The effect of the oral administration of melatonin at two times of the year on ovarian activity in ewes

1986 ◽  
Vol 1986 ◽  
pp. 53-53 ◽  
Author(s):  
S. Wigzell ◽  
J. J. Robinson ◽  
R. P. Aitken ◽  
W. A. C. McKelvey
Keyword(s):  
Oral Administration ◽  
Breeding Season ◽  
Daily Administration ◽  
Ovarian Activity ◽  
Melatonin Treatment ◽  
Breeding Activity ◽  
Normal Period

It has previously been shown (Robinson et al., 1985) that the normal breeding season of Greyface and Scottish Blackface ewes can be advanced by the daily administration of the indoleamine melatonin; the administration of the melatonin beginning midway during the anoestrous period. If melatonin is administered towards the end of the normal breeding season, oestrous activity can be extended, but only for a period of about six weeks until the ewe becomes refractory to the melatonin treatment (Nett and Niswender, 1981). There is no information on the administration of melatonin at the beginning of the anoestrous period.In the following experiments we report results for the influence on the subsequent breeding activity of Greyface ewes of the oral administration of melatonin at the beginning of their normal period of anoestrus. We also report the results of an investigation on the effects of melatonin in advancing the breeding season of Scottish Blackface ewes maintained on either a high or low plane of nutrition. The experiments were carried out under natural daylength conditions at 57°N.

Duration of melatonin treatment and ovarian activity in ewes

1988 ◽  
Vol 1988 ◽  
pp. 92-92
Author(s):  
S. Wigzell ◽  
J.J. Robinson ◽  
J.M. Wallace ◽  
R.P. Aitken
Keyword(s):  
Breeding Season ◽  
Ovarian Activity ◽  
Similar Reaction ◽  
Melatonin Treatment ◽  
Oral Dosing ◽  
Starting Time ◽  
Highly Effective ◽  
Natural Photoperiod ◽  
The Mean

Daily oral dosing in mid afternoon with 3 mg of the indoleamine, melatonin, from early June onwards is highly effective in advancing the breeding season of both Greyface and Scottish Blackface ewes kept under a natural photoperiod; the mean reaction interval from initial dosing to the onset of ovarian activity in Scottish Blackface ewes being around 65 days compared with 110 days for untreated controls (Robinson et al 1985). Advancing the starting time for the melatonin treatment to mid-March gave a similar reaction interval with behavioural oestrus occurring in late May/early June (Wigzell et al 1986a). Following this reversal of the breeding season by melatonin, continued melatonin treatment in unmated ewes resulted in a period of oestrous cyclicity lasting 4 to 5 months. Thereafter the ewes became refractory to melatonin and returned to anoestrus at a time when untreated controls were commencing ovarian activity (Wigzell et al 1986b). These observations prompted us to investigate the effects of different durations of melatonin treatment on ovarian activity.

HORMONAL CONTROL OF REPRODUCTION IN EWES DURING THEIR NORMAL BREEDING SEASON

1967 ◽  
Vol 47 (1) ◽  
pp. 71-76
Author(s):  
Sheikh Saif-Ur Rahman ◽  
W. D. Kitts
Keyword(s):  
Oral Administration ◽  
Breeding Season ◽  
Dosage Level ◽  
Hormonal Control ◽  
Post Treatment ◽  
Breeding Activity ◽  
Intramuscular Injections

Injected or orally-administered progestagens have been shown to synchronize estrus in mature ewes during their normal breeding season. Oral administration of 6–methyl-17-αα-acetoxyprogesterone (MAP) or 6-chloro-Δ6-dehydro-17-acetoxyprogesterone (CAP) for 10 days was more effective in synchronizing estrus than intramuscular injections of repositol progesterone. CAP appeared to be more active in controlling breeding activity than MAP (2.5 mg CAP per head vs. 60 mg MAP per head). The administration of 2.5 mg CAP per head per day for 18 days was as effective as the feeding of 3.5 mg per head per day for 10 days. CAP, at a dosage level of 2.5 mg, administered over a 10-day period to motivate first post-treatment estrus, was more effective when injected intramuscularly than when administered orally. The administration of Pregnant Mare Serum did not result in an increase of lambing percentage.

