The Indian poultry sector is one of the most vibrant, fastest growing, agro-based, techno-commercial Industry (Bhadauria et al., 2014). There are several constraints affecting growth of the poultry industry, among which temperature-associated environmental challenges, especially adverse environmental condition (hot and cold climate) imposes severe stress on birds and leads to reduced performance. Thermal discomfort may result in improper expression of genetic potential in birds (Kataria et al., 2008) and production performances of broiler chicken are greatly affected due to adverse ambient temperature Zahraa et al., 2008). At present, climatic variation is a key threat for poultry industry, especially for marginal poultry farmers in open-house systems (Osti et al., 2017). During this season the highest temperature and humidity inside the broiler shed (i.e. micro-climate) was recorded as 36.39C and 85.37 per cent respectively and the highest outside (macro-climate) temperature recorded was 40.7C. Further, at high temperature birds tend to consume less feed (Abu-Dieyeh, 2006; Akyuz 2009 and Ali et al., 2015) affecting the body weight gain.
Moreover, during monsoon due to heat stress the serum cortisol level increases. Cortisol, involves in production of additional glucose from non-carbohydrate sources of the body, particularly through catabolism of muscle proteins i.e. gluconeogenesis. The wasting of muscle protein was another reason for lower body weight of broiler chicken during monsoon (Anonymous). The significantly (P≤0.05) higher body weight during winter as compared to other seasons might be due to in-house comfortable condition resulting favourable microclimatic condition for broiler chicken and higher feed intake. More feed consumption resulted in higher body weight gain (Al-Fataftah and Abu-Dieyeh, 2007 and Ali et al., 2015).
Broiler chickens adapted more easily to lower temperature than to higher temperature (Manning and Wyatt, 1990). The optimal temperature range for efficient production for broiler chickens over 4 weeks of age is 18 – 21C (Aengwanich and Simaraks, 2004) and the thermo-neutral zone of poultry is 12.77 – 23.89C. El Boushy and Van Marle (1978), further defined the comfort zone of broilers with temperature between 15 to 25°C and 60-65% humidity, where the birds are able to regulate their heat balance relatively well and do not spend much energy on activity (Syafwan et al., 2011). During winter season the temperature and humidity inside the broiler shed (i.e. micro-climate) was recorded as 25.10- 19.95C and 57.82–72.71 per-cent, respectively, which falls almost within the thermo-neutral i.e. comfort zone. At thermo-neutral zone the birds exhibit its maximum genetic potential in obtaining body weight and growth (Anonymous).
The mean feed consumption of broiler chicken among different seasons differed significantly (P≤wherein the broilers consumed significantly (P≤0.05) higher feed in winter followed by pre-monsoon, post-
The poor FCR during monsoon season might be the result of high environmental temperature during
Monsoon that brings about a reduction in feed consumption and efficiency in the utilization of feed energy for production purposes (Howlider and Rose, 1989). (P≤0.05) lower livability percentage was recorded during winter season followed by monsoon season. The significantly (P≤0.05) higher livability percentage in the present study during pre-monsoon and post-livability (P≤0.05) of adult broiler chicken (29-42 days of age) during monsoon season might be due to higher environmental temperature which increased the incidence of heat stroke (Anonymous). On the other hand significantly (P≤0.05) lower livability of broiler chick (0 – 14 days of age) during winter season was due to low temperature which was sometimes worsened by power cut particularly in night time resulting in sudden huddling and consequent death of the chicks. However, the overall liveability was found to be above 95% that is considered normal for broiler enterprises.
The rainy season is usually synonymous with an increase in relative humidity and a reduction in temperature; rainfall affects both the quality and quantity of feeding, while wind speed has an impact on the outbreak of diseases.
The birds are stressed, and their ability to withstand diseases or immune system is seriously affected during monsoon season .Some certain poultry diseases are rampant in the wet, rainy or cold seasons i.e. the onset of rain favors the propagation and spread of the causative organisms of these diseases and parasites. Hence, most poultry farmers experience high morbidity and mortality rate during this period.
Some of the diseases common during the rainy season will be discussed below.
