| The trial | Results | Observation | Conclusion
In late 2004, an outbreak of ileitis occurred at the Swine Research and Technology Centre (SRTC), University of Alberta. A water vaccination scheme was implemented in the nursery and was successful in controlling the problem.
However, a stubborn diarrhea started occurring about 11 days after weaning. Colitis, a condition causing a painful distension of the abdomen, was also observed in several pigs. Lab results from necropsy pigs traced the problem to Escherichia coli, primarily K88.
In spite of these health conditions, little mortality occurred and most pigs recovered and showed improved (compensatory) growth during their last two weeks in the nursery.
The Trial
One way of coping with diarrhea and colitis was to use water medication once physical symptoms were observed. However, the cost per room was high (about $80 per 100 pigs) and not sustainable in the long term. We decided to investigate how feed antimicrobials would work for preventing and treating symptoms of E. coli at a more reasonable cost compared to water medicating.
We tested five diets:
- Control diet containing zinc oxide (3,000 parts per million (ppm) at Phase 1 and 1,000 ppm at Phases 2 and 3)
- Flavomycin® 4 (12 mg/kg diet bambermycin as per veterinary prescription at Phases 1, 2 and 3)
- Neo-terramycin* 50/50 (220 mg/kg diet neomycin sulphate, 220 mg/kg diet oxytetracycline hydrochloride as per veterinary prescription at Phases 1, 2 and 3)
- Tylan® (44 mg/kg diet tylosin phosphate at Phases 1, 2 and 3)
- Increased zinc oxide level (3,000 ppm at Phase 1 and 1,500 ppm at Phases 2 and 3)
The trial was divided into four feeding phases. A common non-medicated diet was fed in Phase 4 because of the water soluble ileitis vaccine. Pigs had free access to feed and water during the entire trial (Day 0 to 35).
- Phase 1 - Day 0 to 2
- Phase 2 - Day 2 to 11
- Phase 3 - Day 11 to 25
- Phase 4 - Day 25 to 35
Pigs were individually tagged and weighed at weaning. Pigs within a gender and weight category were randomly allotted to pens. Each pen housed four gilts and four barrows. The 20 day-old pigs weighed an average of 5.69 kg at the start of study.
Pigs were individually weighed at the beginning and end of each feeding phase. Feed intake was measured on a per pen basis for each feeding phase. In addition to these measures, individual pigs were scored for the presence of diarrhea, dirty bum (another indicator of diarrhea) and for symptoms of "poor doing."
Aside from weighing the animals and feed, as well as scoring symptoms, the animals in this trial were cared for following typical commercial nursery management practices.
Results
The antimicrobial treatments had no effect on daily feed disappearance (feed intake plus waste), weight gain or feed conversion for each feeding phase and the overall trial.
The incidence of diarrhea and "poor doing" was lower in pigs fed the antimicrobial diets and the increased zinc oxide level. By the end of Phase 2 and 3, pigs offered the control diet looked more gaunt and dehydrated than pigs fed antimicrobials or the increased zinc oxide level. Pigs fed bambermycin generally did not score as well as those fed other antimicrobials or the increased zinc oxide level.
Considering no effect on animal performance, the cost of treatment per kilo gained was the lowest for pigs fed zinc oxide and bambermycin, was intermediate for neomycin-oxytetracycline and was the highest for tylosin.
Observation
The most striking fact that came to light in this study was that gilt litters were most affected by E. coli. Litters from the fewer grandparent (GP) sows were spared. Despite routine E. coli vaccination of gilts prior to farrowing, it appears that immunity was not developed fast enough in parity one (P1) piglets compared to older parity sow's litters at weaning.
The most important implication from our experience is that P1 herds in production systems adopting a segregated parity structure will face unique challenges, like this stubborn E. coli condition in the SRTC nursery.
Conclusion
The results of this study indicate no benefit in animal performance in this barn and merely a slight improvement in physical appearance associated with antimicrobial inclusion in nursery diets for pigs affected by E. coli K88. The addition of zinc oxide to the nursery diets in this barn was the more cost-effective antimicrobial compared to the inclusion of bambermycin, neomycin-oxytetracycline and tylosin at the levels tested.
We are thankful to Elanco Animal Health, Philbro Animal Health and Intervet Canada Ltd. for the donation of antimicrobial products for this trial.
Eduardo Beltranena
Alberta Agriculture, Food and Rural Development
Telephone: (780) 427-4567, Fax: (780) 427-1057
E-mail: eduardo.beltranena@gov.ab.ca
Olufemi Omogbenigun
Alberta Agriculture, Food and Rural Development
Telephone: (780) 422-3095, Fax: (780) 427-1057
E-mail: olufemi.omogbenigun@gov.ab.ca |