Benefits of fly control in dairy heifers

Abstract Text:

This presentation discusses the role of the horn fly (Haematobia irritans) in the initiation and spread of staphylococcal mastitis among dairy heifers, how this insect vector can be managed, and the benefits of control for animal health and well-being, as well as producer profits. The horn fly is an irritant to livestock, and in response to the incessant painful biting, blood sucking, and stress, cattle expend a great deal of energy in defensive behavior, resulting in elevated heart and respiratory rates, reduced grazing time, decreased feeding efficiency and rate of gain, and reduced milk production. Additionally, the horn fly can serve as a disease vector, such as in the initiation and spread of mastitis in dairy heifers. As such, it is one of the most economically important pests of cattle worldwide. In the US, $700M to $1B in losses are attributed to the horn fly each year, while additional $60M is spent annually on parasite control. Herd surveys have revealed that the prevalence of mastitis in heifers is markedly lower in dairy herds using some form of fly control compared with herds without a pest control program. The horn fly has a demonstrated role in the development of teat lesions on heifers that develop into chronic Staphylococcus aureus mastitis, which is then spread among heifers by these same insect vectors. Such infections, if left untreated, negatively affect the development of milk-producing tissues in the udder, resulting in less than optimal yield and quality during the first and subsequent lactations. The implementation of horn fly control measures, such as aerosols, bait, strips, foggers, dust bags, traps, oilers, ear tags, pour-ons, natural predators, and insect growth regulators is instrumental in reducing the new infection rate, while existing mastitis cases can be eliminated with antibiotic therapy. Such management practices will promote animal health and well-being, as well as ensure that heifers calve with low SCC and the potential for maximum milk yield, thereby enhancing producer profits.  

Keywords: Horn fly, dairy heifer, staph mastitis