Fowl Pox
Fowl pox is a highly contagious disease that affects poultry birds at any age. It is caused by poxvirus transmitted by mostly mosquitoes and other blood-sucking insects. The reason why fowl pox is prevalent during the wet season is that mosquitoes, being the vector, breed well in this season due to the abundance of stagnant water. Also, the incidence of wet litter becomes apparent when poultry houses are not adequately shielded from rain. This leads to the development of wet liter which then predisposes to fly problems in the pen.
How to Recognize Fowl Pox in Chickens : There are some visible things you will notice, which are proofs that your chickens have come down with fowlpox disease. Fowl pox leads to the development of round lesions with scabby centers on the skin of the birds. The majority of the skin lesions are located on the wattle, face, comb, and some are occasionally located on the legs. This disease also affects the mouth and windpipe linings. The lesions that are formed in the throat can develop to the extent of blocking the throat and it could eventually lead to death as a result of suffocation. Lesions on the face can extend to the eyes, causing temporary or permanent blindness of the affected bird.
How to Prevent Fowlpox in Chickens :The mechanical carriers of fowl pox are mosquitoes. So it is advisable to reduce the mosquitoes around your farm or environment. Ordinary sanitation and management practices will not avert this disease, so vaccination is often the solution. It is recommended to vaccinate chickens ,such as breeders, egg layers, and those that are highly susceptible to fowl pox. Live fowl pox vaccine is administered in the wing web of birds within age 6 and 10 weeks. If aggressive pecking is controlled among birds, skin damage which fowl pox causes is reduced.
How to Treat Fowlpox in Chickens
Unfortunately, fowlpox has no treatment once the fowlpox virus has affected a bird. But as long as a diseased bird is eating and drinking, it will recover from the disease in about two weeks or more with low mortality rate. When a bird recovers successfully from fowlpox, it is immune to the disease permanently.
Fowl Cholera
Fowl Cholera is a bacterial disease that affects birds of age 6 weeks old and above. The bacterium responsible for this is Pasteurella multocida. It is highly contagious and mortality in acute cases is high. The causative organism is spread readily during the rainy season because wet liter serves as an abode of numerous microorganisms.
How to Recognize Fowl Cholera in Chickens
In acute cases, birds that appear healthy die suddenly while in chronic cases the affected birds show the following:
- Yellow, green or grey diarrhoea
- Loss of appetite
- Laboured breathing
- Drooped wings and tail feathers
- Ruffled feathers
- Swelling of the leg joints, sinuses, wattle and foot pad
- Twisting of the neck (torticolis)
- Discharge from the nostril or beak
Note: The above signs are also similar to those of fowl typhoid.
How to Treat, Prevent, and Control Fowl Cholera in Chickens
Fowl cholera can be treated using sulfa drugs, tetracycline, and erythromycin. Poultry birds can be vaccinated against fowl cholera by administering a fowl cholera vaccine. Maintain proper hygiene and sanitation. Practice a high level of biosecurity and prevent rodents, wild birds, and other animals.
Salmonellosis, Escherichia coli, Pullorum Disease (Bacillary White Diarrhoea)
These bacterial diseases affect birds of all ages. They are endemic in farms or pens with poor sanitation, such as is seen when wet liter is allowed to stay for a long time. They affect the digestive system of the infected birds.
How to Recognize Salmonellosis, Escherichia coli, Pullorum in Chickens
- Severe diarrhoea
- Loss of appetite
- Depression and emaciation
- Chicks suffer omphalitis
- White pasty diarrhoea in pullorum disease
- Huddling together and laboured breathing
How to Treat, Prevent, and Control Salmonellosis, Escherichia coli, Pullorum
Salmonellosis, E. coli and Pullorum diseases can be treated by administering a broad spectrum antibiotics to the flock. High-level farm/pen hygiene and sanitation must be maintained. Biosecurity measures should be in place. Avoid feeding birds with contaminated feeds.
Aspergillosis
Aspergillosis is the disease caused by Aspergillus fumigatus in poultry. Due to the high humidity during the cold season, feeds or litter dampens, thus creating a favourable environment for fungus to grow and thrive. The birds also inhale Aspergillus spores and these spores develop into lesions filling the lungs causing respiratory problems or discomforts. Birds under intensive management systems would experience high disease spread if the stocking density is high and ventilation is inadequate or poor.
