By Andi Anderson
Hot summers pose a serious threat to livestock, especially cattle. In states like Kentucky, extended high temperatures and humidity have created dangerous conditions, often leading to reduced productivity, lower pregnancy rates, and higher death losses.
Heat stress in cattle affects feed intake, increases disease risks, and leads to early embryo loss. Cattle dissipate heat less effectively because they don’t sweat well. Instead, they breathe faster, eat less, and try to radiate heat by expanding blood vessels near the skin.
The problem becomes worse when cattle graze endophyte-infected fescue. This common pasture grass contains a fungus that produces alkaloids, which constrict blood vessels and prevent heat release from the body. This can lead to reduced pregnancy rates, premature births, and even calf loss.
Studies show spring calving herds grazing on infected fescue have seen pregnancy rates drop as low as 55%. Heat also causes conception rates to fall dramatically in summer, often dropping below 40%.
To manage heat stress, producers can:
- Avoid grazing infected fescue in summer, if possible.
- Adjust the breeding season to cooler months like early spring.
- Provide high-fat supplements such as soybeans or distillers' products, which may improve pregnancy rates.
- Use minerals containing selenium yeast and sodium selenite to support early pregnancy hormones.
- Include red clover or soy-based feeds in pastures or supplements. These contain isoflavones that help dilate blood vessels and reduce heat stress effects.
Farmers should also plan pregnancy checks and, if needed, consider short fall calving seasons. While the heat cannot be controlled, a good heat stress management plan can make a big difference in cattle health and profitability.
With cattle markets staying strong, protecting herd fertility and productivity from summer heat is more important than ever. A few changes today can bring big gains tomorrow.
Photo Credit: gettyimages-ahavelaar
Categories: Ohio, Livestock