Chicken tapeworm disease is a parasitic disease caused by tapeworms living in the intestines. It causes watery droppings, a lower egg production rate, paler eggshells, lighter eggs, and an increase in deformed eggs. The disease can occur throughout the year and is more prevalent in 6~11 months. Tapeworms have a complex life cycle and require one or two intermediate hosts. Ants, beetles, flies, and some mollusks are the main hosts that transmit them. Once infected, laying hens suffer impaired production performance, causing serious economic losses for many farmers.
I. Disease occurrence
On 2014 year 7 month 3 day, Zhang, a farmer in Xinghuacun, was raising 5 000 190-day-old Hy-Line Brown laying hens. Within 7 days, the egg production rate fell from 95% to 80%. Egg weight was low, and the eggs were small. About 10%~15% of the hens had pale combs that drooped. The eggshell color was pale, with about 10%~30% of the eggs showing obvious whitening. Feed intake was normal, while water consumption increased. Treatment with Shuanghuanglian Oral Liquid and enrofloxacin for 5 days had no effect.
II,Clinical symptoms
Sick chickens become thin, reluctant to move, and stand listlessly; their feathers are loose, disheveled, and dull. Their droppings may contain varying numbers of white, rice-grain-sized, rectangular tapeworm segments. Mature segments contain eggs.
Three、Pathological changes
Sick chickens become thin. Worms can be seen about 10 centimeters from the descending part of the duodenum, extending downward into the jejunum. The small intestinal mucosa is thickened, and the cecal tonsils are hemorrhagic and swollen. No obvious changes are observed in other organs.
Four、Treatment
Mix praziquantel 20 milligrams per kilogram of body weight into the feed and administer it all at once in 1 dose(s). Use it again 1 time(s) after 5 days. Add fish liver oil at 500 grams per ton of feed and use for 7 consecutive days.
Administer an areca nut decoction in the drinking water. To prepare the decoction, use 1 grams of areca nut powder per kilogram of body weight (the amount of areca nut powder should not be too large to avoid poisoning), add water and boil to make an areca nut liquid, filter out the dregs with gauze, and set aside to cool before use. Generally, worms begin to be expelled within 2 hours after the medication is finished, and expulsion is completed over 1~2 hours. After the second deworming with praziquantel, the egg production rate begins to recover, and egg production returns to normal after 20 days.
Five、Analysis of the causes of tapeworm infection in caged laying hens
Chickens become infected with tapeworms by ingesting intermediate hosts such as ants, flies, beetles, slugs, and snails. They will not become infected if they do not come into contact with these intermediate hosts. Due to poultry-house conditions, caged laying hens can mainly come into contact with flies, so Raillietina tapeworms and Choanotaenia tapeworms are common in clinical practice. Since the hens do not come into contact with slugs and snails, they will not become infected with Davainea tapeworms.
Apart from coccidia, the main infection in caged laying hens is chicken tapeworm, because flies reproduce in large numbers in summer and autumn, and chickens become infected with tapeworms by pecking at flies. Chicken nematodes and chicken roundworms are transmitted directly through eggs and do not require an intermediate host. Caged laying hens do not come into contact with the ground, so the likelihood of infection is very low. Therefore, deworming caged laying hens should focus on chicken tapeworms.
The current practical problem for laying-hen farmers is that small-scale operators generally have poor environmental hygiene; for them, biosecurity is merely a concept, and most cannot implement it. Laying-hen farms are not as large in scale as broiler farms, and laying-hen farms are currently highly dispersed. In summer, flies swarm around poultry houses, and tapeworm infections are also very common. Ordinary poultry farmers have rudimentary poultry houses, and most lack sufficient funds to invest in farm infrastructure, so automatic feeding and automatic manure scraping are out of the question.
Six、Observations
In recent years, tapeworm disease has not been uncommon in laying-hen production. Because awareness of parasite prevention is low and the harmful effects on production performance are not well understood, parasitic infections are easily overlooked. They are often misdiagnosed in clinical practice, delaying treatment and causing certain economic losses. Some farmers do not recognize tapeworms and only take notice after administering deworming medication and seeing the shed segments. In addition, many farmers commonly use ivermectin as a broad-spectrum dewormer; however, practice has shown that this class of drugs does not kill tapeworms.
In chicken houses with poor environmental hygiene, after chickens become infected with tapeworms, pinhead-sized nodular lesions with central depressions appear at the intestinal sites where the parasites are attached. When large numbers of worms accumulate, they can cause intestinal obstruction, which may lead to intestinal rupture and peritonitis, resulting in deaths in the flock. In addition, the worms’ metabolic products can cause autointoxication in sick chickens, with neurological signs such as spasms.
Flies are important intermediate hosts of tapeworms. Tapeworms are rarely seen in chicken houses without flies. However, very few caged-layer houses can achieve sealed rearing. If deworming is not carried out around the onset of laying, chickens may become infected with tapeworms, which will not pass out on their own and can only be eliminated with medication.