Ruminant Digestion and Metabolism Flashcards
What are the two models of herbivore fermentation?
Foregut and Hindgut
Foregut includes ruminants, hippos, and camelids; Hindgut includes horses, rabbits, and elephants.
What is the primary reliance of herbivore fermentation?
Micro-organisms within the GIT to digest cellulose and other plant carbohydrates
What are the three phases of cellulose degradation?
1) Complex sugars to simple sugars
2) Simple sugars to pyruvate
3) Pyruvate to Volatile Fatty Acids (VFAs)
The VFAs include acetate, propionate, and butyrate.
What are the percentages of the Volatile Fatty Acids produced during fermentation?
- Acetate (60-70%)
- Propionate (15-20%)
- Butyrate (10-15%)
What gases are produced during fermentation?
Carbon dioxide (CO2) and Methane (CH4)
Up to 30L/hr/cow.
What is Ketosis in cows?
A metabolic disorder that occurs in cattle when energy demands (e.g. high milk production) exceed energy intake and result in a negative energy balance
Milk yield normally drops before this happens.
What is the difference between primary and secondary ketosis?
- Primary: nutritional cause, unable to meet metabolic demand
- Secondary: caused by another disease reducing food intake
What is Pregnancy Toxaemia?
A syndrome in sheep due to increased demand for glucose from multiple foetuses
What is a solution for Pregnancy Toxaemia?
Boost glucose intake or perform a caesarean
What happens to dietary protein in the rumen?
Some passes through to the abomasum and small intestine; some is digested into amino acids and incorporated into microbes
What is produced when dietary protein is deaminated in the rumen?
Volatile Fatty Acids (VFAs) and Ammonia (NH3)
What can rumen microbes use ammonia for?
To make new amino acids that become part of microbial protein
What change occurs in the rumen size as a cow approaches giving birth?
Rumen size decreases to accommodate a larger foetus
What treatment can be used to support gluconeogenesis in pregnant cows?
Increase concentrate (cake) in the diet
Contains VFA proprionate
Fill in the blank: Fermentation relies on a _______ environment.
constant
True or False: Continuous food intake in herbivores matches with outflow.
True
What can non-proteinaceous nitrogen, such as urea, be used for in the rumen?
To manufacture amino acids by ruminal microbes
Non-proteinaceous nitrogen is a crucial component for ruminants as it allows them to synthesize essential amino acids from low-quality protein sources.
What happens to microbes after they pass through into the rest of the GIT?
They are digested enzymatically, releasing amino acids which are absorbed into the body
This process highlights the importance of microbial protein in the nutrition of ruminants.
What can ruminants do with essential amino acids?
They can make their own essential amino acids
This ability allows them to thrive on a low protein or poor quality protein diet.
What additional nutrient can microbes manufacture in the rumen?
Vitamins
These vitamins are absorbed in the small intestine, contributing to the overall health of the ruminant.
What occurs in foregut fermenters after the ingesta leaves the rumen?
It enters the abomasum and intestines, where it is digested and absorbed similar to monogastrics
This process contrasts with hindgut fermenters, which have a different digestive sequence.
How do hindgut fermenters differ from foregut fermenters regarding fermentation?
Fermentation occurs after conventional digestion, leading to limited absorption of fermentation products
This results in a greater need for higher quality diets in hindgut fermenters.
What is bloat in ruminants?
An abnormally enlarged rumen or ruminal tympany
Bloat can be classified into two types: free gas bloat and frothy bloat.
What characterizes free gas bloat?
Physical obstruction to the esophagus and lack of motility in the rumen/reticulum
Conditions leading to free gas bloat include tetanus, hypocalcaemia, rumen acidosis, and vagal indigestion.
