Clinical Conditions Flashcards
Grain overload
-rapid ingestion of concentrates (grains, and corn, processed/finely ground grain)
-results in rapid fermentation of starch and sugar which drops pH. Also see a decline in gram negative and overgrowth of gram positive bacteria, protozoa die off, and potential for frothy bloat.
Lactic Acidosis
-low pH promotes the growth of lactic acid producing bacteria (step. Bovis, and lactobacillus).
>they produce both D- and L- lactate. But D lactate is not used as rapidly as L-form which means it accumulates in the rumen. Mostly ionized (A-) form and not readily absorbed.
>increases the osmolarity of rumen which results in water being pulled in and dehydration
-pH lower than 5 shifts to a HA (non ionized form) form which are absorbed in the blood and causes acidosis because D-form is slowly metabolized
Lactic acidosis symptoms
-dehydration
-diarrhea
-tachypnea= respiratory compensation
-depression/lethargy
Sequelae (compounding issues) of lactic acidosis
-chemical rumenitis= low pH damages the epithelium allowing for mycotic rumenitis which is the overgrowth of fungi (mucor or Rhizopus species)
-liver abscesses- damage to epithelial barrier
-ruptured liver abscesses= caval syndrome which erodes the vena cava
Lactic acidosis treatment
-rumen lavage
-oral rumen alkalizing agents
-IV NaHCO3-
-rumenotomy and grain removal
Lactic acidosis prevention
-slow transition to a high concentrate diet
>increase in lactate-using bacteria
>increase in protozoa
-ionophores
-effective fiber size
Rumen tympany/bloat
-gas build up in rumen
>blood supply affected when pressure compresses vena cava resulting in bloat line
>prevents lungs from expanding
Free-gas bloat
-physical obstruction or impairment of eructation
>foreign body
>pressure or stenosis on esophagus/cardia (eg. Abscess from hardware disease)
>dorsal recumbency
Frothy bloat
-build up of foam prevents cardia from opening
>Forage: pulses like alfalfa, clover are soluble leaf proteins that create a foam
>grain: growth of strep bovis at lower pH which produces slime and increases viscosity and traps gas
-treated with mineral oil as it acts as a surfactant
Bloats effect
1.motility changes
2.Compression of diaphragm
3.compression of blood supply= bloat line (congestion cranially, pale caudally)
Motility changes with bloat
-frothy will initially increase secondary contractions
-high pressure detected by rumen high tension receptors inhibits motility
-Pain from stretch and diaphragm compression will also inhibit motility
Ketosis (or acetonemia)
-high concentrations of ketone bodies in the blood
>beta-hydroxybutyrate, acetone, acetoacetate
-result of metabolic disorder (animal with negative energy balance)
When does ketoacidosis occur?
1.dairy cows in early lactation= high energy demands
2. Sheep/goats in late pregnancy= because they have high energy demands but low rumen capacity because fetus’ are taking up space. Known as pregnancy toxemia
3.Secondary ketosis due to starvation or other disease reducing feed intake
Ketosis pathogenesis
1.Blood glucose decreases resulting in glucagon being released
2.Glucagon stimulates lipolysis of adipose tissue
>Non-esterified fatty acids (NEFA) supplies energy for other tissues (mostly muscle and liver), fatty acids for milk production. Also spares glucose for use in brain and milk lactose.
3.Fatty acids metabolized in the liver (beta-oxidation to convert them to acetate and acetyl-CoA which can be used for TCA when oxaloacetate present)
4.When liver capacity for beta-oxidation is exceeded, the excess acetyl-CoA is converted to ketone bodies
>some ketone bodies can be used by peripheral tissues for energy
5. Ketones can accumulate in blood (resulting in smell in milk, urine, and breath) and be converted to isopropyl alcohol in the brain
5.When the liver capacity to produce ketone bodies is exceeded, results in FAs converted to tryglycerides and stored in liver. Can result in fatty liver disease= steatosis
Ketosis in dairy cows
-usually self-limiting
-appetite will decreased when blood pH decreases
-milk production will decreases
-energy demands decreases resulting in decreased lipolysis
