Johnes disease beef farm walk presentation
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This document discusses Johne's disease, a contagious bacterial disease affecting cattle. Some key points: 1) It is spread through fecal contamination and causes reduced nutrient absorption over 3-7 years. Infected cows have reduced lifetime milk production and fertility. 2) Testing found no positive animals on the dairy farms studied but some positives on beef farms, with more positives found in the second year of testing. 3) To control the disease, farms should test herds regularly, cull positive animals, improve calving area hygiene, and separate infected and non-infected groups. This can slowly reduce disease levels on infected farms over time.
Johnes disease beef farm walk presentation
- 1. Piers Pepperell & Alastair Caygill JOHNES DISEASE PROJECT â 1ST YEAR RESULTS
- 2. What is it? ⢠Itâs a contagious bacterial disease of the bovine intestine ⢠Slow growing bacteria that usually takes around 3-7 years to start causing problems ⢠Causes a slow thickening of the intestinal wall => reduced absorption => less nutrient uptake ⢠Causes reduced immunity to other conditions, reduced growth rates and increased culling rates ⢠Eventually ends as a terminal scour ⢠No treatment and no recovery
- 3. Reduces Lifetime performance ⢠Cows give >2000kgs less milk in a lifetime ⢠Causes financial loss by causing decreased calf 1. Loss of carcass value of growth rates the dam ⢠5 X more likely to be 2. Decreased calf growth lame rates ⢠2 X more likely to have 3. Loss of premium from mastitis high health status of ⢠2 X more likely to have pedigree herds digestive or respiratory disease
- 4. Usually subclinical disease ⢠Many farms may never have seen a case because infected animals are culled for poor performance or fertility before they start to show symptoms ⢠For this reason if you have a clinical case, there may well be several more subclinical cows in your herd (some estimates are 10-20 subclinical cases for every clinical case)
- 5. Farms which had seen a case previous to the start of the project Beef farms Dairy farm Yes Yes No No
- 6. How is it spread? Faeces contaminating calves/ udders Colostrum and milk 10-40 % in utero infection depending on level of infection Carriers shed intermittently in times of stress, shedding more and more as the disease advances
- 7. Main risk areas ⢠Contaminated calving areas â dung gets onto teats of non infected cow and is consumed by calf ⢠Cross suckling ⢠Feeding colostrum from another cow ⢠Hygiene usually better at pasture so housing is main area of spread
- 8. Other sources of infection ⢠Bought in Cows, Bulls and replacements ⢠Standing water sources â small lakes, ponds ⢠Slurry from other farms ⢠Sheep/Goats ⢠Rabbits?
- 9. Susceptibility decreases with age ⢠When a calf is born it has a large number of areas in itâs gut called Peyers Patches. Their job is to allow antibodies to be absorbed into the blood from the colostrum ⢠These shrink over time until they have gone by around 10mths of age ⢠It is through these that the Johnes enters the calf though colostrum, milk or dung consumed by the calf ⢠80% of Johnes infections occur in the 1st month of life
- 10. Main spread area ⢠It is a shit into mouth disease. A carrier will shit onto the bedding, onto feed areas and even directly onto calves. ⢠A âsuper shedderâ can discharge enough bacteria in 24 hours to infect 50000 calves
- 11. How can we test for it? ⢠The closer the animal comes to developing symptoms, the more sensitive the tests become. This means testing is ineffective under 2 years of age. ⢠Test the dung. This is the best test but quite expensive ⢠Blood test. This will pick up around 50% of infected cows. Best to do it as close to calving period as possible as increased stress increases the chance of picking it up ⢠Better to think of negative cows as âlow risk of spreadâ cows ⢠If there is any risk the animal might be a carrier e.g. born to a positive mother, they should be treated as high risk until proven otherwise
- 12. Which animals to test? ⢠Regular quarterly whole herd samples Most reliable but very expensive ⢠Regular whole herd annual sample fairly reliable, more affordable and helps management decisions ⢠Whole herd individual sample useful but can give a false sense of security if not done regularly ⢠30 cow screen okay start but may well miss some positives ⢠Individual/cull cows least reliable, very random
- 13. What we found in our 1st year Beef farms Dairy farms Positive Positive animals animals found found No positive No positive animals animals found found
- 14. Numbers on each farm Testing positive 16 14 12 10 8 Testing positive 6 4 2 0 B D
- 15. ⢠Positives were rebled a month later ⢠Double positives were then dung tested if requested ⢠Several blood positives have been dung negative. These are treated as medium or high risk depending on the farm history ⢠However we have now done the second year testing on 6 beef herds. Only 1 of them had positives last year and this year 5 out of the 6 have had positives!
- 16. What can you do to prevent Johnes disease becoming a problem ⢠Nothing â risky ⢠Test a few â might give you a false sense of security ⢠Test whole herd and cull â this has been shown to only reduce the disease level very slowly ⢠Test, cull and make changes to stop the spread â shown to be the most effective
- 17. How to reduce spread of Johnes in infected herdâ low level ⢠Clean calving areas- well bedded ⢠Calve cows outside ⢠Test all animal prior to calving and remove test positive and clinical cows early ⢠Only feed colostrum taken from a young negative cow
- 18. Additional changes to reduce the spread of Johnes in medium to high infected herd ⢠Bleed everything prior to calving period. ⢠Separate infected and non infected cows into two groups if prevalence is high ⢠Source replacements from low prevalence herds or low prevalence groups ⢠Ensure the last calf from test positive animals are not kept as replacement breeding stock
- 19. Environmental controls ⢠Keep cows and their environment clean and free from faecal contamination, especially during calving period and first 6months of calvesâ lives ⢠Prevent faecal contamination of feed and water supplies. ⢠Keep feed and water troughs clean ⢠Provide mains water and fence off other water sources
- 20. Environmental controls ⢠Spread dung or slurry on arable land, OR ⢠Do not graze youngstock for at least 1 year on ground that has had dung or slurry spread on it ⢠Avoid co-grazing youngstock with other livestock that can be infected with Johnes ⢠Control rabbits
- 21. Any Questions?