Abstract

The effect of the hepatic migratory phase of Fasciola gigantica infections on estrus response to synchronization, conception rates, serum enzyme and biochemical changes in Yankasa ewes was investigated. Twelve adult Yankasa ewes were randomly assigned to one of two groups of 6 animals each. The ewes in Group 1 were each infected with 1,200 metacercaria of F. gigantica each while Group 2 served as non infected controls for the study. The ewes in both groups were then synchronized for estrus at 7 weeks post infection (WPI), and intact rams were introduced for heat detection and breeding. Pregnancy was confirmed by progesterone levels and non-return to estrus 21 days post breeding. Estrus response was 66.6 and 100% in infected and controls, respectively, but all infected animals returned to estrus by 42 days post breeding, indicating conception failure or an early embryonic death. Pathophysiological signs included anorexia, progressive anemia, emaciation and significant hypoproteinemia. Hepatic dysfunction was indicated by the significant increases in liver enzymes; aspartate amino transferase, alanine amino transferase and alkaline phosphatase levels in infected ewes and at post mortem hepatic fibrosis of the liver with intra-hepatic hemorrhage was observed. It is concluded that fasciolosis has an adverse effect on conception and establishment of the fetus in the acute migratory phase.

Key words: Fasciola gigantica, estrus, conception, ewes, productivity, Nigeria.