Tissue Support Flashcards
Why is there a lag in DMI behind milk yield?
90% uptake of glucose production in mammary glands, >75% Metabolizable Protein intake going towards mammary gland
overall: negative energy balance >100% NE output as milk/ fetus energy
therefore use body reserves for nutrients to support demand
What’s insulins normal role?
stimulate lipogenesis in adipose and protein synthesis in muscle tissue
- inhibits hydrolysis of TAG + protein
- stimulate glucose uptake into tissues
- inhibits oxidation of FA’s
what causes insulin resistance in onset of lactation + why?
Growth Hormone because allows favouring towards nutrient partitioning into milk
Mammary lactose synthesis causes what to drop?
plasma glucose and insulin
Adipose lipolysis increases resulting in what to rise?
plasma NEFA
what suppresses Dmi?
elevtated NEFA
where are NEFA oxidized?
liver
with elevated NEFA what happens to the liver?
partially oxidized NEFA > BHB because elevated NEFA cause fatty liver resulting in less active liver tissue
what does bST do?
a GH that enhances cell proliferation, incr insulin resistance in adipose tissue
- acetyl coA carboxylase causing FA synthase in mammary gland higher than fat tissue
- protein synthesis in mammary gland
incr insulin causes acetate to do what ?
incr lipogenesis in adipose tissue
Insulin > GH
due to fed non lactating sheep have higher acetate uptake (higher fat uptake)
- fed lactating have decreased acetate uptake but still more than fasted non lactating
low producing cows have higher what than high producing cows?
plasma insulin- due to high producing cows have higher insulin resistance
high producing cows have higher what than low producing cows?
GH - due to incr insulin resistance for nutrient partitioning before calving
whats ketosis?
metabolic acidosis due to hyperketonemia + hypoglycemia
how does ketosis occur?
due to negative energy balance before calving causing low blood glucose, cows use body fat stores to utilize for energy. this occurs by incr NEFA from FA stores which are partially oxidized in liver due to elevated amounts. therefore BHB (ketone) produced.. in combination with low plasma glucose and insulin (from GH resistance) leads to hyperketonemai, acidosis..
