Production Diseases: Rumen Health & Cecum Flashcards
what is the rumen composed of
30litres/hour
40% methane
40% CO2
3 types of microbes:
- Bacteria (10^10/g)
- Protozoa (10^6/g)
- Fungi (10^4/g)
what are the characteristics of a healthy rumen (temp, pH, etc)
Warm:
- 37.5-42ºC
Moist:
- Large quantity of water
Anaerobic:
- Free of oxygen
pH:
- >6.2 to neutral
Active:
- 1-3 contractions/min
Microbes:
- Bacteria, protozoa, fungi
Large fermentation vat
what is the lactic acidosis spiral
Rapid ingestion of starch causes formation of VFAs to form which drops pH
The drop in pH causes Streptococcus bovis to take over which produces lactic acid
Lactic acid drops the pH further and causes only Lactobacillus bacteria to grow which produce more lactic acid
Eventually leads to death
what is ruminal acidosis
Metabolic disorder arising into the rumen, which affects body fluids overpassing the body buffers for a determined amount of time
To be differentiated by metabolic acidosis is a condition resulting from accumulation of acid or depletion of the alkaline reserve in body fluid
what are the 2 syndromes of ruminal acidosis
Acute ruminal acidosis
Sub-acute ruminal acidosis (SARA)
describe the fermination pattern and rumen environment
describe the pathogenesis of ruminal acidosis
Rapidly fermented:
Starches —> glucose
what effects does free glucose have on the rumen environment (3)
- Ruminal bacteria like S. bovis (lactic acid producer), which aren’t usually competitive can thrive
- Opportunistic bacteria such as E. coli can prosper and produce endotoxins or amides (histamines) when they die
- Free glucose increases osmolarity which can exacerbate accumulation of acids in the rumen by inhibiting VFA absorption
what effects does a low pH have on osmotic pressure
With low (more acidic) pH osmotic pressure is increased by greater ionization of VFAs
The ruminant absorption rate decreases
This exacerbates acidity and osmolarity
pH buffers such as bicarbonate come from saliva, the rest enters the rumen from blood in exchange for ionized acids
With concentrate diets the ruminal input of saliva decreases
A higher proportion of bicarbonate must be derived from blood
This decreases the base excess of blood leading to acidosis
what is acute ruminal acidosis
Well recognized and described
Intake of high quantities of rapidly fermentable CHO
Ruminal and metabolic acidosis
L- and D-lactate acidosis
Rapid decrease in pH
Seen in feedlots, grain beef system
Severe ruminitis
what are the clinical signs of acute rumen acidosis
Bloat
Anorexia/ruminal stasis
Severe metabolic acidosis — tachypnea, hyperpnea
Diarrhea
Dehydration, shock, recumbency
DEATH
how is acute ruminal acidosis diagnosed
History
Clinical signs
Rumen pH (<5), rumen fermentation ceased
Plasma pH or TCO2
PM
describe what happens in the rumen during acute rumen acidosis
In a relatively short time 4-8 hours ruminal pH drops until 4.5-5
At this pH, S. bovis a “ lactate producer” microbe thrive and this leads to a rapid accumulation of lactic acid in the rumen
Increased osmolality and dehydration
In addition, the chemical (acid) damage to the rumen mucosa, cause endotoxin release (LPS) and amides (histamine) and bacteria access to the portal circulation
what is the clinical picture of acute rumen acidosis
Affected cattle are completely off feed, exhibit drastically decreased milk production, dehydration and elevated HR and RR
Splashy, static rumen, cool skin surface
Subnormal temp
Diarrhea or loose manure
Weak and can be recumbent depending on the entity of electrolyte imbalance
what are the consequences of acute ruminal acidosis
Ruminitis (rumen papillae deformation, parakeratosis)
Ruminitis liver abscess complex
how is acute rumen acidosis treated
n severe emergency consider rumenotomy
Correct ruminal and metabolic acidosis and dehydration (sodium bicarb per os and IV)
Encourage feeding on forage
Rumen function stimulants ex. Pro rumen or vetrumex
Transfer or rumen contents from healthy cattle
Consider on farm emergency slaughter
what is subacute rumen acidosis (SARA)
Feeding of diets of high energy density and low fibre
Rumen pH <5.5 or 5.2
Fermentation disturbances
Economical important in high yielding dairy cattle and intensive fattening operations
Animals do not show specific clinical signs
what are the consequences of subacute rumen acidosis (SARA)
Decreased feed intake
Loss of body condition (mainly in early lactation)
Increase lameness (laminitis/white line disease)
Infertility
Diarrhea/soft feces containing undigested material
Milk fat depression (fermentation changes, decreased ratio acetate/propionate)
High culling rate
Increased mastitis
Dirty
what should be investigated during a rumen health visit (10)
- cattle outputs
- cow signs
- rationassessment and cow management
- milk records
- blood parameters
- BCS
- rumen fill score (1-5)
- fecal consistency (1-5)
- fecal sieve score (1-5)
- ruminal fluid pH