Indoor management of weanling replacement heifers

Housing time is a great time to separate the lighter heifers for preferential treatment over the winter. This is important to ensure that they reach the target weight required for successful rearing. George Ramsbottom, Teagasc Dairy Specialist, gives us more detail.

Their target live weight depends on their maintenance sub index – see Table 1 for target weights around housing and pre-breeding for various maintenance sub indices. Underweight heifers are those that are 5% or more below target. So for example weanling heifers with a maintenance sub index of €20 that weigh less than 205 kg on November 1^st fall into the under weight category.

Live weight gains of at least 0.5kg/day and 0.7 kg/day are required for on-target and lighter heifers over the winter period.  The longer term aim is to ensure that all heifers are at planned pre-breeding target liveweight at the start of the breeding season; and secondly to minimise the variation in live weight around breeding time. 

To achieve such gains the following actions need to take place now:

1. Treat heifers for parasites at or shortly after housing.
2. Segregate light from on-target/above target heifers.
3. Feed heifers according to the quality of the silage and liveweight.
• On 67% DMD well preserved grass silage underweight heifers will require 1.5-2.0 kg concentrate/day.
• Reduce allowance by 1kg/day if silage is 5% higher DMD / heifers are at or above target weight.
4. Ensure that 0.3m (1ft) of feeding space is available per heifer – this is especially important for the lighter heifers or indoor performance will be reduced.
5. Plan to turn the lighter heifers out to grass in early February – heifers will gain 1kg /day on spring pasture alone or on a combination of grass and meals if grass is scarce.

Table 1: Target 1^st November 2021 and 1^st May 2022 live weights for replacement heifers of different maintenance sub indices.

The Teagasc Dairy Specialists issue an article on a topic of interest to dairy farmers every Monday here on Teagasc Daily. Find more on Teagasc Dairy here