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DISEASE CONTROL

Maximum potential genetic performance can only be obtained when disease influence is minimised. Disease control is best accomplished by a combination of sanitation programmes, which help prevent exposure to disease organisms, and vaccinations. Certain diseases are quite common among all poultry populations worldwide and should be included in all standard vaccination programmes. In addition, sanitation efforts to prevent disease exposure or at least reduce the level of exposure, will allow the vaccinations to be most effective.

SANITATION

Cleanliness, sanitation, and strict traffic control are the most effective and least expensive tools in a disease prevention programme. Physical removal of all litter, manure, dust, feathers, and other poultry house debris to a spot remote from the poultry house is the first step in an efficient cleanout programme

An effective sanitation programme must include removal, dismantling, and disinfecting all equipment in the house, before the house itself is cleaned and disinfected. High-pressure sprayers and an effective disinfectant are necessities for eliminating disease carryover. This must be supplemented by a rodent and insect control programme. These efforts must be continued for maximum effectiveness.

After housing the flock, dead birds must be removed and incinerated daily. Rubbish and debris should be moved out on a regular basis, and not allowed to accumulate.

VACCINATION PROGRAMMES

Vaccination programmes need to be individually designed with consideration for maternal immunities of the chicks, disease exposures expected, vaccines available, routes of administration preferred and planned use of inactivated injectable products.

Because of the extreme variability of these factors among producers worldwide, it is difficult to recommend one programme which would be satisfactory for all. I therefore recommend that you consult your Veterinary Adviser on a programme suitable for your particular circumstances.

Regardless of the exact programme, care always needs to be exercised to ensure each bird is given an adequate dose of viable vaccine. In my experience, most vaccination failures relate to improper administration techniques.

TRAFFIC CONTROL

Foot and vehicular traffic threaten constant import of disease organisms. Locked doors and a policy of no visitors is advisable. When it becomes necessary to permit entrance of visitors, clean disinfected footwear and outer garments should be provided. Feed and egg trucks, and their drivers, must be isolated from the bird area.

Portable equipment should be confined to as few houses as possible and should be cleaned and disinfected when transported between houses.

COLIBACILLOSIS

It can frequently appear in these operations as a consequence of pecking and prolapse. It is particularly troublesome since the authorised treatments call for withdrawal of the eggs from the market during treatment and while residues are eliminated.

  Prevention rests upon:

PARASITIC DISEASES

EXTERNAL PARASITES

External parasites, particularly lice are more common on slats than on the floor. On litter the birds can dust bath and get rid of the lice. On slats the problem is frequent. Treating empty houses with insecticide, direct spraying of birds with authorized insecticides can limit the consequences.

RED MITE

Red Mite is a very common external parasitic infection that may result in a loss of production. Red Mite are migratory spending the day hidden in secluded areas such as cracks and crevices in the framework of the house, on perches and feeder tracks. At night they become active crawling onto birds to feed. Control is through use of insecticides but is only effective if they are applied correctly and with care. To prevent resistance insecticides should be rotated.

COCClDIOSlA

Coccidia are protozoan parasites which invade and eventually destroy the intestinal lining.

Symptoms include

Cause

1. Oocysts are ingested by the birds from the litter

2. The oocysts are crushed by the action of the gizzard and release sporozoites which penetrate the intestinal wall.

3. The sporozoites grow within the cells of the intestinal wall, divide and rupture the wall of the intestine.

4. Male and females sporozoites fuse forming oocysts which pass in the droppings

5. The oocyst sporulates in contact with oxygen and moisture

The length of the life cycle varies from 4-7 days depending on the species of the coccidia, as many as l00 million oocysts may be eliminated per bird. They can survive and remain infective for over 18 months.

Control

Farm Biosecurity

Wearing protective clothing, using foot dips and wheel sprays will minimise the spread from farm to farm and house to house. Using an effective oocidal disinfectant at turn round will reduce the challenge on site. Oocyts can also be destroyed by hot water, dehydration and freezing.

Coccidiostats

Ionophores / chemicals which are included in the rearing ration and attack the coccidia. These products allow controlled exposure to coccidia to allow immunity to develop.

Coccidiosis vaccination

Live vaccine comprising a suspension of seven species of attenuated sporulated oocysts adapted to make them harmless to the birds but allowing the birds to build up immunity. Birds must be litter reared to allow for recycling of the oocysts.

Treatment

Treatment is available via drugs, which attack the coccidia in the gut. There are no products licensed for laying hens (UK) so if used they must be under veterinary direction and eggs must be withdrawn from human consumption during treatment and for a further 7 days after treatment

WORMS

Symptoms

Cause

The birds ingest worms eggs found in the litter and the soil. The three most common worm types found in the growing pullet or the laying hen are large roundworms, capillaria worms (hairworms) and caecal worms.

