Project code: D-76-15



Recent CAFRE analysis has estimated heifer rearing to cost £2,000/heifer or 6ppl of milk produced.  Calving at the optimum weight and age has shown previously (Pirlo et al., 2000) to result in improved fertility, longevity and potential lifetime performance.  However, the average age at first calving in Northern Ireland dairy herds is still estimated to be over 30 months, therefore, costing the industry a considerable amount of money.  Possible reasons for producers failing to calve heifers at 24 months of age are:


  • Lack of monitoring equipment on farms

  • Producer uncertainty over the longevity of heifers that first calve at 24 months of age

  • Lack of precise information/nutritional guidance to assist producers/advisers to correct under or over performing animals when offered varied diet types

  • Inability to deliver nutritional programs individually to heifers depending on performance

  • No real time delivery of performance and guidance data


This project will address these issues through the work packages outlined below. 


Work package 1

Review existing literature regarding the nutrient requirements and responses for growing dairy heifers when offered indoor diets or when grazing.  Identify gaps in the knowledge particularly relating to energy and protein requirements and protein quality for the period between weaning and calving in dairy heifers.  Conduct a number of nutritional studies to address the knowledge gaps and address industry and producer concerns.  These nutritional studies will include indoor and outdoor studies potentially using cutting edge individual feeding behaviour monitoring systems (e.g. GrowSafe) and novel grazing strategies.  GrowSafe allows the daily individual intake of animals to be calculated which can be used to calculate the animal’s energy and protein intake.  Furthermore, it allows the feeding behaviour of the animals to be determined.  Novel grazing strategies could include rotationally grazing of calves and yearling heifers looking at stocking rate, pre and post grazing height or grazing the two groups of animals separately or together.  This will lead to the development of grazing wedges and blueprints for grazing dairy heifer replacements similar to that promoted for lactating dairy cattle. 


Work package 2

Farm modernisation schemes will have helped producers to purchase weighing equipment and low cost systems such as the heifer weighband developed by AFBI can assist farmers in monitoring heifer weights.  However, with heifers handled less frequently than dairy cows and heifers often on out farms away from the main home farm, the possibility of remotely weighing/assessing heifer development must be examined.  This work package will identify, develop and test precision systems that enable remote assessment of heifer development both during the indoor and outdoor periods.  This could include instruments such as weigh scales with electronic identification positioned in front of water troughs both indoors and outdoors.  The advantages and disadvantages of these systems will be identified.  The use of these technologies for other reasons such as oestrus detection and ill health will be explored.  These technologies could potentially be used by other livestock sectors (i.e. beef) as is shown by the interest from EBLEX. 


Work package 3

 Information will be sourced, collated and analysed from local Northern Ireland milk processors to determine the impact of age at first calving on lifetime performance. 

Based on the information from work package 1 and 2 ‘How to guides’ will be developed and an update to the heifer growth programme completed to give nutritional advice on how best to achieve individual and group performance targets.  A SMART phone app could potentially be developed and used to give group and individual heifer information to farmers so that targets are met.  This is planned to form part of a Knowledge Transfer Partnership bid currently being put forward by AFBI and AgriSearch. 



 Rearing replacement heifers is an important part of the dairy industry.  This project will help address the industry and farmer concerns by enhancing knowledge on heifer rearing systems and developing monitoring and decision support systems which will lead to better nutrient utilisation, reduced Greenhouse Gas emissions, increased financial performance allowing livestock to fulfil their genetic potential. 



 Rearing dairy herd replacements is a considerable cost to the dairy industry.  Therefore, improvements in rearing efficiency that also enable heifers to fulfil their genetic potential have a direct impact on the sustainability and profitability of the dairy industry.  The overall objective of this project is to improve the efficiencies of rearing replacement heifers for the Northern Ireland dairy herd.  The proposed project will address this objective through three work packages.  Specifically work package 1 will first identify and confirm knowledge gaps followed by detailed nutritional studies that will fill these gaps in the knowledge on the nutrient requirements for rearing replacement heifers.  Within this work package studies will also provide information to inform the industry how best to manage over and underperforming animals so that they achieve the target liveweights at key stages.  Work package 2 will identify, develop and test precision systems that enable remote assessment of heifer development both during the indoor and outdoor periods.  Such systems will also be assessed as methods of oestrus and health issue detection.  Work package 3 will combine the information from work package 1 and 2 into ‘How to guides’ for farmers.  Furthermore, modifications to the existing BovIS online growth monitoring tool will be conducted to provide real time data and nutritional advice to inform producers on how to achieve target growth based on the quality of their diets. A SMART phone app will be explored that would allow real time information to be used by farmers when making management decisions about dairy heifers.  Information from Northern Ireland milk processors will be obtained and used to determine the impact of age at first calving on lifetime performance of dairy heifers and be used to further strengthen the case for 24 month calving.  In conclusion, the findings of this research will be crucial to DARD and the Northern Ireland agricultural industry from the perspective of increasing production efficiency, improving precision in the use of feeds, improving nutrient use efficiency and improving grazing systems through improved dairy heifer rearing regimes.


 Additional Information that this project will provide

 This project will better quantify nutritional requirements of growing heifers offered a range of forage types and concentrate formulations.  How to address under and over performing animals will be determined along with the feasibility of precision technologies for weighing and feeding dairy heifers.  This project will also compliment a project proposal being put forward by a commercial company to Invest NI on heifer rearing systems.  The data generated from this project will also be used in a Technology Strategy board and AgriSearch proposal to look at feed rationing systems in the UK.  Blood and tissue samples could be collected and used for genomic evaluations in the future.  The feeding behaviour information could be used as indicators of ill health or oestrus detection.  Information on feeding replacement heifers TMR rations and high concentrate low forage rations will also be produced.  This project will go a long way to addressing producer and industry concerns over rearing replacement heifers for the dairy industry.