Effect of early photostimulation at 15-weeks of age and everyday spin feeding on broiler breeder performance.

To prevent broiler breeders from growing too quickly and becoming too large for optimum reproduction, their dietary intake is restricted. While current restricted feeding programs, such as skip-a-day feeding (SAD), improve the economic efficiency of broiler breeder operations, this management practice impacts bird welfare. There is an interest in finding strategies that could reduce the impact of feed restriction during broiler breeder rearing. This research investigated the effects of feeding pullets on an advanced growth curve for early photostimulation at 15 wk (15P) or standard growth curve for photostimulation at 21 wk (21P), using either an every-day-spin feeding program (EDS) or SAD feeding, on the reproductive parameters of broiler breeder hens in a 2 × 2 factorial arrangement. Overall, advancing the growth curve (15P) decreased blood corticosterone levels compared to 21P, but EDS resulted in higher blood corticosterone levels compared to SAD. At the end of rearing in both 15P and 21P, EDS pullets weighed less than SAD pullets. The onset of egg production was 20 and 24 wk of age for the 15P and 21P hens, respectively. Despite an earlier onset, 15P hens did not produce more eggs than 21P hens through 65 wk of age. Egg weight was reduced for 15P compared to 21P until 30 wk of age. The 15P hens had a greater number of double yolk eggs than the 21P hens. Fertility and hatch were not impacted by the advanced growth curve and early photostimulation. Although the current research indicates the potential to reduce feed restriction associated welfare issues by rearing broiler breeder pullets for an earlier photostimulation onset, further research in needed to determine if this management technique can be improved to optimize hen reproductive efficiency.

A model for polygenic inheritance of abdominal tergal scale pattern in Aedes aegypti.

There is much variation in the amount of white scaling on the abdominal tergites of Aedes aegypti. The genetic basis for this white scale pattern was investigated in two laboratory strains established by selection from the CARN Strain of Ae. aegypti. These experimental strains were crossed in all possible directions in single pair matings. Based on analysis of their progeny it is proposed that genes at three separate independently assorting loci control abdominal tergal scale pattern. Correlation of observed data and expected data was high. Since the abdominal tergal scale pattern in Ae. aegypti appears to be controlled by one major polygenic system with modifiers, it is proposed that it is better to consider differences in ethology, physiology, and reproductive behavior as the bases for separation of the species into intraspecific groups.