We want cows to lie down as much as they want. We want housing that cows will like and we want housing that is easy for cows to use. This whole topic has been a subject of much research into cow behaviour (can barns be designed and built that are easier for cows to use) and cow preference (can we make barns that cows will prefer to use). The research shows that cows prefer soft and dry bedding surfaces. They prefer sufficient room so they can easily get up and down. They prefer lying down in an open space, like a pasture or bedded pack rather than in a stall.
A recent research project investigated whether it is more important to cows to have a lying surface that they preferred or more room to get up and down easily. They set up a research trial where they offered cows a choice of lying down in free stalls on one of three different surfaces. The choices were free-stalls with 20 cm of dry sand, 20 cm of wheat straw or a mattress covered with sawdust. The free-stalls had a bedded area 1.2 m wide and 1.9 m from the brisket-board to the curb and an additional 0.5 m of lunge space. The neck rail was 1.3 m high and 2.2 m from the curb. The cows were milked in a parlor twice daily and the stall bedding was maintained each morning and cleaned as necessary after the evening milking.
Each cow was given access to one free-stall bedded with one of the bedding materials for two days for each bedding material so they could get used to each surface. After that, they were offered an opportunity to use any of three stalls with each stall bedded with one of the three different bedding materials. Essentially, they could choose which they liked best. Best was defined as the bedding in the stall where they spent the most time lying down.
This part of the experiment was used to identify which bedding surface each cow preferred in free stalls. It turned out that most cows, though not every cow, preferred straw bedding followed very closely by mattresses/sawdust.
In the next part of the experiment, the free stalls were removed. Then each cow was offered a choice of lying down on any of the three different bedding materials on an open platform rather than in a stall. Most cows, but not every cow, still preferred straw. One thing that was clear from this part of the experiment was that once the free stalls were removed, straw, the favorite in free stalls became the most preferred bedding by many more cows. Cows that had used free stalls bedded with mattresses/sawdust switched to using straw-bedding on the open platforms.
In the last part of the experiment, each cow was given the choice of lying down in a free stall bedded with their favorite bedding material or on an open platform bedded with their least favored bedding material. It turned out that almost 75 % of the cows would rather lie down on the open platform on their least-favoured bedding material than use the free stall bedded with their preferred bedding.
Essentially, the project found that most cows found that lying down in open space was more important than bedding material. Not all cows are the same though. There were still about 16 % of cows that selected the free stall with their preferred bedding instead of the open platform. There was also 10 % of cows that did not seem to have any bedding or stall preference at all.
While sand was consistently least favoured by cows in this experiment, the researchers cautioned against interpreting this finding as a general preference for dairy cows. Sand bedding was new to the cows in this experiment. They had been more accustomed to straw and mattress/sawdust bedding. This could be the reason why sand bedding was used less often.
These cows had been previously housed in a free-stall barn. It is difficult to know if that influenced their preferences for free stall or platform use in this experiment. It does illustrate how difficult it can be to interpret experiments where any animal is offered an opportunity to select between something that is new to them versus something that they already know.
Dr. Robert Tremblay is a veterinarian for Boehringer-Ingelheim and lives near Guelph.