How to Recognize Aspergillosis in Chickens
There are a wide range of clinical signs presented in birds with aspergillosis. This is because they vary depending on how the chicken became infected, where lesions develop in their body, organ(s) involved, and their overall health status (immune system). Aspergillosis may be acute or chronic in nature.
- Acute form: This generally occurs in young chicks and results in high morbidity and mortality. Onset is very quick and usually develops within a week. Most affected birds will die within a few days without emergency veterinary care. The most common signs include; Lethargy, depression, loss of appetite, difficulty in breathing, and cyanosis (bluish/purplish comb).
- Chronic form: This is usually very subtle in onset, and it may take several weeks or months to develop. It is most common in older birds, many with a history of malnutrition, stress, concurrent illness, or prolonged antibiotic/corticosteroid use. The entire course of the disease ranges from less than 1 week to over 6 weeks in duration. The most common clinical signs observed include: Weight loss, reduced appetite, exercise intolerance, increased respiratory rate, changes in vocalization (voice), often more apparent in roosters, audible respiratory sounds, tail bobbing, open-mouthed breathing.
A presumptive diagnosis of aspergillosis can usually be made based on the history of the flock, clinical signs, and physical examination. In order for your veterinarian to obtain a definite diagnosis of aspergillosis, they will need to collect some samples and send to a diagnostic laboratory, to confirm the presence of Aspergillus in the bird.
How to Prevent Aspergillosis in Chickens
Dry, good quality litter and feed and hygiene will help in the prevention of aspergillosis. Antifungal drugs such as Thiabendazole or Nystatin can be used in feed.
How to Treat Aspergillosis in Chickens
Usually none. Environmental spraying with effective antifungal antiseptic may help reduce the challenge. Amphotericin B and Nystatin have been used in high-value birds.
Coccidiosis
Coccidiosis is caused by protozoan Eimeria sp in poultry, most species infect various sites in the intestine. The infectious process is rapid (4–7 days) and is characterized by parasite replication in host cells with extensive damage to the intestinal mucosa. Poultry coccidia are generally host-specific, and the different species parasitize specific parts of the intestine. However, in game birds, including quail, the coccidia may parasitize the entire intestinal tract. Coccidia are distributed worldwide in poultry, game birds reared in captivity, and wild birds.
The wet litter and the hot pen temperature commonly observed in the rainy season favours the sporulation of the coccidian oocyst and therefore, the outbreak of coccidiosis.
How to Recognize Coccidiosis in Chickens
Clinically, bloody faeces, ruffled feathers, anaemia, and somnolence are observed. Other signs of coccidiosis range from decreased growth rate to a high percentage of visibly sick birds, severe diarrhea, and high mortality. Feed and water consumption are depressed. Weight loss, development of culls, decreased egg production, and increased mortality may accompany outbreaks. Mild infections of intestinal species, which would otherwise be classed as subclinical, may cause depigmentation and potentially lead to secondary infection, particularly Clostridium spp infection. Survivors of severe infections recover in 10–14 days but may never recover lost performance.
The lesions are almost entirely in the intestinal tract and often have a distinctive location and appearance that is useful in diagnosis.
How to Prevent Coccidiosis in Chickens
Basic hygiene is your first step for prevention. It is good to ensure that the poultry house is generally clean and dry.
- Ensure water is clean and fresh. Keep feeding areas clean and dry.
- Ensure the birds have enough space i.e. overcrowding should be prevented as it is a predisposing factor for coccidiosis. Chickens need an average of a square meter for 3-5 birds.
- If your chicks have not been vaccinated against coccidiosis, provide medicated starter feed for them. Anticoccidial medication should be given to the chicks at around 12 days of age (this might vary depending on the vaccination schedule being followed).
- An all-in all-out method should be employed on the farm in order to prevent a horizontal transfer of infection. If this method is not feasible, keep the new batch quarantined for a minimum of two weeks, for the protection of the current stock.
How to Treat Coccidiosis in Chickens
Once coccidiosis is diagnosed in a flock, all the birds need to be treated. Also, the litter needs to be changed so that birds do not pick up the sporulated oocyst from the droppings of affected birds common anticoccidial drugs include ; Amprolium, toltrazuril, sulfaquinoxaline etc.
Dr.Yogesh Paharia
B.V.Sc & A.H , M.V.Sc ( Nutrition )