The effect of low protein feeding and realimentation on skeletal growth and proportions in two strains of male Turkey

Synopsis

Two experiments were conducted to study the effect of feeding a low protein diet in early life and subsequent realimentation on skeletal growth and proportions in turkeys. In the first experiment male poults of a “small” strain were fed isocaloric diets containing either 27.0% followed by 25.0% or 19.8% followed by 16.6% crude protein from o to 6 and 6 to 11 weeks of age respectively. At 11 weeks of age regressions of length of lower‐leg and mid‐wing on body weight for the two treatments indicated that normal skeletal proportions were not disturbed by the 11‐week period of moderate undernutrition. Percentage depressions in length of lower‐leg and mid‐wing, due to undernutrition, were 5.3 and 2.5% respectively. These were of a similar order of magnitude as the corresponding depression in the one‐third power of body weight, 3.4%, rather than that of simple body weight, 9.9%. Nutrition did not materially affect individual variation in body weight at n weeks of age, but coefficients of variation for lengths of lower‐leg and mid‐wing tended to be greater for undernourished than for fully‐fed turkeys.

In the second experiment male poults of the same small strain and of a faster‐growing larger strain were fed isocaloric diets containing 26.2 or 16.8% crude protein from 0 to 5 weeks of age. Thereafter all groups were fed the same adequate diets until 21 weeks of age. At 5 weeks of age growth depressions in live‐weight and linear measurements, due to undernutrition, were relatively greater in the faster‐growing strain. In the slower‐growing strain, mid‐wing length of retarded turkeys was appropriate to their body weight at the time; length of lower‐leg was only slightly shorter compared with fully‐fed poults when they were at the same live‐weight. However, skeletal proportions were apparently reduced by undernutrition in the faster‐growing strain. In this experiment low‐protein feeding had no adverse effect on individual variation of body weight or linear measurements in the smaller strain. But the 5‐week period of undernutrition tended to increase variability of live‐weight and bone length in the faster‐growing strain. Neither strain exhibited compensatory gains in live‐weight during the recovery period. This was probably due to an outbreak of sinusitis at about 12 weeks of age. However, this did not prevent recovery of normal bone length, which was completed by about 10 weeks of age in the smaller strain but not until each bone was approaching its mature length in the faster‐growing strain.

Notes

Present address: Loughry Agricultural College, Cookstown, Co Tyrone, N. Ireland.