Winter Months Bring on Lice

When calves enter the winter months, you may notice them exhibiting itching, scratching and rubbing behaviors.

Contrary to what you may have heard, they do NOT have dry skin, according to Jerry Bertoldo, DVM, Northwest New York Dairy Specialist for Cornell University.

Bertoldo told the audience of a recent Cornell PRO-DAIRY Webinar that the culprit is almost surely lice. “Lice are the forgotten winter parasite,” he said. “They tend to ‘bloom’ during the initial surge of cold weather.”

Left untreated, lice can be extremely damaging to the health and productivity of young calves. “Sucking lice can cause anemia quickly in young calves,” shared Bertoldo. “One bug can remove .10 mL of blood per day, and it’s common that more than 1,000 lice can infest one animal.”

The veterinarian said lice often are acquired by young calves from older animals, and are less of a problem when young animals are segregated from their older herdmates. “Lice will be more obvious after calves are weaned, although their exposure may have happened as early as the calving pen,” he said.

Bertoldo said visual diagnosis of lice is challenging because they are so tiny. Some easily blend into the skin and hair coat, and they don’t hop around like fleas. For control, he recommends anthelmintic treatment with a labeled dose of one of the older, alcohol-based pour-ons that are commercially available. Other ectoparasite products also may be useful. Consult your veterinarian for the best treatment approach for your herd.

He said treatment in early December is a good time to bring lice under control. That protection should last through the winter months.

Source – Dairy Herd

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