11 April 2008

6 minute read

During the search for the ideal free-stall base over the last 20 years, one option-waterbeds-has never gained much favour in Ontario. However, it's now attracting interest resulting from recently published research.

Cow waterbeds, first developed in Europe 15 years ago, never caught on in our market for several reasons. The original version had a single water chamber that provided little cushioning for a cow's knees. It resulted in poor drainage as it took on the shape of the cow's body and cost more than rubber-filled mattresses. Moreover, European trials showed cows preferred a rubber-filled mattress.

More than a decade of experience with rubber-filled mattresses has identified definite limitations for these bedding systems. The waterbed, meanwhile, has markedly improved with a dual-chamber design that has helped overcome earlier deficiencies. Waterbeds are sold as a rubber roll of any length, and are filled with 13 US gallons of water per stall through a valve at the front.

Cow preference for rubber-filled mattresses over waterbeds requires some interpretation, as pointed out in a University of Wisconsin study published in the June 2003 Journal of Dairy Science by A.M. Wagner-Storch, R.W. Palmer and D.W. Kammel. Cows have to overcome the impression of instability when they step on wobbly waterbeds, and farmers report they spend less time in the stalls the first few weeks after waterbeds are installed. Since most research trials are fairly short, this affects their results.

The Wisconsin trial was the first to take a longer look. It followed stall use for nine months using video cameras. The first two columns of the table below show percentage of time cows occupied stalls of each type, either standing with two or four feet in, or lying down. The second two columns show how much of the time cows were lying down. In each case, the first column of the pair represents the entire nine months and the last column only the final two months.

These trial results show cows spent the most time lying down in sand, but occupied the best mattress stalls for a greater percentage of the time, often standing. It also shows not all mattresses offer equal comfort. There is a clear difference between the two commercial products included in the trial.

Waterbeds had a lower occupancy initially, but near the end of the trial, as cows overcame stability issues, lying times were comparable to those for Mattress 2, as shown in the table. Since rubber-filled mattresses pack down and tend to get harder with age, one might speculate waterbeds could come out ahead in a preference test after several years.

However, factors beyond cow preference should be considered when you evaluate a free-stall base. Cleanliness, injuries, health and production are important criteria. Cost, life expectancy, bedding requirements, and labour and management demands also affect a system's usefulness.

Waterbeds fared well in field study by W.K. Fulwider, T. Grandin, D.J. Garrick, W.D. Lamm, N.L. Dalsted and B.E. Rollin, published in the July 2007 Journal of Dairy Science. It compared 38 farms with rubber-filled mattresses, 27 with sand bedding and 29 with waterbeds. They scored cows for cleanliness, and lesions and swelling on their front and rear legs.

Among these herds, 72 per cent of cows in herds bedded on mattresses had hairless spots on their hocks, and 17 per cent had swollen lesions. Hock damage was rare in sand-bedded herds-only 25 per cent had hairless spots and less than three per cent had swollen hocks. At 35 per cent, cows on waterbeds had less than half the lesions of those on mattresses, and three per cent had swollen hocks. Although knee injuries were uncommon, they occurred most frequently in sand-bedded herds using very course recycled sand. Herds on waterbeds had the second highest occurrence.

Cows in sand-bedded stalls were slightly dirtier than those on waterbeds or rubber-filled mattresses, the study found. There was no clear difference in somatic cell counts, and cull rates were lowest for herds with waterbeds and highest for those with mattresses.

Waterbed herds had a lower hock lesion incidence because water moves with cows, eliminating pressure points while they are lying down. Waterbed owners also report the surface of a dual-cell bed stays dry and clean. Moisture drains away, and flexing the surface dislodges dried-on manure. They suggest the beds require less bedding than rubber-filled mattresses, and they like the fact the cushioning effect doesn't deteriorate over time.

One common question is whether the beds freeze in cold weather. I have spoken to Ontario and Wisconsin producers who report no problems, even when barn air temperatures dip below freezing for several weeks at a time.

While these studies rank waterbeds as moderate for cow preference and comfort, and high for hock scores, research results never provide complete answers. The studies didn't consider newer rubber mat products and mattresses made with combinations of foam and rubber instead of rubber crumb. These models may perform equally well or better.

The final question is whether more comfort and freedom from injury makes a difference in cow health or production. A Norwegian study provides some answers. At the Sixth International Dairy Housing Conference last June in Minnesota, researchers L. E. Ruud and O. Osteras presented data from a field survey of 370 Norwegian herds that replaced concrete stalls with various types of softer base materials.

The researchers grouped stall bases according to softness by using a standardized test. It measured surface penetration depth by a standard weight dropped from a standard height.

Stall bases that offered a penetration of one to eight millimetres were associated with a 2.7 per cent production increase. Nine to 16 mm resulted in 4.8 per cent more milk, 17 to 24 mm led to a 7.3 per cent increase, and cows on the softest beds with greater than 24 mm penetration gave 7.7 per cent more milk than animals in concrete stalls. Although this study did not specifically mention how many, if any, waterbed herds were included, waterbeds would rank in this highest category for softness with the testing method used.

These Norwegian cows gave more than 500 extra litres of milk per year when provided with a softer stall base, and most likely paid for the added investment in little more than one year.

Stall preferences for cows given a choice of stall base materials at 100% stocking density Percentage of time stalls are occupied

This article first appeared in the Ruminations column of The Milk Producer Magazine, October, 2007.