Project code: D-17-03

Duration 3 years commencing October 2003

Team and Leader Arnoud Hameleers, Sinclair Mayne, Nick Friggens

Organisations Involved ARINI, Department of Agriculture and Rural Development for Northern Ireland, Danish Institute of Agricultural Sciences

Background and Summary

Supplementation of forage with concentrates is an important management tool to achieve improved efficiency and economic sustainability of dairy cow production systems. The current approach to rationing of dairy cow diets is to evaluate the basal forage, combine this with target milk yield and formulate a diet according to nutrient demands. 

Genetic merit has improved dramatically, possibly changing also the utilisation of energy reserves. These two factors might explain the current problems been experienced by dairy farmers in terms of health and fertility with the high productive dairy cow. Conception rates as low as 38% have been reported with major implications for lifetime productivity. Recent AgriSearch and MDC studies have shown that fertility is the single largest culling factor in dairy cows in Northern Ireland and the UK.

Lactation is a natural process, which has developed after a long period of evolution, associated with taking care of the recently born and subsequent reproduction. It may therefore be assumed that certain processes like utilization of body reserves are genetically driven. However this is normally ignored in current rationing systems and this might explain the great variability found in responses to supplementation. Current health and fertility problems are indicating that we are not responding to the needs of the dairy cow in terms of feeding. On the other hand, with the automation of the milking process (and in some cases the feeding process) information is generally on a daily basis, which could improve the feeding of the average cow whilst also enabling feeding to cows individually.

New rationing systems should not only examine the current state of the dairy cow but also incorporate long term objectives. This will not only result in more efficient use of feeds but also could improve herd life of the dairy cow. Recent work in the link project "Feed into Milk" has provided us with excellent instruments to predict nutritional needs. It is however necessary to start incorporating long-term objectives in feed rationing programmes. The objectives of the present study are to investigate responses of dairy cows to supplementation and determine the relationship with the use of body reserves, fertility and health aspects in high productive dairy cows.

This will involve a series of studies:

a) The effect of supplementation during different stages of lactation and parities and its relation with productivity and indicators of health and fertility
b) The effect of supplementation of cows being offered high and low energy density diets and its relation with productivity and indicators of health and fertility
c) The development of a cow response model on the basis of the two studies mentioned above
d) The effect of individual supplementation of dairy cows on their productivity and health and fertility
e) Model validation and preparation for its incorporation in dairy rationing programmes


1. October 2003 - Start of first supplementation experiment
2. October 2004 - Presentation of preliminary report and start of second supplementation experiment
3. August 2005 - Presentation of dairy cow model
4. October 2005 - Start of validation experiment
5. June 2005 - Seminar with sector to discuss results and their implications
6. October 2006 - Presentation of final report


1. More efficient feed use in dairy production systems in Northern Ireland
2. Reduction in health and fertility problems in dairy production systems in Northern Ireland
3. Improved feed rationing programmes available to the sector

Technical report can be found here.

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Download this file (Final report for AgriSearch (D-17-03).pdf)Developing supplementation strategiesDeveloping supplementation strategies for dairy cows - A new approach incorporating cow status and cow potential - D-17-031932 kB