Elevated cluster take-off level and the risk of dry off in dairy cows

Abstract: To achieve a profitable milk production in a more and more automated dairy production, well adapted milking equipment and milking routines are essential. Many factors affect the milk production and the possibilities to enhance production. Different settings for take off level in the milking stations is one example. Research has shown that automatic cluster removal (ACR) can be possible to adjust for increased milk production. By increased ACR thresholds on the last milked udder quarter production can be rationalized. However there is a notion that increased ACR threshold increase the risk of drying off that udder quarter due to incomplete milkings. The aim of this study was therefor to examine the risk of drying off an udder quarter by increased ACR threshold on the last milked quarter from 210 g/min to 500 g/min. A crossover design was used on three different farms provided with DeLaval automatic milking equipment (VMS™). Two different treatments were used on 236 dairy cows divided into two even groups on each farm. Treatment A (control) used ACR threshold 210 g/min on all four udder quarters and treatment B (elevated) ACR threshold 210 g/min on the first three milked quarters and 500 g/min on the last milked quarter. The trial proceeded for eight weeks, with treatment A and B interspersed between the two groups the first four weeks. The remaining four weeks one group got treatment A and the other treatment B. Data was automatically recorded in the VMS station and exported to Excel for further analysis in a PROC MIXED model in SAS version 9.4. The effect of treatment on milk yield, milking time and milk flow was analyzed and the results showed no significant difference on milk yield or milk flow between treatments. There was a significant difference in milking time the first four weeks, with longer milking duration for treatment B. No significant treatment effect on milking time could be seen the last four weeks but a shorter milking duration for treatment B could be noted. The results also showed that the last quarter being milked varied between milkings, both between cows and within individual cows. To increase the ACR threshold from 210 g/min to 500 g/min on the last milked udder quarter had no effect on milk yield and showed no risk of drying off a quarter. These results are in line with previous studies and the fact that the last quarter being milked varies, could contribute to decreased risk of incomplete milkings. However, more research would be beneficial to further investigate the effects.