Resistance of cattle to cattle tick, Boophilus microplus. II. The inheritance of resistance to experimental infestations
Fifty-nine quarter-bred Zebu steers by six half-bred Zebu bulls were exposed to four infestations of 40 000 larval ticks at 7-11 week intervals, followed in another 7 weeks by a paddock infestations. All developed a strong resistance to artificial infestations with cattle ticks by the third infestation. There was no sire difference at the first infestation and a zero heritability estimate for tick resistance. At the fourth infestation there was a heritability of 28 percent, which increased to 42 percent at the fifth infestation. Female tick weights, egg-laying ability of ticks, and viability of eggs laid appeared to be affected by sires. Heritabilities of these characters are discussed
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Format: | biblioteca |
Published: |
1968
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Subjects: | GANADO BOVINO, ECTOPARASITOS, GARRAPATAS, HEREDABILIDAD, CRUZAMIENTO, RESISTENCIA A LOS PARASITOS, |
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Summary: | Fifty-nine quarter-bred Zebu steers by six half-bred Zebu bulls were exposed to four infestations of 40 000 larval ticks at 7-11 week intervals, followed in another 7 weeks by a paddock infestations. All developed a strong resistance to artificial infestations with cattle ticks by the third infestation. There was no sire difference at the first infestation and a zero heritability estimate for tick resistance. At the fourth infestation there was a heritability of 28 percent, which increased to 42 percent at the fifth infestation. Female tick weights, egg-laying ability of ticks, and viability of eggs laid appeared to be affected by sires. Heritabilities of these characters are discussed |
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