1. Nutritional Disorders in Beef Cattle
Rumen acidosis liver abscess
Polioencephalomalasia, or Polio, or PEM, or “Brainer”
Nitrate poisoning

2. Feedlot: Acidosis and other “digestive” problems
Acute
Laminitis, founder
Hopelessly off-feed
Sell immediately
Chronic or sub-acute
A little off feed, poor performers
Long term effect
Rumenitis: more problems as we have longer fed cattle – calf-feds, Holsteins, Japanese
Probably bigger problem in the PNW with barley, wheat and potato feeding
Best symptom is liver abscesses (Fusobacterium necrophorum; Actinomyces pyogenes)
Its all about bunk management !!

3. Ruminant system of carbohydrate digestion and absorption: Effect of feeding grain
Acidosis symptoms
variable feed intake (symptom and cause)
feces: loose – splattering, less than 1” high, no dimpling/concentric rings
lack of cud chewing
hoof lines, abnormal hoof growth
dairy: milk fat inversion
beef: liver abscesses

4. Acidosis
Indicates rumen insult
Grows .25 inch (6 mm) / month

5. Liver Abscess Classification

6. A+ Liver Abscesses, 1990 to 1999
sbl 00

7. Total Abscesses by Month, 1990 - 1999 Tylan Fed Steers, All Districts
sbl 00

8. EFFECT OF RUMENSIN PLUS TYLAN ON LIVER ABSCESS INCIDENCE
CONTROL
RUMENSIN +TYLAN
NO. HEAD
976
1937
% A-
7.7
5.4
% A
8.4a
3.5b
% A+
20.1a
3.5b
TOTAL
36.2a
12.4b
LAUDERT, 1990, 4 TRIAL SUMMARY ab (P<0.02)

9. Polioencephalomalasia, or Polio, or PEM, or “Brainer”
Classically associated with periods of rumen digestive upset
irregular feed intake
Consumption of moldy feed
Lush highly fermentable forages – rapeseed forage
Classically considered to be thiamine deficiency
Usually from presence of thiaminases
Administer thiamine – oral or injectible

10. Polioencephalomalasia, or Polio, or PEM, or “Brainer”
Symptoms:
Laminar cortical necrosis (brain damage)
Blindness
Staggering
Down
Seizures
Recent understanding: high dietary sulfur is a predisposing factor: rumen bacteria convert sulfur to hydrogen sulfide, enters the blood, interferes with energy metabolism, “starves” the CNS

11. Polioencephalomalasia, or Polio, or PEM, or “Brainer”
Current issue is with corn byproducts – wet milling involves softening the grain with sulfuric acid
Inclusion of high levels of corn gluten feed or corn distillers grain can increase risk of PEM
Low rumen pH increases production and absorption of sulfide
No amount of dietary thiamine can completely eliminate the risk – may reduce the incidence
Formulate diets to have 0.4% Sulfur (or less)

12. Nitrate poisoning
Ruminal conversion of nitrates in plants to nitrites (instead of ammonia to microbial protein), enters blood, binds with hemoglobin to form methemoglobin, reduces oxygen transport to cells.
Formation of methemoglobin is normally reduced (via electron donation) by protective enzyme systems:
e.g., NADH methemoglobin reductase (cytochrome-b5 reductase)

13. Nitrate poisoning, cont
Symptoms:
Respiratory distress
Incoordination
Weakness
muscle tremors
Collapse - dead
Don’t stress affected cattle!

14. Nitrate poisoning, cont
Common feeds:
Stressed crops (drought, frost, hail)
Cool, overcast climate
Lower portion of stem/stalks of certain plants: pigweed, sorghum, corn, Sudan grass, barley and oats
High N fertilizer
Immature more than mature forages

15. 15 to 45 g of Nitrate per 100 pounds body weight – from feed and water
1% nitrate in forage DM
1,500 mg/ml nitrate (ppm) in water
Younger cattle are more susceptible

16. Generally safe for beef cattle and sheep
Category
NO3
NO3-N
KNO3
Remarks 1
<0.5
<0.12
<0.81
Generally safe for beef cattle and sheep 2
Caution - some subclinical symptoms may appear in pregnant horses, sheep and beef cattle 3
1.0
0.23
1.63
High nitrate problems - death losses and abortions can occur in beef cattle and sheep 4
<1.23
<0.28
<2.00
Maximum safe level for horses. Do not feed high nitrate forages to pregnant mares.