Efficient and well-managed heifer rearing plays a vital role in the productivity and profitability of any dairy herd. Grazing systems offer a cost-effective alternative to housing, significantly reducing inputs such as feed, bedding and labour. However, this lower-cost approach must be matched with structured management to ensure heifers reach key development milestones and grow into high-performing replacements.
Achieving Growth Targets
Rearing heifers to meet their target weights at key ages is essential. Heifers that reach their target breeding weight between 13 and 15 months are more likely to calve at 24 months. This age is associated with improved fertility, better lifetime milk yields, and reduced rearing costs per litre of milk produced.
Recommended benchmarks include:
- At 6 months: ~200 kg
- At 12 months: 300–330 kg
- At breeding (13–15 months): 55–60% of mature weight (330–360 kg)
- Pre-calving: 85–90% of mature weight (540–580 kg)
Aim for a daily live weight gain (DLWG) of 0.7–0.8 kg/day from weaning through to breeding. Regular weighing every 4–6 weeks helps identify issues early and supports timely intervention.
Grazing Management and Supplementation
Grass quality and grazing practices significantly influence heifer performance. Implement rotational grazing to provide consistent access to fresh pasture. Target pre-grazing sward heights of 8–10 cm and aim to graze down to 4–5 cm.
In periods of poor grass growth or extreme weather, supplementing with 2 kg/head/day of concentrate helps maintain target gains and ensures nutrient needs are met. Normally once we come to the beginning of July, and grass quality starts to deteriorate it is good practise to start to introduce a small amount of concentrates into the diet. This ensures performance is maintained and sets the animals up when housing comes around.
Health Planning and Group Management
Heifers at pasture face challenges from parasites and disease. Maintain a proactive health plan including vaccinations (BVD, IBR, and leptospirosis), targeted worming, and fly control during warmer months. Faecal egg counts are an important tool, as in recent times we have witnessed calves loose in their manure with poor thrive, which in turned was a heavy worm burden. These faecal egg counts can help guide anthelmintic use and ensure performance is maintained.
Group heifers by size and age to minimise competition and bullying. Stocking rates should reflect grass availability and quality to support optimum growth and prevent sward damage.
For tailored advice on grazing management and heifer nutrition, contact your local Fane Valley Feeds representative or call 028 8224 3221.
