SKELETAL INTEGRITY IN LAYERS AT THE COMPLETION OF EGG-PRODUCTION

Skeletal integrity of end-of-lay birds is becoming a major concern for both egg producers and meat processors. Osteoporosis induced by conti nual demands for shell calcification causes loss in skeletal integrity as the layer gets older. This loss in bone structure, coupled with mi nimal exercise, leads to very fragile bones in older birds. Bone break age as high as 20% has been reported in birds entering the processing plant, while some degree of bone breakage is found in a much higher pr oportion of eviscerated carcasses. Bone breakage on the farm, during t ransport and subsequent handling is obviously a welfare concern, while processors are also concerned about bone contamination of meat produc ts. Factors affecting the development of osteoporosis are discussed an d include genetics, level of egg production, environment and nutrition . There is no simple solution to the problem in terms of long-term or short-term nutritional modification. In the case of caged birds, bone strength characteristics can be improved by removing them to other sys tems for a period of time prior to transport, although this is rarely a commercial solution. However, so-called alternative housing systems are themselves responsible for skeletal defects in some birds.