Milk Synthesis Flashcards
Why is nutrition important in dairy cow milk production?
It optimizes milk yield and quality, influencing over 50% of production costs and supporting rumen fermentation for nutrient absorption.
What role does rumen fermentation play in dairy cows?
It provides 60-70% of energy through volatile fatty acids (VFAs) and ~60% of amino acids needed for milk synthesis.
What is the primary composition of milk?
Milk is mainly water (87.7%), with protein, fat, lactose, minerals, and vitamins.
How does the lactation phase affect milk composition?
Early lactation (first three weeks) is crucial, with high milk fat indicating an energy deficit and risk of ketosis.
What determines milk volume in dairy cows?
Lactose synthesis, which depends on blood glucose levels, is the primary factor for milk volume.
How does high starch intake affect milk production?
It increases propionic acid, boosting glucose and lactose synthesis for higher milk yield, but may reduce milk fat.
What is the ideal milk fat content and its primary source?
Ideal milk fat is 3.5-4.5%, mostly composed of triacylglycerols from VFAs like acetic acid and butyric acid.
How does diet impact milk fat content?
High-fiber diets promote milk fat, while high-starch diets favor lactose, reducing milk fat.
What does a high fat-to-protein ratio in milk indicate?
It signals an energy deficit and may suggest ketosis risk, especially in early lactation.
What causes low milk fat syndrome?
High grain and unsaturated fat diets disrupt rumen fermentation, increasing trans-fatty acids and reducing milk fat.
What factors impact milk protein levels?
Milk protein (3.2-4.0%) depends on rumen degradable (RDP) and undegradable protein (RUP) ratios and available energy.
What leads to decreased milk protein content?
Energy deficits, high degradable protein, or low bypass protein in feed reduce protein content.
How are milk urea levels used to assess diet in dairy cows?
Milk urea (ideal 15-30 mg/100 ml) reflects nitrogen-energy balance; high levels suggest protein wastage or energy deficit.
What does elevated ketone in milk indicate?
High ketones (>0.4 mmol/l) suggest energy malnutrition, particularly in early lactation.
Why is milk profile testing important?
It provides insights into nutrient intake, energy balance, and metabolic health by analyzing milk urea, protein, and fat levels.
