If you are a poultry farmer, you may have experienced the unpleasant situation of finding some of your layer chickens dead without any apparent reason. This can be very frustrating and alarming, especially if the mortality rate is high and affects your production and profit. Sudden death in layers can have various causes, ranging from infectious diseases to nutritional deficiencies, environmental stress, or genetic factors. In this article, we will explore some of the most common causes of sudden death in layers and how to prevent or treat them.
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Infectious Diseases
One of the main causes of sudden death in layers is infectious diseases, which can be caused by bacteria, viruses, fungi, or parasites. Some of the most prevalent infectious diseases that can cause sudden death in layers are:
- Avian influenza: This is a highly contagious viral disease that affects the respiratory system, nervous system, and other organs of birds. It can cause severe symptoms such as depression, ruffled feathers, respiratory distress, coughing, sneezing, and a drop in egg production. In some cases, it can cause death within hours or days of infection. Avian influenza is a reportable disease and strict biosecurity protocols must be followed to prevent its spread. There is no treatment for avian influenza, and infected birds must be culled and disposed of properly. According to MSD Veterinary Manual, vaccination may be used in some regions to prevent or control the disease.
- Coccidiosis: This is a parasitic disease caused by protozoa that infect the intestinal tract of birds. It can cause symptoms such as diarrhea, blood in the droppings, weight loss, anemia, and reduced feed intake. Coccidiosis can be fatal if not treated promptly, especially in young birds or birds under stress. According to Poultry Farm Guide, coccidiosis can be prevented by maintaining good hygiene, providing clean water and feed, and using anticoccidial drugs or vaccines.
- Fowl cholera: This is a bacterial disease caused by Pasteurella multocida that affects the respiratory system, joints, and other organs of birds. It can cause symptoms such as fever, depression, loss of appetite, nasal discharge, swollen wattles, and lameness. Fowl cholera can cause sudden death in layers, especially if the infection reaches the heart or brain. According to MSD Veterinary Manual, fowl cholera can be prevented by improving biosecurity, sanitation, and rodent control, and by using antibiotics or vaccines.
- Fowl typhoid: This is another bacterial disease caused by Salmonella gallinarum that affects the blood, liver, spleen, and other organs of birds. It can cause symptoms such as weakness, diarrhea, pale comb, and reduced egg production. Fowl typhoid can cause sudden death in layers, especially if the infection is severe or complicated by other diseases. According to MSD Veterinary Manual, fowl typhoid can be prevented by improving biosecurity, sanitation, and rodent control, and by using antibiotics or vaccines.
Nutritional Deficiencies
Another cause of sudden death in layers is nutritional deficiencies, which can affect the health and performance of birds. Some of the most common nutritional deficiencies that can cause sudden death in layers are:
- Calcium depletion: This is a condition that results from the depletion of calcium from the bones and starts as soon as egg production begins. It can be caused by high egg production, low feed intake, disease, or other stresses that increase the demand for calcium. Calcium depletion can lead to hypocalcemia, osteoporosis, or cage layer fatigue, which can cause symptoms such as paralysis, soft bones, fractures, and death. According to MSD Veterinary Manual, calcium depletion can be prevented by providing the correct balance of calcium, phosphorus, and vitamin D3 in the diet, and by using large particle calcium, midnight feeding, or stacked feedings.
- Vitamin E deficiency: This is a condition that results from the lack of vitamin E in the diet or the destruction of vitamin E by oxidation. It can affect the immune system, nervous system, and muscular system of birds. Vitamin E deficiency can cause encephalomalacia, exudative diathesis, or muscular dystrophy, which can cause symptoms such as paralysis, hemorrhages, edema, and death. According to MSD Veterinary Manual, vitamin E deficiency can be prevented by providing adequate vitamin E in the diet, and by using antioxidants or selenium.
- Vitamin B12 deficiency: This is a condition that results from the lack of vitamin B12 in the diet or the interference of vitamin B12 absorption by parasites or drugs. It can affect the blood, nervous system, and reproductive system of birds. Vitamin B12 deficiency can cause pernicious anemia, nervous disorders, or reduced egg production, which can cause symptoms such as weakness, pale comb, ataxia, and death. According to MSD Veterinary Manual, vitamin B12 deficiency can be prevented by providing adequate vitamin B12 in the diet, and by using cobalt or antibiotics.
Environmental Stress
Another cause of sudden death in layers is environmental stress, which can affect the physiological and behavioral responses of birds. Some of the most common environmental stressors that can cause sudden death in layers are:
- Heat stress: This is a condition that results from the exposure to high ambient temperature or humidity, which can increase the body temperature and respiratory rate of birds. Heat stress can cause dehydration, electrolyte imbalance, or heat stroke, which can cause symptoms such as panting, spread wings, prostration, and death. According to Poultry Farm Guide, heat stress can be prevented by providing adequate ventilation, cooling, shade, water, and electrolytes, and by reducing stocking density, feed intake, and metabolic heat production.
- Cold stress: This is a condition that results from the exposure to low ambient temperature or wind chill, which can decrease the body temperature and immune function of birds. Cold stress can cause hypothermia, frostbite, or respiratory infections, which can cause symptoms such as shivering, huddling, reduced feed intake, and death. According to Poultry Farm Guide, cold stress can be prevented by providing adequate insulation, heating, lighting, water, and energy, and by increasing stocking density, feed intake, and metabolic heat production.
- Lighting stress: This is a condition that results from the exposure to inappropriate light intensity, duration, or spectrum, which can affect the circadian rhythm, hormonal balance, and reproductive performance of birds. Lighting stress can cause photorefractoriness, photostimulation, or phototoxicity, which can cause symptoms such as reduced egg production, abnormal egg quality, or blindness. According to Poultry Farm Guide, lighting stress can be prevented by providing adequate light intensity, duration, and spectrum, and by using gradual changes, dimmers, or timers.
Genetic Factors
Another cause of sudden death in layers is genetic factors, which can affect the susceptibility or resistance of birds to certain diseases or conditions. Some of the most common genetic factors that can cause sudden death in layers are:
- Ascites syndrome: This is a condition that results from the accumulation of fluid in the abdominal cavity, which can compress the organs and impair their function. It can be caused by high altitude, low oxygen, high metabolic rate, or pulmonary hypertension. Ascites syndrome can cause symptoms such as abdominal distension, cyanosis, difficulty breathing, and death. According to MSD Veterinary Manual, ascites syndrome can be prevented by selecting resistant breeds, reducing growth rate, and improving ventilation.
- Sudden death syndrome: This is a condition that results from the sudden death of apparently healthy birds, which can occur without any warning signs or lesions. It can be caused by cardiac arrest, stroke, fright, or unknown factors. Sudden death syndrome can affect any age or breed of birds, but it is more common in fast-growing broilers or broiler breeders. According to Extension, sudden death syndrome can be prevented by reducing stress, improving nutrition, and avoiding overcrowding.
Conclusion
Sudden death in layers can have various causes, which can affect the health and performance of birds. It is important to identify and address the underlying cause of sudden death in layers to prevent further losses and improve the welfare and productivity of the flock. Some of the most common causes of sudden death in layers are infectious diseases, nutritional deficiencies, environmental stress, or genetic factors. These causes can be prevented or treated by improving biosecurity, sanitation, nutrition, ventilation, lighting, and management practices, and by using antibiotics, vaccines, or supplements when necessary.
