Spot it early, act fast. A summer one-pager for farms across Donegal, the northwest and Northern Ireland.
What it is
Heat stress isn’t just about heat — it’s heat and humidity together. On a close, muggy day a cow can’t shed her own body heat, so she eats less, stands more, and milk quietly slips, often before you’d notice. The higher-yielding cows feel it first, and the milk tank shows it days too late.
Spot it fast — let the cows tell you
Count her breathing. Pick a cow at rest and count her breaths for a minute or count for 15 seconds and multiply by four. The faster and harder she’s breathing, the more trouble she’s in:
| Slow & easy | Comfortable. Steady, relaxed breathing — she’s coping fine. | |
| Around 65/min | Heat stress starting. Yield is already slipping — get water and shade to her. | |
| 75–85+/min | Serious strain. Fast, shallow breathing — she needs help cooling down. | |
| Panting, 120+ | Emergency. Open-mouthed panting and drooling — cool her and get water in now. |
Watch the cud. When the herd’s resting, a good share should be lying down chewing. If far fewer are cudding than usual on a hot day, the heat’s getting to them (rumination collars flag this automatically).
What to do about it
- Water, within reach. Fresh and plentiful, close to the grazing — and check the troughs keep up when the whole herd drinks at once.
- Use what shade you’ve got. A hedgerow or tree line helps; save the open, exposed paddocks for the cooler hours.
- Keep yard time short. Cows packed into a warm collecting yard heat up fast — don’t leave them standing.
- Feed for the extra demand. Her energy needs rise as intake falls; concentrate in the parlour helps bridge the gap — ask your Smyths rep about the right level.
- Housed cattle: move the air. Open sheds up to maximise air movement.
How Smyths Daleside helps
Heat stress causes less rumination and weaker natural buffering, which is exactly why rumen support matters through the summer. That’s why Smyths Daleside have a range of summer dairy diets formulated with Acid Buf and live yeast — buffering to help steady rumen pH, and a conditioner to keep the rumen working. To find the right one for your herd, talk to your local Smyths Daleside representative today — +353 (0)74 917 1300.
Feeding Champions Since 1865