Effect of Positive Tactile Stimulation and Prepartum Milking Routine Training on Behavior, Cortisol and Oxytocin in Milking, Milk Composition, and Milk Yield in Gyr Cows in Early Lactation

Positive interactions with humans can improve cow behavior and facilitate farm management, especially in dairy production systems in which milking occurs daily. Therefore, this study aimed to investigate the impact of positive tactile stimulation on behavior, and its effect on the milking routine, milk ejection, and milk yield of Gyr cows. Experiment 1 was performed with 40 cows: 20 cows (5 primiparous and 15 multiparous) received positive tactile stimulation (by hands and brushes) in the aisle of the corral during the prepartum period for 14 days; the other 20 cows (5 primiparous and 15 multiparous) did not receive any kind of tactile stimulation (control). Experiment 2 was performed with 40 heifers: 20 heifers were trained to enter the milking parlor and were progressively submitted to positive tactile stimulation (by hands and brushes) and to the milking routine during the prepartum period in the milking parlor for 14 days; the other 20 heifers did not receive any kind of training or tactile stimulation (control). Behavioral data were observed during the beginning of lactation: when the animal entered the milking parlor (stalled, needed help, and attempted to escape), during milking preparation (reaction to udder massage and to the strip cup test), and during milking (reaction to teat cups and whether the animal pulled off the teat cups). Milk yield and residual milk volume were measured and milk samples were collected for analysis of milk composition, somatic cell count, and cortisol and oxytocin in milk. All the experimental cows were suckled on one teat by their calf. Entry into the milking parlor and preparation of the animal for milking are the most critical moments for detecting reactivity to milking procedures. At the same time, the two positive stimulations studied (i.e., handling in the corral or training in the milking parlor) were efficient in improving the behavior of Gyr cows at the beginning of lactation, thus demonstrating that prepartum positive stimulation was effective at reducing the negative behavior of cows during the firsts milkings. Indeed, the percentual of residual milk in primiparous cows subjected to positive milking training was significantly lower than those measured in untrained primiparous and multiparous cows. This result is very promising because it indicates that Gyr heifers, when positively stimulated and trained in the milking routine during the prepartum period, will maintain adequate behavior and excellent milk ejection during their firsts milkings.