COMPARISON OF THE EVOLUTION OF THE BEDDIN G OF 2 DEEP LITTER SYSTEMS,DEEP SAWDUST AND DEEP STRAW, FOR FATTENING PIGS

Two rooms of a pig house were used to study 2 deep litter systems wher e the animals were kept on a 50 cm thick layer of sawdust or of choppe d straw (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 seventien pigs on straw (f loor spaces : 1.4 and 1.2 M2/pig) were fattened from 23.1 to 93.1 kg l ive weight. Excreta from pigs was dung into the bedding weekly and tre ated with the microbial product. This labour was considered as too har d in the straw room and was ended at day 105. No sawdust was added dur ing the fattening period but straw was added 5 times to keep the pigs clean and to keep the temperature in the bedding higher than 30-degree s-C. The mean temperature in the sawdust bed was higher (38 +/- 5,4-de grees-C vs 35 +/- 6,7-degrees-C, p > 0,001) and more constant (mean da ily variation 1,3 +/- 1,6 vs 2,2 +/- 2,4-degrees-C, p > 0,001) than th e temperature recorded in the straw bed. The air temperature and the r elative humidity were similar in the 2 rooms (21-degrees-C and 60 The concentrations of ammonia in the air were measured with Gastec tubes. The average ammonia concentrations recorded during the 7 days before t he arrival of the animals (48 +/- 36 ppm vs 12 +/- 9,2 ppm) and those recorded after the eighth day (11 +/- 5,6 ppm vs 6,7 +/- 3,9 ppm) were significantly higher with the straw system compared with the sawdust system.The daily gains were not significantly different in the 2 rooms (552 g on average) and the food conversion ratios in the 2 rooms were 3,6 kg/kg (on sawdust) and 3,85 kg/kg (on straw). Carcasses were of e qual quality. In conclusion, results were better with the sawdust bed than with the straw bed. The sawdust bed provided a higher temperature in the bedding and a lower ammonia concentration in the air. The rout ine weekly task of digging was easier in the sawdust bed and the beddi ng was used for a second batch.