In May 2008 I was notified by a local veterinary practitioner that Trichomoniasis had been diagnosed on a large local beef cattle enterprise. What followed was an interesting journey involving corporate agriculture absentee owners and large numbers of neighbours. I will focus on the eradication options chosen and the costs to the enterprise.
The property was quarantined on 8th May 2008 and released on 21st June 2009. Whether this is considered a success depends on what measures are used.
145/340 cows were found empty when pregnancy tested in March 2008. They were joined in November/December 2007.
Similar results were seen in 2007. At this time an investigation was carried out by a local practitioner where cows in three mobs were found with BVDV antibody 2 and 3 levels. As BVDV was considered to be actively circulating in the herd BVDV vaccination was not undertaken.
Introduced cattle were tested to determine if they were immunologically naive. The property now (2009) vaccinates all breeding stock with Pestigard.
Testing in 2008 identified continued BVDV activity but no Leptospirosis titres. An effective Vibriosis vaccination program was in place. With no reasonable explanation for a second successive poor pregnancy test result further testing was undertaken for Trichomoniasis. 14/61 bulls were positive.
The property was quarantined and tracing was undertaken.
Neighbours were identified and contacted. They were asked to complete a questionnaire focused on reproductive indices and any history of stray cattle from the infected properties. This information was used to assess the likelihood of spread between properties and whether subsequent testing was required.
There were 15 neighbours. Six were tested. None returned positive tests.
The remaining properties either ran no cattle, fattening only or had reproductive histories not indicative of infectious infertility.
Tracing was undertaken using property records and the NLIS database.
Trace forwards were investigated locally or forwarded to the DV in the corresponding RLPB including:
A number of these cattle were fattened and slaughtered or entered feedlots.
Bulls were traced back to 2 large studs. The likelihood of infection on these properties was considered low as young bulls from the studs were not infected but older bulls previously joined to the cow herd for 1 or 2 years were more likely to be infected.
Cows were traced back to a number of properties in Queensland.
1. The enterprise was made up of 6 properties and these were segregated and labelled as 'clean' or 'infected'.
Pregnant potentially infected cows and bulls during testing were on the 'infected' property.
Heifers, weaners and steers were placed on the 'clean' property. A deactivated PIC was reactivated for the 'infected' property for ease of auditing movements off the property.
All movements were notified and were direct to slaughter.
2. Bulls: All bulls were tested. All test positive bulls will be sold as slaughter only.
1. Breeding Cows
a. PTIC Empties - were sold as slaughter only
b. Pregnant cows - were calved down. Were not to be rejoined and were sold as slaughter only
c. Calves - were weaned and entered clean herd
d. Unjoined heifers and heifer calves of pregnant cows were moved to clean paddocks. And were able to be sold for fattening or as replacement breeders.
Eradication Cost (approximate)
|650 cows culled and replaced with PTIC females||(sold @ 600 per head)||390,000 (purchased @ 850 per head) 552,500||-162,500|
|Improved fertility from 65% to 95% across 900 breeders||(270 more calves @ 500 per weaner) 180,000||This not an extra income source but brings operating costs back to where they should be|
|Diagnostic costs, testing, etc||7,000#||-7000|
|Labour||(3 on farm employees for 5 days @ 120 per day)||-1800|
Trichomoniasis is a notifiable disease in NSW and under the policy (AI 97/35) and under the terms of the Undertaking the owner or manager must agree to develop and implement a management plan for the eradication of Trichomoniasis from the property.
The cost of the eradication program equated to the gross return that could be expected from the breeding herd in the year following the eradication of Trichomoniasis.
What does the current NSW Trichomoniasis program do for an enterprise that has spent a quarter of a million dollars complying with policy?
The enterprise sold 650 empty cows and replaced them with PTIC.
This strategy allowed the enterprise to maintain its calving time and avoid stretching out the joining as a result of the sexual rest requirement and maintain tight joinings and early calvings. A proportion of those 650 cows sold were highly prised large frame Angus cows. The replacements while nearly twice as expensive were of poorer quality.
The current program provides no tool to minimise the risk of re-infection. There is no Quality Assurance program.
There is no prevalence information for Trichomoniasis. The enterprise has developed an in house strategy to manage the risk of re-introducing Trichomoniasis and other causes of infectious infertility.
1. Only purchase virgin bulls.
2. Join heifers to new bulls.
3. Avoid joining heifers to old bulls and old cows to young bulls as older animals are more likely to be carriers while young animals will have no immunity through exposure (although only transitory).
4. Join bulls to same cow group each year so if Trichomoniasis is detected in a mob it only impacts that unit.
5. Management strategies are in place to protect against other forms of infectious abortion. Vaccination with 7 in 1, Vibriosis vaccination for bulls and vaccination against BVDV are given annually to all breeding stock.