Health promotion and disease prevention

Summary
Part 1 of the project was an experimental sudy on a potential relationship between behaviour of free range slaughter pigs and their parasitological status. Hierarchy and grazing behaviour was recorded and infectons with parasites was followed during the grazing season using feacal- and blood samples. Contamination of the grass land was measured by analyzing grass and soil samples and by 6 x 10 parasite free tracer pigs. The experiment has significantly expanded our knowledge on out door parasitic infestations and free range pigs’ use of available grass land.

Part 2 of the project was an investigation of the health and parasitological status in organic pig herds. Systematically performed sampling in groups of slaughter pigs during the rearing period showed that parasitic infestations were present in all the herds although no clinical symptoms were recorded. No or only small parasitic contamination was recorded on free range. Piglet mortality was relatively high. The sows on free range did not suffer from essential infectious nor nutritional disorders which on the contrary was the case among the slaughter pigs. These problems were related mainly to lack of managers experience, inexpedient organizationof buildings and pens as well as malproper group dividing and moving of the animals.

Part 3 of the project was an experiment on the effect on egg laying hens’ behaviour in relatio to parasitic infection. Group A was infected with Ascaridia galli, group D with Dermanyssus gallinae and grup C was the control group. Behaviour, parasitological status, level of testosteron, haematocrit values and haemoglobin content were recorded. The results showed a significant effect of the mite infection on behaviour especiellay preening and head schratching and on haematology. A previously not reported masculinizing effect caused by the infection with Ascaridia was found in the hens.

Part 4 of the project was a survey on the presence of blood mites in 400 egg producing units. The biggest problems in relation to presence of blood mites were recorded in egg laying units with free range hens. Approx. 70% of these herd had recorded the presence of blood mits within the last 3 years. This figur was 35% in organic egg producing herds.