Comparative study of two vaccines against neonatal diarrhea on a Canadian commercial farm

摘要

Infection with pathogenic Escherichia coli is a common cause of diarrhea in suckling pigs worldwide and is becoming an important and devastating disease for swine producers. It is also responsible for a substantial economic impact on farms worldwide,due to high morbidity, mortality and reduced growth rates.' In some studies, conducted in Europe, diarrhea is estimated to account for 5-24% of overall pre-weaning mortality and to reduce average daily gain (ADG) by 8-14 g per day.2,3 Based on these effects, the cost of neonatal diarrhea was recently estimated to be ?134 per sow per year.4 There are different products on the market that will help us to control neonatal diarrhea through vaccination. Suis-eng~R, which is one of the vaccines involved in this trial, is a sub-units vaccine that contains purified adhesion factors (F4ab, F4ac, F5 and F6) and the heat-labile toxin (LT) of Escherichia coli, the (J toxin of Clostridium perfringens type C, to prevent neonatal diarrhea in piglets through passive immunization, and the a. toxin of Clostridium novyi, to protect sows suffering from sudden death by active immunization. Moreover Suiseng~R includes a new, state-of-the-art adjuvant, Hipramune~R G, based on ginse-nosides, saponins from ginseng root, whichenhances an animals' antigen presentation process.5 An increase in the number of APCs (antigen-presenting cells) and the amount of antigen on their surface is one of the keys in the ability of adjuvants to increase the effectiveness of vaccines.6 On the other hand, the other vaccine used in this comparative study, Vaccine B, which is a pure bacterin, contains Escherichia coli adhesion factors F4, F5, F6 and F41, and the |3 toxin of Clostridium perfringens type C, with an aluminum hydroxide adjuvant.