Production Effects of Liver Fluke in Cattle I. the Effects of Infection on Liveweight Gain, Feed Intake and Food Conversion Efficiency in Beef Cattle

Abstract

A trial is described in which the effect of infection with Fasciola hepatica on the performance of beef cattle was studied. Liveweight gain, dry matter and energy intakes were examined in relation to two levels of infection and to a superimposed infection. It is concluded from the results that sub-clinical infections derived from 600 metacercariae, which gave an estimated, average infection of 54 fluke per animal 26 weeks after infection, reduced the weight gain by 8% over the first six months of the infection (P < 0 · 05). After six months this infection had little effect on performance. Higher levels of infection (1000 metacercariae) reduced the weight gain by 28% (P < 0 · 05) and caused the appearance of clinical signs in some animals. The superimposed infection generally did not produce as marked a reduction in performance as the same level of infection in previously uninfected animals. However, the reduced weight gain (17%) was still significantly worse than that of the uninfected control cattle (P < 0 · 05). The impaired performance appeared to be due to impaired feed conversion efficiency at the low level of infection, while at the higher infection level, inappetance also contributed to the loss.