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Acidic bedding conditioner can help reduce bacteria levels

PD Editor Karen Lee Published on 09 August 2013

At certain times of the year and in certain climates, environmental bacteria can be a real challenge. Bedding conditioners have been developed to help reduce bacteria levels in the stall.

Sheila Andrew, professor and dairy extension specialist with the Department of Animal Science at the University of Connecticut evaluated the effects of a clay-based acidic bedding conditioner on sawdust bedding.



Andrew and her team of researchers looked at pH, dry matter and environmental pathogen counts of the bedding and environmental bacterial counts on the teat ends of lactating dairy cows.

Using the university herd, 16 Holstein cows were selected and randomly assigned to a control or bedding conditioner group for two three-week periods.

The stalls were power-washed and bleached before the start of each period.

The rubber-filled mattresses in the stalls were covered with sawdust to a depth of 4 inches.

In the bedding conditioner group, the clay-based acidic bedding conditioner containing 45 to 65 percent sulfuric acid was added according to the manufacturer’s direction.


Prior to the sawdust, 1 pound of conditioner were applied to the back one-third of each stall, and another 5 ounces were applied to the sawdust.

Even though it is a typical practice on the farm, no lime was applied to the stalls, in order to prevent a confounding factor.

Cows were milked three times a day, and at each milking the stalls and alleys were cleaned of all visible manure.

For both treatment groups, sawdust bedding was added throughout the period to maintain a depth of 4 inches.

In the conditioner group, 5 ounces of the conditioner product was re-applied every three to four days.

Stall cleanliness was evaluated with a nine-square grid. The stalls were significantly dirtier during period two, and that is when the bedding conditioner had a greater effect.


According to Andrew, the major difference was found in pH, especially in period two. Here the pH remained below 5.15 (in the acidic range) for at least 77 hours when the conditioner was re-applied.

A low pH is associated with decreased bacterial counts. As pH increased, counts of Klebsiella spp., coliforms and streptococci increased on the sawdust and on the teat end.

There were no clinical mastitis cases reported during the study. Of the few subclinical cases, mainly Staph species were found to be the culprit.

Averaging more than 90 pounds of milk per cow, the university herd maintains a somatic cell count average of less than 100,000.

Andrew notes the study was for a short time, and therefore the effect of the conditioner on clinical mastitis was not an objective of the study.

Instead, they were focused on bacterial counts on teats and teat-end condition because bacteria migrate to the udder through the teat canal.

Use of the conditioner reduced bacterial counts on teat ends for all three environmental bacteria, with significant differences apparent after day two of the study.

There was no difference in teat-end porosity, cracked versus smooth, Andrew says.

There were also no reports of teat irritation mentioned by the milking crew at the farm.

Even though the material was clay-based, suggesting the clay would serve as a drying agent, Andrew reports there was no difference in dry matter of the sawdust bedding in the stalls.

Andrew acknowledges this conditioner should be evaluated over a longer range of time and in commercial herds in different geographic regions to be able to speak to its efficacy across the board.

“Stall management is most important in reducing bacteria,” she says. “A bedding conditioner can be an added benefit, particularly during a time of year when environmental mastitis is likely to be a problem – warm, damp weather.”

Starting with a clean stall that has been thoroughly cleaned and sanitized will help a producer get the most value.

She sees this as being useful with other bedding types, such as digested, dried or separated manure solids.

An active member of the National Mastitis Council, Andrew says she agrees that clean sand is the best bedding material, but even that has to be properly managed.

“Beds should always be dry and free of manure and urine to reduce bacteria levels that can affect milk quality,” she says. This is true no matter the bedding type or use of a conditioner. PD


Karen Lee
Progressive Dairyman