Infestations of the bont tick Amblyomma hebraeum (Acari: Ixodidae) on different breeds of cattle in Zimbabwe.
Infestations of adults and nymphs of Amblyomma hebraeum were counted on Brahman (Br), Brahman x Simmental (BS), Sanga (Sa) and Hereford (He) steers exposed to infested pastures at Mbizi in southern Zimbabwe in 1986-1987. Herefords were always the most heavily infested, while the Sanga tended to carry the fewest ticks with the Brahman and Brahman x Simmental groups being in between. The ratios of the engorged females on the four breeds were 2.3:1.4:1.4:1.0 for He:Br:BS:Sa. The ratios of the standard nymphs were 2.2:1.4:1.7:1.0 for He:Br:BS:Sa. The results confirm earlier observations in Africa and support the view that there are genetic differences between breeds in the expression of resistance to this tick species.
Norval
R A
RA
Veterinary Research Laboratory, Causeway, Harare, Zimbabwe.
Sutherst
R W
RW
Kerr
J D
JD
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000469:parasitology*; D005260:Female; D008297:Male; D013984:Tick Infestations / Q000662:veterinary*; D013987:Ticks; D015030:Zimbabwe