LIVER FLUKE Fasciola hepatica
GUTWORMS Ostertagia ostertagi, Cooperia oncophora , Trichostrongylus spp.
DISTRIBUTION: Predominates on the west coast of the South Island, although present all over NZ. PERFECT CONDITIONS: Areas with stagnant water. Requires the mud snail to complete its life cycle. The mud snail is found around stagnant water all over NZ. SIGNS: Low growth rates, reduced milk production and fertility. Reported on kill sheets. TREATMENT: Generally, only flukicides will kill liver fluke. These are different from the BZ, Lev and MLs that are used to kill gutworms and lungworm. Some flukicides kill liver fluke from 2 weeks of age and some only kill adult fluke. TIPS: Use knowledge of the lifecyle to determine the likely age of the liver fluke population in infected cattle, bearing in mind withholding periods and administration method, to determine which product to use.
PERFECT CONDITIONS: Warm and wet. Irrigated blocks. SIGNS: Poor growth rates, reduced milk production. Diarrhoea if heavy challenge. TREATMENT: Cattle under 18 months of age require treatment with a combination drench (more than one drench family). Triple combinations are only available for oral drenching. Single active MLs that do not partition in milk are best for adult dairy cattle. TIPS: All the gutworms encyst over winter inside the calf allowing reinfection in spring. Adult dairy cattle will increase their milk solids on average by 0.03kgMS/day after treatment with EPRINEX Pour-On. RESISTANCE: Significant resistance seen in Cooperia against ML and BZ. Resistance in Ostertagia against Lev and low levels to BZs and MLs.
Adult liver fluke can live for 2 years in the livers of cattle. RESISTANCE: None currently reported in cattle in NZ.
Boehringer Ingelheim Animal Health New Zealand Ltd Product Guide 2022 23
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