SKELETAL GROWTH OF COMMERCIAL POULTRY SPECIES

There have been significant increases in growth and development of com mercial broilers, turkeys, and ducks. The large decline in days to mar ket and disproportional increases in breast yield have contributed to greater incidences of various skeletal anomalies. Across all three spe cies, tibial dyschondroplasia is observed about half-way through the g rowing period (50%), but in each case the birds have achieved 40% or l ess of their final BW. Relative tibia development (length and width) i s significantly slower in broilers compared with turkeys and ducks, wh ich suggests a greater susceptibility to biomechanical problems, the e nd result of which is abnormal long bone development. There are relati vely few studies that have addressed changes in the femur as well as t he tibia. There are indications that mineralization rates and other as pects of femur development occur more slowly than what is observed for the tibia. In this regard, the femur may be the weak link with respec t to long bone developmental abnormalities. Nutrient restriction durin g short periods of the growout has proven to be an effective way of de creasing leg abnormalities. In all cases, however, there are correspon ding declines in BW at normal market ages and associated declines in a bsolute breast muscle development. In the future, however, these fract ional losses in measures of carcass yield may still be economically ad vantageous compared with the cost of increased leg problems under fiel d conditions.