HEALTH CLASSIFICATION OF MULTISOURCE FEEDER PIGS - A FIELD TRIAL

Health classification of purchased multisource feeder pigs was tested in a field trial. Feeder pigs transported to the all-in all-out finish ing units were classified according to the health status of the source herd. Health class (HC) feeder pigs originated from the farrowing uni ts which were free of clinical signs of respiratory diseases and swine dysentery, and free of Mycoplasma hyopneumoniae antibodies. Performan ce and meat inspection results of 20 HC and 384 conventional control b atches (health status unknown) were analysed. Previous batches from th e same herds were used to adjust the differences between HC and conven tional batches by herd effect. Mean average daily gain (ADG) was 839 g in the HC group and 803 g in the conventional group. ADG improvement from previous batch to test batch was 28 g better (P < 0.01) in the HC group than in the control group. After adjusting the results for slau ghter weight, supply district and herd effect, the obtained difference in ADG between the HC and the conventional batches was 24 g. Mortalit y in the HC batches was 20% less (P < 0.1) than in the control batches . Organ condemnations were about 40% less frequent in the HC group tha n in the control group (P < 0.01). There were no significant differenc es in whole carcass or liver condemnations. Partial carcass condemnati ons (PCC) were 1.4 times more frequent in the HC group than in the con trol group (P < 0.01). Joint infections were the specific reason for i ncreased PCC. Abscesses (another usual cause of PCC) did not differ be tween the HC and the conventional batches. The greatest differences we re found in pneumonia and pleurisy. Pneumonia findings were almost nin e times more frequent (P < 0.01) in the control group (11.1%) than in the HC group ( 1.3%). Pleurisy findings were nearly twice as common ii i the control group than in the HC group (P<0.01).