Forage MacroMinerals Ca P K Mg Na Cl

Forage Macro-Minerals (Ca, P, K, Mg, Na, Cl, S) and Dairy Cow Requirements Jim Linn, Ph. D Professor Emeritus – University of Minnesota Milk Specialties Global Waconia Farm Supply

Importance of Minerals Animal Health Production/Reproduction Ration cost Lactating Cow Close-Up Dry Cow 8 to 10% of total $/cow/day 0. 75 - 1. 00 18 – 22% of total $/cow/day 0. 75 - 1. 00

Nutrient Composition (% DM) of Dairy Rations 100 90 5. 5 3. 5 7. 0 80 17 14 28 36 44 39 Lactating Cow Close-up Dry Cow 70 60 50 40 30 20 10 0 Fat Minerals Protein NDF Non. Fiber CHO

Forage Minerals Forage minerals Contribute to animal requirement Variability – species, maturity, soils, fertilization Animal – Plant Imbalances

Forage Mineral Analysis NIRS or Wet Chemistry? – NIRS doesn’t measure minerals only C, N, O bonds – Are the minerals reported on NIRS forage tests accurate? – At the end of the day, when nutritionists have several rations to formulate, can NIRS predicted forage minerals be used?

NIR Prediction of Minerals Haylage Calibration Data Mineral Mean SEC RSQ SECV Ca 1. 12 . 15 . 86 . 16 P . 34 . 04 . 61 . 04 Mg . 32 . 05 . 69 . 05 K 2. 66 . 32 . 81 . 32 S . 26 . 04 . 75 . 04 SEC – Std Error Calibration – lower better (± 1 SEC – 67% of values) RSQ – R 2 1 = perfect prediction SECV – Prediction validation – lower the better NIR mineral validity depends on good reference wet chemistry methods and equation(s) development Source – Dairyland Labs, Arcadia WI

NIRS Analysis – Forage Minerals Macro Minerals – – Lactation rations • Acceptable estimator – Ca, P, K, Mg and S • Rationale – Most rations over formulated and supplemented – Small range in P, Mg and S within species – Salt meets Na and Cl req’t – Dry cow • NIRS not recommended for mineral analysis • Forages are large proportion of diet • Accuracy needed for DCAD and requirements Trace minerals – NIRS not recommended

Forage Macro Minerals SGS Forage Summary - 2012 Mineral Legume Haylage Grass 2+ Haylage Mixed Haylage Mix-Leg Haylage Corn Silage ---------------- Mean / SD ----------------------- Ca SD P SD K SD Mg SD 1. 13 0. 67 0. 75 1. 05 1. 33 0. 22 0. 37 0. 26 0. 25 0. 39 0. 34 0. 07 0. 29 0. 31 0. 32 0. 29 0. 30 0. 21 0. 07 0. 08 0. 07 0. 06 0. 03 2. 46 2. 57 2. 65 2. 41 0. 88 0. 54 0. 78 0. 58 0. 63 0. 54 0. 27 0. 25 0. 30 0. 26 0. 31 0. 18 0. 08 0. 06 0. 08 0. 07 0. 06

Mineral bioavailability (%) estimate of forages NRC 2001 Ca 30 – 35 P 60 – 65 K >85 Mg 15 – 20 S 85 – 90 Na >85 Cl >85

Minerals in Rations of Lactating Dairy Cows

Feed DM (lb) – 85 lb Milk S g. M % K- 53 K- rb Bi ca lt Sa Ca l M g. O x o b M on ca r % Ca 46 y- GS So DD as s y. P d So Bl oo n Co r Sil n Co r D M ge F e e d 52 lb DM 17% CP 1. 18 Mcal ME/lb 32% NDF 25. 5% Starch 61 % Forage DM Ha yla L b 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Macro Minerals for Lactating Cows Requirements vs. Ration Formulation Mineral 2001 NRC Updated NRC Weiss 1 Formulated ---------------- % of DM -----------------Calcium 0. 6 – 0. 75 0. 70 - 0. 86 0. 9 – 1. 0 Phosphorus 0. 32 – 0. 40 0. 38 – 0. 48 >0. 42 Magnesium 0. 20 0. 28 0. 32 – 0. 38 Potassium 1. 0 1. 15 >1. 5 Sodium 0. 22 0. 25 0. 4 – 0. 6 a Chloride 0. 26 0. 30 >0. 4 b Sulfur 0. 20 0. 25 1 Weiss – Hoards Dairyman Feb 10, 2013 Sodium Buffers b Higher forage concentrations - legume a

