Timing of melatonin treatment: differential effects on oestrus and coat growth in goats

Abstract

To avoid winter scarcity of fresh goat milk, simple methods of advancing the season of kidding would be commercially valuable. A combination of long-day light treatment followed by melatonin is successful but other aspects of seasonality including coat growth are also reset. To investigate whether effects on breeding season and coat growth can be dissociated, British Saanen dairy goats (no. = 30) were randomly allocated to one of six groups. Control goats were untreated.

An analysis of canine hair re‐growth after clipping for a surgical procedure

“…November 15, 2002; http://lwf.ncdc.noaa.gov/ao/ncdc.html– accessed November 2002), the temperature was controlled artificially in the environments where these dogs resided. Temperature fluctuations reported to affect hair growth have ranged from 8 to 10 °C 5,11,18 . The highest variation in temperature throughout the year inside the houses of the dogs in our study was 5.6 °C and, in most of them, the environmental temperature varied by 1 to 3 °C.…”

“…November 15, 2002; http://lwf.ncdc.noaa.gov/ ao/ncdc.html -accessed November 2002), the temperature was controlled artificially in the environments where these dogs resided. Temperature fluctuations reported to affect hair growth have ranged from 8 to 10 ° C. 5,11,18 The highest variation in temperature throughout the year inside the houses of the dogs in our study was 5.6 ° C and, in most of them, the environmental temperature varied by 1 to 3 ° C. As a result, the animals in this study were not exposed to large seasonal variations in ambient temperature except for brief periods when they were let outside. Therefore, it is likely that the modest variations in the proportion of hours of light vs. hours of dark and the mild changes in ambient temperature during the different seasons were not sufficient to affect the time required for hair re-growth on the dogs in our study.…”

“…Important exogenous factors include photoperiod and temperature. These environmental‐related factors control the secretion of melatonin and prolactin, which directly influences the cyclical activity of the hair follicles observed throughout the year 5–10 . It is also believed that photoperiod, with some participation of temperature, can indirectly influence the hair cycle by acting on the hypothalamus‐hypophysis axis and affecting the secretion of steroid and thyroid hormones known to influence the hair cycle activity in humans and animals 11,12 …”

“…These environmentalrelated factors control the secretion of melatonin and prolactin, which directly influences the cyclical activity of the hair follicles observed throughout the year. [5][6][7][8][9][10] It is also believed that photoperiod, with some participation of temperature, can indirectly influence the hair cycle by acting on the hypothalamus-hypophysis axis and affecting the secretion of steroid and thyroid hormones known to influence the hair cycle activity in humans and animals. 11,12 Hair growth and replacement have been studied extensively in humans, sheep and laboratory rodents, but few studies have been published in other mammalian species.…”

The impact of body site, topical melatonin and brushing on hair regrowth after clipping normal Siberian Husky dogs

“…Melatonin is thought to play either a direct or an indirect role in the neuroendocrine control of moulting and hair growth in mammals 13–15 . In dogs, oral melatonin has been used to treat various forms of alopecia, such as recurrent flank alopecia, pattern baldness and alopecia‐X of the Nordic breeds, with variable success 16–19 .…”