Rumen Acidosis

Question 1

What is the function of the rumen?

Answer 1

promote slow digestion of roughages (insoluble fiber) via fermentation by microbes

Question 2

What is normal rumen pH?

Answer 2

6.5

Question 3

What is rumen pH if acidosis?

Answer 3

4 to 5

Question 4

What dietary considerations predispose the cow to rumen acidosis?

Answer 4

• ingestion of too much starch or sugar, especially if ingested rapidly
  (ie. grain diets like wheat, high moisture corn, dry corn, feed beets, sugar beets, potatoes)

-alterations in feed intake patterns

Question 5

What does a change in diet predispose the ruminant to rumen acidosis?

Answer 5

• microbial environment of rumen gets disrupted

- this causes overgrowth of microbes that produce high amounts of lactic acid and VFAs, thus decreasing rumen pH

Question 6

Why does varying feed intake predispose a ruminant to rumen acidosis?

Answer 6

• it means the rumen microbes have to adapt frequently which promotes periodic production of excessive acid
• papillae aren’t able to properly acclimate to the proper length for the amount of acid being produced

Question 7

Physiological Effects of acute rumen acidosis

Answer 7

• CNS Dz (sudden blindness, alterations in alertness of mental status, aimless wandering, head pressing) –> due to microorganisms or rumen being unable to produce thiamine (B1) in an acidic environment. B1 is needed for proper CNS function
• sudden death
• decreased weight gain and diarrhea –> due to direct damage to GI mucosa –> actue inflammatory response –> destruction of mucosal villi –> malabsorptive condition

Question 8

Complications of acute rumen acidosis

Answer 8

• sudden death
• Polioencephalomalacaia (neuro Dz)
• progressive CNS signs

Question 9

What are papillae responsible for?

Answer 9

the absorption of VFAs

Question 10

How does diet influence their growth (length)?

Answer 10

• more digestible diets w/ higher concentrates = longer papillae
• less digestible diets w/ fewer concentrates = shorter papillae

Question 11

When does rumen acidosis occur as relates to papillae?

Answer 11

• when production of VFAs and lactic acid is increased relative to their absorption
• this occurs when papillae aren’t long enough to absorb enough VFAs fast enough to prevent an acidic environment

Question 12

What are clinical signs of subacute/chronic rumen acidosis?

Answer 12

• malabsportion +/- diarrhea –> due to direct damage to mucosa
• partially off feed
• decreased weight gain
• panting
• pytalism (excessive salivation)
• eating dirt

Question 13

Complications of subacute/chronic rumen acidosis

Answer 13

• chronic laminitis
• ruminitis –> damage to GI mucosa allows for transmigration of organisms into circulatory system –> inflammatory response
• Hepatic abscess –> if microorganisms travel to the liver
• GI clostridial infection –> due to alteration in microbe environment allowing opportunistic infections to grow unchecked

Question 14

List the possible treatments for rumen acidosis

Answer 14

• oral magnesium hydroxide
• transfaunation
• IVF w/ sodium bicarbonate
• alter feeding management practices

Question 15

How does oral magnesium hydroxide help correct rumen acidosis?

Answer 15

re-establishes a more neutral environment in the rumen

Question 16

What is transfaunation?

Answer 16

the transfer of normal rumen contents from a healthy ruminant to the rumen of an unhealthy ruminant via orogastric intubation to help repopulate the rumen with appropriate microorganisms; also helps rumen environment return to a more neutral pH

Question 17

How do IVF with sodium bicarbonate help rumen acidosis?

Answer 17

helps return fluid balance to normal

Question 18

What feeding practices should be altered to help prevent rumen acidosis?

Answer 18

• no unlimited access to grain

- for finishing feedlot cattle/lactation promotoion, add ionophores to the feed

Question 19

What do ionophores do?

Answer 19

increase efficiency of digestion of grains in ruminants , thus decreasing production of acid by-products