Calcium Toxicosis in Broiler Chicks

Abstract

A number of food ingredients and other feed additives are used routinely in formulating poultry rations. Some of these additives are used to produce a premix which is added to the feed at a prescribed concentration level, and others are added individually at the feed mixer. Although the majority of poultry feeds are made to specifications, errors are occasionally made. Limestone and dicalcium phosphate are generally added to poultry rations as a dietary source of calcium and phosphorus. When added at the correct concentration, no harm results. High dietary calcium concentrations, however, have been implicated as a cause of nephrosis and visceral gout. Young et al. reported hyperuricemia and hypophosphatemia in pullets fed a ration containing 3.0% calcium (2). Nephrosis with renal failure and visceral gout have been produced in 16-week-old pullets consuming rations containing 3.0% calcium and 0.4% phosphorus (3). This report describes two cases in which large numbers of young chicks died after consuming feeds containing high concentrations of calcium. The first case involved 25,000 broiler chickens eleven days old. The birds were housed in a conventional broiler house with a dirt floor and Saran curtains on the side walls. The litter was pine shavings. The house was equipped with a chain feeder and 8-ft.long automatic drinkers. Feeder lids and one-gallon water jars were used to brood the chicks. Mortality began in this flock when the chicks were three days old and continued until the flock was two weeks old. Clinical signs