Dean's Lunchtime Clinical Club - 6 March 2018 - Ciara Hayes
Ciara Hayes, UCDVH Resident in Bovine Health Management, presented on ‘Lungworm – A Herd Investigation’ at the Clinical Club on 6 March. This herd health investigation, involving two suckler herds, was carried out by the UCD Herd Health Management Group last Summer.
Ciara began her presentation by looking at the background of each farm. Farm 1 was much larger with 500 animals and 350 acres. It had a year-round calving pattern, with calves sold as weanlings. It had also had a severe Johnes Disease problem recently diagnosed. Farm 2 had 40 cows plus calves and weanlings, 40 acres plus a further 20 acres aftergrass, with animals rotated through the home grazing block; this farm was grazed quite tightly. They had spring calving, with calves kept over winter and sold off grass at 18 months. Ciara then described the parasite control procedures on both farms, looking at when this happened and what was used; she noted that the cows on Farm 2 had been treated in May of last year for the first time.
The history of the problem was then examined. On Farm 1, there was respiratory disease in youngstock, and a recent PM of a heifer had shown lungworm. The farm also had cows coughing, with one animal confirmed as IBR positive; an IBR live vaccination programme was underway. On Farm 2, all cows had begun coughing in June, there was IBR positive serology, and this had responded to levamisole and the IBR live vaccine. The movement on this farm had created significant issues. There was recurrent free gas bloat in 3 animals and this was the reason for the initial call out; Ciara outlined that the underlying issue in the herd is often different to what you're called out for.
Investigations were carried out at both farms and a bronchoalveolar lavage was used and faecal and blood samples were taken and analysed. Results from Farm 1 showed live lungworms; Ciara noted that it's interesting to be able to see the issue straight away, and that the farmer was pleased that he could see the actual problem in front of him. A patent lungworm infection is unusual in adult cows as they usually have good immunity to this. Ciara detailed that this indicates the scale of the burden these animals were faced with and also showed a very compromised respiratory function. On Farm 2 it was a case of reinfection, and Ciara then detailed the life cycle of lungworm in cattle.
The recommendations were different on both farms – they were dealing with different problems and both had different management systems in place. On Farm 1, they needed to treat the current infection and provide anthelmintic cover until housing in the short term. In the medium to long term, vaccination was not suitable due to their year round calving pattern. It was recommended that they prevent the build up of larvae on pasture next year by treating the calves; Ciara highlighted the importance of strategic anthelmintic treatment in this case. In Farm 2, paddock 1 had a massive burden and they were advised to avoid using this; moving the weanlings there had allowed a large burden to develop. They were also advised to provide anthelmintic cover until housing. In the medium to long term, grazing management and a vaccination programme were recommended.
Ciara concluded by highlighting that the UCD Herd Health Management Group would keep in contact with both farms to see if things improved this grazing season. Lungworm was quite a big problem last Summer, possibly due to the mild winter, and it's an issue that is possibly becoming more prevalent.