Gastric Ulcers in Finishing Pigs at Slaughter in Western Santa Catarina, Brazil: Frequency and Severity

Abstract

Background: Gastric ulceration of the pars oesophagea is a multifactorial disorder of intensively raised pigs that may impair welfare and performance and cause gastrointestinal bleeding or sudden death. Reported prevalence varies among production systems, and lesions may remain subclinical until slaughter. Slaughterhouse inspection therefore offers an opportunity to estimate lesion burden and identify factors that merit on-farm investigation. This study evaluated the frequency and severity of gastric lesions in finishing pigs at slaughter in western Santa Catarina, Brazil.
Materials, Methods & Results: A cross-sectional observational study was conducted between February and May 2020 at a federally inspected abattoir. Pigs originated from 8 commercial farms in the same integrated production system. The farms housed 7,293 finishing pigs; 3,798 were followed at slaughter, and 380 stomachs, approximately 10% of each slaughter batch, were selected systematically. Each stomach was opened along the greater curvature, emptied, washed and examined macroscopically. Lesions in the pars oesophagea were classified from grade 0 to grade 4: normal mucosa (grade 0), parakeratosis (grade 1), parakeratosis with ulceration affecting < 33% (grade 2), ulceration affecting 34-66% (grade 3), or ulceration affecting 67-100% of the mucosal surface (grade 4). For analysis, grades 1 and 2 were considered mild and grades 3 and 4 severe. Production records included flooring type, mortality, disease occurrence and treatment, and environmental enrichment. Absolute and relative frequencies were calculated, and univariate logistic regression was used to test associations between lesion severity and flooring or enrichment at a significance level of 5%. Gastric lesions were detected in 376/380 stomachs (98.9%); 4/380 (1.1%) had no lesions. Grade 1 was most frequent (178/380; 46.8%), followed by grade 2 (155/380; 40.8%), grade 3 (30/380; 7.9%) and grade 4 (13/380; 3.4%). Mild lesions represented 87.6% and severe lesions 11.3% of examined stomachs. Lesion distributions were similar across farms. Grade 0 ranged from 0 to 7.7% by farm, grade 1 from 35.9 to 53.1%, grade 2 from 33.3 to 57.1%, grade 3 from 4.0 to 12.0%, and grade 4 from 0 to 9.5%. Neither flooring type nor environmental enrichment was significantly associated with lesion severity (P > 0.05). During finishing, 163 pigs died, corresponding to a mean mortality of 2.23% across farms; respiratory disease accounted for 66 deaths and gastric ulcers for 27. Six farms had no environmental enrichment, 1 had partial enrichment, and 1 had enrichment in all pens. Six farms used solid flooring with a water layer, whereas 2 used partially slatted flooring.
Discussion: The predominance of mild lesions and the absence of associations with the evaluated housing variables suggested that unmeasured factors, including feeding practices and pre-slaughter management, may have contributed to lesion occurrence. Because the farms shared 1 integrated production system, limited variation in management may also have reduced the ability to detect associations. The high prevalence confirmed that clinically silent gastric lesions were common in finishing pigs. Routine slaughterhouse monitoring, particularly of severe lesions, was therefore considered a useful tool for herd-level surveillance of gastrointestinal health and animal welfare and for guiding targeted investigation of nutritional, health and management risk factors.
Keywords: gastric ulceration, pars oesophagea, slaughterhouse monitoring, animal welfare, prevalence, swine.