Evaluation of the ethogram of Italian Simmental dairy cows during the activity in an outdoor fence and the effects on milk production

Animal welfare and animal health can be improved by providing adequate exercise in a more natural environment. Intensification within the dairy industry has led to an increase in use of more restrictive indoor housing systems (most commonly tiestalls and freestalls) and less use of the pasture-based housing systems used in past generations. The latter is recognized to be an excellent solution as it allows the cow to express species-specific behaviours, as proposed by the Farm Animal Welfare Council, and prevent various disease or dysmetabolism. Since the availability of pasture areas in Italy is rather scarce, one possible alternative could be the use of areas or paddocks outside the barn to encourage functional exercise. The aim of this study was to evaluate the behavioural patterns of Italian Simmental lactating dairy cows (n=10) during the 2-hours activity in an outdoor fence (1500 m2), and to evaluate if the moving to the adjacent outdoor area could affect their milk production and milk composition. Selected cows were equipped with a validated activometry system (Lely Astronaut A4, Maassluis, Netherlands), which had already been installed on the dairy cow farm where the study was carried out (La Fattoria di Pavia, Udine, Italy). The behavioural expressions were daily monitored using 6 CCTV cameras but also through the use of the automatic milking system that recorded the activity level of cows on a daily basis. A total of 240 hours were observed at the end of the trial. Milk samples per each cow were collected before the beginning of the trial and at the end of every experimental period (2 weeks) and then analysed in laboratory (DAFNAE Department, University of Padua). Results of the present study indicate that moving cows on an outdoor fence has positive effects on both animal behaviour and milk production. Behavioural expression depends on cow effect ; in fact, each cow has its own temperament. U2A cows (exit during the first two week of the experimental trial) exhibited more movement behaviour (walking and running) and explored the surrounding environment, and U2B cows (exit during the second two week of the trial) spent more time grazing even if the fresh grass was cut before the beginning of the trial and interacting between conspecifics. During the 2-hours outings cows ruminated less (about 11 minutes) then when they stayed inside the barn but increased the rumination time (about 4 minutes) the next two hours after they return to the barn. No correlation was found between the rumination time monitored by the AMS and observations of rumination. The time spent eating in the feeding lane and the assumption of compound feed (kg) depend on the cow. The outdoor activity decreased the time spent eating in the feeding lane for U2B cows as they spent more time grazing on the outside and increased it for U2A cows. Also, the outdoor activity increased the milk production and the number of milkings in U2B cows. Moreover, cows, that spent more time grazing and ingested the lower amount of compound feed, had the highest increase in milk production and the higher percent protein content, so casein. Lastly, urea content was higher in treatment cows’ milk (U2) as they eaten a higher amount of fresh grass during the outings, than when they belonged to control group (CTR). In summary, providing exercise in an outdoor fence is feasible in commercial farms and could have positive effects on cows’ milk production by reducing their stress. However, further research in necessary to identify the optimal way to manage the outing time in herd with automatic milking system.