Unit 13 General Animal Diseases Unit 13

Unit 13: General Animal Diseases

Unit 13: General Animal Diseases n Blackleg n n Acute, highly contagious, febrile, non-contagious Affects cattle & sheep Most common in Midwestern, Southern, and Western U. S. (where cattle are on grass) Affects all ages n Most common from 4 mos to 2 yrs

Unit 13: General Animal Diseases n Cause n n Caused by anaerobic bacteria Clostridium Ingestion of spores from contaminated pastures Spores enter blood system from digestive tract and colonize in muscle tissues Clinical Signs n May die suddenly without symptoms § Death usually w/in 12 -36 hrs n n Sudden, high fever Labored breathing, lameness

Unit 13: General Animal Diseases n Swelling in heavily muscled areas § § § n n Neck Loin Legs First hot and painful Become cold, painless, and filled w/ gas Pressure to skin results in crackling sound Carcasses bloat & decompose quickly Very infectious in sheep § Ultra-high temperature § Recoveries are rare

Unit 13: General Animal Diseases n Prevention n Calves § Vaccinate twice at 2 wk intervals § Between 2 & 6 mos of age § Revaccination may be warranted in high risk areas each year n Sheep § In high risk areas: vaccinate every 2 -4 wks prior to shearing, castrating, docking

Unit 13: General Animal Diseases n Do not open carcasses of suspected blackleg deaths § Burn where they die, if possible n Treatment n n If caught early, high doses of penicillin Best control is w/ vaccination

Unit 13: General Animal Diseases n Swine Erysipelas n Infectious disease affecting swine of all ages n n Occurs in a variety of forms Can result in large death losses Most economic losses caused by chronic form n n Most common in young & growing pigs General unthriftiness and poor performance Can affect other animals & humans n May cause economic losses in turkeys & sheep

Unit 13: General Animal Diseases n Cause n n n Bacterial infection Highly resistant to natural means of eradication Lives and reproduces in alkaline soils § Can survive in dead carcasses > 1 yr n n Spreads by direct contact Often introduced to a herd through breeding stock or feeder purchases

Unit 13: General Animal Diseases n Clinical signs n Three forms: § Acute § Sudden death of 1 or more animals § Very high fever § Appetite affects vary § Vomitting § Skin blotchiness § Severe joint pain

Unit 13: General Animal Diseases § Subacute § Less severe symptomology § Some skin lesions § Course of the disease is much shorter § Chronic form § Causes most dramatic physical changes § Lose portions of their skin, tail, ears, feet § Dark, firm skin lesions leaving ugly scars § Stiff, swollen, painful joints § Lameness in one or more legs § Bacteria localizes in joints and/or heart valves

Unit 13: General Animal Diseases n Prevention n Sound herd health management § Biosecurity § Vaccination program § Killed or MLV n n Revaccinate breeding stock twice/yr Treatment n n Acute form: treat w/ most any form of antibiotic (penicillin, oxytetracycline, tylosin, chlorotet. ) No practical treatment for chronic form

Unit 13: General Animal Diseases n Johne’s Disease n n Aka paratuberculosis Primarily occurs in ruminants Increasing importance in the U. S. Emerging as a significant economic disease n Herds w/ 10% infection rate – lose ~$230/cow/yr § From decreased production of subclinical cows

Unit 13: General Animal Diseases n Cause n n Bacterial infection caused by Mycobacterium paratuberculosis Ingestion of organism in contaminated milk, feed, water Nursing calves born to infected mothers have high risk for infection Organism is shed in extremely high numbers from infected animals before clinical symptoms § Fecal contamination considered to be #1 mode of infection

Unit 13: General Animal Diseases n n n Animals up to 6 most susceptible for infection Bacteria enters the S. I. tissue Diagnosis through ELISA blood test, or fecal culture § Can easily have false negative tests due to low shedding numbers and low antibody levels early in life n Clinical Signs n n n Persistent diarrhea, unresponsive to treatment Maintain good appetite Rapid weight loss, w/ no fever

Unit 13: General Animal Diseases n Disease often doesn’t become evident until 3 -5 yrs of age § Only subtle symptoms may be apparent earliers n Prevention n Don’t permit feeding utensils to come in contact w/ manure § Tractors, skid loaders, etc. n n Separate calves from their mother ASAP Feed only colostrum from negative test cows § Don’t use pooled colostrum

Unit 13: General Animal Diseases n n n Feed milk replacer or used a pasteurizer instead of waste milk House calves away from cow manure areas to prevent cross-contamination Treatment n n No cure available Some drug therapies can prolong life and improve body condition, but doesn’t eradicate disease

Unit 13: General Animal Diseases n Dangers of Johne’s n Questions of infections passing to humans § How could it be transmitted? n n What is the related human disease? What effect could this have on the dairy industry?