Worms pose a constant challenge to poultry, and this year has proved no different. The more common types of worm – Ascaridia, Heterakis, Capillaria, Syngamus trachea, Gape worm all live in the bird and cause major health issues in poultry.
In recent years, variations in the weather have allowed the worms to maintain their life cycles and infect poultry and we believe this may be a reason that worm burdens have been particularly high in recent years.
Gut health in poultry is extremely important. All worms are detrimental to health of the gut, some more than others. It is critical that laying hens reach the ideal body size and weight (not fat) in order for her laying apparatus to develop and then maintain egg production throughout lay, or for meat birds, to develop ample muscle. Poor gut health due to worms jeopardise production, have a negative effect on egg quality and also makes the birds more susceptible to other diseases.
Some worms can cause obstructions whilst others directly damage the gut wall. Either way they are all parasites and live off the host. The damage they cause means the cells lining the intestines are no longer able to efficiently transfer nutrients across from the intestines to the rest of the body. As a result of this, the bird does not have enough energy to fulfil their purpose i.e. lay eggs or grow. Therefore the end goal we want from our birds is compromised.
More importantly than this though, is the welfare of the birds. Damage to the gut wall is painful and should not be overlooked.
There are many different types of worm which infect poultry and gamebird, each posing their own risk.
Ascaridia spp (round worms)
These are the most easy to identify on the basis of their size. These live within the intestine and in high number can cause obstruction as well as enteritis. They look like pieces of spaghetti in the lumen of the gut and so are easy to see at post mortem.
This type of worm is the most pathogenic worm as it lives within the gut wall so can therefore cause the most damage. These cannot be seen by the naked eye easily if at all and hence need a microscope and a vet to really make the diagnosis. They can kill the birds.
These worms live within the birds caecum and can act as a host to the Histomonas parasite which causes Black Head. This is a deadly condition in laying birds and adult pheasants.
Syngamus trachea or Gape worm
This type of worm lives within the windpipe of the bird and causes irritation as it latches to the wall. This is more commonly seen in pheasants so it’s a good idea to try to keep them off your range area! The worm can cause the birds to gasp for air and can kill them.
Recently we held a meeting for poultry producers with Elanco Animal Health. An important point discussed was that regardless of treating the worms within your bird, you must remember that whilst these birds are alive, the worms are reproducing and laying eggs of their own. These are excreted by the birds and can live in the environment for years. So even if you don’t have a problem with one flock, you are posing a greater challenge to the next as there are already an increased amount of worm eggs in their environment, which once ingested, can start their own lifecycles.
On the back of this a control strategy was discussed which is aimed at decreasing the challenge from worms in the environment. While strict cleaning and disinfection is required at turn around, worm eggs have proved to survive extreme conditions and still remain viable. Therefore a worming programme can help to control worm burdens in your environment as well as adult worms in your birds.
It is very important to know what worms are causing a problem on your site, as their life cycles can vary in time and therefore have an influence of the frequency of worming. This can be achieved by sending a faeces sample to your vet or a poultry laboratory. The test will allow us to see what species of worms are present on your site, whether treatment is required and the frequency of treatment. The frequency of treatment is particularly important at reducing the overall burden on the pasture e.g. for certain worms to break the life cycles repeat worming at three week intervals is recommended which is then be gradually spaced out depending on what worm is present on your site. Regular monitoring of the levels of worms via worm egg counts or post mortem is an important part of the health planning of your flock.
There are several treatments for worms available and it is essential to use those that are licensed in the particular species that you are treating. Flubenvet (in feed), Panacur Aquasol (in water) and Flimabo (in water) are licensed for laying poultry. These all have a nil egg withhold. Meat withholds are seven, six and two days respectively.
Flubenvet is the only licensed wormer in game birds and has a seven day withhold for both meat and eggs.
In summary, worms need to be controlled for the sake of the health and welfare of the birds and your profits.
Hannah Griffiths BVetMed Sci BVM BDS MRCVS
Stuart Young BSc (Hons) BVet Med MRCVS