Animal-based measures on fattening heavy pigs at the slaughterhouse and the association with animal welfare at the farm level: a preliminary study

Abstract

Monitoring animal welfare (AW) in pig farms requires both proper indicators and a feasible approach. Animal-based measures (ABMs) are well-established AW indicators. Furthermore, AW screening at the slaughterhouses could be useful for identifying problems on farm. The aim of this study was to evaluate ABMs at the slaughterhouse and, when possible, to compare these ABMs with those collected on the farm. The study was carried out in northern Italy in a commercial abattoir and in a sample of farms. Animal-based measures were recorded on pigs from 62 batches of 54 farms, during ante-mortem (n=10 085 pigs) and post-mortem (n=7952 pigs) inspections. Sixteen of 54 farms were selected to compare ABMs collected at the slaughterhouse with ABMs collected on the farm. Overall, 2295 pigs (mean pigs examined per farm 119±45) were inspected at the slaughterhouse (group S) and 420 pigs (mean pigs per farm 26±5) on the farm (group F). Non-animal-based measures were also collected at the 16 farms. Differences between groups S and F, at the animal level, were assessed by a two-tailed paired Wilcoxon–Mann–Whitney test. Differences at the site of observation level (farm and slaughterhouse) were assessed by Fisher’s exact test using a hierarchical log-linear modelling for contingency tables. The most frequent ABMs at the slaughterhouse were manure on the body (47.7%), followed by dermatitis (28.0%), white spot (25.4%) and bursitis (24.7%). Recording ABMs at the slaughterhouse and on the farm usually yielded similar results; however, there were some exceptions. In particular, significant differences were found for non-uniformity of size (P<0.05) and dermatitis (P<0.001), which were higher at the slaughterhouse than on the farm. Results of log-linear modelling underlined the effect of the farm of origin on the percentage of pigs with bursitis, manure on the body and ear injuries that were observed at the slaughterhouse. In group S, significant associations between manure on the body and insufficient presence of clean and dry areas in the corresponding farm were found (P<0.05). Although these results should be interpreted with care due to the limited sample of farms, the slaughterhouse could be a feasible site of observation of ABMs, which could then be integrated in monitoring of AW on farm. Considering the number of slaughtered batches per farm, it would be possible to repeat assessments several times throughout the year for each farm, which could help provide an index for the continuous monitoring of AW.

A Retrospective Study after 10 Years (2010–2019) of Meat Inspection Activity in a Domestic Swine Abattoir in Tuscany: The Slaughterhouse as an Epidemiological Observatory

“…The main cause is by far the so-called “milk spot liver”, deriving from the larval migration of Ascaris suum [ 62 ] and responsible for 91.79% of the condemnations. This is in agreement with most of the studies in the literature in Italy [ 22 , 24 , 51 ] and in other European countries, such as Portugal [ 63 ] or Northern Ireland [ 64 , 65 ]. The frequent finding of this lesion confirms that ascaridosis is still a widespread disease and a potential cause of high economic losses, both for the reduced growth in the breeding phase and for the increased percentages of slaughterhouse discard [ 63 , 65 , 66 ].…”

“…Although generalized jaundice was the second cause of carcass condemnation, its percentage on slaughtered pigs (0.007%) was much lower than the percentage of 0.09% observed by Maisano et al [ 51 ], a work in which jaundice was the first cause of condemnation, and also of the percentage of 0.04% of another recent Italian study [ 24 ], while it was more similar to the finding of Portuguese authors (<0.01% [ 30 ]). Several causes may be responsible for this condition in pigs, including viral (e.g., circovirosis), bacterial (e.g., leptospirosis), and parasitic (e.g., ascaridosis) infections, as well as intoxications [ 59 , 60 ].…”

“…The overall percentage of condemned carcasses out of the total slaughtered pigs (0.03%), which was constant over the years, is significantly lower compared to partial condemnations, as already reported in a previous study of Ceccarelli et al [ 22 ]. Higher percentage values (0.17% and 0.12%) are reported in two Italian studies [ 22 , 51 ], which collected data in a slaughterhouse in Central and Northern Italy, respectively. However, it should be specified that the rate reported by Maisano et al [ 51 ] considers not only the carcasses condemned at the post-mortem visit, but also the animals killed during transport and emergency slaughter.…”

“…Higher percentage values (0.17% and 0.12%) are reported in two Italian studies [ 22 , 51 ], which collected data in a slaughterhouse in Central and Northern Italy, respectively. However, it should be specified that the rate reported by Maisano et al [ 51 ] considers not only the carcasses condemned at the post-mortem visit, but also the animals killed during transport and emergency slaughter. Therefore, it is more correct to compare this value with the percentage (0.12%) obtained adding deaths during transport with whole carcasses condemned in the present study, which is in fact perfectly in agreement with the rate found by the aforementioned study [ 51 ].…”

“…However, it should be specified that the rate reported by Maisano et al [ 51 ] considers not only the carcasses condemned at the post-mortem visit, but also the animals killed during transport and emergency slaughter. Therefore, it is more correct to compare this value with the percentage (0.12%) obtained adding deaths during transport with whole carcasses condemned in the present study, which is in fact perfectly in agreement with the rate found by the aforementioned study [ 51 ]. Differences in the approach to the collection, analysis, and presentation of data between the various studies represent an issue for their comparison, in addition to other factors discussed below ( Section 4.5 ).…”