manipulating milk yield and composition leo timms iowa state university
TRANSCRIPT
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• Correlation between yield and lbs. fat / prot. ++
GENETICS• Milk composition/ yield highly heritable
• Species and/ or 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)
WATER!!!!!
H2O
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