As mornings turn crisp and days shorten, pressure on youngstock increases. April and May are busy months for drying off, but youngstock shouldn’t be an afterthought. Feed quality, parasite control and trace elements all matter. Animals entering winter behind the eight ball pay a high price later to catch up.
Weighing: Data Beats Guesswork
Regular weighing is the only reliable way to know heifers are on track. In autumn, declining pasture quality can trigger a silent growth check that’s easy to miss by eye.
Rising one-year-olds should be around 40% of mature weight at nine months and 60% by 15 months1. With reduced winter growth rates common, all animals need to be at or above their autumn targets to avoid a check.
Navigating the Parasite Peak
Autumn often brings a higher pasture larval challenge. While drenching removes adult worms (assuming the drench is effective), it’s managing larvae year-round that prevents an autumn peak.
Tools that help include using adult cattle to clean up pasture, cross-grazing, crop rotation, leaving higher post-grazing residuals, and—most importantly—growing calves quickly to shorten the risk period.
Before reaching for the drench gun, use Faecal Egg Counts (FECs) to understand the true burden and whether treatment is needed. Strategic drenching—treating the animals that need it rather than blanket treatment—helps slow the development of drench resistance.
For youngstock in higher-risk areas, especially those grazed off-farm, don’t forget liver fluke. Talk with your vet about appropriate testing and treatment options.
Nutrition and Trace Elements
As pasture quality plateaus, check whether feed demand is still being met. Heifers need enough high-quality feed to maintain steady growth through autumn.
Use weighing data to identify poor performers. Splitting these animals into a separate mob reduces competition and allows preferential feeding to meet their higher requirements.
In facial eczema-prone regions, maintaining zinc protection into May may be necessary. Subclinical liver damage can severely limit growth rates and have lifelong impacts.
Autumn is also the time to review trace element status, particularly copper and selenium. Testing shows whether heifers are entering winter with a full tank—or running on empty, which can compromise growth and immune function.
Three Autumn Priorities
- Weigh – Schedule a weighing this month and compare results against the 40% (9 months) and 60% (15 months) targets. Preferentially feed animals that are behind.
- Monitor – Use FECs to guide parasite control and confirm drench effectiveness with a faecal egg count reduction test 10 days post-treatment. Consider feed quality testing to support accurate feed allocation.
- Supplement – Fill any energy gaps with supplementary feed and address trace element deficiencies where testing shows a need.
Act Now
Don’t wait for the first frost to discover your heifers have fallen behind. Acting now builds more resilient, high-performing animals ready for spring.
Talk with your local Farm Source TSR or vet about autumn youngstock priorities. For more on parasite management, visit Wormwise. You can also check DairyNZ’s liveweight target guide to keep heifer growth on track.
1. https://www.dairynz.co.nz/animal/heifers/lw-targets/
