Light treatment to alter photoperiod response is a well-known synchronization and/or induction method for out-of-season breeding in the dairy goat industry. Artificial lighting is mostly employed for long day simulation, administered as 16 hours of daylight followed by eight hours of darkness. To simulate long days it is not necessary to provide the entire 16-hour light period, but treatment can be divided into the natural daylight period followed by an appropriately timed one hour light stimulus at the time of desired dusk. Most practical systems have focused on the extension of the natural breeding season, combining a period of long days followed by short- day simulation. Use of controlled lighting requires the availability of a light proof barn to house the goats. Time and housing constraints may be impractical for commercial meat goat producers.
Administration of melatonin to mimic altered photoperiod may be an effective alternative to light treatment. The typical protocol includes administering melatonin orally or as an implant for three months. To enhance the effectiveness of a shorter light treatment, a combination treatment of light and melatonin might also be an option.
For additional reading on more treatment options used for out-of-season breeding please follow the link below:
Keywords: light treatment, melatonin, out-of-season breeding, daylight
References: Whitley, N.C. and D. J. Jackson. 2004. An update on estrus synchronization in goats: a minor species. J. Anim. Sci. 82: E270-276E (Proceedings); http://www.luresext.edu/goats/training/reproduction.html