The cost of heating poultry houses in the winter has increased over the past several years, and these costs can significantly add to the cost of raising broilers or producing eggs. Producers look for ways to reduce heat loss from buildings in order to reduce heating costs. One negative effect of tightly controlling ventilation in the winter is the potential to increase the concentration of ammonia in houses.
Ammonia is a colorless gas produced by the action of microbes breaking down the nitrogen-rich fractions of waste. Humans can typically detect the smell of ammonia at concentrations greater than 25 ppm. Poultry can be negatively influenced by long term exposure of ammonia at concentrations as low as 20 ppm.
A condition known as keratonconjuctivitis can result from exposure to high levels of ammonia.
Birds will often have matted, damp feathers on their back and be extremely sensitive to light and may even have their eyes closed or covered by their wings. Birds are often more susceptible to infections of the respiratory tract when exposed to high levels of ammonia. Damage to the mucus membranes and lung tissue is not uncommon.
Human Farm Animal Care, HFAC, and other animal welfare organizations, have established the acceptable level of ammonia present in cage free egg production houses at 10 ppm. Birds can be briefly exposed to ammonia levels of up to 25 ppm. The ammonia level must never be above 25 ppm. During the warmer times of the year (spring, summer, and early fall), this is typically not an issue since chicken houses are well ventilated at these times. However, during late fall and winter months, when little ventilation is needed or used, increased ammonia levels can be a problem.
Several published research trials have established the benefit of adding yucca schidigera extracts to diets to reduce aerial ammonia concentrations. During the times of the year when issues with higher ammonia levels are a challenge, Wenger Feeds adds yucca schidigera extract containing products to diets to help combat increased ammonia levels.
Wenger Feeds has conducted three trials over the past few winters to compare yucca schidigera products and their ability to reduce ammonia levels to acceptable levels in cage-free layer houses.
Wenger Feeds has been using a yucca product in diets during the winter in cage-free houses. We were interested in comparing the performance of the current product to another product on the market. In the first trial, the current product was used in feed for the test houses (3 locations, 2 barns per location) from October 2011, until the start of the trial in early December 2011. At the start of the trial, the 2 barns at each location were assigned to one of the two yucca products. The results for the trial are presented in Table 1.
|Table 1. Trial 1- Effect of Yucca Extract Products on Ammonia Levels|
|Current Product||Alternative Product|
|End of Trial Ammonia||20.2||21.1|
|Change in Ammonia||+2.5||+4.5|
During the test period, ammonia levels increased in both treatments. Although, both products appeared to be similar, in controlling ammonia concentrations, neither yucca product was able to keep ammonia levels below the 10 ppm threshold. Since both products appeared to be similar in their ability to control ammonia and the alternative product was lower in price, a switch was made to the alternative product.
In the second trial, we compared the “new” current product with two other alternative yucca products. This trial was conducted during late winter in 2013. Again, all of the yucca products performed similarly in controlling ammonia concentrations. However, none of the products were capable of reducing ammonia concentrations below the 10 ppm threshold.
These same three treatments were evaluated in a third trial conducted from October 2013 to March 2014. In this trial, the initial ammonia levels were at or below the 10 ppm threshold at the beginning of the trial. This was most likely due to the houses not being tightly sealed since the trial started in mid-October. As in the other trials, all products were similar in their ability to control ammonia but were unable to keep levels below the 10 ppm threshold.
In summary, high ammonia levels in poultry houses can have a negative effect on the performance and health of birds, especially in the winter when ventilation is tightly controlled. Yucca products added to the feed can be effective in preventing excessively high levels of ammonia concentrations in poultry houses. However, of the products tested, none can be used solely to keep ammonia levels below the established 10 ppm threshold.