A total of 95 herds took part in the Dairy Cow Weighing Programme in 2026, with 19,046 cows weighed across participating farms. Herds were selected based on their participation in Dairy Gene Ireland in both 2023 and 2026. This allowed weight records to be linked back to daughters that calved for the first time in 2026.
Why Is the Dairy Cow Weighing Programme Important?
The Dairy Cow Weighing Programme is an important initiative aimed at improving the accuracy of the Maintenance Sub-Index within the Economic Breeding Index (EBI). The project focuses on collecting liveweight records from dairy cows, helping to build a more accurate understanding of the relationship between cow size, maintenance requirements and overall production efficiency.
Cow liveweight is a key measure of efficiency in dairy production. Weighing milking cows helps identify animals that are producing milk solids most efficiently, as a heavier cow generally requires more feed and maintenance than a lighter cow producing the same level of output. The data collected through the programme will be incorporated into future EBI evaluations, helping farmers make more informed breeding decisions and supporting the continued improvement of the national dairy herd.
The 2026 programme data also reinforced the relationship between the Maintenance Sub-Index and cow liveweight. Among parity 3+ cows, every €1 increase in the Maintenance Sub-Index was associated with a 1.5 kg reduction in liveweight. This demonstrates how the Maintenance Sub-Index can be used to help identify cows that require less maintenance while maintaining strong production performance.
Farmers interested in understanding how cow liveweight affects maintenance requirements can use the ICBF Estimated Maintenance Sub-Index Calculator, available through ICBF HerdPlus. The calculator provides an estimate of an animal’s mature weight based on its Maintenance Sub-Index and can be accessed through the Estimated Maintenance Sub-Index Calculator.
How Was the Data Collected?
The Dairy Cow Weighing Programme has now been running for three years, providing valuable information that strengthens genetic evaluations and improves the accuracy of breeding indexes. Weighing was carried out by trained weighing technicians using their own weighing scales. The target was to weigh cows during mid-lactation, at approximately 150 days in milk, to ensure weights were recorded at a consistent stage of production.
The participating herds were predominantly Holstein Friesian, with 91% of cows recorded as Holstein Friesian and 9% recorded as Jersey as their main breed.
Dairy Cow Liveweight Distribution in 2026
The average cow liveweight recorded was 535 kg. Analysis of the weight records showed that 10% of animals weighed less than 444 kg, while 10% weighed more than 628 kg. This means that the middle 80% weighed between 444 kg and 628 kg, providing a representative picture of the liveweight distribution across participating herds.
The results highlight the natural variation in cow liveweight across Irish dairy herds. Recording this information across a large number of animals provides valuable insight into the range of weights within the national herd and supports ongoing research into dairy cow efficiency.
Cow Efficiency Results by Parity
Analysis of the results showed notable differences in efficiency across parities. Efficiency improved after first parity, peaking around parities three and four before gradually declining in older cows.
Efficiency increased from 0.926 at parity one to a peak of 1.007 at parity three, remaining similar at parity four before declining thereafter. By parity ten, average efficiency had fallen to 0.878, although the number of cows in the older age groups was smaller.
These findings provide valuable insights into how cow maturity can influence efficiency and reinforce the importance of collecting performance data across a cow’s lifetime.
Supporting More Accurate EBI Evaluations
As more data becomes available through initiatives such as the Dairy Cow Weighing Programme, ICBF can continue to enhance the accuracy of dairy breeding evaluations and support farmers in breeding more efficient, profitable and sustainable dairy cows. The programme provides an important source of information that will help drive genetic improvement within the national herd for years to come.
Record Dairy Cow Weights and View Your Heifer and Cow Weight Profile
Regular weight recording can provide valuable insights into cow efficiency, replacement heifer performance and overall herd management. Farmers can record liveweights directly through ICBF HerdPlus using Record Events → Liveweight, arrange for a weighing technician to visit their farm, rent a scales from a weighing depot or use their own weighing scales.
Farmers can then monitor performance through the Heifer and Cow Weight Profile, available in ICBF HerdPlus → View Profiles → Dairy → Heifer and Cow Weight. The profile combines weight, performance and genetic information to support management and breeding decisions.
