It is rare in Ireland that farmers are discussing the management of livestock in a heatwave scenario and generally short-lived – as is the case this week.

This situation also means that livestock in Ireland are not acclimatised to temperatures of 27°C to 29°C and possibly exceeding 30°C in places. Therefore, it is important that farms take appropriate action to minimise the risk of problems emerging.

The experience of recent years has taught us that rams can experience short-term heat-related fertility issues where a ram's body temperature exceeds 40°C.

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The rams likely to be facing the highest risk are those on an intensive concentrate-based diet, such as 2026-born ram lambs, and those which do not have access to good shelter during peak daytime temperatures.

Concentrates

This is as ram lambs on an intensive diet will already be under pressure in digesting high levels of concentrates – with the spike in temperatures potentially pushing body temperatures into dangerous territory.

Such a scenario occurred in recent years during spikes in temperature, with some rams experiencing temporary fertility issues or testing with poor-quality semen six to seven weeks later. This is a concern where early lambing is being practiced or rams are being fertility tested ahead of breeding sales.

Good shelter and access to water

It is important to ensure that rams have good access to shelter and a convenient water supply.

Rams may not leave shelter freely to seek out water if they are facing heat stress and, as such, a temporary water supply may need to be provided adjacent to where rams are eating and sheltering.

Where no shelter is readily available, then rams should be moved into paddocks where mature hedging or trees are present.

While another good option, if it is feasible, is allow rams have access to a shed with good ventilation.

However, beware that some sheds with a poor airflow can become too hot.

Safe transport of sheep

Transporting livestock during peak temperatures can also trigger an increased risk of issues.

This is true of ram lambs for the reasons outlined above, while there is also a risk of all animals succumbing to intense heat where they are packed tightly and the appropriate stocking rate is not adhered to. Sheep that go down in a load will survive for a much shorter timeframe.

It is wise to operate at a lower stocking rate and make regular stops to check that all animals are standing. Ideally animals would be transported outside of peak temperatures.

Sunburn in freshly shorn sheep

While this is likely to only affect a small number of animals, it is important to provide freshly shorn sheep with shelter to prevent their skin getting sunburnt.

Sheep should be flocked where possible early in the morning or later in the evening to reduce the risk of heat stress.