Why is it important to keep ammonia levels low in animal housing?
Ammonia present in the air acts as an irritant to eyes and airways. Ammonia inhibits the action of hair-like cilia lining the trachea, potentially allowing pathogens to enter the lower respiratory tissues. This typically leads to respiratory infections such as pneumonia.
Where does ammonia in animal housing come from?
The main source of ammonia in animal housing is urine with faeces a second major source of ammonia. Nitrogen present as urea in urine is hydrolysed by bacteria present in bedding while nitrogen in faces breaks down more slowly. The result in both cases is the production of ammonia.
Under what conditions does bacterial hydrolysis of nitrogen occur?
Urease, the bacterial enzyme which breaks urea and protein into ammonia and carbon dioxide, has a pH optimum of about 7.7 – 8.0. This means that if we can reduce the pH of the bedding we can reduce the urease activity.
What is pH?
pH is a measure of the acidity of a solution. The scale ranges from acidic at 0 to neutral at 7 to alkaline at 14. Each number represents a 10-fold increase in the acidity/alkalinity of the solution. For example, Orange Juice with a pH of 3 is 10 times more acidic than tomato juice with a pH of 4.
Some examples of the pH of different solutions are shown below¹.
What is the typical pH of bedding?
Some work carried out in the Waikato in the early 90’s showed fresh bedding to have a pH under 7. Once used the pH of the bedding increased with areas where there was a higher concentration of urine and faeces increasing to above 8 in most cases.
Stalosan F has a low pH. Is this the only aspect of the product which helps to reduce ammonia in sheds?
No, beside the acidity, Stalosan F also contains copper, a very powerful inhibitor urease.
We know that the high pH of ammonia damages the skin, but what about the low pH of Stalosan F – can this damage the skin?
Healthy skin has a pH value typically under 5 and can handle pH values down to 2. The pH of Stalosan F at 3.5 is, therefore, not a problem.
Ammonia is a gas and thus in the air. To bind ammonia, water and Stalosan F are needed. How is the ammonia in the air reduced with Stalosan F?
By reducing ammonia production and binding ammonia in bedding, less ammonia vaporises into the air, thus reducing environmental ammonia levels. If the pH of the bedding is low enough, e.g. through application of Stalosan F, ammonia present in the air can be drawn back in to the bedding.
Why are so many products used in animal housing based on limestone?
It is probably a combination of tradition and price since limestone has been used for many years and the price is very low. Also, limestone is readily available.