Milk production increases following treatment of subclinical parasitisms in Wisconsin dairy cattle

Abstract

Abstract Extract Over the past 20 years a series of surveys based on worm egg counts has been conducted on the prevalence of worm parasitisms in Wisconsin dairy cattle. In full acceptance of the many uses, limitations and interpretations of egg counts, these nevertheless have led us to conclude that, when eggs are found, live worms are present within the cattle, that is, that active and important parasitisms are present. Our first state-wide surveys of Wisconsin dairy herds, conducted in the early 1950s, established universal prevalence of active worm parasitisms in the herds, and the latest stated-wide surveys in the 1970s established the same continuous prevalence (Cox and Todd, 1962; Meyers, 1970; Todd et al., 1972; Bliss, 1973; Bliss and Todd, 1973). In the past 20 years the parasitisms have not been controlled, have scarcely ever been treated until recent years, and have not declined.