Lecture 9: Milk Component Synthesis

Concept: Milk Synthesis

a.Filtration Process ?

b.Cell Metabolism?

• a.filtration

• -water: ensure water availability

• -minerals: mineral content does not differ

• -vitamins: ensure water soluble or fat soluble

• b.Cell metabolism

• -mammary glands need to produce these componets

• -milk lactose, protein, fat

Concept: Milk Lactose Synthesis

-how is glucose utilized and how is produced?

-Rumen converts carbs into propionate, propionate converted into glucose in liver, mammary gland converts glucose to galactose to make lactose

Concept: Amino Acids for Mammary Gland

-what is rumen degradable protein?

-what is rumen undegrable protein?

-what is both of their significance in small intestine?

degradable protein: protein available to rumen microbes

undegradable protein: protein not available to rumen microbes

both are absorbed in small intestine(metabolizable protein), become available for mammary gland

Concept: Milk Protein Synthesis

-how do amino acids become available to mammary gland?

-within rough endoplasmic reticulum, protein granulates form that accumulate in golgi apparatus

-within the Golgi apparatus form capsules around the protein, transport the amino acids into the lumen of alveolus

Concept: What is milk fat depression?

-when does this condition occur?

-is it influenced by diet?

-what occurs to composition of the milk?

-does it reduce genes that express enzymes involved in milk fat synthesis?

-what factors can cause milk fat depression?

-how can the diet be manipulated to reverse milk fat depression?

-milk fat yield is reduced and all other components of milk remain the same

-the cause may be to bioactive biohydrogenation that reduced milk fat synthesis

-diets that are too high in energy, gain body weight, body prioritizes storage for adipose tissue

-reduced milk production

-it reduces enzymes involves in milk fat synthesis

-low rumen pH, reduced feed particle size, high starch, change in feeding pattern

-high fiber + saturated fat diets allowed for more energy to be given to milk fat

What is biohydrogenation?

-rumen tries to convert unsaturated fatty acids into saturated fatty acids

-this is done to protect microbial community

-unsaturated fats can be toxic to specific microbes

Concept: Seasonal effects of milk fat synthesis + protein

-Fat levels are highest in the Early Winter( Jan-March) and late winter( oct-dec)

-fat levels are lowest in summer

-Protein levels are highest in early winter( jan-march) + oct-dec

-protein levels are lowests in summer