Heifer replacements are the future of your herd and achieving good growth rates has a positive impact on their future production, reproduction and longevity in the herd.

An El Niño weather pattern is predicted for the coming summer, bringing reduced rainfall for much of the country and a chance of higher temperatures.

To be prepared for a summer dry, planning ahead is vital to achieving good growth rates. From the day they are born, heifers need to achieve 700 g per day average daily growth rates for the entire rearing period. This enables stock to reach 90 percent of live weight by 22 months of age for a 500 kg mature live weight target. Late-born calves may need to be preferentially fed before and after weaning to achieve the higher growth rates required.

To achieve good growth rates consider:

» Weighing heifers every two months, increasing to monthly in high-risk periods. This allows the ability to respond to animals not performing and make strategic feed and drenching decisions.

» Implementing an effective worm management programme.

» Facial eczema and its large impact on animal health and performance. Ask yourself, what is the plan to monitor for facial eczema risk? What preventative methods are going to be used in at-risk areas?

Target liveweights¹

These targets are the minimum for all animals in the mob:

» Sixty percent of mature live weight by the mating start date. This helps ensure heifers have had more than one cycle, increasing their chances of a successful mating.

» Ninety percent of mature live weight at 22 months of age. Well-grown heifers produce more milk, compete better with mature cows, and survive longer in the milking herd.

For young stock on summer pastures, protein can be in short supply. This deficit can be met by specialty summer crops, quality silages such as lucerne or grass silage and supplementary feeds brought in. Specialty forage crops are a great tool for supplying quality leafy green feed over summer. Have the crop yielded with dry matter testing to ensure adequate feed is available over the period required.

Fast-growing young stock need quality feed. Lower-quality silages will not support good growth and should be prioritised for mature stock that are not milking. Feed testing can provide valuable information on the quality of the silage.

Contact your local PGG Wrightson Technical Field Representative for assistance in forming a nutritional programme for your heifer replacements during summer.

1 Blackwell, M., Roberts, K., Ellison, R., & Penry, J. (2017). The Incalf Book for New Zealand Dairy Farmers (2nd ed.). DairyNZ. ISBN 978-0-473-42232-5.