Large roundworms (Ascardia galli)

These worms inhabit the large intestine. Their lifecycle takes around 10-14 weeks.

Hairworms (Capillaria species)

Hairworms infect mainly the small intestine causing damage to the intestinal lining. Their lifecycle is 6-7 weeks.

Caecal worms (Heterakis gallinarium)

Ingested eggs hatch in the small intestine and work down to caecum where they burrow into the walls and emerge in mucus. They are known to be a carrier for Histomonas (Blackhead). Their lifecycle takes 6-8 weeks

Diagnosis

Through worm egg counts from droppings

Through Post mortem, worms may be found in the gut and/or the caeca

Treatment

Flubenvet is the only licensed poultry wormer available (UK) without veterinary subscription. It has the advantages of killing mature and immature stages and eggs of Large Roundworm, Caecal Worm and Hair Worm. Eggs must be withdrawn from human consumption during treatment (usually 7 consecutive days) and for 7 days after the end of treatment.

Piperazine is no longer licensed (UK), but can be prescribed by a vet. Eggs must be withdrawn during treatment and 7 days following the last day of treatment.

1. Roundworms only

Piperazine salts in drinking water (citrate, adipate, dihydrochlorure, dichlohydrate).

Dose: 2 g for 10 kg liveweight or litre of water per day.

This is active against adult round worms. Treat every 3 weeks.

Piperazine solution at 34-35 %

Dose: 3 ml/10 kg liveweight.

Piperazine salts in feed

Dose : 4 kg/tonne for one day. Repeat every 3 weeks.

Piperazine is not authorized for birds in lay. Residue delay for meat birds is 2 days.

Levamisol

Dose: 20 mg/kg live weight

Levamisol solvable powder 20 % :Dose: 100 g/1000 kg live weight.

Levamisol 8 % liquid: 0.25 litre / 1000 kg live weight.

Residue delay for eggs is 5 days.

Tetramisol

Dose: 40 mg/kg liveweight

8 % solution: 0.5 litre / 1000 kg liveweight

12 % solution: 0.33 litre / 1000 kg liveweight

40 mg tablets: 1 tablet per kg liveweight

125 mg tablets: 1 tablet per 3 kg liveweight

Residue delay for eggs is 6 days.

2. Round & Capillary worms

The active ingredient most used is Flubendazol that is used for poultry with runs or on

litter at a dose of 60 ppm for 7 consecutive days. Residue delay for eggs - none.

3. Caecal worms

The most efficient ingredient for these parasites is Niclosamide.

The dose used is 80 mg/kg liveweight.

It can be given as a suspension in water or in feed (Yomesane). It also exists in association with Tetramisol in tablet form given as I tablet per bird in the beak.

The residue delay for eggs is 5 days.

Flubendazole is also suitable.

Prevention and Control

Ideally pullets should be routinely wormed before leaving the rearing farm or within the first weeks of housing on the laying farm. This will ensure that the pullets will start their laying life free of worms. Pullets remaining in cage units should then be free from infestation as the system minimises contact with faeces and hence with any worm eggs~

Birds placed on free range units will be at risk from worm infestation. The worm eggs are difficult to kill and may survive in the soil for up to one year. The best methods to control the worm eggs are paddock rotation and harrowing the pasture to expose the worm eggs to sunlight, lethal to the worm eggs. Worm egg populations are seasonal since they favour warm, wet conditions. Keeping pastures short or grazed through the year will reduce the survival time of worm eggs. Good hygiene will reduce the spread of infestation.

It is advisable to routinely check for worms through taking representative dropping samples 2 or 3 times during a flocks life. This is a simple test and can be carried out by any veterinary practice. (A representative sample would be a pot containing 40-50 faeces).

BEAK TRIMMING

The two main reasons for beak trimming are:

Beak trimming is a highly skilled operation which should be carried out by trained people in accordance with Welfare Codes. If there are any doubts, please consult your local veterinarian.

The following precautions should be observed at all times:

Beak tipping between 8 and 10 days will not totally prevent pecking. Trimming too severely reduces growth and causes unevenness. So in addition to the tipping it is advisable for a second trimming between 9 and 10 weeks.

TRIMMING AT 9 TO 10 WEEKS

To do this correctly, place a finger between the upper and lower beak; trim and cauterise each beak separately. The blade must be at the correct temperature. Cauterisation must be done with care, in particular at the sides of the beak to prevent regrowth.

Poor beak trimming is a sure cause of an uneven, flock and may handicap some of the birds (causing difficulty in feeding and drinking). It should be done with care.

TRIMMING AT TRANSFER

Transfer time or last vaccination provides a good opportunity to check beak quality and to re-trim where necessary.