Ruminant Metabolism Flashcards
where does carbohydrate digestion primarily occur in ruminants? how?
in the rumen; microbes digest carbs into VFAs
list the 3 volatile fatty acids and how many carbons each has
- acetate: 2 carbones
- proprionate: 3 carbons
- butyrate: 4 carbons
how are VFAs absorbed in ruminats?
through the rumen wall; don;t have to travel through the rest of the tract
once absorbed through rumen wall, where do VFAs go?
enter hepatic portal system and go to liver
what happens once VFAs get to the liver?
liver converts VFAs to other products for energy
what is acetate converted to in the liver and what is it used for (3)
acetate converted to acetyl CoA for
- fatty acid synthesis
- citric acid cycle
- cholesterol synthesis
what is proprionate converted to in the liver and what is it used for? (2)
proprionate converted to succinyl CoA for
- citric acid cycle
- also is a precursor for glucose in ruminants to maintain blood glucose and provide energy
what is butryate converted to in the liver and what is it used for?
butryate is converted to B-hydroxybutyrate, a ketone body that is used for energy in extrahepatic tissues
describe energy content of roughages
low in energy
what animals are roughages used by? (2)
ruminants and non-ruminant herbivores
give 5 generalexamples of roughages
- pasture
- hay
- silage
- crop residues
- by-products
what do roughages contain to provide protein? (3)
- amino acids
- nitrates
- ammonia
describe vitamin content of roughages
B vitamin content is generally high in roughages
what does the mineral composition of roughages depend on? (2)
- plant species
2. soil mineral content
decribe calcium and magnesium content in legumes
high
describe phosphorous content in legumes and grasses
low
describe potassium content in forages
generally high
what kind of climate do cool-season grasses prefer?
cool climate (duh)
give 4 examples of cool season grasses
- timothy
- orchardgrass
- tall fescue
- ryegrass
what is a deleterious factor of fescue and ryegrass?
they are prone to ergot
what is ergot? what does it cause (3)
a fungus of fescue and rygrass that causes
- loss of tips of extremities
- abortion and agalactia
- fat necrosis: hard, large clumps of fat around organs
how do you identify ergot infection of ryegrass and fescue?
brown curls on grass
what climate do warm-season grasses prefer?
temperatures consistently above 75 degrees
give 2 examples of warm season grasses
- bermudagrass
2. bahiagrass- prefers even warmer temps
why are legumes seen as superior forages compared to grasses? (3)
due to their high protein content (nodules) and energy content (leafy) and high in calcium and magnesium
why do legumes have such high protein content?
rhizobia bacteria forms nodules that fix nitrogen from the air which is then incorporated into nitrate into the plan and increase crude protein content
give 5 examples of legumes
- alfalfa
- red clover
- white clover
- alsike clover
- sweet clover
what is the most common legume in animal nutrition?
alfalfa
what does grazing allow?
allows the animal to harvest the forage themself, bring animals to food source
what are the 2 types of grazing systems?
- extensive: not labor intensive, leave the animals be, leads to animal loss
- intensive: manage and maintain and check animals, have to move animals because pasture utilization is high so more labor involved
list and describe the 3 types of intensive grazing systems
- continuous grazing: continously stock pasture with animals, low labor but no time for pasture to regrow
- rotational grazing: animals move to different pasture every few days, more labor but allows pastures to rest some
- strip grazing: move animals to new strip of pasture every day, usually by moving fences. most labor intensive
describe haymaking
dehydrating green forage to a moisture content of 15% or less
what is the issue with hay?
it is hard to get a decent yield with both volume and nutrition
what will younger hay yield
higher TDN, but lower total volume yield
what will older hay yield?
higher fiber, lower TDN, higher total volume yield
what do most people try to do when making hay?
maximize TDN with yield by harvesting in the early bloom/early flower stage
how is silage created?
anaerobic fermentation of carbohydrates
with is the dry matter content of silage, what does this mean?
only 25-35% DM, very high water content, wet product
