The effects of hair density of beef cattle on Haematobia irritans horn fly populations

Abstract

We show the relationships that exist between the amount of hair and quantity of sebum on cattle skin and the population density of the horn fly, Haematobia irritans. Brahman and Chianina steers had means of 2390 and 1587 hairs per cm2, respectively, significantly more than the mean number of hairs on Angus, Brahman x Angus Crossbred, Charolais, and Red Poll steers. The Chianina steers had > 30% more sebum present on their skin and hair (0.58g/929 cm2) than the Angus, Charolais, and Red Poll steers at the Beef Cattle Research Station Savoy, Arkansas. The Brahman steers had a significantly greater amount of sebum present on the skin (1.51 g/929 cm2) than the Crossbred and purebred Angus steers (0.55 and 0.25 g/929 cm2, respectively) at the South Central Family Farms Research Centre Booneville, Arkansas. The Brahman and Chianina steers had means of 61.9 and 17.0 horn flies per steer, respectively, during the fly season, whereas the Angus, Crossbred, Charolais and Red Poll steers had fly season means that ranged from 76.9 to 265.8 flies per steer. Regression analysis showed that an increase of 100 hairs per cm2, was associated with a reduction of 11 horn flies in the Angus II, 5 in Angus I, 20 in Charolais, 37 in Red Poll, and 0.4 in Chianina steers at the Savoy Station and a reduction of 6.6 horn flies for the Angus, Brahman, and Crossbred steers at the Booneville Centre. Regardless of cattle breed, an increase of 1.0 g of sebum per 929 cm2 output by the steer was associated with 478.5 additional hairs per cm2 on the animal. Each increase of 0.25 g of sebum per 929 cm2 resulted in a decrease of 9.2 horn flies per steer. We conclude that some of the factors responsible for fly-resistance in cattle are hair density and the corresponding amount of sebum present on cattle skin and hair.

Dynamics of Haematobia irritans irritans (Diptera: Muscidae) infestation on Nelore cattle in the Pantanal, Brazil

“…The zebu breed (Doube 1984, Steelman et al 1997) may explain the relatively low number of flies/cow observed in this study (maximum of 84). Low infestations have been found in other parts of the Brazilian mid-west, where zebu cattle have been raised extensively.…”

Dinâmica populacional da mosca-dos-chifres (Haematobia irritans) em bovinos da raça Guzerá e mestiço em Selvíria, MS

“…A desproporcional distribuição da mosca-doschifres em hospedeiros individualmente tem sido atribuída às características morfofisiológicas tais como, cor da pele (FRANKS; BURNS; ENGLAND, 1964), temperatura da pele (MORGAN, 1964), cor do pelo (PRUETT et al, 2003), densidade do pelo, e secreções sebáceas (STEELMAN et al, 1997). H. irritans ainda tem preferência por bovinos machos adultos (FARIA, 1998) e animais de sangue europeu (FARIA, 1998;CASTRO et al, 2008) ou mestiço (FARIA, 1998).…”

Effect of Aggregation of Horn Fly Populations Within Cattle Herds and Consequences for Sampling to Obtain Unbiased Estimates of Abundance

“…The more uniform horn ßy numbers on these cattle may reßect the uniform genetics, coat color, and coat density. Horn ßy numbers tend to decline as hair density increases (Steelman et al 1997) and may be less variable among cattle that have reduced hair density. Herds classiÞed into the moderate aggregation group included the small-frame Angus (Ͻ112.5 cm at the hips), Brahman, Charolais, LRC1, and LRC5 herds.…”

“…In a group of 23 breeding cows, the mean percentage of horn ßies on four ßy-resistant cows averaged Ͻ2% of the herd mean, whereas the mean percentage on Þve ßy-susceptible cows averaged Ͼ6% of the herd mean. The proportion of ßy-susceptible and ßy-resistant cattle in a herd can vary within and among breeds (Brown et al 1992, Steelman et al 1993) and may be inßuenced by factors such as size (Steelman et al 1996) and hair coat density (Steelman et al 1997). One consequence of this tendency for ßy populations to be aggregated within a herd is that estimates of horn ßy population density made by sampling within a herd may depart from the true mean if ßy-resistant or ßy-susceptible cattle are over-or underrepresented in the sample.…”