You’ve seen it on the first real hot week. Cattle standing at the water, bunks still half full at noon, and intake falling right when they need the energy most. Heat stress is already hitting feedlot pens and dairy sheds across South Africa and Australia. Managing heat stress in cattle feeding takes more than shade and water.
When feed hits the bunk, and how fresh it is when it gets there, decides whether cattle keep eating through a hot spell. The good part? Changing the feed wagon schedule costs you nothing.
Why Heat Knocks Intake Down
Digesting feed makes heat. When cattle can’t get rid of heat fast enough, they eat less so they make less of it. Intake drops, rumination slows and the risk of digestive trouble goes up, especially when cattle gorge once it finally cools off. High-producing dairy cows and heavy cattle on hot finishing rations feel it first.
Heat Stress Cattle Feeding: Move the Clock
Feeding times should follow the thermometer, not the schedule that worked in winter:
- Put more of the day’s ration out in the cool hours, early morning and evening, when cattle actually want to eat.
- Skip big deliveries in the hottest part of the afternoon. That feed just sits there and cooks.
- Change gradually. Cattle are creatures of habit, and a sudden switch in feeding time can knock intake as hard as the heat does.
A lot of feedlots move to an earlier first feed and a later evening feed once summer settles in. Dairies often time the main delivery around cows coming back from afternoon milking.
Keep the Ration Fresh
A mixed ration starts heating the minute air hits it, especially with silage and wet by-products in there. In hot weather that happens a lot faster. Heated feed tastes worse, feeds worse and can carry moulds or yeasts that push intake down even more.
- Smaller loads, more often. Split the day’s ration into more deliveries and there’s fresher feed in front of cattle.
- Clean bunks. Pull refusals daily. Don’t lay fresh feed on top of leftovers that are already heating.
- Look after the silage face. Take enough off every day and keep it tidy so the feed isn’t spoiling before it even gets to the mixer.
- Mix it right. A well-mixed ration is harder to sort. In the heat, sorting means cattle eat concentrate early and fibre late, and that’s an acidosis risk.
Push Up Often
Pushing feed back up more often pulls cattle back to the bunk during the cooler moments. It also gets somebody’s eyes on the bunk more often, which is half the battle. On dairies, regular push-ups after milking are about the cheapest intake help you’ll find.
Ration Tweaks to Talk Over With Your Nutritionist
Ration changes go through your nutritionist. Period. But common hot-weather adjustments include:
- Bumping nutrient density so cattle get what they need from less dry matter.
- Managing fibre so there’s enough effective fibre without loading up on bulky, heat-producing roughage.
- Looking at buffers, electrolytes and minerals lost through sweating and panting.
- Using ration conditioners or preservatives to slow bunk heating where it makes sense.
Water Is Part of the Ration
Water intake jumps in the heat, and cattle that can’t drink won’t eat. Check trough space, flow rate and cleanliness as it warms up. Make sure the troughs near the bunk aren’t the bottleneck. Fix leaks and slow refills before the first heatwave, not during it.
Know the Warning Signs
- Fast breathing and panting in the morning, not just the afternoon.
- More refusals than usual, or a change in what’s being left behind.
- Cattle bunched up around water or shade at feeding time.
- Milk yield or butterfat dropping, or loose manure that points to digestive upset.
Write down bunk scores and refusals every day next to the temperature. A few weeks of that and you’ll know how fast your herd reacts, and when to switch to the hot-weather routine.
Is Your Mixer the Right Size for More Frequent Feeding?
The easiest summer fix, smaller and more frequent loads, depends on the mixer. A big machine running way below its practical volume might not mix a small batch properly. Augers need enough material to move and blend, and a lot of part-loads in a big tub can raise fuel use per tonne. Plenty of smaller dairies and backgrounding operations find a compact mixer sized to the herd makes several fresh loads a day realistic. Our LEO mini mixer range is built for that size of operation, with a compact footprint that fits existing sheds and yards. On bigger operations the answer is usually splitting the day’s feed across more trips, not buying a second machine.
Shade, Airflow and the Feed Lane
Bunk management works best when the area around the bunk works too. Shade over the feed lane gets cattle eating in the warmer hours. In sheds, fans and sprinklers over the feed alley make the bunk a cooler place to stand. In open feedlots, keep pens drained and clean so cattle aren’t standing in manure that holds heat. Every one of these makes the feeding changes above work better.
Plan Before the Heatwave Hits
Heat events usually come with a few days’ warning. Use them. Check the water setup, line up extra hands for the extra feeds, get the mixer and loader serviced, and agree the hot-weather ration with your nutritionist ahead of time. Reacting on the first 40-degree day is too late.
Final Truth
You can’t change the weather. You can change when the feed meets it. Feed in the cool part of the day, mix smaller loads more often so the ration stays fresh, push up more and keep water ahead of demand. Talk ration changes through with your nutritionist first. If your mixer is too big to run small loads well, that’s worth a conversation with your dealer before February, not during it.
Related reading: What summer heat exposes about your mix · Truck-mount settings for dry lots through summer heat · Why precise TMR batches matter
