Endoparasiten und Milchqualität bei Ziegen im Ökologischen Landbau

Effects of subclinical parasitism on productivity parameters like milk yield and fat have been described previously in cows. Until now only a few data were reported for goats. Two main topics of the institute’s research focus on milking of small ruminants and strategies to reduce anthelmintic treatments. In 2003 45 goats were monitored during lactation. Milk yield and milk composition (fat, protein, lactose) were registered monthly. Every two weeks, samples for cyto-bacteriological analysis were gained of each half of the udder. At the end of April the grazing season started and individual faecal samples were collected monthly. A first data evaluation showed no significant relationship between the severity of the infection with gastro-intestinal-strongyloides (GIS), estimated by the number of eggs counted in the faeces (FEC), and milk yield and milk quality . In a second step, animals were grouped according to their course of infection in “mild” and “serious”. “Mild” means that an FEC over 300 Epg was only registered at the end of the investigation period in August. Compared with the “mild” group, the FEC of animals with “serious” infection courses immediately increased after the beginning of grazing. The new analyses revealed differences between these groups for the content of lactose and protein, even if they were not statistically significant. During mid of July and August, when the prevalence of GIS was highest, the group with the “mild” course of infection showed a lower decrease of milk production compared with the higher infected group. No relationship could be found between FEC or course of infection and udder health. However, further research is needed to evaluate, and maybe confirm our observations that the course of infection with GIS might be an interesting parameter to express the resistance to parasitic diseases in goats and might be related to the parameters of milk production and composition