ARCHIVE FILE
This article was published in 1980
See the original document
Brucellosis Eradication - Problems Encountered
M.R. Barry, B.V.Sc., Veterinary Inspector, Albury
Herd at Tooma
History - No known history of Brucellosis. Vaccination routinely carried out until 1975 but stopped for 3 years. All heifers were fattened and sold until 1979 when vaccination was resumed.
| 17.1.79 | E1P | 141 cattle | 5 vaccinated females reacted 3 x CFT 8 1 x CFT 16 1 x CFT 4 |
| 12.1.79 | E1F | 53 cattle tested | 2 vaccinated females reacted 1 x CFT 128 1 x CFT 8 |
| All seven to be sent for slaughter. | |||
| 5.2.79 | Retest Black E.T. 39 - CFT 64 | ||
| (1 wrong number at E1 - recorded as E.T. 49, reaction CFT 128 above) All seven sent for slaughter and killed on 22. 2.79. | |||
| 8.3.79 | E2P | 183 cattle | vaccinated female B48 inconclusive 2/4 to be retested in isolation. |
| 9.3.79 | E2F | 4 bulls | all negative |
| 10.4.79 | Retest of B48 | Sample to Glenfield RBT 1 CFT O IHLT 8 Isolated and taken as negative but cow to be sent for slaughter after calving. Owners agreeable to this action. | |
| 27.4.79 | E3P | 118 cattle | all negative. (B48 not included) |
| 30.4.79 | E3F | 69 cattle | all negative. |
| 29.6.79 | Traceback:- Moss Vale Abattoir 1 x CFT 16 (cow B48 was sold at Wodonga on 27.6.79 before she calved). | ||
| 28.9.79 | CP | 87 cattle | all negative. |
| 2.10.79 | CF | 105 cattle | all negative. Herd given provisionally clear status. |
Points to Note
1. One eartag was incorrectly recorded at E1P but it was a high titre and detected on retest of the animal. If it had been a low titre it may have been hard to find for months. There is a definite need to have accurate specimen advice sheets.
2. An inconclusive at E2 was retested and showed negative CFT but
was just positive IHLT.
Interpretation - pass but sell for slaughter anyway as a doubtful animal.
3. Abattoir traceback detected this doubtful animal at slaughter 10 weeks later.
Herd at Henty
History
| 6.3.74 | 22 cattle bled by practitioner during survey testing 6 x R3T 2 3 x CFT 5 1 x CFT 20 The owner was advised one animal had failed to pass tho test. This herd was not vaccinated. |
|
| 3.7.74 | Retest of the failed animal - RBT -ve No CFT test. The animal remained in the herd. | |
| 21.8.79 | E1 | 59 cattle in this not vaccinated herd were bled with 24 reactors 7 x CFT 128 1 x CFT 64 8 x CFT 32 5 x CFT 16 3 x CFT 8 - x CFT 4 |
| (One reactor died after the test and the rest were slaughtered on 12th-14th September 1979 Wagga.) | ||
The owner was visited on 27.8.79 when he could not understand why he had such a high percentage of reactors.
The animal detected in 1974 was discussed as a source of later infections. He said that his herd had an odd dead calf each year. The calves were fully formed but only the size of a kelpie dog.
His herd had an 83% calving in 1978 but it was usually 90-95%. Some cows took 2-3 days to lose their foetal membranes. Usually the bull was put in for 90 days but in 1978, the bull was in for only 60 days.
It was agreed that the reactors would be picked out for slaughter at Wagga Abattoir.
Voluntary depopulation of the herd was discussed and the owner undertook to look for replacement cattle.
The owners have a separate farm, which had no cattle and could be used for a new herd under a separate tail tag.
On 18.9.79, he bought 29 cast for age cows with calves at foot at Cootamundra saleyard and a further 32 heifers from the same vendor to stock the separate farm. Two of the cows died of tetany when untrucked at Henty.
By early October, 1979 the owner had selected a Friesian milker, a red milker, the bull and 3 heifers from milkers as the only cattle of his original herd to keep provided they continued to test negative. The rest of the original herd was sold for slaughter.
E2 test of these 6 cattle in October gave a negative result.
E3 test of these 6 cattle in February revealed 1 reactor. It was the red milker. The owner suspected it was this cow when he was advised of the test result by phone.
When the property was visited by the Ranger to arrange for its slaughter, the owner's wife revealed that the red cow had aborted.
The property was visited on 7.3.80 when it was established that this red cow had been due to calve on about 20.2.80 but it had aborted in January. The owner dragged the foetus away behind his motor bike to bury it but fortunately the abortion occurred in a fairly bare lupin stubble paddock.
It was suggested on 7.3.80 to both the owner and his wife that they should locate a new tested house cow and to dispose of the Friesian cow and the 3 heifers for slaughter to provide safer milk and reduce the chance of continuing infection.
This was accepted and it is expected they will be slaughtered shortly. The bull is to be retained until mating in June until August, 1980, then fattened and sold also.
Retesting of the bull will be continued and the 4 females if they are not sent for slaughter before 8 weeks from the last test.
Role of the Interpreting Veterinarian
The interpreting veterinarian needs not only to sight results of tests and decide on those cattle which should be slaughtered but also to educate stock owners of risks involved with this disease.
The owner has a close association with his animals and if he appreciates the situation he can regularly take measures to safeguard his herd while the veterinarian is involved with other herds elsewhere in his area.
In Tooma herd, the owners were aware of the danger of infection and the risk involved so they were prepared to accept the short term inconvenience of disposing of all animals which showed any reaction at all in order to gain more security in the long term.
The next check test will indicate whether this goal has been achieved.
The success of a programme such as brucellosis requires a blending of technology to test animals, knowledge of the disease and owner co-operation to keep pressure on the disease if it is to be eradicated.
In the case of the Henty herd it would seem that infection was becoming established in the herd when the survey test took place in 1974, but there was limited evidence only. Disposal of reactors at that time was difficult and not compulsory.
It appears that the owner did not understand the implication of odd dead calves or slowness to clean after calving so no subsequent testing occurred for 5 years. By that time 24/59 were reactors.
Even after testing with this number of reactors, the owner did not realise the need to report the abortion in January 1980 so that the foetus could be examined or for full hygiene measures to be adopted.
Voluntary disposal of the original herd has been partially successful, however, and it is expected to be completed this year.
Restocking with tested cattle is expected to follow after paddock spelling.
These 2 cases are presented to illustrate how adequate understanding has assisted in the control of brucellosis in a vaccinated herd while inadequate understanding of the disease in unvaccinated herds has prolonged the testing.