#17-124

Complete

Date Full Report Received

Date Abstract Report Received

Investigation

Institution:
Primary Investigator:
Co-Investigators: Locke Karriker, Anna Forseth, Justin Brown

As the FDA continues to receive pressure to reduce antibiotic use in livestock species, there will be additional scrutiny on antibiotic usage. In particular, the routine application of antibiotics to animals that may be deemed as preventive use will be examined more thoroughly. To justify the current practice of antibiotic usage at the time of piglet litter processing, scientifically validated data must be collected that demonstrates the improvement of animal health and well-being. Conducting these evaluations within commercial swine production facilities increases the likelihood of direct applicability of research findings to the swine producer.

The primary objective was to evaluate the potential benefit of antibiotic use in a preventive manner compared to not using antibiotics at the time of piglet processing. The deliverable from this objective was to demonstrate value of antibiotic use over no antibiotic use when given around the time of piglet processing in terms of percent pre-weaning mortality (post-application), average daily gain (ADG) from processing to weaning as well as additional clinical parameters. A second deliverable was to compare three different classes of antibiotics against the use of no antibiotics to identify differences in value between each antibiotic class. Nine hundred and sixty piglets (n=960) from four commercial sow farms (approximate herd size of 4,000 sows) within the same production system, with differing health statuses, were enrolled in the study and data collection occurred June-July 2017. Two hundred and forty piglets from each farm were assigned to one of four treatment groups: beta-lactam (procaine penicillin G – 15,000 IU/lb.), macrolide (Draxxin 25 – 2.5 mg/kg), tetracycline (oxytetracycline – 19.8 mg/kg), or saline control (2cc/piglet). At the time of processing, treatments were administered via intramuscular injection in the post-auricular region using a 20-gauge x 0.5-inch needle. The outcomes measured from processing to weaning included percent mortality, wound healing, complete blood cell counts (CBC), average daily gain (ADG), and navel size. Scoring of castration and tail-docking wounds occurred two days post-processing, seven days post-processing and at the time of weaning.

Data analysis did not reveal statistically significant (p< 0.05) differences of antibiotic treated and non-treated animals on growth (ADG), pre-weaning mortality, castration or tail docking wound scores, navel size or infective leukograms (CBC). There was a gender difference that was statistically significant (p< 0.05) with the barrows (castrated males) having a 2.1 mm larger umbilicus at weaning in comparison to gilts. Data analysis did not reveal statistically significant differences (p< 0.05) for growth (ADG), mortality, or castration and tail docking wound score between the three antibiotic classes evaluated within this study. There were statistically significant differences between the farms (p< 0.05) for growth (ADG), with the highest health status farm having the highest ADG, but no statistically significant farm treatment interaction was noted on any of the farms. Comparing the different antibiotic treatments when analyzing CBC results for infective leukograms did not reveal any statistically significant differences (p< 0.05).

Industry Takeaways
• Macrolide, tetracyclines and beta-lactam antibiotics given at processing (1-4 days of age) to sow litter piglets did not change % mortality or ADG from processing until weaning when compared to piglets who did not receive antibiotics at processing.
• Macrolide, tetracyclines and beta-lactam antibiotics given at processing (1-4 days of age) to sow litter piglets did not change wound healing scores, navels scores or infectious leukograms (defined by CBC) when compared to piglets who did not receive antibiotics at processing.
• No statistically significant differences (p<.05) were noted between barrows and gilts when evaluating ADG, % mortality, or wound healing scores were evaluated.

This study begins to take a closer look at the necessity of preventive antibiotic use given at the time of processing due to the presence of open wounds from tail docking and castration of males. Differences between using antibiotics, any of the three classes, and not using antibiotics were not appreciated on production parameters nor indicators of infection as defined by the ability of pigs to heal wounds or by evaluating blood parameters (CBC). This research was conducted on four commercial farms of varying health status and the same result was observed on each of the four farms. Differences were appreciated between farms on ADG independent of the treatment, which may indicate that there were health differences between the farms. Study treatments were completed on sow litter piglets only and did not include any piglets from gilt litters. The range in processing times were from 1-4 days of age and did not include any litters that were within 24 hours. One limitation of this study was the lack of a ceftiofur class antibiotics in the treatment evaluation. Ceftiofur class antibiotics are commonly prescribed by veterinarians for preventive use based upon farm diagnostics demonstrating the presence of a pathogen that is susceptible to this drug. The results from this study suggest that veterinarians and producers should examine and discuss the necessity of antibiotic use at processing within herds that have a high health status.