Calcium Contribution From Feeds Lactating cow diet – 0. 90% Ca 45. 0 % Ca lb Feed 40. 0 35. 0 30. 0 25. 0 lb 20. 0 or % 15. 0 10. 0 5. 0 % KM g. S 53 K- rb Bi ca lt Sa rb M on o Ca l M g. O x ca % Ca 46 y- So DD GS s as y. P d So oo Bl rn Co l Si rn Co Ha yl ag e 0. 0

Phosphorus Contribution From Feeds Lactating cow diet – 0. 40% P 25. 0 % P contribution lb Feed DM 20. 0 15. 0 lb or 10. 0 % 5. 0 S g. M % K- 53 K- rb Bi ca lt Sa Ca l M g. O x o b M on ca r % Ca 46 y- GS So DD as s y. P d So Bl oo n Co r Sil n Co r Ha yla ge 0. 0

Magnesium Contribution From Feeds Lactating cow diet – 0. 35% Mg 40 % Mg contribution lb Feed DM 35 30 25 lb 20 or 15 10 5 S g- K- M % 53 K- rb Bi ca lt Sa Ca l M g. O x o b M on ca r % Ca 46 y- GS So DD as s y. P d So Bl oo n Co r Sil Co r n ge 0 Ha yla %

Potassium Mineral required in the highest amounts in lactating dairy cows • K balance studies indicate 1. 6% K needed in early lactation for positive balance • Heat stress increases requirement Forage K >85% available

Potassium Contribution From Feeds Lactating cow diet – 1. 5% K 60 % K contribution 50 40 lb 30 or % 20 10 Ha y la g Co e rn Sil Co rn Bl oo So d y. P as s DD G So S y 46 % Ca c M arb on o Ca l M g. O x Sa lt Bi ca rb K 53 % KM g. S 0

Sulfur Contribution From Feeds Lactating cow diet – 0. 28% S 35 % S contribution 30 25 20 lb or 15 % 10 5 Ca l M g. O x Sa lt Bi ca rb K 53 % KM g. S o b M on ca r % Ca 46 y- GS So DD as s y. P d So Bl oo n Co r Sil n Co r Ha yla ge 0

Sodium and Chloride Contribution From Feeds Lactating cow diet – 0. 5% Salt 60 Ration – 0. 5% Na and 0. 62% Cl 50 40 lb 30 or % 20 10 S KM g- % 53 K- rb ca Sa lt Bi Ca ca rb M on o Ca l M g. O x % 46 y- GS So DD s as y. P d So oo Bl rn Co l Si rn Co Ha yl ag e 0

Minerals in Rations of Close-up Dry Dairy Cows

Close-up Dry Cow Diet 28 lb DM/day • • • Grass hay Corn silage Corn Protein Macro minerals TM/Additives lb/cow/day 8. 3 13. 7 0. 8 3. 8 1. 04 0. 64

Close-up Dry Cow Diet % Macro Mineral from Forage 80 Diet mineral % Ca – 1. 60 P – 0. 38 Mg – 0. 41 S – 0. 36 Na – 0. 09 Cl – 0. 50 DCAD +0. 3 70 60 % 50 40 30 20 10 e id or Ch l um di So r lfu Su m ta ss iu Po su m M ag ne us or ph os Ph Ca lci um 0 77% Forage diet – 13. 7 lb Corn sil + 8. 3 lb Grass Hay DM

Minerals from Forages in Dry Cow Diets • Forages can supply 20 to 70% a mineral • Accuracy on mineral concentration in forages more important – less error tolerance v Cation – Anion balance v Metabolic problems – greater risk with mineral imbalance • Wet chemistry analysis recommended for minerals in dry cow forages

DCAD, m. Eq/100 g = [(%Na 43. 5 + %K 25. 6) (%Cl 28. 2 + %S 62. 5)]

DCAD, m. Eq/100 g = [(%Na 43. 5 + %K 25. 6) (%Cl 28. 2 + %S 62. 5)] LACTATING COWS CLOSE-UP DRY COWS

Macro Minerals in Forage Summary • Forages are an important source of most macro minerals in lactating and dry cow rations. • Ration formulation needs to consider – – Requirements Sources Amounts fed – excess as well as deficiencies Interactions amongst minerals fed in excess

Macro Minerals in Forage Summary • NIRS acceptable estimator of Ca, P, K, Mg and S in lactating rations. – Formulations usually exceed minimum requirements • Forages are a greater proportion of dry cow ration and mineral formulation requires accuracy – Wet Chemistry mineral analysis recommended. • Precision feeding lactation and/or dry cow diets require wet chemistry analysis of minerals.

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