FEED ADDITIVES IN DIETS OF TRANSITION DAIRY COWS Jos

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FEED ADDITIVES IN DIETS OF TRANSITION DAIRY
COWSJosé Eduardo P. SantosVeterinary
Medicine Teaching and Research Center School of
Veterinary MedicineUniversity of California -
Davis
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Objectives

• Discuss the metabolic and endocrine effects of
  feed additives during the transition period
• Potential impact of the use of feed additives
  during transition on performance and incidence of
  metabolic disorders in dairy cows

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Rumen Fermentation
Propionate
Microbial Protein NH3
CO2 CH4 H2
CHO Protein
Pyruvate
Acetate Butyrate
Glucose
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Effect of Ionophores on Rumen Bacteria (Gram )

• Extracellular Intracellular
• ATP
• H H
• ADP
• H H
• K K
• Na Na
• H H

M
M
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Results of Ionophore Use

• Reduces Gram population
• Proteolytic and amilolytic bacteria
• Decreases proteolysis ----gt Greater flow of
  nonammonia-nonmicrobial nitrogen to the duodenum
• Reduces lactate producing bacteria Streptococcus
  bovis and Lactobacillus spp.
• Increases molar concentration of propionate
• Reduces CH4 concentration ---gt Less energy loss

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Why Ionophores Would Benefit Transition Cows?

• Improves efficiency of energy metabolism
• More propionate
• More glucose
• Less BHBA
• More insulin
• Less lipid mobilization
• Lower incidence of subclinical ketosis
• Reduces the risk for ruminal acidosis and bloat
• Increases the flow of true protein (It may not
  change total protein flow because of the negative
  impact on microbial N)

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1.01
0.94
444/530
438/526
283/486
271/497
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Gluconeogenic Precursors

• 4 major sources
• Propylene glycol
• Calcium propionate
• Sodium propionate
• Glycerol
• Poorly fermented in the rumen
• Calcium propionate is also a source of Ca

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Effect of Propylene Glycol on Liver Lipids and TG
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Effect of PG on Transition Cow Performance

• PG had no impact on milk composition and plasma
  insulin
• PG increased IGF-I, plasma cholesterol and
  decreased MUN and NEFA

P gt 0.15
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Niacin
Blood Compartment
Adipose Tissue
Triacylglycerol
Niacin
-
HSL
Diacylglycerol Monoacylglycerol NEFA
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Ruminally Protected Amino Acids

• AA can be used as gluconeogenic precursors
• Enhance oxidation of fatty acids by the hepatic
  tissue
• Enhance VLDL synthesis and secretion
• Reduce ketogenesis
• Supply limiting amino acids for milk and milk
  protein synthesis

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• Bauchart et al. (1998) observed that
  rumen-protected lysine reduced hepatic
  triglyceride content
• Review by Garthwaite et al. (1998) - 6 studies
• Rumen protected Lys and/or Met supplemented pre-
  and postpartum
• ? DMI 0.5 kg/d, ? milk yield 1.5 kg/d, ? milk
  protein yield 79 g/d, and ? milk fat yield 85 g/d
• 2 studies, supplemental Met was detrimental to
  performance

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Yeast Culture

• Possible reasons for feeding Saccharomyces
  cerevisiae in transition diets
• Increase rumen pH (Selenomonas ruminatium)
• Stimulate the growth of fiber digesting bacteria
• Increase NDF digestibility
• Reduce the depression in DMI immediately before
  calving
• Improve DMI postpartum

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Effect of Saccharomyces cerevisiae on transition
cow performance (Robinson and Garrett,1999)

• Feeding YC from d -28 to d 56 had no effect on
  DMI, DMI as BW, BW and BCS changes, and NEL of
  diets during the pre- and postpartum periods
• Feeding YC had no impact on concentration and
  yields of fat, protein, and lactose of
  primiparous and multiparous cows

P lt .28
P lt .09
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Hypocalcemia (clinical or subclinical)
? Smooth Muscle Function
? Rumen and GI Tract Motility
? Uterine Motility-Immunity
? RP ? Involution
? DMI
? DA
? NEB
? Metritis
? Ketosis
? Milk Production
? Fertility
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Bone Resorption
Diet
PTH/Vit D Calcitonin ? Hypercalcemia ?
Intestine
Vit. D
Extracellular Ca Pool (8 to 10 g)
Plasma Ca Pool 2.5 to 3.0 g
PTH and Vit D
Fecal Loss 6 - 10 g/d
Milk 20 - 80 g/d
Fetal Bone 2 - 10 g/d
Urinary Loss 0.25 - 1.0 g/d
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Acidogenic Salts

• High chloride and sulfate salts
• CaCl2, NH4Cl MgCl, MgSO4, CaSO4, (NH4)2SO4
• HCl
• Acidify the blood by increasing H absorption
• S is poorly absorbed --gt It is not a good
  acidifier

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Intracellular and Intravascular Spaces
Lumen GI Tract
Cell Membrane
-
SO4-2
? H
-
? pH
-
Cl-
? HCO3-
-
H
-
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Strategies for Prevention of Hypocalcemia
DCAD lt 250 mEq/kg
DCAD gt 250 mEq/kg
? Calcitropic Hormones
? Passive Absorption
? PTH Receptor Sensitivity
Addition of Anions
Low Ca diets lt 20 g/d Vit. D Analogues
Ca Gels
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Equations to Calculate DCAD

• DCAD mEq/kg (0.38 Ca 0.3 Mg Na K) - (Cl
  0.6 S 0.5 P)
• (NRCs coefficients)
• DCAD mEq/kg (0.15 Ca 0.15 Mg Na K) - (Cl
  0.2 S 0.3 P)
• (Goffs coefficients)
• DCAD mEq/kg (Na K) - (Cl S)
• Assumes equal rate of absorption for all strong
  ions

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How to Use Them

• Step 1
• Analyze all feed components for their mineral
  content
• Na, K, S, Cl, Ca, P, and Mg
• Select forages and ingredients with low K and Na
  content
• Grain silages, low K alfalfa (mature), brewers
  grains, beet pulp without molasses, citrus pulp
• Basal diet DCAD lt 250 mEq/kg

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• Step 2
• Adjust mineral content
• Provide Mg to achieve 0.4 diet DM
• MgSO4, MgCl, MgO
• Increase S up to 0.35 to 0.4
• CaSO4
• S gt 0.4 may cause PEM and may interfere with Cu
  and Se
• Keep P at 0.35 to 0.4
• High P intake (gt 80g/d) may cause milk fever

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• Step 3
• Acidify the diet
• Keep K as low as possible (K lt 1.2)
• Keep Na as low as possible (Na lt 0.15)
• Increase Cl
• CaCl2
• Keep Cl lt 0.8, but high enough to lower urine pH
  
• Adjust Ca content to 1.0 to 1.2
• Ca Propionate or CaCO3

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Mineral Profile of a Close Up Diet

• Dietary DCAD should be
• Multiparous cows - 50 mEq/kg
• Primiparous cows 0 mEq/kg
• Monitor urine pH
• Urine pH should be between 5.8 and 6.8

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Conclusions

• Ionophores (Monensin)
• Prepartum 30 ppm and Postpartum 10 - 15 ppm
• PG and Ca Propionate may be used in the
  concentrate or as an oral drench. Consider Ca
  Prop. when using anionic salts
• Niacin Controversial results
• Lipotropic agents and Yeast Not recommended
• Acidogenic salts Highly recommended when
  hypocalcemia is a concern
• RP AA positive effects on milk protein content
  and yields of milk and milk protein when
  supplemented pre- and postpartum

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