Court Farm Project Introduction: How to identify, control and eradicate iceberg diseases in sheep.

Site: Court Farm

Address: Llanthony, Abergavenny, Monmouthshire

Technical Officer: Elan Davies

Project Title: How to identify, control and eradicate iceberg diseases in sheep.


Introduction to project:

Iceberg diseases, such as OPA (ovine pulmonary adenocarcinoma), Johne’s, MV (Maedi Visna), CLA (caseous lymphadenitis) and Border disease, are of great significance to the UK sheep industry. These are diseases which are present as a small number of clinically affected cases with a larger number of sub-clinical cases in the rest of the flock.

These diseases are of great significance due to the following:

  1. Animal welfare – these diseases once contracted are ultimately fatal, for example OPA results in overproduction of lung fluid.
  2. Effects on productivity due to poor mothering, poor lamb growth and lower birthweights of lambs.
  3. Inappropriate use of antibiotics – often thin ewes are assumed to be suffering from chronic bacterial pneumonia and treated with antibiotics

There have been several studies into the prevalence of these iceberg diseases but there is little published data into the cost-benefits of identifying and eradicating these diseases on commercial farms.

In addition, EID tags and electronic software to allow useful data to be recorded and used to make ongoing breeding decisions is a tool that is underused. In this project, we hope to showcase the real benefits of using this technology for the farm through aiding in breeding decisions and monitoring productivity. 

Over the past few years there have been issues with poor body condition scores in adult ewes, however no excessive deaths were noted. Investigation into this was carried out with some significant findings which were rectified (cobalt deficiency), otherwise no evidence of Johne’s, MV or liver fluke were detected. Despite this, the poor condition of ewes was a constant underlying issue on the farm. At a visit in November 2020, several ewes were seen to have heavy breathing and excessive nasal discharge was noticed on a few thin ewes in the group. One of these was sacrificed for on-farm post mortem to identify extensive OPA lesions. This disease had never been diagnosed in this flock previously.


Project Objectives: 

The main objective of the project is to establish the true incidence of the OPA within the flock by using thoracic ultrasound. This flock represents many that are affected with this type of disease. We also want to establish if culling of affected ewes over a period of time has a true cost-benefit relationship between the cost of establishing disease and the benefits of identifying and removing affected individuals. This will look at the costs associated with vet fees, on-farm deaths of thin ewes in comparison to costs of culling ewes, before they reach the terminal stage. We are aiming to look at other parameters of improvement over the project such as increased scanning figures and increased lamb survival.  

By improving the health status of this flock, productivity and efficiency will hopefully increase. A long term aim, in coordination with the local vets, will be to look at future health planning and limiting the risk of this disease being re-introduced and ongoing disease monitoring. This is also an opportunity to maximise use of improved record keeping and electronic tags. Currently, the farm uses EID but not to its full capacity.  Changes in management of tag use should help improve record keeping and future breeding decisions to help eliminate diseases.


Key Performance Indicators Set:

Due to the nature of this project, identifying short-term, specific key performance indicators is difficult. The long-term benefits of undertaking work to identify, control and eradicate iceberg diseases from the flock would mainly be improved productivity and longevity, however, it might not be seen for many years following this work.


Timeline and Milestones: