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Biomedical subjects

Alberto B Broce

Publications and source records attributed to Alberto B Broce.

6 recordsLinked to original sources
PubMed2006

Ectoparasite control.

The severity of damage that insects, ticks, and mites may have on their bovine hosts ranges from undetectable effects on energy expenditure to the death of the host. These pest insects can cause direct damage to their hosts by their annoyance, irritation, blood feeding, modification of host behavior, and invasion of tissues. This direct damage can result in such direct losses as dermatitis, anemia,reduction in weight gain performance, devaluation of carcass,injury during pest avoidance, injury by chemical control of pests,necrosis, and death. The main flies that affect cattle performance and specifically, stockers, are discussed in this article.

Animal Husbandry↗
PubMed2005

Winter feeding sites of hay in round bales as major developmental sites of Stomoxys calcitrans (Diptera: Muscidae) in pastures in spring and summer.

The stable fly, Stomoxys calcitrans (L.), historically has been a pest of livestock in confined operations but seldom of animals on pastures or rangelands. In the past two decades, however, S. calcitrans has become a major pest of cattle and horses on pastures in the midwestern United States. Although there usually is an overabundance of diverse stable fly and house fly, Musca domestica L., larval habitats in confined livestock operations, no larval habitat for stable flies has been clearly identified in the pasture-range environment. Because the winter feeding of hay in round bales results in significant amounts of hay wastage that when mixed with manure, might develop into suitable larval habitats, this study evaluated these areas as developmental sites for the abundant stable flies in pastures. There was a trend for fly traps placed in the vicinity of hay feeding sites to catch more stable flies than those placed distant from these sites. Estimates of stable flies emerging from these sites ranged from 102 to 1225 flies per core sample (25 by 25 cm). The mean number of adult stable flies during May and June 2001 through 2004 correlated negatively with the average minimum temperatures during the preceding winter (November-February) but not with rainfall or temperatures during the spring. These results support the hypothesis that winter feeding sites of hay in round bales are the main source of stable flies in pastures.

Animal Feed↗
PubMed2005

Relative efficiency of biological transmission of Anaplasma marginale (Rickettsiales: Anaplasmataceae) by Dermacentor andersoni (Acari: Ixodidae) compared with mechanical transmission by Stomoxys calcitrans (Diptera: Muscidae).

Anaplasma marginale Theiler is a tick-borne intraerythrocytic rickettsial pathogen of cattle that also can be mechanically transmitted by biting flies. Rickettsemia during the acute phase of infection may reach as high as 10(9) infected erythrocytes (IEs) per milliliter of blood. Animals that survive acute infection develop a life-long persistent infection that cycles between 10(2.5) and 10(7) IE/ ml of blood. We compared stable fly Stomoxys calcitrans (L.) -borne mechanical transmission during acute infection with Rocky Mountain wood tick, Dermacentor andersoni Stiles-borne biological transmission in the persistent phase of infection to demonstrate quantitatively that biological transmission by ticks is considerably more efficient than mechanical transmission by biting flies. Stable flies that partially fed on an acutely infected calf and were immediately transferred to susceptible calves to complete their bloodmeals failed to transmit A. marginale. Ticks that fed on the original acquisition host after it reached the persistent phase of infection (>300-fold lower rickettsemia) successfully transmitted A. marginale after transfer to the same calves that failed to acquire infection after fly feeding. Failure of fly-borne mechanical transmission at a rickettsemia >300-fold higher than that from which ticks transmit with 100% efficiency demonstrates that tick-borne biological transmission is at least 2 orders of magnitude more efficient than direct stable fly-borne mechanical transmission.

Anaplasma marginale↗
PubMed2002

Chronological age-grading of house flies by using near-infrared spectroscopy.

The sensitivity and accuracy of near-infrared spectroscopy (NIRS) was compared with that of the pteridine fluorescence technique for estimating the chronological age of house flies, Musca domestica (L.). Although results with both techniques were significantly correlated with fly age, confidence limits on predicted ages generally were smaller with NIRS. Young flies could be readily differentiated from old flies by using NIRS. Age predictions using the pteridine method are dependent upon size, sex, and temperature at which adult flies are exposed. In contrast, those factors do not need to be determined for age-grading using NIRS. Classification accuracy using the NIRS method was similar for whole flies, fresh heads, dried heads, and ethanol-preserved heads. The NIRS method was also suitable for predicting age of stable flies, Stomoxys calcitrans (L.), and face flies, Musca autumnalis De Geer. NIRS has several advantages over the measurement of pteridine levels for age-grading field-collected flies, including speed and portability of instrumentation, and not needing to determine sex, size, and temperatures to which adult flies were exposed.

Animals↗
PubMed2002

Insecticide susceptibilities of cat fleas (Siphonaptera: Pulicidae) from several regions of the United States.

Eleven cat flea, Ctenocephalides felis (Bouchè), strains, seven field-collected and four laboratory-colonized, were assayed for susceptibilities to five insecticides (carbaryl, chlorpyrifos, malathion, permethrin, and pyrethrin) with an insecticide-treated, horizontally-oriented, Nylon 6,6 disk in a test tube. The pyrethrin was synergized using piperonyl butoxide (PBO). Flea mortality at two doses was recorded after 4 and 24 h exposures. The field strains from Texas and Florida tolerated carbaryl, chlorpyrifos, and malathion; and carbaryl and PBO-synergized pyrethrin, respectively. Tolerance was observed in a field strain from Kansas against malathion. Colonies from California and North Carolina were susceptible to malathion and PBO-synergized pyrethrin, and chlorpyrifos and permethrin, respectively, but three colonies showed tolerance. The insecticidal response of the California colony varied; when exposed to a chlorpyrifos dose of 10 mg (AI)/m2 for 24 h, at various times had mortality of 3-100%. With a PBO-synergized pyrethrin dose of 396 mg (AI)/ m2 for 4 h, the mortality ranged between 4.2 and 97%. Colonized strains were more susceptible than field strains at 4 h exposure to all insecticides except PBO-synergized pyrethrin. Colonized strains survived better in control tubes. The colony strains' susceptibility and variability are of considerable importance because these strains are used for flea product efficacy evaluations and bioassays. The differences in susceptibility between laboratory colonies and the field strains suggested development of both adaptation to colonization, and extensive, multiple cross-resistance to insecticides in field strains. Varying susceptibility of cat fleas may affect control success.

Animals↗