Effet de l’incorporation de farine de luzerne dans l'alimentation et de l’ajout de paille sur le bien-être des porcs et le risque d’odeurs sexuelles en élevage

Elever des porcs dans le respect du bien-être animal est un objectif majeur de l’agriculture biologique. Cependant, la castration est toujours pratiquée pour éviter les odeurs sexuelles des viandes de mâles non castrés. Afin de tester le potentiel de réduction du risque d’odeurs par l’addition de fibres dans l’aliment distribué au cours du dernier mois d’engraissement et de l’apport de paille supplémentaire en engraissement, plus particulièrement dans les derniers jours précédant l’abattage, un essai a été mené dans un élevage de type commercial. Cette stratégie a été choisie car des essais en élevages conventionnels ont montré son efficacité pour réduire la teneur du tissu gras en scatol (S) qui est, avec l’androsténone (A), en grande partie à l’origine des odeurs de la viande de verrat (Parois et al., 2018).

Effect of adding lucerne to the diet and additional straw bedding on the welfare of pigs and the risk of boar taint in organic farming

Raising pigs while respecting animal welfare is a major goal of organic farming; however, castration is still practiced to prevent boar taint. A trial was conducted on an organic farm to test a strategy to reduce this risk. This strategy included adding fibre to the diet and additional straw distributed into the pen during fattening and just before slaughter. Four fattening batches (sow Naïma X boar Piétrain) consisting of 337 pigs, including 165 non-castrated males) were used. Two conditions were tested: a control group and a test group with an additional 20 % of bedding during the rearing process, along with the addition of straw 48 hours before the first departure to the slaughterhouse. Additionally, the Test group received feed enriched with 10 % lucerne meal during the last month. Health indicators (presence of coughing, lameness, hernias, etc.) and well-being indicators (aggression, cannibalism, human-animal relationship test, etc.) were recorded three times per group (beginning, middle, and end of the fattening period). To assess carcass quality, carcass characteristics were collected from all non-castrated males. Analyses of androstenone and skatole levels were performed using backfat samples. Welfare indicators and carcass characteristics were similar in both groups of pigs. However, fewer carcasses were above the consumer rejection thresholds for androstenone (3 μg/g liquid fat) and skatole (0.15 μg/g liquid fat) in the test (respectively 27 % and 3 %) than in the control group (respectively 41 % and 20 %). The combination of both strategies had no impact on the well-being of the pigs but is effective in reducing the risk of sexual odours.