T. foetus in Females Disease Process Infection leads to inflammation, but does not interfere with conception Early embryonic death and abortion at 50 – 80 days Immune response clears infection Infertility for 2-5 months => normal fertility Unusual outcomes Clinical Signs Mild discharge Return to estrus Extended calving season ≥ 40% reduction in % pregnant cows
Carrier Cows No apparent carrier cows Barling et. al. Bov Pract 2005 Post calving – 63-97 days Goodger et. al. JAVMA 1986 – 9 weeks Skirrow JAVMA 1987 Post breeding – 22 months Alexander Aust Vet J 1953 – 300 days Mancebo et. al. Vet Parasitol 1995
T. foetus in Males Disease Process No tissue invasion No detectable immune response Preputial crypts aid in parasite survival Chronic carriers in bulls > 3 years of age Clinical Signs None (Courtesy of Dr. Bruce Brodersen, University of Nebraska- Lincoln Veterinary Diagnostic Laboratory) Treatment Test and slaughter!
Testing Errors Pre-analytical Phase – Error sources include wrong sample, mishandled sample, improper sample collection, etc. Analytical Phase (the equipment/technician) – Error sources include mechanical wear and tear, bad sensors, inherent errors, software errors, and improper cutoff values. Post-analytical Phase – Reporting errors include misread or misreported values, transposition of figures, etc. Reports from our human counterparts indicate up to 90% of diagnostic test error occurs in the pre and post analytical phase of testing. While less than 10-13% of the error occurs during the analytical phase.
Herd Health Assurance: At-risk Herds Communication Veterinarian producer Producer producer Planned grazing Appropriate fencing Maintain a closed herd Monitor fences and cattle Observe regulations Purchase only virgin or pregnant replacements Isolate and test herd additions Isolate and test herd reintroductions Utilize artificial insemination Records
b 12.2% open in the exposed group a 8.9% open in the exposed group 2004 4.8% 2005 5.4% 2006 13.9% 2007 27.0%Herd A (1500 cows) 4.1%3.8% 4.2% a 4.2% b Herd B (3000 cows) Herd C (3000 cows) Historically ~7% 2008 14% Group% Open 1234512345 9% 8% 15% 14% 19%
Herd Health Assurance: At-risk Herds Communication Veterinarian producer Producer producer Planned grazing Appropriate fencing Maintain a closed herd Monitor fences and cattle Observe regulations Purchase only virgin or pregnant replacements Isolate and test herd additions Isolate and test herd reintroductions Utilize artificial insemination Surveillance testing Records
Herd Health Assurance: Low Risk Herds Communication Veterinarian producer Producer producer Maintain a closed herd Monitor fences and cattle Observe regulations Purchase only virgin or pregnant replacements or purchase from a reputable source Isolate and test herd reintroductions? Utilize artificial insemination Records Surveillance testing?????
Herd Health Assurance: Infected Herds Test and cull Bull management Communication Veterinarian producer Producer producer
Comparison of First Test Efficiency 1st Culture8 2nd 2 3rd 1 Total 11 First Test Efficiency.73 95% CI.39-.94 q PCR93012.75.43-.95 Gel PCR84113.62.32-.86
Herd Health Assurance: Infected Herds Utilize artificial insemination Maintain a young bull battery Test and cull Establish “clean” and “dirty” herds Surveillance testing Cull all non-productive cows Bull management Cow management Cull Communication Veterinarian producer Producer producer Records
“…it is my opinion that if more care was taken in the sale and purchase of barren cows, in the purchase of bulls of breeding age, and if the farmers could be sufficiently educated to the unique opportunities for control that this disease offers, then its total elimination should be practicable in the quite near future.” H.P. Harding The Veterinary Record September 16, 1950