Life before entering the milking herd influences the performance of young cows once they join the herd. Their success is linked to how they hit milestones from colostrum feeding as a newborn through to when they themselves calve.
The weaning process is a critical stage where liveweight targets must be met to ensure their liklihood of reaching mating targets as rising two-year olds (RD) with yearlings.
In New Zealand's pasture-based systems, once calves have met key liveweight target by weaning, the challenge is then to maintain steady growth rates through to mating .
Ideally, heifer calves should be at least 90 to 100kg liveweight at weaning, depending on breed. From there, they need to average 0.7 to 0.8 kg per day liveweight gain (LWG) to hit 60 percent of mature cow weight by 15 months, at first mating. Falling behind in early life often leads to a growth lag that is difficult to recover from, contributing to higher empty rates in second lactation, and higher culling pressure.
Supportive weaning
- For the first six weeks, milk is the primary energy source. Gradually transitioning from milk drives increased calf meal or pellet intake, the starch contributing to rumen development. Calves need at leave 1 to 1.5 kg of quality meal or pellets daily before completely removing milk.
- Maintain access to clean water, shelter, and avoid stressful handing or abrupt diet changes.
- Offer high-quality pasture early, valves are slective graziers at this age. To reduce the lilihood of a growth check, continue supplementing with meal for at least a month after removing milk from the diet.
- Calves' rumens are still developing so when pasture quality and/or quantity is reduced, meal supplementation needs to continue longer, with only small amounts of silage or hay offered.
Post-weaning strategies
- Introduce trace minerals needed for health and immune function.
- Implement an integrated planned drench programme over summer/autumn.
- Regularly monitor weight and invest in good scales. Weighing every four to six weeks identifies underperformers and allows for timely intervention with corrective dietary change.
- Manage pasture to keep covers in 2,000 to 2,800 kg DM/ha range to maintain quality.
- Introduce forage crops like chicory, clover, or leafy turnips if quality pasture is not abundant at weaning time. They are highly digestable and good for liveweight gain. Fibre supplementation is also required.
- Later in summer/autumn, when rumens are more fully developed, consider supplementing with good silage or meal/grain during feed pinches.
- Avoid overtocking. Calves need adequate space and access to feed.
With good weaning management, consistent feeding, and pasture quality control, calves will grow well and be ready for their first calving as they approach two years of age. Early investment pays dividents in higher lifetime production, better fertility, and reduced replacement costs.
