REPRODUCTIVE EFFECT OF EXPERIMENTAL FASCIOLA GIGANTICA INFECTION ON THIRD TRIMESTER PREGNANT EWES

Résumé

The effect of experimental Fasciola gigantica infection on pregnant ewes at third trimester of pregnancy was investigated using twelve non-pregnant ewes aged between 10-12months old belonging to the Reproduction unit of the National Animal Production Research Institute (NAPRI), Shika, Zaria. The ewes were synchronized using injectable PGF2a (Lutalyse, 10mg/ewe) at the dose rate of 5mg/ml and bred naturally with two rams. Pregnancy was confirmed by progesterone levels of 0.5-1.0ng/ml after breeding and non-return to estrus 22 days post-breeding. The experimental animals were divided into two treatments (infected and control) of six animals, with two replicates per treatment and each replicate made up of three animals each. Weekly measurement of progesterone levels were carried out for a period of 7 weeks during the third trimester period of pregnancy. Six ewes in the infected group were each infected orally with 500 Fasciola gigantica metacercariae at day 100. One of the infected ewes had a sharp drop in progesterone level (0.4ng/ml) from week 19 of pregnancy and had a still birth at week 21 of pregnancy. Out of the 5 ewes infected, 4 lambed while one (20%) had a still birth. It is concluded that Fasciola infection has adverse effect on pregnant ewes at third trimester of pregnancy. It is recommended that sheep of reproductive age should be routinely dewormed and managed under control grazing to avoid reproductive wastages.