80 0.80 0.75 0.90 0.64 0.70

P Content of Feeds - Examples Feed P % CP % CP-to to-p Blood meal 0.30 95 318 Corn gluten meal 0.69 65 108 SBM, 44% 0.70 50 71 Corn silage 0.25 10 40 DDGS 0.83 30 36 Corn grain 0.30 8 27 Corn gluten feed 1.00 24 24 Hominy 0.65 12 18 Wheat bran 1.18 17 15

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?

Topic 3: P Requirements for Dairy Cattle

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

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 25 33 (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)

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)

Total Dietary P Requirement (grams/day) Total Dietary P, g/d 140 120 100 80 60 40 20 0 NRC (2001); AC = 0.72; AC varies with diet 0 40 80 120 3.5% FCM, lb/d

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

Dietary P Recommendation (% of ration DM) Dietary P, % 0.5 0.4 0.3 0.2 0.1 0 NRC (2001) 0 40 80 120 3.5% FCM, lb/d

P Feeding Recommendations (NRC, 2001) MY, lb/day 0 (dry cow) 40 60 80 100 120 Ration P, % of DM 0.24 0.29 0.33 0.35 0.36 0.38 (max)!

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

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?????

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

Dietary P and Reproduction Summary: 6 research studies (1971 1998) 1 no evidence that feeding P in excess of requirements improved reproductive performance P ranged from 0.24 to 0.62% among studies ------- 1 (Beede and Davidson,1999; NRC, 2001)

Recent Study: P and Reproduction NRC: excess Item 0.37% P 0.57% P P < First blood P 4 surge 53 53 NS Days to first service 89 90 NS Concept. rate at d 60, % 29 32 NS Average days open 112 116 NS Services/ conception 2.9 2.6 Lopez et al. (2004). J. Dairy Sci. 87:146. Univ. WISCONSIN n = 267 Holstein cows. NS

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

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

Prepartum P Intake P Intake (g/d) 80 70 60 50 40 30 20 10 Trt 1 Trt 2 Trt 3-28 -25-22 -19-16 -13-10 -7-4 -1 Days before Parturition Trt 0.01 Trt*Time 0.01

Transition Serum P Serum P (mg/dl) 9 8 7 6 5 4 Trt 1 Trt 2 Trt 3 3-7 -6-5 -4-3 -2-1 0 1 2 3 4 5 6 7 Days around Parturition Trt NS Trt*Time 0.01

Transition Serum Ca S e rum C a lc ium (m g/dl) 11 10 9 8 7 6-7 -6-5 -4-3 -2-1 0 1 2 3 4 5 6 7 Trt 1 Trt 2 Trt 3 Days around Parturition Trt NS Trt*Time 0.02

Lowest Serum P mg/dl 12 10 8 6 4 2 0-7 -6-5 -4-3 -2-1 0 1 2 3 4 5 6 7 Days around Parturition Serum P Serum Ca Cow 3109, Trt 3, Parity 5; no clinical signs

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) 88:3582-3594. 3594.

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).

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

Concept: P Intake Manure P Manure P, g/d 80 70 60 50 40 30 20 10 0 Holstein cow: P requirement for 70 lb MY 0 10 20 30 40 50 60 70 80 90 100 110 120 P intake, g/d

P Balance (Intake P - Milk P) Relationship with P Excretion Measured P Excretion (g/d) 100 80 60 40 20 0 R 2 = 0.86, P < 0.01 0 20 40 60 80 100 Measured Intake P - Milk P (g/d)

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

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

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 5610 0.34 19.6 Med: 70 lb 4884 0.33 16.1 Low: 60 lb 4532 0.32 14.5 Total 49.7

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: 49.7 18.9 = 30.8 lb/ day

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 5610 0.44 {0.34} 24.7 {19.1} Med: 70 lb 4884 0.43 {0.33} 21.0 {16.1} Low: 60 lb 4532 0.42 {0.32} 19.0 {14.5} Total 64.7 {49.7}

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: 64.7 18.9 = 45.8 lb/ day

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 30.8 45.8 +15.0 49% 12,443 lb (P 2 O 5 ) 12,443 lb (

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

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

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!

Thanks! Questions? Discussion