Compensatory growth after under-nutrition in market turkeys

Five levels of protein were fed from o to 6 weeks of age, resulting in groups of poults whose body weights at 6 weeks were depressed by 8, 25 and 50 per cent below maximum. After 6 weeks, all groups were fed adequate amounts of protein and the undernourished poults showed substantial compensatory growth. The treatment which resulted in a mean body weight 25 per cent below controls at 6 weeks gave only a 3 per cent reduction in live‐weight at 14 weeks of age.

Undernourished poults ate more food at any given live‐weight between 6 and 14 weeks of age than did fully fed controls when they were at the same live‐weight. Food conversion was better in undernourished than in fully fed poults in the 6 to 14 week period even after a correction had been made for differences in the food required to maintain different body weights.

Taking the whole period from o to 14 weeks, there was a small improvement in the efficiency of food conversion and a large increase in the efficiency of protein conversion to body weight in favour of the poults which had been undernourished to 6 weeks of age.     

The recovery of laying birds from a period of low protein feeding

Laying pullets which had been fed diets containing 7, 8½, 10, 11½, 13 and 14½ per cent crude protein for 10 weeks were returned to a normal diet containing 14½ per cent crude protein. For birds which had received the lowest protein diet, rate of lay improved from about 30 per cent to over 80 per cent in 4 weeks. Egg weight, body weight and food consumption also increased rapidly. In the period from 3 to 20 weeks after restoring a normal diet the pullets which had previously been fed 7 per cent and 8½ per cent crude protein showed a rate of lay and an average egg weight substantially better than that of control birds which had always received the 14½ per cent crude protein diet.

It is concluded that a period of low protein feeding does not impair the subsequent ability of the laying bird to reach normal levels of output. On the contrary, birds which are denied a normal protein intake for a time tend to compensate when returned to normal feeding by laying more eggs and bigger eggs. However, in this experiment, the compensation was not enough to offset the loss in yield incurred during low protein feeding.     

Effects of Vegetation-Free Strip Width and Irrigation on Newly Planted Peach

Field experiments were conducted at two locations (Clayton and Jackson Springs, NC) to determine the influence of vegetation-free strip width (VFSW) and irrigation on newly planted peach growth and yield in a low-density orchard with a volunteer weedy ground cover. The experiments included VFSW of 0, 0.6, 1.2, 2.4, 3, or 3.6 m under irrigated or nonirrigated conditions. Seasonal variation in the orchard floor vegetation was observed as different weed species reported in summer and winter. However, this difference was not apparent with respect to VFSF and irrigation. At Jackson Springs, NC, the predicted irrigated VFSW which would produce the same trunk cross-sectional area (TCSA) as the grower standard (3-m nonirrigated) was 1.5, 1.3, and 0.8 m for one-, two-, and three-year-old trees, respectively. The predicted irrigated VFSW which would produce the same yield as the grower standard was 1.16 m. At Clayton, TCSA and fruit yield were not different by irrigation, but did increase linearly with VFSW. At both locations, leaf nitrogen (N) concentration was lower in irrigated trees than nonirrigated trees. Leaf N, leaf area, and SPAD were positively related to VFSW at Jackson Springs. In contrast, leaf N concentration was not different by VFSW at Clayton. However, leaf area and SPAD were positively related to VFSW at Clayton. These results suggest that a 1.5 m VFSW combined with proper irrigation and fertilization will produce tree growth and yield in newly planted orchard with volunteer weedy vegetation similar to the current grower standard in the southeastern USA.