Submitted to: Poultry Science
Publication Type: Abstract Only
Publication Acceptance Date: 4/18/2008
Publication Date: 7/20/2008
Citation: Cheng, H., Lay Jr, D.C., Marchant-Forde, R., Pajor, E. 2008. Effects of alternatives of molting on bird well-being [abstract]. Poultry Science. p. 129.
Technical Abstract: Induced molting by feed withdrawal may cause stress in birds and affect bird well-being. The objective of this study was to develop a welfare friendly alternative for molting by evaluating the effects of currently available molting alternatives on bird stress responses and well-being. One thousand, two hundred 60-wk-old hens were used in the study. The hens were housed in 2-bird cages, and randomly assigned into one of the five treatments: control (C); feed withdrawal (FW); low energy diet (LE), low salt (LS); and melengestrol acetate (MGA, at 4mg/hen/day). The lighting schedule was 8:16 h (light:dark). The birds were on the treatment for 26 days. For the FW treatment, feed was withdrawn from the birds for 9 days, followed by grower diet for 17 days, and then returned to layer ration; and for all other treatments, the relative diet were used up to 26 days. Physical and physiological changes were analyzed at various periods of time during the molting. Compared to the controls, body weight (BW) was significantly reduced in the birds from all treated groups except MGA (P>0.05). BW loss in the FW treated birds started at 3 days post-treatment (P<0.01), reached a peak at 9 days (P<0.001), and then recovered after feeding with grower diet (P>0.05); while LE and LS treated birds’ BW did not reach a significant loss until 9 days post-treatment (P<0.01), and did not fully recover up to 26 days post-treatment in LE treated birds (P=0.07). The changes of blood glucose concentrations were paralleled to the changes of BW. The FW treated birds had lower levels of glucose at both 3 and 9 days post treatment (P<0.05, and 0.01, respectively), which was recovered following feeding with grower diet; while LS treated birds had a significantly lower glucose concentration at 9 days post-treatment (P<0.05), which did not recover during the period of molting (P<0.05); and LE treated birds had a tendency for a lower glucose concentration from 9 to 17 days during the molting (P=0.052). These results suggest that MGA could be used as a welfare-friendly alternative for molting. The results also provide evidence that it is valuable to further examine if low energy diet fed birds are still hungry.