The influence of the stag on pubertal development in the red deer hind

1995 ◽  
Vol 60 (3) ◽  
pp. 503-508 ◽  
Author(s):  
M. W. Fisher ◽  
L. M. Meikle ◽  
P. D. Johnstone
Keyword(s):  
Breeding Season ◽  
Social Factors ◽  
Red Deer ◽  
Pubertal Development ◽  
Ovarian Activity ◽  
Melatonin Treatment ◽  
Timing Of Puberty

AbstractThe possible influence of social factors on the timing of puberty in the hind was investigated utilizing seasonally advanced (melatonin-treated) hinds and stags. Melatonin treatment of both sexes resulted in a significant advancement in the onset of pubertal ovarian activity (26 days, P < 0·001) and calving (27 days, P < 0·001) in the treated hinds and antler casting (25 days, P < 0·001) in the treated stags. Ovarian activity and calving were not influenced by melatonin treatment of the stags alone and similarly, antler casting was not affected by melatonin treatment of the hinds alone. However, a group of hinds without stags until after the onset of the breeding season, reached puberty later (5 days, P < 0·05) than hinds with stags, suggesting the presence of the male is important in determining the timing of puberty.

A preliminary report on regulation of oestrus and fertility in cyclic ewes by an oral administration of 6-methyl-17-acetoxyprogesterone

1963 ◽  
Vol 3 (8) ◽  
pp. 78 ◽  
Author(s):  
EM Roberts ◽  
BM Bindon ◽  
PM Houlahan
Keyword(s):  
Oral Administration ◽  
Breeding Season ◽  
Preliminary Report ◽  
Preliminary Investigation ◽  
Ovarian Activity ◽  
Wheat Group ◽  
Conception Rates ◽  
Group 1

A preliminary investigation has been carried out to test the value of 6-metbl-17-acetoxjprogesteron (MAP) as a suppressor of ovarian activity. The progesterone derivative (MAP) was given to Merino ewes for 16 days during the breeding season. It was fed at s rate of 50 mg a day in 1/2 lb crushed wheat (group 1) or administered in capsule form at the rate of 50 mg a day (group 2a), 100 mg every two days (group 2b) or 200 mg every four days (group 2c). Suppression and synchronization of oestrus and conception were satisfactory in group 1, 2a and 2b, but not in 2c. In groups 1, 2a and 2b, 37 ewes were treated, 30 (eighty one per cent) muted in a space of three days and 25 (sixty eight per cent) of these. were found pregnant at slaughter. These results suggest that administration of MAP at a rate of 100 mg every two days will be followed by satisfactory synchronization of oestrus and normal conception rates.

The effect of the presence of the ram on the ovarian activity of the ewe.

1954 ◽  
Vol 5 (3) ◽  
pp. 465 ◽  
Author(s):  
PG Schinckel
Keyword(s):  
Breeding Season ◽  
Primary Effect ◽  
Ovarian Activity ◽  
Peak Incidence ◽  
Breeding Activity

Observations were made on the effect of the presence of the ram when introduced to Merino ewes in the transition from the "non-breeding" to the "breeding" season in the Roseworthy environment. These observations showed that the primary effect was to stimulate ovulation without oestrus ("silent heat") in the majority of those ewes which had not already commenced cyclic breeding activity. This effect occurred within 6 days of joining the rams with the ewes. It is concluded that this mechanism explains the "lag and peak" incidence of oestrus previously observed under these conditions (Underwood, Shier, and Davenport 1944; Thompson and Schinckel 1952; Schinckel 1954).

