Rearing dairy heifer replacements

(A Greenmount College Technology Project in partnership with J. Bibby Agriculture)

Dairy heifer replacements should be considered as an investment in the future. Recent improvements in breeding have accelerated the production of Holstein heifers with the potential for high milk output. However many farmers find that heifers reared on their own farms may not always meet their expectations. Research has shown that the management regime adopted when rearing heifers can have a major impact on cow performance, cow health and the costs of rearing. This information has been brought together to provide management guidelines to help dairy farmers rear high production heifers in a cost effective manner through a Greenmount College Technology Project.

The project aims to demonstrate heifer rearing skills using the heifers born within the College dairy herd. The importance of this project to the wider industry was recognised when animal feed manufacturers J. Bibby Agriculture agreed to support the project.

The five year project started in September 1997 and aims to be completed by September 2002.

To demonstrate a cost effective rearing system for high production dairy heifer replacements. The following targets are set to achieve this:

Manage the heifers to calve down at two years of age

Achieve a pre calving weight of 600kg by following specific weight targets throughout the rearing period. Target weights are given in Table 1

Demonstrate the management skills involved on commercial farms in Northern Ireland

Table 1. Target liveweights for the dairy heifer 2000 project

Heifer calves originate from the Protein Improver, High Forage and CREAM herds within the College. Examples of sires used include Fatal, Mascot and Formation.

Calves eceive colostrum as soon as possible after birth and remain with their dams for up to four days. The calves continue to receive milk for up to seven days. Calves are usually dehorned at around three weeks of age.

Calves are introduced to milk replacer after seven days and a coarse calf concentrate mix. Silage is offered as calves approach weaning. Target age at weaning is 6 – 8 weeks. Intakes of coarse calf mix at weaning are on average 1kg/head/day. The amounts of coarse calf mix are increased to two kilograms per day after which calves receive ad lib silage plus a concentrate supplement. Levels of supplementation at this and subsequent stages vary according to animal performance.

Silage for the heifers is made with targets of :

The concentrate rations are specially formulated by J. Bibby Agriculture. They include quality energy sources and a range of protein sources.

Turnout to grass generally occurs during April and calves at this stage are treated with anthelmintic as part of a parasite control programme. Grass is managed to provide high quality, leafy swards. The heifers are grazed in a leader and follower system with young calves in the leader group (first summer) and in-calf heifers in the follower group (second summer). Supplementation levels vary according to liveweight gains.

Young calves are housed in individual straw bedded pens. After a few weeks the calves are moved to kennel housing, with good ventilation, cubicles, solid floors and an easy feed passage. Calves are trained to lie in cubicles fitted with rubber mats.

Maiden heifers are also housed in a kennel house. The cubicles in this house are fitted with comfort mattresses.

The target age for first insemination of heifers is 15 months. AI sires are selected for easy calving and according to project criteria. Sires which have been used include Lava, Demand and Rudolph. A sweeper bull is also used on any heifers not holding to a second insemination.

The target age at calving is 24 months, while target condition score at calving is 3.0. In an effort to minimise stress, the following steps are taken to help settle heifers into the milking herd:

Students at Greenmount College regularly assess heifer performance. Measurements taken include:

Changes in liveweight gain are monitored closely and are used to adjust concentrate feeding levels as required. Information on animal performance is regularly updated on the Greenmount website.

Technical Note prepared by: Aidan Cushnahan, Greenmount College

Copies of this leaflet can be obtained from Greenmount College.Tel:028 94 426772

Further information on Greenmount College Technology Projects can be found on our website at www.greenmount.ac.uk

ISBN 1 85527 383 7 ©

Greenmount College of Agriculture and Horticulture