MANIPULATING MILK YIELD AND COMPOSITION by 12lsX9q

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									MANIPULATING
MILK YIELD AND
 COMPOSITION



      Leo Timms
  Iowa State University
  POUNDS

    VS.

PERCENTAGES
           GENETICS
   • Milk composition/ yield highly heritable
              • Heritability (h2)
               • milk yield .27
                  • % fat .58
                • % protein .49
                • % lactose .55
 • Correlation between % fat and protein: ~.5
 • Correlation between yield and % fat : ~ -.2
• Correlation between yield and % protein: -.1
          GENETICS
• Milk composition/ yield highly heritable
           • Breed differences
            • Fat / protein %
         • Milk fat globule size
             • Beta carotene
          • Fatty acid profiles
           • Casein genotypes
 PHYSIOLOGICAL FACTORS

                      • Age
               • Stage of lactation
        - colostrum - rest of lactation
          • Dry period ( non-lactating)
       • Milking fraction (fat, SCC, IG?)
                • Milking interval
• Reproduction: estrus/ follicular cyst/pregnancy
                  • Temperature
   • Factors that affect/ compete for nutrients
PHYSIOLOGICAL FACTORS

       • METABOLIC DISEASES
• Ketosis (glucose shortage – fat mobilized)
     may increase or decrease yield
       increased fat test ( lipolysis)
          increased milk ketones
          • Milk Fever (Ca drain)
           decreased production
        • MASTITIS ( Future talk)
NUTRITIONAL FACTORS

 IF YOU DON’T
  FEED THEM,
  THEY WONT
  MILK! (DMI)
NUTRITIONAL FACTORS

     • Underfeed energy (CHO)
       Volume, lactose, protein

        • Underfeed protein
      Volume, lactose protein

Underfeeding energy: greatest effects!
LACTOSE (VOLUME)
        • GLUCOSE demands!
    • Traditionally hard to change!
 • Propylene glycol/ glycerol drenches
         (bolus effect important!)
               • Rumensin
              • Chromium
       • Cobalt and Vitamin B12
• Niacin and choline (rumen protected)
      MILK PROTEINS
     • Not as easy to change as one thinks!
     • Worth lots of $ so want to increase!
       • Dietary protein: minimal effects
• Protected proteins/AA: minimal when protein
                    is sufficient
            • Oilseeds: protein%

  • Hyperinsulinaemic/ euglycaemic clamp
       • Increased milk protein 25%
• Same plasma AA: blood flow/AA extraction
       VITAMINS
• Vitamin A: fresh vs stored feeds
  • Increase feed Vit A/E: milk
  • May be more important for
     mastitis and somatic cells
       MINERALS
•   Very hard to change!!!


       IODINE!
    MILK LIPIDS
   • Easiest to change: diet labile
• Change amount and types of FA
 • Saturated/protected oils: temp
  • Excessive grain / limited fiber
    • Rumen buffers: if low, will
      • Excess or free oilseeds:
  • Fiber digestion , CLA isomer
      • Feed CLA: CLA ; Fat

								
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