Daily administration of a GnRH analogue enhances sperm quality in bucks during the non-breeding season

2019 ◽  
Vol 200 ◽  
pp. 43-50 ◽  
Author(s):  
Julia Giriboni ◽  
Özdal Gökdal ◽  
Vadullah Eren ◽  
Engin Yaralı ◽  
Julián Santiago-Moreno ◽  
...  
Keyword(s):  
Breeding Season ◽  
Sperm Quality ◽  
Daily Administration ◽  
Gnrh Analogue

The effect of melatonin treatment during the seasonal anoestrus on the superovulatory response and embryo production of high-prolificacy Rasa Aragonesa ewes before culling

2003 ◽  
Vol 2003 ◽  
pp. 82-82
Author(s):  
F. Forcada ◽  
J.A. Abecia ◽  
J.A. Valares
Keyword(s):  
Embryonic Development ◽  
Breeding Season ◽  
Litter Size ◽  
Direct Effect ◽  
Ovulation Rate ◽  
Corpora Lutea ◽  
Melatonin Treatment ◽  
Embryo Production ◽  
Spring Equinox

The efficacy of melatonin implants inserted around the spring equinox to improve fertility and ovulation rate or litter size in Mediterranean ewes has been previously reported (Chemineau et al., 1996; Forcada et al., 2002a.), indicating the ability of the hormone to regulate the hypothalamic activity (Viguié et al., 1995). Moreover, a direct effect of melatonin on corpora lutea and embryonic development has been also reported (Wallace et al., 1988; Abecia et al., 2002). The use of prolific Rasa Aragonesa (RA) ewes (a Mediterranean breed) before culling as embryo donors has been previously tested in the breeding season (Forcada et al., 2002b.). The aim of this experiment was to improve embryo production during the seasonal anoestrus period in selected superovulated RA ewes at the end of their reproductive lives through the use of melatonin.

scholarly journals Suppression of ovarian activity during the breeding season in suckling Japanese monkey (Macaca fuscata)

Reproduction ◽  
1991 ◽  
Vol 92 (2) ◽  
pp. 371-375 ◽  
Author(s):  
K.-I. Maeda ◽  
H. Tsukamura ◽  
S. Ohkura ◽  
T. Kanaizuka ◽  
J. Suzuki
Keyword(s):  
Breeding Season ◽  
Macaca Fuscata ◽  
Japanese Monkey ◽  
Ovarian Activity

Effect of melatonin treatment on semen parameters and endocrine function in Black Racka rams out of the breeding season

2014 ◽  
Vol 116 (2-3) ◽  
pp. 192-198 ◽  
Author(s):  
I. Egerszegi ◽  
P. Sarlós ◽  
J. Rátky ◽  
L. Solti ◽  
V. Faigl ◽  
...  
Keyword(s):  
Breeding Season ◽  
Endocrine Function ◽  
Semen Parameters ◽  
Melatonin Treatment

An intraruminal soluble glass bolus containing melatonin — a potential system for early lamb production

1997 ◽  
Vol 1987 ◽  
pp. 25-25
Author(s):  
A.L. Poulton ◽  
A.M. Symons ◽  
M.I. Kelly ◽  
J. Arendt
Keyword(s):  
Seasonal Changes ◽  
Commercial Application ◽  
Economic Pressure ◽  
Melatonin Secretion ◽  
Melatonin Treatment ◽  
Neural Signal ◽  
Breeding Activity ◽  
Soluble Glass ◽  
Potential System ◽  
The Hours

Seasonal changes in daylength (photoperiod) are effectively monitored by the eye transmitting a neural signal to the pineal gland which responds by secreting a hormone, melatonin, during the hours of darkness. Decreasing daylength is accompanied by an increase in the duration of melatonin secretion and stimulates breeding activity in sheep.It has been demonstrated that both timed (afternoon feeding and injection) and continuous (subcutaneous and vaginal implant) administration of supplementary melatonin to ewes in mid-summer mimics the effect of short or decreasing photoperiod and can advance the onset of breeding activity. Such treatments can also increase relative fecundity at early mating by phase-advancing the mid-breeding season peak in ovulation rate. As the U.K. is not sufficient in lamb production and bearing in mind the economic pressure for early lamb marketing, effective melatonin treatment offers considerable potential for commercial application.

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