Selection of cattle for tick resistance, and the effect of herds of different susceptibility on Boophilus populations
Twelve two-year old heifers were selected as relatively tick-resistance and 12 as relatively tick-susceptible. Each of these groups was divided at random into herds of six. A herd was sprayed with 0.5 percent DDT emulsion when its average count of ticks (adult females over 5 mm in length) on one side of the animals exceeded 40. There was no significant correlation between tick resitance and coat score, sweat gland dimensions, or total skin thickness. There was no evidence of adaptation of cattle ticks to the resistant animals, either in the field experiment or in observations on stalled cattle
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Format: | biblioteca |
Published: |
1962
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Subjects: | GANADO BOVINO, SALUD ANIMAL, ECTOPARASITOS, BOOPHILUS, SELECCION, RESISTENCIA A LOS PARASITOS, |
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Summary: | Twelve two-year old heifers were selected as relatively tick-resistance and 12 as relatively tick-susceptible. Each of these groups was divided at random into herds of six. A herd was sprayed with 0.5 percent DDT emulsion when its average count of ticks (adult females over 5 mm in length) on one side of the animals exceeded 40. There was no significant correlation between tick resitance and coat score, sweat gland dimensions, or total skin thickness. There was no evidence of adaptation of cattle ticks to the resistant animals, either in the field experiment or in observations on stalled cattle |
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