Submitted to: International Poultry Forum Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 11/1/2004
Publication Date: 1/24/2005
Citation: Murase, T., Sato, T., Miyahara, S., Otsuki, K., Holt, P.S. 2005. Comparison of effects of induced molting through feeding of wheat middlings or feed withdrawal on humoral immunity of laying hens in a commercial egg-laying farm. International Poultry Forum Proceedings. Interpretive Summary:
Technical Abstract: While induced molting provides the benefit of extending the effective egg-laying life of the flock, an altered immune response has previously been observed in birds subjected to experimentally induced molting through feed withdrawal (FW). Recently, it was demonstrated that feeding layers wheat middlings (WM), as an alternative method to FW, could successfully molt birds. In the present study, antibodies in sera of commercial layers subjected to molting through feeding of WM were compared with those molted through FW. All the flocks were given Newcastle disease (ND) vaccine through drinking water 3 to 4 times at 3- to 5-month intervals. Production of antibodies in sera was calculated by titrating HI titers against ND virus strain La Sota. Flocks 1 to 4 were molted through 11- or 12-day FW and flocks 5 and 6 were molted through 25-day feeding of WM. In flocks 3, 4, and 5, birds were vaccinated when the birds restarted egg lay after molt while flocks 1, 2 and 6 did not receive this postmolt vaccination. Sera were obtained at the following times: before the molting treatment; when the birds went totally out of egg production after the treatment; when the birds restarted laying after they returned to feed, and when the egg production reached a plateau. Among the flocks receiving ND vaccine only prior to molt, a mean titer in sera obtained from flock 6 given the WM were unchanged through the period, whereas titers in sera from flock 2 treated by FW decreased after the birds restarted egg lay. Among the flocks receiving ND vaccine before and after molt, a mean of the last titers in sera from flock 5 given the WM increased, whereas those in sera from flock 3 and 4 treated with FW were unchanged. These results suggest that molting via feeding WM exerts minimal negative effects on antibody production against ND vaccine compared with FW. Key words: induced molting, wheat middling, feed withdrawal, Newcastle disease vaccine, humoral antibody.