IXODID TICKS (ACARI, IXODIDAE) AND LIVESTOCK PRODUCTION - EFFECT OF VARYING ACARICIDE TREATMENTS ON TICKS AND PRODUCTIVITY IN EAST-COAST FEVER-IMMUNIZED WEANER AND DAIRY-CATTLE

In a pilot trial to evaluate cost-effective methods of acaricide appli cation, east coast fever-immunized weaner and dairy cattle were subjec ted to varying tick control regimens. All experimental cattle were mai ntained under the same extensive system of management. Their monthly t ick load, packed cell volumes, incidence of blood protozoans, weight c hanges, and daily milk production were noted. Apart from Rhipicephalus appendiculatus Neumann, other tick species found in the study site we re R. pulchellus Gerstacker, Amblyomma gemma Donitz, Boophilus decolor atus Koch, and A. variegatum F. The control group under a weekly regim en of dipping had fewer ticks than each of the other groups for both w eaner and dairy cattle. However, the percentage of increase in weight of the weaner cattle was least for the control group. The milk product ion of none of the groups was significantly different from that of the control group, although profit per animal for groups maintained under a monthly or six-weekly regimen of acaricide use was highest. The age of the experimental dairy cattle was found not to have any effect on their milk production. It is suggested that with successful immunizati on against east coast fever, both dairy and weaner cattle may be subje cted to reduced dipping or spraying, the level of relaxation being dep endent on the tick challenge. However, similar studies should be carri ed out in as many agroecological zones as possible using different bre eds of cattle. Information on the level of acaricide residues in lives tock products from different farming systems should also be generated. Only then can a definitive recommendation for a change from the prese nt national intensive dipping policy be made.