Heat Stress in Sheep and Cattle: Spotting Trouble Early with Activity Data

British livestock aren't bred for heat, and neither is British grazing. A 28°C afternoon that a Queensland herd would shrug off can put a full-fleece ewe or a dark-coated suckler under genuine strain — and on open hill or common, where shade is scarce and nobody walks the stock twice a day, the first you hear of it can be an animal down. The useful signs come earlier, and they show up in how animals move.

What heat stress looks like

• Grazing stops in the heat of the day and shifts to early morning and evening.
• Animals bunch tightly around whatever shade or breeze exists — a wall, a hawthorn, a ridge line.
• Panting, open-mouth breathing and restlessness in cattle; sheep standing head-down, unwilling to move.
• Water visits get longer and more frequent — or stop, which is worse.

Full-fleece ewes in the weeks before shearing, heavily pregnant animals, dark-coated cattle and anything already lame or sick sit at the top of the risk list. Heat rarely kills a healthy animal outright in the UK — it finds the compromised one.

Shade and water on hill and commons ground

On enclosed ground you can move stock to the shaded paddock and check the trough on each round. On a common or open hill, the practical moves are different: know where the natural shelter and reliable water actually are, time gathers and handling for early morning, and put off anything stressful — dosing, moving, weaning — during a hot spell. If troughs are the main supply, a failed ballcock in a heatwave is an emergency, not a job for the weekend.

What the movement data shows

Tracked animals make heat behaviour visible from the kitchen table. The mob's daily pattern shifts: less distance covered, long stationary spells through midday, tight clustering at shade and water points. Those are normal coping responses. The animal to worry about is the outlier — stationary away from the group, away from water, through the hottest hours.

• A mob that stops travelling in the middle of the day is coping — expect activity to return by evening.
• An animal still flat-out stationary once the day cools deserves a look.
• Several animals static at a trough zone that's stopped drawing visits can mean the water's failed.
• No evening grazing rebound after a hot day is the pattern that precedes losses.

Where Flockarewe fits

Flockarewe already watches for the shape of the problem: Shep's sweeps flag the animal that's gone unusually still or dropped out of the mob's pattern, and zone alerts tell you when stock aren't visiting water the way they were yesterday. In a hot week, that turns a daily worry into a short list — usually empty, occasionally the ewe that needed you an hour ago.