DAIRY PEST MANAGEMENT (ARTHROPODS) Phillip E. Kaufman Cornell University, Ithaca, New York, U.S.A. INTRODUCTION documented to mechanically transmit more than 100 known disease organisms. Monetary damage estimates There are 10 major arthropod pest species affecting dairy have not been calculated for the house fly, however, los- cattle including six fly and four louse species. Damage ses can be expected to increase as urban expansion con- inflicted by arthropods falls into two categories: direct dam- tinues to encroach on traditionally agricultural areas. age and indirect damage. Direct damage includes blood The stable fly is a blood-feeding insect that causes loss, introduction of salivary secretions, tissue damage, considerable distress to cattle (2). It is often observed reduced value of saleable animal products, and annoyance. feeding on the lower legs of cattle and its presence is Indirect damage includes transferring pathogenic organ- indicated when animals stomp. Stable flies and house flies isms and decreased vigor. breed in similar material, however, stable flies also breed Pest management procedures follow integrated ap- in grass clippings and other types of decaying vegetative proaches discussed elsewhere in this publication. To be matter (3). Reported losses (milk production, butterfat, successful, the tactics utilized must disrupt the arthropod etc.) attributed to stable fly infestation have varied from life cycle at several places. significant damage to no observed effect. Additionally, At any given time, cattle can be infested with several observed weight losses have been shown to be offset by species of arthropods and as parasite levels rise and fall supplementing animal diets with grain. It has been es- with the seasons, animals often experience compensatory timated that stable flies annually result in losses of more gains offsetting earlier damage. However, when consider- than $398 million. ing losses in milk production, compensatory gains are not House fly and stable fly populations can be monitored applicable. Determining which species is responsible for a in the barn using spot cards (3). Stable flies can also be given amount of damage is difficult. A consensus on the monitored by counting the number of flies on all four legs losses as well as the costs attributed to arthropod in- of at least 10 animals. Flies can be managed successfully festations on dairy cattle is not available. The monetary by integrating intensive manure management with cultu- figures presented here have been estimated for all cattle ral, biological, and chemical controls (2, 3). Manure man- (beef and dairy) in the United States (1). Most studies agement is the primary method of confined fly control. investigating the effects of individual parasite species have Removing or drying breeding areas can considerably been limited to beefcattle. reduce fly abundance. In areas that cannot be cleaned reg- ularly (such as calf pens and silage storage areas) or in outdoor hay storage areas, fly management can be aided FLIES AFFECTING CONFINED ANIMALS with good water drainage. Utilizing augmentative bio- logical control, including parasitoid releases, in areas tra- The house fly, Musca domestica (L.), and stable fly, ditionally difficult to clean can help to reduce fly popu- Stomoxys calcitrans (L.), are the primary pests of con- lations further. The correct species of parasitoid to be used fined dairy cattle (2, 3). House flies are nonbiting insects depends greatly on the region of the United States and that breed in animal droppings, manure piles, decaying facility type. silage, bedding, and other organic matter (3). Their re- When needed, chemical control should be used with an productive potential and movement to off-farm locations overall IPM approach in mind. Fogs or space sprays makes fly management imperative. House flies have been containing pyrethrins should be the first choice (3). Py- Encyclopedia of Pest Management 181 Copyright D 2002 by Marcel Dekker, Inc. All rights reserved. 182 Dairy Pest Management (Arthropods) rethrin fogs and fly baits are compatible with biological efficiency and increases the risk of self-inflicted injuries. control. Residual premise sprays should be reserved for The migration of the larvae through animal tissues results emergency and late season uses only. in losses in weight gain, delayed time to first lactation and long-term production losses. Finally, breathing holes cut by larvae into the animal’s hide severely reduce the value FLIES AFFECTING of the leather. Meat surrounding the warbles is discolored PASTURED ANIMALS and often must be trimmed further reducing the carcass value. Unlike damage inflicted by other cattle pests, a Two flies, the horn fly, Haematobia irritans (L.) and the portion of the economic damage inflicted by grubs (hide face fly, M. autumnalis De Geer, are the primary pests of damage and systemic insecticide-related paralysis and pastured cattle in most areas of the United States (2). Both death) to dairy cattle can be directly compared with that flies breed only in freshly deposited cattle