Reproductive physiology of the stallion. VIII. Artificial photoperiod, collection interval and seminal characteristics, sexual behavior and concentrations of LH and testosterone in serum.
نویسندگان
چکیده
Stallions were subjected to a gradually increasing photoper iod beginning on October 15, 1973. The maxi,mum artificial daylength (16 hr) was imposed on February 8, 1974, and maintained until October 6, 1974. Two ejaculates were collected from each of five treated and four control stallions weekly, with an interval of 24 hr between the paired ejaculates on the first and alternate weeks, and an interval of 1 hr on the second and alternate weeks. During summer, stallions subjected to the artificial photoper iod produced less (P<.05) gel-free semen and gel per ejaculate and had more (P<.05) spermatozoa per ml of gel-free semen than untreated stallions. Consistent differences due to artificial photoper iod were not observed for spermatozoa per ejaculate or percentage of motile spermatozoa. Light t reatment did not affect mounts per ejaculate or seminal pH, but stimulation time was reduced (P~.05) in treated stallions during late winter. Mean concentration of LH in the serum of untreated stallions varied (P<.01) over t ime and appeared to be highly seasonal. A corresponding change in concentration of testosterone was not observed (P>.05). Mean concentrations of both LH and testosterone were greater (P<.05) in the serum of treated stallions than in
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ورودعنوان ژورنال:
- Journal of animal science
دوره 44 4 شماره
صفحات -
تاریخ انتشار 1977