Bernie Peet is president of Pork Chain Consulting Ltd. of Lacombe, Alberta, and editor of Western Hog Journal. His columns will run every second week in the Manitoba Co-operator.
Coccidiosis in suckling piglets is a widespread problem in Canadian herds and causes scouring and reduced growth.
The only effective treatment for this disease is Baycox, a five per cent suspension of toltrazuril. Although this drug was never approved, it was available to producers from 1992 to 1998 through Canada’s Emergency Drug Release program. Its unavailability since then has led to a significant increase in the incidence of coccidiosis but with the recent approval of Baycox, producers once again have an effective weapon against this damaging and expensive disease.
Coccidiosis is caused by an internal microscopic protozoan parasite. A coccidial infection is one of several causes of diarrhea in piglets and is noted in the latter half of the suckling period as a whitish-yellow pasty stool. Although its prevalence has not been scientifically studied in Western Canada, Dr. Mike Sheridan, a veterinarian and partner in Swine Health Professionals in Steinbach, Man., says “easily 30 per cent of the herds” that he consults on show signs of coccidiosis.
A 2006 research study in Eastern Canada led by Andrew Peregrine of the University of Guelph looked at 50 representative Ontario herds ranging in size from 30 to 1,700 sows (with an average 411 sows) and the causal organism – Isospora suis – was detected in 70 per cent of them. This finding is similar to a European study of 324 farms in Germany, Austria and Switzerland in which 76 per cent of herds were found to have coccidia infections.
“Coccidiosis occurs when piglets ingest coccidial oocysts – the external stage of the life cycle – from the farrowing pen surroundings,” says Dr. Bruce Kilmer, director of veterinary services and regulatory affairs at Bayer HealthCare. “These oocysts are found in feces and on pen surfaces, usually having been carried over from the previous litter.
“Once ingested, the oocysts begin a maturation process while moving down towards the small intestine, where they enter the intestinal wall and undergo multiple cell divisions and stages of their life cycle.
“After five to seven days of infection the coccidia re-emerge from the intestinal wall as oocysts and are excreted back into the external environment. This mass emergence of mature coccidia from the intestinal wall causes diarrhea.”
Dr. Sheridan notes that the first signs of an infection occur about eight to 12 days after birth, when a piglet develops diarrhea with the feces changing to a creamy tan colour.
“This occurs when the organism is exiting the gut. The damaged intestines can’t absorb the fat, which is why the scours are a greasy, creamy consistency.”
Not all piglets in a litter will necessarily be infected, but quite often, one or two piglets will be smaller, less thrifty, lose weight or gain more slowly, and eventually produce lower weaning weights – all of which can cause economic loss.
“Once coccidiosis is present in a herd, eradication is very difficult, if not impossible,” says Dr. John Harding, associate professor, swine production medicine at the Western College of Veterinary Medicine, Saskatoon.
Recommended pract ices include frequent sanitization of the barn, degreasing pens and farrowing areas, eliminating porous surfaces in the barn by painting plywood and cement floors. Ultimately, though, these practices can only minimize the impact since the oocysts are very difficult to control or eliminate in a barn environment, says Dr. Harding.
The difficulty in controlling the disease means that the availability of Baycox 5% will be a godsend for producers whose herds are affected. Baycox 5% is administered as a prophylactic treatment to piglets, at three days of age, prior to clinical signs of coccidiosis.
“This administration controls coccidial infection by halting the single cell development of the protozoa, killing the parasite in the gut before it damages the intestinal walls,” explains Dr. Kilmer. “Also, because Baycox 5% does not have any activity against the natural flora in the gut, the prevention of coccidiosis results in improved gut health and better performing piglets.
“If there isn’t any damage to the intestinal lining, it acts as a barrier to colonization of bacteria that can cause secondary infections. With a healthy gut, research has shown that piglets have a higher growth rate and improved weaning weights.”
While the western Canadian prevalence of coccidiosis may not be as high as in Eastern Canada or in Europe, both Dr. Harding and Dr. Sheridan agree that Baycox 5% will be a valuable tool for hog producers. They say that if clinical evidence of coccidiosis has been present in the past, a Baycox 5% treatment should be considered.
“Our goal is to get the herd on Baycox 5%, clean up the infection, sanitize and clean up the barns, and then hopefully we will be able to eventually get the herd off the treatments,” says Dr. Sheridan.
Dr. Harding believes that using any preventive treatment is a balance between benefit and cost. “I would recommend the use of Baycox 5% for a period of time, reduce the burden of oocysts shed into the environment, improve sanitation and then try to pull back and re-evaluate the clinical situation,” he advises.
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– DR. JOHN HARDING, WESTERN COLLEGE OF VETERINARY MEDICINE