14 December 2023

Feeding replacement heifer weanlings this winter

The winter management of your replacement heifers is crucial to ensure they meet their target weights at breeding next spring, writes Stephen O’Callaghan, Walsh Scholar, Teagasc Navan.

We want to ensure all heifers meet the planned pre-breeding targets, and to minimise liveweight variation within the group. Key target weights are that heifers are 30% of mature bodyweight at six months of age and 60% of mature bodyweight at the start of breeding.

Underweight heifers are considered to be animals that are 5% or more below target bodyweight. Regular weighing of heifers can help us to keep track of performance through the season.

Table 1: Bodyweight targets for maiden heifers at breeding and for heifers pre-calving by breed/crossbreed

In order to achieve these targets we need to:

• Ensure heifers are treated for parasites at or shortly after housing;
• Separate lighter heifers from on-target heifers and give preferential treatment;
• Feed heifers according to the quality of the silage and liveweight. On 67% DMD silage, lighter heifers will require 2kg of meal per day, you can reduce meal by 1kg/day if silage is 5% higher DMD or heifers are on/ahead of target;
• Ensure that 0.3m (1ft) of feeding space is available per heifer;
• Plan to turn the lighter heifers out to grass first in February, heifers will gain up to 1kg on good spring grass. However don’t rely on early turnout to make up for poor performance during the winter period.

Following these key steps will help us to meet our targets and give heifers the best chance to succeed within the herd.