Innovative Approach to Tackle Red Mite Infestation in Layer Farms

Red mites are one of the most important pests of laying hen farms worldwide. More than 50% of layer batches encounter difficulties in managing red mite problems.

Poultry red mite (PRM), scientific name Dermanyssus gallinae, is a nocturnal blood feeding ectoparasite of birds. PRM is an acarus that requires blood of its host for development and reproduction.

It particularly infests laying farms due to long production cycles. Red mites feed by attaching themselves to the hens during brief periods of time throughout the night. The rest of the time, it hides in dark places such as egg bands, under feeding dishes, cages, wood equipment (perch, nest,...) or under droppings or feathers).

Parasites consume 0.2 µl of blood in each bite. As a consequence, anaemia can appear on hens with massive infestation of PRM, leading to performance reduction (weight loss, reduced feather quality, reduced laying rate up to 25%) and, in some cases, mortality due to exhaustion and reduced immune system favouring Escherichia coli problems. Stress behaviour as higher level of preening, head scratching and feather pecking have also been reported, as well as mortal hurts and cannibalism. In addition, PRM are suspected to transfer pathogens such as Marek, Newcastle, and Zoonotic bacteria such as salmonella.

Innovative Approach to Tackle Red Mite Infestation in Layer Farms - Image 1

Finally, the rate of downgraded eggs due to bloodspots from crushed mites on the eggshell can be significantly higher (up to 20%) in cases of high infestation.

In conclusion, PRM reduces the profitability of laying hen farms. The global impact is difficult to evaluate and probably underestimated by producers. However, Mul (2009), has recently estimated an annual loss of 11 million Euros in the Dutch layers sector, thus accounting for at least 0.3 € per hen per year. This does not include the effects of PRM on human health such as skin irritation, itching, dermatitis, and allergies.

• Resistance to insecticides are now emerging, as PRM is highly adaptable to its environment due to its very short reproduction cycle.
• Evolution of welfare regulations (ban of light programs, red mite repellent) and European directives on residues in eggs (MRL) are limiting the treatments during the production period thereby making it increasingly difficult to control these nocturnal acari.
• Alternative solutions have been developed by spraying natural insecticides in the houses or by blowing inert dust on the hens to destroy the red mite cuticle, ultimately leading to its dehydration. However, these techniques are time consuming; require special equipment and protection for the workers so their efficiency depends on how carefully they have been applied

INNOVATIVE SOLUTIONS TO ELIMINATE RED MITES

To cope with these disadvantages and propose a solution based on an in-feed patented non medicated mixture of aromatic extracts to farmers, PARALICE has been tested in a large scale field trial involving several French farms encountering PRM problems.

EFFICIENCY TRIALS: MATERIALS AND METHODS

Fourteen (14) French farms representing a total of 650,000 hens, encountering PRM problems were selected (7 farms in cages and 7 free range). The methods consisted of evaluating PRM population in the buildings before and after the inclusion of Paralice in the feed of laying hens. In order to evaluate the PRM population of the buildings, mite traps made of double folded cardboard kept closed by two staples were built (dark and narrow spaces that could be used as shelters for the PRM after their blood meal).
The traps were hidden below the feeders in different places of the houses during a 24 hour period. (two days before giving the treated feed to the layers to determine the initial infestation level of the house and 4 days after the end of the distribution of Paralice at the same place as the first set of traps.) The number of PRM in each trap was measured by counting under a microscope.
The tested feed additive, Paralice, was incorporated in the layer feed between 2 and 4 kg per ton of complete feed, depending on the initial infestation level in the farm. The Paralice-supplemented feed was fed to the layers for 10 to 20 days.
The effect of the treatment was evaluated by calculating the reduction of the population of PRM found in the traps after the treatment, as a percentage of the population found before the treatment (initial population).

Innovative Approach to Tackle Red Mite Infestation in Layer Farms - Image 2

Innovative Approach to Tackle Red Mite Infestation in Layer Farms - Image 2

Innovative Approach to Tackle Red Mite Infestation in Layer Farms - Image 3

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Results of the 14 tests showed a reduction in the PRM population after using Paralice in the layer feed that varied between 67 and 88% of the initial population. On average, the reduction of the PRM population was 80.4%

Some interesting comments on the use of the product were also collected from the farmers :
• They all confirmed a very positive general feeling after they started Paralice. Hens appeared as quieter and the general atmosphere of the house seemed better.
• They particularly appreciated the easy use of the product as it was introduced into the feed by the feed manufacturer together with the premix. Home-mixing farmers also find it easier to incorporate the product in their mixer than to spray a liquid product on material.
• They noticed a better resistance of the hens to high temperature as some trials were run during summer with high temperatures. They especially reported a better feed consumption in the houses receiving the product in comparison with non treated houses and a lower mortality during hot periods. This last point, which remains to be validated by performance figures, could be explained by an increase of the PRM population in the non treated houses, generating discomfort for the layers, while the level of infestation in the Paralice-treated houses remained low.
• Finally, farmers did not notice any adverse effect of the inclusion of the Paralice, even at 4 kg/T, on the feed palatability.

CONCLUSION

This large scale field study has enabled to validate PARALICE as a new non medicated alternative approach to efficiently manage red mite infestation in layer farms even during production period.

PARALICE presents the advantage to be easy to use as it can be included in feed (15 day treatment approximately 3 to 4 times per year).

Paralice can be used preventively, starting use at the arrival of a new flock to keep red mite levels low thereby decreasing economic loss and discomfort for the farmer.