Western
Meeting of Poultry
Clinicians and Pathologists
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Clinicians and Pathologists
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Sudden Increase in Mortality in Broiler and Broiler Breeder Chicks S.J. Ritchie Canadian Poultry Consultants Ltd.
Case 1: A broiler farm consisting of two barns, on barn housing 4,300 and the 2nd housing 17,000 birds, reported higher than normal mortality, especially the smaller barn. At three days of age, six hundred chicks out or 4,300 were found dead. A sample of 25 chicks was submitted for necropsy. The majority of the chicks showed omphalitis and yolk sac infection. No pericarditis was noted. A swab from the yolk sac revealed the presence of a heavy growth of E. coli. The E. coli was found to be sensitive to enrofloxacin only. Treatment was not recommended. On day 4, it was noted that 7 chicks were found dead in the small barn. On day five, while the grower was gathering mortality in the small barn, he witnessed 100 percent of the chicks drop down, necks extended and die. The grower immediately called the feed and hatchery service persons, who immediately called the veterinarian. On arrival at the farm, inspection of the larger barn revealed chicks that were bright, alert and active. Inspection of the smaller barn revealed 100 percent mortality (one cull chick in a bucket was alive). The door was left open while chick samples were taken. Necropsy at the farm revealed pulmonary congestion. Samples of chicks were retrieved for submission to the Animal Health Centre Diagnostic Laboratory. Pulmonary edema was found. At the farm, 25 chicks were removed from the larger barn and placed in the smaller barn. All 25 chicks died within 20 minutes. This was repeated with the same results. The forced air furnace was removed and a different heater was put in place. A small sample of chicks were placed in the barn again and appeared normal after one hour. A decision was made to re-stock the small barn on the same litter with the different space heater installed. The original flock in the large barn and the replacement flock in the small barn, when shipped, performed extremely well. The heater was examined by B.C. Hydro and no problems were detected. Tentative diagnosis: Anoxia or respiratory toxin. Questions to be answered: What killed these chicks? Should the grower attempt to use this heater again as the gas company indicated that the heater was functioning normally? What safety precautions were learned? Case 2: A broiler breeder farm reported high mortality in 3-day-old chicks, both male and female. A sample of chicks were necropsied at the farm and a tentative diagnosis of dehydration was made. The ureters were obvious, the gall bladders were distended, pericardial gout was noted in a small percentage of the necropsied chicks, and the yolk sacs appeared normal. The chicks were scheduled to arrive Friday morning, however, they were not placed until very late Friday. On day four, mortality increased significantly to 40 percent of females and 10 percent of males. Necropsy of a sample of chicks on day five revealed a significant number of chicks with anasarca. Inspection of the brood layout revealed ample access to feed, water and heat. Brood conditions were considered excellent. The majority of the chicks were bright, alert and active. Each brood ring was supplied with water via a common line of nipple drinkers. Gallon founts, and egg flats containing extra water were also used. The egg flats were added by the producer in view of the fact that these chicks were held up in transit. Inspection of the water in the gallon founts and the egg flats revealed a strong orange colour and a salty taste. The water in the nipple drinkers was supplied directly from a well and was hooked up to a proportioner, this water appeared normal. The stock solution consisted of 4 gallons of water and approximately 400 grams of a commercial soluble vitamin. The producer then indicated that the stock water solution was used directly in the gallon founts and the egg flats. Inspection of the commercial vitamin product revealed that product consisted of a significant amount of sodium chloride and other sources of sodium. A sample of the water/vitamin solution and feed was submitted for sodium analysis and on-farm samples of water and feed were administered to a small group of chicks and 100percent mortality resulted. No evidence of anasarca was noted in these birds, only obvious ureters and pulmonary congestion. The feed and water were assayed: 0.70 percent sodium chloride was found in the feed and 2.00 percent sodium chloride was found in the water. Definitive diagnosis: Salt toxicosis. Questions to be answered: What long-term effect would this incidence have on the performance of this flock in terms of production and hatchability? Should nutrition via the drinking water be objectively evaluated? What benefits are salts (electrolytes) to baby chicks or to poultry in general? Should the vet taste feed and water to help diagnosis? |
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