Effect of camel's previous experience on behavioural response and milk production during training to machine milking

At the onset of lactation, dairy animals are exposed to novel stimuli within the mechanical milking environment, which can induce stress. This is particularly pronounced in camels due to their sensitive and potentially maternal aggressive nature. To propose strategies to reduce these stress, this study aimed to assess the behavioural and milking responses of dairy camels during their first milking sessions with a focus on the influence of dams' experience. Eleven dairy camels were included in this study, with 5 undergoing their inaugural milking season (designated as the N_Exp group) and 6 camels having prior exposure to machine milking during previous lac-tations (designated as the Exp group). Camels were milked with an individual portable milking machine set to 48 kPa Vacuum and 60 pulsations/min. Throughout this trial, behavioural data, rumination occurrence, need of oxytocin injection to induce milk ejection, milk yield, time to milk ejection and milking duration were recorded during the 3 weeks training period of camels. A training index (T.I.) was calculated to quantify milking adap-tation from behavioural responses. Stress-related behaviours were classified into fear-related behaviours such as jumping, decubitus, trembling, vocalization and escape attempts) as well as defensive behaviours including kicking, stepping, spitting, and biting. Results showed that N Exp camels expressed fear-related behaviours more frequently (P < 0.05) while displaying a lower training index (P < 0.0001) compared to Exp camels. All stress behaviours decreased significantly throughout the training period for both groups. The need for exogenous oxytocin decreased from 100% at the first day of machine milking to 35% for N_Exp group and from 27.8% to 8.3% for Exp group. The camel's experience had no effect (p = 0.4200) on the rumination frequency. However, rumination occurred more and more frequently (P < 0.0001) during the camels' training period. Time to milk ejection, total and effective milking durations were significantly shorter for experienced camels and reduced throughout the camels' training period (P< 0.0001). Milk production increased gradually for both groups by 71.75% and 61.83% for Exp and N_Exp respectively during camels' training period. In conclusion, acclimation of camels to machine milking was accompanied by a reduction of acute stress behaviours occurrences, an increase in milk production and a shortening and normalisation of milking sessions. Experienced camels were easier to train to machine milking. These results underscore the importance of improving procedures of milking habitu-ation to mitigate stress of the first milking session and improve the welfare of dairy camels.