Evaluation of the incidence and prevalence of major diseases and conditions of British dairy cows

Dairy cows in GB are affected by a number of infectious and non-infectious diseases that occur regularly in dairy herds and are know as “endemic” diseases. Althogh endemic diseases tend to receive less attention than new or emerging (epidemic) diseases, they can be responsible for important economic losses and even small reductions in their frequency can siginficanlty increase the efficiency of dairy farms. 

Key Findings

For infectious diseases:

• A large proportion of GB dairy herds (40% or more) for MAP (Johne’s disease), BVDV, BHV-1 (IBR), Leptospira, Neospora, Fasciola and Ostertagia have ongoing or previous infections. 
• Diseases such as Ostertagia or Fasciola it is very difficult to prevent some animals from becoming infected.
• Other diseases, such as BVDV, it is possible to reduce considerably the proportion of herds experiencing infection in their animals.
• It is estimated that 68% of GB herds are effecetd by Johne’s Disease (as determined by bulk tank testing).
• There are some geographic differences in the distribution of infectious diseases across GB, with a tendency towards lower prevalence in South East England compared to other areas.
• The study confirmed the importance of good biosecurity: operating a closed herd reduces risk for most of the pathogens.

For non-infectious diseases:

• Incidence remains high in some farms in which there is potential for more effective disease prevention.
• For most of the conditions (abortions, retained placenta, displaced abomasum (DA), Ketosis, milk fever) incidence based on farmers’ perceptions was higher than based on records, which suggests relying on farm records may underestimate their true incidence.
• At national level, we estimate that every year abortions cost farmers £49M, retained placenta £36.9M, milk fever £26.7M, ketosis £24.1M and Left DA £8.3M.
• Although it is unrealistic to completely prevent the losses associated with these diseases, these figures suggest that slight reductions in their incidence would result in significant economic benefits for farmers.

Aims and Objectives:

The main objective was to update, enhance and provide new information to quantify disease levels in British dairy cattle.

More specifically, the objectives were to:

1. Identify health issues for which having up-to-date estimates is of importance for dairy farmers and for the industry as a whole
2. Identify databases keeping relevant information
3. Conduct a formal evaluation of existing databases
4. Identify key issues not been appropriately recorded and that therefore should be included in a cross-sectional study
5. Provide estimate of disease frequency and risk factors from a cross-sectional study
6. Model financial and environmental effects of major health events