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

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 !!

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

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

Liver Abscess Classification

A+ Liver Abscesses, 1990 to 1999 sbl 00

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

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)

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

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

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)

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)

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

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 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

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 0.5 - 1.0 0.12 - 0.23 0.81 - 1.63 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.