Developing Improved Heifer Rearing Systems

Project code: D-03-97

Team and Leader A.Carson (ARINI)

Organisations Involved Agricultural Research Institute of Northern Ireland (A Carson, F J Gordon, A R G Wylie) Veterinary Sciences Division, DANI (J.E. McEvoy), 11 Northern Ireland milk producers

Background and Summary

Feeding and management during the heifer rearing period has a major impact on subsequent animal performance, health and welfare. The systems for rearing dairy herd replacements presently adopted were developed from research carried out 30 years ago. Since then the genetic merit of the Northern Ireland diary herd has changed considerably.

It is crucial that rearing information is obtained for todays high genetic merit heifers. With present genetic progress the high merit animals of today will be the norm in 3-4 years.

The key questions which arise in relation to heifer rearing are:

1. What should be the weight at calving of todays high genetic merit heifers?
2. If higher weights at calving are necessary, and hence high growth rates during rearing, then is the type of diet important?

To address these key issues a study has been set up in partnership with Northern Ireland milk producers. Eleven producers have supplied to ARINI high merit, autumn 1996 born, heifers (110 heifers; representing top 2% of registered UK animals in terms of genetic merit). These are being reared under experimental regimes at Hillsborough and will return to the farms in autumn 1998. This present proposal is to develop this programme further, rearing an additional 110 autumn born 1997 calves under the experimental regimes already set up. This will increase the reliability of the milk production data and will enable a more comprehensive analysis of the impact of rearing on fertility, lameness, calving difficulties, metabolic disorders and linear traits likely to reflect longevity.

Timescale

Benefits

This programme will improve efficiency of the whole diary sector by providing it with higher quality replacement animals entering the herd. This could influence both performance efficiency and longevity of animals in the herd.

See the farmer booklet here.