Fat Digestion & Absorption
What organ produces bile for fat digestion?
Where in the cell does B-oxidation occur?
Mitochondria
Ketones elevate when what molecule is limited?
Glucose
What portion of feed is used by the animal?
Digestible portion
True digestibility corrects apparent digestibility by subtracting ____?
Metabolic fecal nutrient
What structure forms when fayyt acids, monoglycerides and glycerol cluster together in the SI?
Micelles
Enven # fatty acids break down into what 2-carbon unit?
Acetyl-CoA
Name 1 species group highly likely to get pregnancy toxemia
Does or ewes
Name one thing excreted in urine besides water.
Minerals, metabolites, ketones, vitamins, proteins, etc
Biological value measures how much absorbed nutrient is what?
Retained in body
Long chain fatty acids get packaged into what lipoprotein before entering the lymph system?
Chylomicrons
B-Oxidation is the breakdown of what class of macronutrient?
Fatty acids
What is a common treatment for ketosis in cattle?
Propylene glycol/IV glucose
Feces contain both undigested feed and what other category?
Metabolic fecal nutrients
Does true digestibility tend to be higher or lower than apparent digestibility?
Higher
Adding fat to a ration increases what main nutrient value of a diet?
Energy density
Odd chain fatty acids produce what 3 carbon intermediate?
Propionnyl CoA
When in dairy cattle do we typically see an increase in fat mobilization risk for ketosis
Post-calving/early lactation
What are the main requirements for something to qualify as a good digestibility indicator?
It must be inert, non-digestible, doesn't interfere with stretch receptors, and move through the GI tract at the same rate as feed.
Why does apparent digestibility underestimate true digestibility?
Becasue apparent digestibilyt counts metabolic fecal loss as if it came directly from feed
Which type of fatty acid improves digestibility more?
Unsaturated
During periods of extremely high fat mobilization, why can β-oxidation become limited even when there is plenty of fatty acid available?
Because β-oxidation depends on adequate oxaloacetate from carbohydrates to run the TCA cycle — without enough OAA, Acetyl-CoA backs up → slowing β-oxidation and diverting Acetyl-CoA toward ketone formation instead.
When ketones rise due to a lack of _____ for the TCA cycle, what condition forms?
OAA, Ketosis
Why do we use an inert marker when measuring digestibility?
Because it allows us to track movement through the GI tract without being digested so we can estimate the disappearance of nutrients
If an animal retains very little of the absorbed nutrient, what does that say about the Biological Value of that feedstuff?
It has a low BV because the animal is not retaining most of the absorbed nutrient