Multiphasic mixed growth models for turkeys.

Turkeys have been bred for several purposes over the past decades. We studied growth patterns of turkeys of two genetic lines bred for either meat production or egg production. Mathematical equations were designed and fitted to describe the average bodyweight of several consecutively grown groups of turkeys. Similarly, individual body weight was measured and studied in one group of male turkeys, to detect differences in growth patterns between individual turkeys. It showed that there were differences between both sexes as well as between both lines in the shape of the growth curve. The age at which males and females grew fastest was similar between meat production and egg production type turkeys, for males around 13 to 14 wk and for females around 10 to 11 wk. Males of the meat production line grew 6.5 kg heavier than males of the egg production line, whereas females of the meat production line grew 3.8 kg heavier than females of the egg production line. Individual turkeys that have a heavier mature weight grow at a slower pace and delay the growth spurt associated with sexual maturation. With these outcomes, turkey feed producers and genetic companies can better study and steer the desired growth of turkeys.