Effect of different free stall surfaces on behavioural, productive and metabolic parameters in dairy cows.

Two experiments were carried out on 56 lactating dairy cows in an experimental free stall barn comparing four different lying surfaces: straw bedded pack (ST), rubber mat (RM), mattress (MA) and sand (SA). In the first experiment (26 days) cows were allowed to choose between free stalls with each lying surface. The rest area was filmed for three nonconsecutive days to record the total duration of lying and standing in the free stalls with each lying surface, and the duration and frequency of lying and standing bouts. In the second experiment, lasting 50 days, the cows were divided into four groups; each one was kept in a free stall pen with only one kind of lying surface. Milk yield was recorded and individual blood and milk samples were collected. Blood metabolites and milk characteristics of the samples were analyzed. During Experiment 1 the time spent lying down in the free stalls was 631 min cow 1 day 1, and the cows spent more time lying on SA (44.1% of the total lying time) and on ST (33.2%) than on RM (11.6%) and MA (11.1%) (P < 0.001). The total number of lying bouts per day was greater (P < 0.001) on SA and ST than on RM and MA, but there were no differences in the duration of lying bouts. On average, free stalls with SA were occupied for 74.87% of the time, those with ST 60.4%, and those with RM and MA 31.41% and 31.47% respectively. The free stalls with SA and ST were mainly utilized to lie down (85.4% and 80% of the total time spent in these free stalls respectively), while those with RM and MA weremainly utilized to stand (48.4% and 46.4% of the total time spent in these free stalls respectively). Different milk yield change patterns were observed during Experiment 2, with greater values at the end of the experimental period in SA compared with RM (P < 0.001) and MA and ST (P < 0.05). In MA greater plasma ceruloplasmin (cf.RM and SA; P < 0.05), greater plasma globulin (cf. RM, ST and SA; P < 0.05) and lower plasma albumin (cf. ST; P < 0.05) were observed. Furthermore, in MA lower milk protein content (cf. ST and SA; P < 0.05), with greater pH (cf. ST and SA; P < 0.05) and lower titratable acidity (cf. ST; P < 0.05), were observed. In conclusion, our results show that cows spent lying timemainly on the softer surfaces, either sand or straw bedded pack, rather than mattress and rubber mat. It moreover seems that surface characteristics that are desirable for lying (e.g. softness) may not be the properties of surfaces most suitable for standing (e.g. stability). Finally, the results obtained with milk yield, milk characteristics and blood metabolites indicate that sand seems to be the best lying surface for dairy cows.