Comparaison des températures de litières et des niveaux de pollution de l'air lors d'engraissement de porcs sur litières biomaîtrisées à base de sciure ou de paille hachée

Two rooms of a pig house were used to study 2 deep litter systems where the animals were kept on a 50 cm deep layer of sawdust or chopped straw (chopped to lengths of 10 cm). Seven days before the arrival of the animals, slurry and a microbial product used to stimulate the fermentation were added to the litters. Fifteen pigs on sawdust and 17 pigs on straw were fattened from 23.1 to 93.3 kg live weight. Excreta was dug into the bedding weekly and treated with the microbial product. This labour was discontinued on the straw after 105 days as the labour was considered too hard. No sawdust was added during the fattening period but straw was added 5 times to keep the pigs clean and to keep the temperature in the bedding above 30C. The mean bedding temperature was greater for the sawdust (38 5C) than in the straw (35 15C) and the mean daily variations were lower for the sawdust (1.3 1.6C) than the straw (2.2 2.4C). The air temperature and relative humidity were similar for both rooms (21C and 60%). The concentration of ammonia in the air was substantially higher in the room with the straw (48 36 ppm) than with the sawdust (12 9.2 ppm) during the 7 days before the animals arrived and 11 5.6 ppm and 6.7 3.9 ppm, respectively after the eighth day. Dust concentration was 2 times lower in the room with straw. Growth rates and feed conversion ratios were similar for both groups. It is concluded that the results were better for the sawdust litter as it provided a higher bedding temperature and lower ammonia concentration in the air and the routine weekly task of digging was easier.