Lamb liver fluke antibody test results - July



Using abattoir blood samples from slaughtered lambs to detect the timing & spread of fluke infection

Since 2015, from June to December, DAFM has taken lamb blood samples in factories from a proportion of flocks at the time of slaughter. These have been tested for liver fluke antibodies to determine the timing and geographical spread of liver fluke challenge to grazing lambs.

The number of flocks selected for sampling from each county is intended to be proportionate to the sheep population of that county over the entire sampling period (June to November 2019). A number of samples are taken from each selected flock, and these are pooled at laboratory level. The presence of liver fluke antibodies reflects the level of challenge the lambs have experienced during the most recent grazing season. The presence of liver fluke antibodies in 2019 born lambs is therefore a sentinel for exposure to liver fluke in the wider sheep population in the region, as by definition these lambs must have been exposed during the 2019 grazing season.

Results up to June 2019                                                                   

Results for each county for samples taken in June 2019,

ordered by percentage of flocks seropositive in each county, are as follows:

Results for each county for samples taken in June 2019, ordered by percentage of flocks seropositive in each county

Given the moderate fluke forecast provided by DAFM for last winter and the early stage in the grazing season at which samples were taken, it is unsurprising that so many of the samples tested negative. The positive samples seen in Mayo and Donegal serve to remind us of the need for caution when assessing the liver fluke status of Irish sheep flocks, and of the need to consider information from a range of sources when deciding whether or not to dose. 

As the sample size for some counties is small, farmers in these particular counties need to be cautious when interpreting the results of the survey as they relate to their areas. Additionally the county associated with a batch of lambs is that where the flock of submission is registered. In a minority of cases, where the lambs had been purchased shortly before slaughter, the county associated with a batch will not reflect accurately where the batch of lambs spent its life. 

Thanks to Seamus Fagan of Athlone Regional Veterinary Laboratory, Charlie O’Connell of VPHIS and Kate O’Keeffe, DAFM blood testing laboratory in Cork for the information provided.

Species: Multi-Species
10:27 AM on Mon, 22 July