Young Calf In A Nursery For Cows In A Dairy Farm. Newborn Animal.

UCD Veterinary Faculty

Funding was provided for a Calf Housing & Pneumonia Project which ran for a 5 year period, commencing in 2019 and concluded at the end of 2023. The final report has been submitted and the findings of this research are actively being shared with farmers, vets, farm advisers and policy makers.

Young Calf In A Nursery For Cows In A Dairy Farm. Newborn Animal.

This study was conducted to address gaps in the knowledge of dairy calf pneumonia in Ireland. The aims of the study were to understand the level of calf pneumonia in the industry; determine the effect of the respiratory disease on Irish dairy calves (in terms of growth rates and production) and to evaluate new and improved diagnostic methods for detecting the disease in calves. The project started on 1st January 2019 and concluded on the 31st December 2023, and is one of the most comprehensive analyses of dairy calf pneumonia/bovine respiratory disease (BRD) that have been undertaken anywhere in the world. The study encompassed detailed environmental analysis of almost 100 Irish dairy farms and samples from over 2,500 Irish dairy calves.

In brief, the project has shown:

o Pneumonia is a farm, not a calf problem – While overall, relatively few calves (about 4%) are affected by pneumonia on Irish dairy farms, some farms have a significant problem, with up to 1 in 5 calves affected in these herds. Thus the burden of BRD in Irish dairy calves is lower than in other major dairy producing countries.

o Pneumonia farms can manage their risks – Farms with more calf pneumonia have issues with calf colostrum and milk feeding practices; bacterial air contamination and some inlet designs are associated with increased farm prevalence of calf pneumonia. Increasing the amount of straw bedding was protective against calf pneumonia.

o The conditions necessary to produce a ‘stack effect’ for ventilation do not appear to occur in Irish calf sheds.

o Pneumonia calves grow slower, perhaps for life – Calves with BRD in Irish dairy farms grow at approximately 126g per day slower than unaffected herd mates and are lighter at weaning. Further work is ongoing to examine lifetime impacts (milk production and fertility and survival) in these animals.
o Pneumonia is grossly underdiagnosed – A significant proportion (about 50%) of calves with BRD are missed/not treated by current conventional diagnostics. Methods developed in this project detected about 70% of cases. Further work, as a direct spin-off from this research, is ongoing to improve current detection methods.The findings from this study project have already informed housing guidelines for Irish dairy farmers via AHI and other media outlets. The work has been presented at national and international conferences including the World Buiatrics Congress (the largest cattle veterinary conference in the world) in Madrid in September 2022.

To date, 5 peer-reviewed scientific papers have been published / accepted for publication in the Journal of Dairy Science (2), The Veterinary Journal (2), and Frontiers in Veterinary Science (1). The advanced pneumonia diagnostic methods validated and optimized in this study have been disseminated to vets in practice.

The PhD student has also trained researchers in both UCD and Teagasc in the diagnostics used in this project. The PhD student recruited for the project has successfully submitted and defended their PhD thesis, graduating in June 2024.