Severe flea infestation in dairy calves.

An investigation was conducted of a severe flea infestation in Holstein dairy calves. Inspection of the dairy revealed hundreds of cat fleas, Ctenocephalides felis, on 23 calves, and thousands of fleas in the barn where the calves were housed. During the investigation, > 92,000 fleas were collected from the barn. The barn also was inhabited by 30 to 35 flea-infested domesticated and feral cats. Several calves appeared emaciated, and analysis of blood samples from 10 calves revealed that 8 were anemic. A control program was initiated, consisting of insecticide and insect-growth regulator treatment of calves and premises, along with removal of straw bedding from the barn. In addition, domesticated cats were to be treated and feral cats were to be removed by live trapping. Nine weeks after a complete control program was initiated, fleas were not evident on calves or in the barn.