author(s)
Pratik R Wankhade, Diwakar, Vimlesh Kumar, Amol J Talokar, Ganesh N Aderao, Cherryl D Miranda and Diksha P Gourkhede

abstract
Photoperiod is defined as the duration of light an animal is exposed to within a 24-hour period or more precisely the relative duration of light and dark that an animal experiences within a 24 h period. The light is received through eyes, stimulates retinal photoreceptors that transmit an inhibitory signal to the pineal gland for the secretion of melatonin through a series of an endogenous process via the retino-hypothalamic tract. The melatonin hormone plays a significant role in the regulation of the circadian as well as of the annual rhythms in many species, from the more primitive species to man. There is an association of photoperiod length with the growth of calves and heifers along with the mammary tissue growth in heifers. The manipulation of photoperiod during lactation and dry period can offer an effective, non-invasive approach to stimulate the productive performance of seasonal animals like buffaloes. Though buffaloes are polyestrous in nature, their reproductive efficiency varied throughout the year. Reproductive seasonality does not seem to depend on diet, food availability or metabolic status, while it depends on climate and particularly on the photoperiod. However, there is a dispute regarding the effect of supplementary artificial light and features as duration and intensity on all aspects of dairy animal’s behavior.