An on-farm health monitoring of small ruminants: design, data and disease frequencies.

The purpose of this study was to investigate the three-year incidence risk of various diseases of adult sheep and goats through on-farm herd health monitoring. The study was conducted, between April 1989 and March 1992, in three sheep and three goat herds with a rolling average total population of 704 adult animals. A system for on-farm data recording was established at the beginning of the study. The data were recorded on a specially-designed form by a veterinary stock assistant stationed on the farms, and collected by the investigating veterinarian during weekly visits. The results were used to determine the three-year incidence risk, three-year recurrence probability and time to first occurrence of various health problems. The associations between occurrences of various health problems were also determined. In the study herds, the three-year incidence risk was highest for diarrhoea, enterotoxaemia, cough/nasal discharge, laboured breathing with elevated body temperature, and abortion. Significant and strong associations were recorded between digestive disorders and death, and between respiratory disorders and death. Temporal occurrence of these health problems was recorded to determine the seasonality of occurrence. Areas for further research are discussed.