Since previous health monitoring systems have shown themselves to be unsuccessful in predicting health disorders in dairy cows managed on pasture, the aim of this study was to evaluate the performance of automated health monitoring integrated in an accelerometer-based oestrus detection system (ODS) for dairy cows on pasture. Mixed-breed lactating dairy cows (n=109) in a seasonal-calving herd managed at pasture were fitted with an ODS that provided automated health monitoring. The ODS performed multimetric analysis of behavioural patterns to generate health alerts. Data were collected during the artificial insemination period of 66 days. Clinical examinations and farmer’s observations were used to evaluate the performance of automated health monitoring. During the insemination period, the farmer generated two health alerts, which were classified false positives (2/2; 100%). The ODS generated 31 automated health alerts. Of all automated health alerts, 3/31 (9.7%) were confirmed as true health disorders and 28/31 (90.3%) alerts were classified as false positives. The positive predictive value (PPV) of automated health monitoring was 9.7 (95% CI=2-25.8) %. The ODS was able to alert lactating dairy cows on pasture suffering from health disorders. True health disorders were alerted by the ODS before the farmer noticed them, which could provide early and successful treatment when using the system on-farm for automated health monitoring. The evaluated accuracy of automated health monitoring is opposed to a targeted use of the system for on-farm health monitoring. For further validation, testing on other farms and during the transition period would be of interest.

Early castration of male small ruminants is regarded as a risk factor for urolithiasis, although the underlying correlations are still unclear. One possible reason is a deferred development of the penis and the urethra after castration. Therefore, we examined the penis and urethra of castrated and intact lambs by ultrasonography to determine the correlation between urethral area and pe- nile cross-sectional area. Ultrasonography was performed in 6-month-old Lacaune crossbred lambs (early castrated, late castrated, and intact; each group, n = 11). Sectional images at 5 loca- tions (glans penis, penile urethra, distal and proximal sigmoid flexure, and ischial arch) were ob- tained to determine the urethral and penile diameters. Urethral and penile cross-sectional areas were calculated. Grey-scale analysis of ultrasound images was performed to evaluate possible differences in the penile texture between the groups. Correlation analyses between both cross-sectional areas showed a significant general correlation for location 2 in all lambs (R = 0.52; P = 0.003), for location 3 in late-castrated lambs, and for location 5 in early-castrated lambs. Statistically significant correlations between the penile and the urethral area of castrated and intact lambs were not evident. Therefore, measurement of the penile cross-sectional area alone does not allow for accurate estimation of urethral size. Statistically significant differences con- cerning the grey-scale analysis between the groups were also not detectable. Thus, simplification of the formerly presented ultrasonographic examination of the urethra is not recommended. In animals at a risk of obstructive urolithiasis, complete urethral examina- tion is essential.