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.
What causes frothy bloat?
Grain overload and high levels of grain diets
Frothy bloat is also linked to rumen acidosis, especially with finely ground grains.
What types of forages can cause pasture bloat?
Lush pastures, clovers, and alfalfa
Soluble protein in these forages leads to foaming, contributing to bloat.
How can free gas bloat be treated?
By releasing the gas using a stomach tube or trocar and cannula
This treatment helps alleviate the physical obstruction causing the bloat.
What is the treatment for frothy bloat?
Anti-foaming agents that reduce surface tension
These agents allow gas bubbles to coalesce, facilitating gas eructation.
What are some prevention strategies for bloat?
- Pasture management
- Avoid feeding finely ground cereals
- Ensure at least 40% forage in the diet
These strategies help reduce the risk of both types of bloat in ruminants.
What is LDA in ruminants?
Left displaced abomasum
This condition involves the displacement of the gas-filled, distended abomasum to the left side, trapping it between the rumen and abdominal wall.
What does RDA stand for?
Right Displacement Abomasum
RDA refers to the displacement of the gas-filled, distended abomasum.
What is abomasal volvulus (torsion)?
Displacement of the gas-filled, distended abomasum from the ventral abdominal wall into the craniodorsal right abdominal cavity, creating a volvulus by vertical and horizontal rotation
The abomasum is wrapped in the greater omentum during this process.
What are the symptoms of LDA or RDA in cows?
Decreased feed intake, energy deficiency, rising ketone levels in the blood, ketosis
These symptoms indicate a metabolic imbalance.
Define ketosis.
Build-up of ketone bodies in the blood
It is caused by a negative energy balance and fat loss.
What causes ketosis in cows?
Negative energy balance and fat loss (loss of BCS)
Ketones make the cow feel unwell, leading to decreased appetite.
How is ketosis diagnosed?
High levels of ketone bodies in blood or urine, specifically beta-hydroxybutyrate
Diagnosis involves laboratory testing.
What is primary ketosis?
Ketosis with an underlying nutritional cause
It typically arises from inadequate nutrition.
What is secondary ketosis?
Ketosis that occurs due to another disease
It indicates a complication from an existing health issue.
What is fatty liver?
A condition resulting from a negative energy balance, significant in post-parturient dairy cows
It usually develops before and during parturition.
What contributes to the development of fatty liver in cows?
Periparturient depression of feed intake and endocrine changes associated with parturition and lactogenesis
Over-conditioned cows at calving are at the highest risk.
What is Fat Cow Syndrome?
A combination of metabolic, digestive, infectious, and reproductive conditions affecting the obese periparturient cow
It results from multiple interrelated health issues.
What are the clinical signs of Fat Cow Syndrome?
Depression, anorexia, ketonuria
These signs indicate serious metabolic disturbances.
What is the prevention strategy for Fat Cow Syndrome?
Feeding a balanced diet
Proper nutrition helps mitigate risks associated with obesity.
