Article Summary: Supplementary feeding in a grazing system helps maintain livestock performance and protect pasture during feed shortages or high demand. By providing the right type of feed at the right time and in the right amount, farmers can balance animal needs with pasture health for sustainable production.
Pasture forms the backbone of nutrition for grazing livestock. It’s cost-effective, natural, and – when managed well – capable of meeting most of an animal’s dietary needs. However, there are times when pasture alone won’t cut it. High-producing dairy cows may require more energy than grass can provide. Extended dry spells can slow pasture growth to a crawl. Or seasonal changes might mean the grass quality dips below what’s needed for peak performance.
In these situations, supplementary feeding plays a crucial role. The challenge lies in using supplements to support pasture, not replace it. Done well, supplementation keeps animals in good condition, sustains productivity, and protects pasture health. Done poorly, it can waste both feed and grazing potential.
This guide explores when to supplement, how to strike the right balance, and practical strategies for integrating feed into a rotational grazing system without undermining the benefits of pasture.
When and Why to Supplement
In an ideal world, livestock would get all their nutrition from well-managed pasture. Grass remains the cheapest feed available, and optimising its use is usually the first goal for a grazing enterprise. But the reality of farming often calls for more.
Common reasons to supplement include:
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Seasonal shortfalls – In winter or during drought, pasture growth slows or stops. Without extra feed, animals risk losing weight or dropping in production.
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Periods of high demand – A dairy cow in early lactation may have higher energy needs than grass alone can meet. Similarly, ewes late in pregnancy or growing lambs may require additional protein.
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Quality gaps – Mid-summer ryegrass, for example, can be low in protein or energy, making it harder for animals to maintain performance.
In each case, the primary purpose of supplementation is to fill the nutritional gap. Research consistently shows that high-producing dairy cows grazing pasture benefit from extra energy in the form of concentrates to maintain milk yield and body condition. Similarly, beef cattle or sheep grazing mature, low-protein forage often perform better with added protein.
Supplementation can also be used to stretch pasture supply. Feeding hay, silage, or grain reduces grazing pressure, leaving more pasture to recover. This is particularly useful in dry conditions, helping to prevent overgrazing and protect plant persistence.
Striking the Right Balance
One of the most important principles in pasture-based feeding systems is ensuring that supplements complement pasture intake, not replace it.
Overfeeding supplements can lead to substitution, where animals consume less grass because they fill up on hay, silage, or grain instead. This can lead to wasted pasture that is either trampled or left to mature past its best, lowering its feed value.
For example:
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Providing free-choice hay to cattle when pasture is available often results in the animals eating the hay first and ignoring the grass.
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Feeding excessive grain can reduce forage digestion efficiency and make animals less motivated to graze.
The key is finding the “sweet spot” – feeding enough to cover the shortfall without significantly reducing pasture intake. This might mean:
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Offering dairy cows a few kilograms of grain during milking to boost energy without leaving pasture behind.
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Providing a single bale of hay for beef cattle on pasture, rather than free access all day.
If you do increase supplement levels, consider adjusting your grazing plan. With reduced pasture intake, you might rotate stock more quickly or run slightly higher stocking rates to prevent under-utilisation.
Types of Supplements and How to Use Them
Different situations call for different types of supplementary feed. The main categories are:
Energy Concentrates
Grains such as barley, maize, oats, or formulated pellets provide concentrated energy, ideal for dairy cows in early lactation or finishing cattle.
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Feed in moderation to avoid rumen upsets.
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Split into smaller feeds across the day.
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Deliver during milking or in troughs to ensure equal access.
Forage Supplements
Hay and silage add bulk and fibre to the diet when pasture is short.
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Making your own from surplus spring pasture can reduce costs.
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Use hay rings or unroll bales to reduce trampling loss.
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Consider a sacrifice paddock or feed pad in wet conditions to avoid damaging pasture.
Protein Supplements
Feeds like soybean meal, cottonseed meal, or lucerne hay can lift protein levels in low-quality forages.
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Best targeted to growing animals or lactating mothers.
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Avoid routine use unless the benefit is clear, as protein feeds are expensive.
Minerals and Vitamins
Always provide a year-round mineral mix tailored to local soil and pasture conditions.
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Spring pasture may require high-magnesium minerals to reduce the risk of grass tetany.
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Ensure constant access to salt and adjust copper, selenium, and phosphorus as needed.
Integrating Supplements into Rotational Grazing
Timing is critical. Feed supplements at times that won’t interfere with the animals’ main grazing periods. For example:
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Cattle typically graze most in the early morning and late afternoon.
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Offer hay late morning or concentrates during milking to encourage pasture grazing first.
Placement can also influence grazing behaviour.
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Position mineral licks or hay feeders in underutilised areas to encourage even grazing and manure distribution.
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Move feeding areas regularly to avoid pasture damage.
Some farmers also use targeted feeding strategies, such as creep feeding calves while controlling cow intake, to meet different nutritional needs within the herd.
Using Data to Make Smarter Decisions
Modern pasture management tools now allow farmers to link pasture growth data with herd nutritional needs.
For example, by measuring pasture cover and projecting growth, you can calculate whether you have enough feed to last until the next growth flush. If a shortfall is predicted, you can introduce supplements early to prevent a sudden production drop.
Tools like Pasture.io integrate pasture data with herd feed requirements, enabling you to:
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Forecast feed supply against demand.
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Adjust supplement levels based on projected deficits.
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Track supplement use and evaluate its impact on both animal performance and pasture recovery.
By basing supplementation on accurate data rather than guesswork, farmers can avoid both underfeeding and overfeeding, saving money while maintaining performance.
Final Thoughts
Supplementation in a grazing system isn’t about replacing pasture – it’s about supporting it. By providing the right feed, in the right amount, at the right time, you can keep animals in good condition, sustain production, and protect your pasture base for future growth.
Smart supplementation is a balancing act, but when done well, it benefits both the herd and the land – ensuring a sustainable, profitable grazing system year after year.
Until we meet again, Happy Grazing!
- The Dedicated Team of Pasture.io, 2025-06-19