Further evaluation of a novel polymeric antimicrobial for the control of porcine postweaning colibacillosis

Objectives: To evaluate a new polymeric antimicrobial for the control of porcine postweaning colibacillosis (PWC).

Materials and methods: In an experimental infection study, three groups of 12 weaner pigs received either Chemeq polymeric antimicrobial in the food, a therapeutic dosage of apramycin orally, or no treatment. Three days after weaning, the pigs were challenged orally with cultures of [beta]-hemolytic Escherichia coli O8:K87:K88, then monitored daily and euthanized 11 days after weaning. In a field trial, 148 weaned pigs in a commercial swine herd were divided into five groups, receiving polymeric antimicrobial either in their water or food, apramycin in their water, a commercial E coli PWC bacterin, or no treatment. Postweaning performance was monitored.

Results: In the infection study, pigs receiving polymeric antimicrobial had less diarrhea than the apramycin-treated group (P <.01) but not the untreated control group, and had fewer hemolytic E coli in their large intestines than the control pigs (P <.05). In the field trial, pigs receiving polymeric antimicrobial had less diarrhea than pigs in the other groups (P <.05), and fewer were removed from the study because of severe PWC (P <.05).

Discussion: Antimicrobial resistance is increasing amongst PWC strains of E coli, and new antimicrobials and strategies are needed to maintain postweaning health and production. Chemeq polymeric antimicrobial reduced diarrhea after weaning, and was a useful adjunct to the control of PWC.

Implications: Chemeq polymeric antimicrobial has therapeutic advantage in the treatment and control of PWC.