GI Nutrition- The rumen complex Flashcards
What is the purpose of fermentation?
Fermentation transform forage into simple sugars that rumen microorganisms can use for growth
What are the by-products of fermentation?
Volatile fatty acids
What do microbes provide to ruminants?
digestion of cellulose, amino acids, protein, vitamin B
What are calfs?
monogastrics
Oesophageal groove
closed tube that allows milk to bypass the rumen and go straight to the abomasum, this prevents milk from being fermented
What effects the growth rates of calfs?
energy and protein contents of milk, volume and frequency that the milk is supplied
What should calves have first after colostrum?
Milk replacer-it is digested in the abomasum and bypasses the rumen
When should concentrates be fed?
From 3-4 days old, they produce butyrate and propionate which increases papillae size and number which increases the overall size of the rumen
Why should you not feed fibre from birth?
rumen is undeveloped so they cannot digest it, digesting milk and forages does not help papillae to grow
What age should you be concentrate feeding?
3-4 weeks
What is the benefit of feeding fibre?
stimulates rumination and saliva production, increases pH, produces acetate, reduces keratinisation
Why are VFA’s important?
size and length of ruminal papillae respond to VFA’S
What are the benefits of feeding forages?
Increases size of rumen, encourages calf to ruminate
Why do calves need water?
increases intake of grain, reduces incidence of diarrhoea, reduces acidosis
What is the structure of fibre?
a polysaccharide which forms straight chains (B-glucans), mammalian enzymes cannot break it down
What is the ruminant stomach?
4 chambers, 3 of which do not contain digestive enzymes- contains huge number of microorganisms that ferment fibre
How does the rumen work?
Cycles of contractions, belching removes gases every second contraction
What is the function of the rumen?
(the largest chamber, on the left of the stomach) storage site and fermentation, absorbs VFA’s and nutrients
What is the function of the reticulum?
traps large feed particles to make sure they don’t enter the next section of the stomach before they are digested, regurgitation of ingesta followed by re-mastication and re-swallowing
What is rumination?
Eating low quality fibre that requires mechanical breakdown
How does chewing the cud occur?
Swallow fibre whole, rip it up using the tongue- regurgitating and chewing/ruminating the food- maximises intake of food then moves it to an area of safety
How much saliva do ruminants produce during rumination?
150-250 Litres
What occurs during rumination?
Bacteria ferment fibre, fibre is digested by bacteria and used to grow- by-products of fermentation are released into the rumen (By-products are VFA’s)
What happens to plant carbohydrates?
Bacteria bind to the plant cell wall and break them down into smaller monosaccharides, glucose and other monosaccharides are released which are then rapidly absorbed by microbes
Glycolysis releases pyruvate which is transformed into VFA’s
What happens to protein in the rumen?
bacteria break down protein and fibre into amino acids, some of them are used by the bacteria to grow
What are the bacterial byproducts of protein digestion?
Ammonia and VFA’s
What happens to plant protein?
bacteria pass into small intestines and protein digestion provides amino acids for the cow, ammonia and VFA’s are required to make bacterial protein
what is RDP?
rumen degradable protein, feeds the rumen bacteria and ensures an adequate supply of microbial protein, microbial protein is the highest quality available
what is RUDP?
undegradable protein, passes through the rumen unchanged and is digested in the small intestine
