Effect of a daily outdoor access on milk quality and behavior of Italian Simmental dairy cows.

Abstract

This study aimed at assessing the effect of a two and a four-hour daily outdoor access on milk quality and behavior of dairy cows. Six Italian Simmental lactating cows housed in a free-stall were paired and subjected to the treatments: no outdoor access (CTR), two-hour daily outdoor access (U2; 11:30&#x202f;a.m. to 1:30&#x202f;p.m.), and four-hour daily outdoor access (U4) divided into a morning (9:00 to 11:00&#x202f;a.m.) and an afternoon (2:00 to 4:00&#x202f;p.m.) exit. Using a crossover design, each pair of cows was subjected to each treatment for 2&#x202f;weeks, then switched twice, until the completion of 6&#x202f;weeks of evaluation. Variations in milk parameters were determined across the treatments (CTR, U2, U4). Outside behaviors were assessed during the two-hour stay in the paddock, whereas inside behaviors were considered in the same timeslots plus an additional timeslot (4:00&#x202f;p.m.-6:00&#x202f;p.m.) in which the three treatments were inside the stall. Milk yield, composition and cheese-making traits were not affected by the outdoor access, but the coagulation properties were suggestively significant (&#x202f;<&#x202f;0.1). The longest rennet coagulation time (RCT, 21.31&#x202f;min) and the lowest curd firmness (a30, 26.66&#x202f;mm) were shown in U2. During the time spent outdoors, cows significantly increased their time standing resting (60.91 vs. 23.96&#x202f;min;&#x202f;<&#x202f;0.001) and self grooming (6.58 vs. 2.96&#x202f;min,&#x202f;<&#x202f;0.001); whereas, behaviors such as running, recumbency, drinking, eating, exploring and positive and negative interaction were reduced. When outdoors, cows spent most of their time standing resting (60.91&#x202f;min), ruminating (11.10&#x202f;min) and walking (10.62&#x202f;min). Indoors, they spent more of their time eating (35.02&#x202f;min), standing resting (23.96&#x202f;min) and ruminating (13.84&#x202f;min). Behaviors that were significantly affected by the treatment within each timeslot were: running, standing, resting, ruminating and eating. In conclusion, offering lactating dairy cows a four-hour daily outdoor access split into 2&#x202f;h in the morning and 2&#x202f;h in the afternoon appears to be beneficial because it increased the time spent standing resting outdoors which may indicate a calm state for the animals, while maintaining milk quality at a level comparable to that of full indoor management.