dung and nei- observed in beef cattle. Annual losses to the cattle industry ther are pests of confined cattle. Horn flies are blood- are estimated to surpass $66 million (excluding control feeding insects that are found in constant association with costs), however, because many dairy cattle are no longer cattle. The economic losses in the United States associated pastured and thus not infested with grubs, this figure is with horn flies have been estimated at more than $730 predominantly associated with beef cattle (7). million annually (1, 4). Very few natural enemies of cattle grubs have been The nonbiting female face fly visits cattle for short reported (6). Management of cattle grubs is difficult with- periods of time where she consumes animal nasal and oc- out chemical control; however, flies will not enter dark- ular secretions (2). Fly feeding habits, irritancy, and dis- ened buildings (3). Therefore, animals confined in barns ease aspects result in economic loss. The face fly has been will not have cattle grubs. Systemic insecticides should not shown to alter the time of grazing (2), which in turn can be used for control of cattle grubs on lactating animals. alter feed efficiency. While feeding, the fly can mech- Because of larval migration through sensitive areas (eso- anically transmit the causative agent of pink-eye and The- phagus or spinal column), systemic insecticide applica- lazia eyeworms (3). Most research has demonstrated that tions should not be made if larvae have entered these areas face fly infestations do not affect milk secretion (5). (date is dependent on latitude and elevation). Treatments Annual losses to cattle have been estimated to surpass $50 made following the suggested treatment period may result million, predominantly due to pink-eye transmission (1). in paralysis, bloat, and death. Management of these two pests has relied heavily on insecticide applications (2). Currently, few successful, nonchemical options are available (3). The use of sticky CATTLE LICE fly traps, walk-through traps, and introduction of natural enemies has met with mixed success. Cattle dung supports Lice are the primary, permanent ectoparasites of dairy a large number of arthropod species that either prey on, cattle. These include three sucking lice species (Haema- compete with, or alter the dung environment (3). These topinus eurysternus (Nitzsch); Linognathus vituli (L.); arthropods can affect pest fly populations, and current re- Solenopotes capillatus (Enderlein) and the cattle chewing commendations, designed to conserve natural enemies, are louse, Bovicola bovis (L.) (2, 3). All four species cause to avoid systemic and feed-through insecticide applica- extreme annoyance to cattle. Milk production declines in tions during the spring and summer seasons. heavily infested cattle (3). Hair loss, reduced feed con- version, and general unthriftiness also result from louse infestations. Populations of lice on adult animals are gen- CATTLE GRUBS erally highest in the winter months while young stock housed in barns show high levels of infestation throughout Two species of cattle grubs occur in the United States: the the year (3). Cows in stanchion barns and calves housed northern cattle grub, Hypoderma bovis (L.), and the communal pens are much more likely to be infested than common cattle grub, H. lineatum (Villers) (2, 3, 6). Cattle cows in free stalls and calves in hutches, respectively. grubs are usually observed during their larval stage in Initial infestations of lice primarily occur from direct ani- warbles on the backs of animals. These flies are most often mal to animal contact. Because of the environmental con- pests of young stock, as older animals develop a degree of ditions produced in a barn, dairy cattle often carry heavy immunity. Economic losses to cattle grubs result from louse populations longer than beef cattle. Losses asso- several forms of attack. First, gadding behavior in res- ciated with cattle lice have been estimated to surpass $125 ponse to adult H. bovis oviposition activity alters grazing million annually (1). Dairy Pest Management (Arthropods) 183 No louse predators or parasitoids have been reported REFERENCES and pathogens have not been shown effective (2). Infes- tations of cattle lice must be controlled with insecticide 1. Drummond, R.O.; Lambert, G.; Smalley, H.E., Jr.; Terrill, applications; however, good management practices using C.E. Estimated Losses of Livestock to Pests. In Handbook cultural control can reduce the chance of reinfestation and of Pest Management in Agriculture; Pimentel, D., Ed.; thus make subsequent insecticide applications unneces- CRC Press: Boca Raton, FL, 1981; 111–127. sary (3). Following treatment of a herd, all new animals 2. Schmidtmann, E.T. Arthropod Pests of Dairy Cattle. In should be treated and quarantined prior to introduction Livestock Entomology; Williams, R.E., Hall, R.D., Broce, A.B., Scholl, P.J., Eds.; John Wiley & Sons: New York, into the general population. Careful and regular monitor- 1985; 223–238. ing will allow producers to detect louse infestations and 3.