Treatment of Ear Haematomas in Swine

Haematomas [hematomas] of the ear in pigs cause discomfort in swine and are a chronic problem in many swine units. If left untreated, a haematoma will usually resolve by itself; however, this may take several weeks and cause discomfort for the pig. Ear haematomas result from various traumas. Pigs may develop these haematomas from shaking their heads because of irritants in the external ear canal, such as mange, or because of inner ear infections. Haematomas also commonly result from injuries caused by ear biting between pigs, a response to environmental stress. Altering management practices may help to reduce the prevalence of haematomas. However, these may be costly and time consuming to implement. No clear consensus amongst veterinarians exists regarding the best method to treat haematomas to optimize healing and growth rate. The objectives of this study were to determine whether the resolution rate and infection prevalence of haematomas and subsequent growth rate during the two weeks post-treatment varied by treatment method.

Material and methods

A convenience sample of two swine farms was selected to participate in this study: one small operation with an abnormally high prevalence of ear haematomas (3.5%) and one large operation with an average prevalence of ear haematomas (0.05%). All pigs with haematomas over a 4-week period were identified and assigned to a treatment group in a systematic random fashion. The ear was left untreated in the positive control group (n = 13). In treatment 1 (n = 12) the ear was incised with a scalpel; in treatment 2 (n = 12) the ear was incised with a scalpel and the site of incision was cleaned out using iodine and gauze; in treatment 3 (n = 11) the ear was incised with a scalpel and an ear tag was inserted to maintain pressure. The pigs were weighed and assigned a swelling and infection score weekly for 2 to 3 weeks posttreatment (8 pigs were shipped early, thus data for week 3 could not be collected). Swelling and infection were given a score of 0 to 4. The haematoma was considered to be resolved if the ear was not swollen (swelling score 0.5). A group of negative control, weight-matched pigs (n = 22) without haematomas were selected and likewise weighed weekly. Linear regression was used to compare the average daily gain among positive and negative control and treated pigs after controlling for the initial weight of the pig. Descriptive analyses were performed on levels of swelling and infection among the treatment and control pigs (using Statistix).

Results and discussion

Untreated haematomas were more likely to resolve within three weeks than haematomas that underwent treatment (Figure 1). None of the pigs with untreated haematomas developed ear infections during the three weeks posttreatment; however, most of the treated pigs developed varying severities of local infections (Figure 2). Pigs that underwent treatment 2 exhibited the most severe ear infections. In 82 percent of treated pigs, the infection cleared up within three weeks posttreatment, and in no cases did the infection become systemic.

 

 

 

Over two weeks, the average daily gain (ADG) for pigs with haematomas was 0.18 pounds less than for those without haematomas (P = .03). The ADG was reduced by 0.21 pounds (P = .03) and 0.14 pounds (P = .08) for treated and untreated pigs, respectively, compared to negative controls. There were insufficient pigs in the study to determine whether the ADG differed by treatment method or between positive control and treated pigs.

Management practices to prevent haematomas should be implemented, as affected pigs gain less weight. When haematomas are recognized in pig barns, the producer must make the decision of whether to treat the haematoma and what type of treatment to perform. This study indicates it is unadvisable to treat haematomas because treated ears will most likely develop infections and will resolve more slowly than untreated ears.

Acknowledgments

We greatly appreciate the contributions of the participating producers: Janet Sunstrum, BSc; Catherine Dewey, DVM, PhD; Barbara Straw, DVM, PhD.