|Nisbet, David - Dave|
Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/11/2004
Publication Date: 1/20/2005
Citation: Landers, K.L., Woodward, C.L., Li, X., Kubena, L.F., Nisbet, D.J., Ricke, S.C. 2005. Alfalfa as a single dietary source for molt induction in laying hens. Bioresource Technology. 96:565-570. Interpretive Summary: Chickens and other avian species undergo a natural process called molting, where feathers are lost, the reproductive tract shrinks, and the hens quit laying eggs; basically, the hens have a period of rest. This is followed by the growth of a new set of feathers, an increase in the size of the reproductive tract, and the beginning of a second cycle of egg production. In commercial egg production, the hens do not experience molting until the end of a long laying period and the number of eggs and the quality of the eggs decreases as the hens get older. Since it is often economically advantageous to add a second productive egg-laying cycle, producers often induce a molt. Removal of feed and a reduction in the length of time the hens receive light is the primary method used in the layer industry. This method has come under scrutiny because of food safety issues and animal welfare issues, causing much interest in developing molting methods other than feed deprivation to achieve the same benefits without the increased food safety issues and be more acceptable, with respect to animal welfare. This study involved 4 treatment groups: Feeding Alfalfa meal, alfalfa pellets, layer diet (full-fed non-molted control), or feed deprivation for 9 days. Alfalfa meal and alfalfa pellet diets were equally effective in causing a reduction in ovary weights as feed deprivation. Egg production and egg quality from hens molted with alfalfa meal or alfalfa pellets over a 12 week period after molting were similar to hens molted by feed deprivation. This research is important because, based on the results of this study, use of alfalfa meal or alfalfa pellets to molt hens appear to be methods that can be used instead of feed deprivation to get a successful molt with acceptable egg production and quality. Since the hens are not deprived of feed, there should be less stress on the animal and these procedures should be more acceptable from an animal welfare standpoint.
Technical Abstract: Molting is a process by which a hen's reproductive tract is rejuvenated prior to the beginning of a laying cycle. This process is often artificially induced in commercial settings in order to extend the productive life of a flock of hens. The most common method for the induction of molt is feed deprivation for a period of several days. It has been noted that feed deprivation, while effective in inducing molt and allowing an adequate reproductive rest period for the hen, may cause deleterious effects on the animal. This has prompted the investigation of alternatives to feed deprivation for the induction of molt in commercial laying hens. This study involved feeding alfalfa to hens to assess its ability to induce molt as well as to monitor post molt egg production and quality. Alfalfa meal and alfalfa pellet diets were equally effective in causing ovary regression as feed withdrawal. Molted hens induced by alfalfa exhibited post-molt levels of egg production over a twelve week period that were similar to that of hens molted by feed deprivation. The post-molt eggs laid by hens molted by alfalfa were of comparable quality to eggs from feed deprived hens. Alfalfa, a fibrous feed with low metabolizable energy, may be provided to hens on an ad libitum basis for an effective molt induction that retains acceptable egg quality and production.