Objective I; Increased hoof abnormality prevalence (e.g. toe and dew claw overgrowth, hoof wall cracks, and hoof pad abrasions) in sow populations observed at harvest suggest that these hoof defects may be detrimental to sow performance, and in turn, the sow’s productive lifetime. Determining the types of lesions on sows’ feet and how this may affect her performance, behavior and overall productivity was examined. Sows were classified into four groups, (1) cracks in the outer hoof wall [CK], (2) length differences between the toes of the hoof [TS], (3) excessive toe growth [OG] or 4) control sows (no visible lesions or concerns associated with the hooves). There was a trend for sows in the CK group to wean fewer piglets per litter than control sows. As OG got more severe, sows weaned a lighter litter than control sows. When sow behavior was collected 45 minutes before feeding and for 1-h after feed had been provided, control sows spent 18.9 % (19.9 min) of the 105 min observation period standing and 12.7 % (13.3 min) of the total time standing and eating. Sows with OG toes spent 50 % less time kneeling as lesion scores got worse. Post feeding, each OG lesion score increase was associated with a 40.0 % decrease in time spent standing and eating. Results from this study demonstrate that foot lesions can impair productivity and behavior of lactating sows. The degree to which foot lesions impair production and behavior is dependent on lesion type and severity.
Objective II; Images of normal and abnormal hooves were collected throughout the previously reported study. Images collected during the study illustrate the range in severity of hoof cracks, overgrown toes, and toe size differences. At least two quality images were obtained for each severity score within each lesion. Images obtained during the present study will be utilized in extension presentations and publications to educate swine producers on the type and severity of hoof lesions present in swine herds. Further, the pictures will be used in future classification of these specific lesions in an attempt to standardize the lesion identification and scoring process. Also, unique observations were made while photographing sow hooves. In some cases, the lateral claw was observed to be placed between concrete slats in the gestation stalls or between mesh flooring connections in the farrowing stalls. In these cases, sows may use these gaps as anchor points when slipping which may cause hoof cracks. The image library will be maintained at Iowa State University and image requests can be made through the National Pork Board.
Objective III; A targeted, three point, question, was formulated to include the population of interest (adult sows), the condition of interest (lameness) and the intervention (any method of treatment). A comprehensive list of search terms was created to capture all combinations of each point of the targeted question. Seven databases which included agricultural and veterinary based research journals were conducted. Once this expansive and inclusive search identified potential research studies, each report was subjected to additional quality analysis steps to: (1) determine relevance to the question, (2) assess the quality and completeness of the research report data (3) extract and summarize useful data and conclusions for application by producers. The original literature search produced 1560 research reports. A total of 414 duplicate articles were removed. Following removal of the duplicates, the 1146 unique articles were reviewed for relevance. The relevance screen eliminated all but five articles. The five relevant articles were subjected to the quality screening. Two articles were removed because they did not directly test a treatment. Two articles were removed due to failure to randomize treatments which would prevent caretakers from preferentially treating the most clinically affected animals and potentially biasing the outcome. A single article met all of the quality criteria. Wentz et al, detailed the treatment and control populations, the prevalence and severity of lameness at the onset and completion of the trial, and utilized a field setting for this study. Wentz et al, randomized penned groups of sows between two treatments. The intervention treatment utilized a 10% formalin footbath, two or three times a week, applied to the exterior anatomy of the hoof for a five week period. The control group received no footbath treatment. Results showed significant differences in the increased prevalence of sows without clinical lameness and a reduction of ‘severe category’ clinical lameness. This systematic review of the effectiveness of treatment for lameness in sows led to the following conclusions: (1) quality research studies evaluating the treatment of lameness are lacking (2) treatment of lameness has been focused on nutritional manipulation to correct imbalances affecting the feet and legs of sows, but results are variable and take time for maximum benefits to be recognized (3) footbaths may be an option to improving overall foot health, but need to be used at a high frequency to assure maximum benefit (4) producers need tools to treat and prevent lameness in sow herds to improve the animal’s well-being and increase overall herd productivity and (5) since sow welfare is negatively affected by lameness and treatment options need to be fully investigated in a scientifically controlled setting.