Effect of melatonin implants on reproductive performance in ewes

1988 ◽  
Vol 1988 ◽  
pp. 51-51
Author(s):  
W. Haresign ◽  
A.R. Peters ◽  
G.M. Webster ◽  
J.W.B. King ◽  
L.D. Staples
Keyword(s):  
Pineal Gland ◽  
Breeding Season ◽  
Reproductive Performance ◽  
Present Experiment ◽  
Reproductive Activity ◽  
Breeding Cycle ◽  
Melatonin Secretion ◽  
Neural Signal ◽  
Retinal Photoreceptors ◽  
Subcutaneous Implant

It has been known for many years that the annual breeding cycle of the sheep is controlled by photoperiod. More recently it has become apparent that this process involves the pineal gland. Light is effectively monitored by retinal photoreceptors within the eye which transmit a neural signal to the pineal gland, and this in turn responds by secreting melatonin during the period of darkness. As daylength decreases in the autumn, the duration of elevated melatonin secretion increases, and this changing ratio of high:low melatonin during each 24h period stimulates breeding activity.Both timed (by afternoon feeding or injection) and continuous (by subcutaneous or vaginal implant) administration of exogenous melatonin to ewes in mid-summer have recently been shown to mimic the effects of decreasing photoperiod by advancing the onset of the breeding season. The present experiment was undertaken to investigate the ability of a subcutaneous implant of melatonin to manipulate reproductive activity of ewes under field conditions in the U.K.

Association between melatonin receptor 1A (MTNR1A) gene polymorphism and the reproductive performance of Mediterranean Italian buffaloes

2012 ◽  
Vol 24 (7) ◽  
pp. 983 ◽  
Author(s):  
S. Luridiana ◽  
M. C. Mura ◽  
M. Pazzola ◽  
M. Paludo ◽  
G. Cosso ◽  
...  
Keyword(s):  
Gene Polymorphism ◽  
Genetic Marker ◽  
Breeding Season ◽  
Reproductive Performance ◽  
Reproductive Activity ◽  
Allelic Frequency ◽  
Genotypic Frequency ◽  
Melatonin Receptor ◽  
Reproductive Seasonality ◽  
Long Photoperiod

A melatonin receptor 1A (MTNR1A) gene polymorphism in adult buffaloes has been reported to affect reproductive seasonality. Consequently, the aim of the present study was to assess whether this polymorphism can affect age at first conception and the interval between first and second calving in Mediterranean Italian buffaloes. The allelic frequency of the C and T alleles was 0.44 and 0.56, respectively, whereas the genotypic frequency was 26% for C/C, 40% for C/T and 34% for T/T. The average age at first mating was approximately 20 months, whereas that at calving was approximately 32 months. The largest number of calvings of primiparous buffaloes was recorded between June and October. No associations between genotype, first mating and subsequent calving date were found. The duration from first to second calving was longer in buffaloes with the C/C genotype compared with those with the T/T and C/T genotypes (P < 0.01). The period of calving for buffaloes with the C/C genotype was mainly from July to September, whereas that for buffaloes with the T/T genotype was largely from March to May. The MTNR1A gene had no effect on the age of first conception in Mediterranean Italian buffaloes. Rather, the association between the T/T genotype and reproductive activity during days with a long photoperiod indicates that this polymorphism may be considered a genetic marker to identify buffaloes that are able to reproduce out of the breeding season.

scholarly journals Negative regulation of melatonin secretion by melatonin receptors in ovine pinealocytes

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0255249
Author(s):  
Julie Lépinay ◽  
Catherine Taragnat ◽  
Jean-Philippe Dubois ◽  
Didier Chesneau ◽  
Ralf Jockers ◽  
...  
Keyword(s):  
Pineal Gland ◽  
Negative Regulation ◽  
G Protein Coupled Receptors ◽  
Melatonin Receptors ◽  
Camp Production ◽  
Melatonin Secretion ◽  
Adrenergic Agonist ◽  
Retinal Photoreceptors ◽  
First Time ◽  
G Protein Coupled

Melatonin (MLT) is a biological modulator of circadian and seasonal rhythms and reproduction. The photoperiodic information is detected by retinal photoreceptors and transmitted through nerve transmissions to the pineal gland, where MLT is synthesized and secreted at night into the blood. MLT interacts with two G protein-coupled receptors, MT1 and MT2. The aim of our work was to provide evidence for the presence of MLT receptors in the ovine pineal gland and define their involvement on melatonin secretion. For the first time, we identified the expression of MLT receptors with the specific 2-[125I]-MLT agonistic radioligand in ovin pinealocytes. The values of Kd and Bmax are 2.24 ± 1.1 nM and 20 ± 6.8 fmol/mg. MLT receptors are functional and inhibit cAMP production and activate ERK1/2 through pertussis toxin-sensitive Gi/o proteins. The MLT receptor antagonist/ inverse agonist luzindole increased cAMP production (189 ± 30%) and MLT secretion (866 ± 13%). The effect of luzindole on MLT secretion was additive with the effect of well-described activators of this pathway such as the β-adrenergic agonist isoproterenol and the α-adrenergic agonist phenylephrine. Co-incubation of all three compounds increased MLT secretion by 1236 ± 199%. These results suggest that MLT receptors are involved in the negative regulation of the synthesis of its own ligand in pinealocytes. While adrenergic receptors promote MLT secretion, MLT receptors mitigate this effect to limit the quantity of MLT secreted by the pineal gland.

STUDIES ON THE DURATION OF THE BREEDING SEASON AND PHOTOREFRACTORINESS IN FEMALE FERRETS PINEALECTOMIZED OR TREATED WITH MELATONIN

1976 ◽  
Vol 70 (2) ◽  
pp. 255-262 ◽  
Author(s):  
PENELOPE A. THORPE ◽  
J. HERBERT
Keyword(s):  
Pineal Gland ◽  
Breeding Season ◽  
Prolonged Exposure ◽  
Breeding Cycle ◽  
Summer Solstice ◽  
Short Days

SUMMARY Oestrous ferrets became anoestrous on exposure to short photoperiods (8 h light: 16 h darkness, 8L:16D) at the summer solstice, and this effect was prevented by pinealectomy. Removal of the pineal alone did not alter the duration of oestrus in animals kept in natural daylight. Melatonin (1 mg, thrice weekly) given to oestrous ferrets kept in daylight also terminated oestrus prematurely. Animals made photorefractory by prolonged exposure to long photoperiods (14L:10D) became photosensitive again if either given melatonin or transferred to short photoperiods (8L:16D) for 7 weeks. These findings show that the pineal gland of the oestrous ferret is involved in the termination of oestrus when the animal is exposed to experimental short photoperiods. This is in addition to its role in inducing oestrus when anoestrous animals are exposed to long days, an effect shown previously. Thus, neither phase of the annual breeding cycle is altered by experimental lighting regimes in pinealectomized animals. Furthermore, some of the effects of short days (but not of long days), including that on photosensitivity, can be replicated by melatonin in the ferret.

scholarly journals Effects of management system on beef heifer growth and reproductive performance

2020 ◽  
Author(s):  
Parker A Henley ◽  
Frank A Ireland ◽  
Igor F Canisso ◽  
J Lannett Edwards ◽  
Daniel W Shike
Keyword(s):  
Development Strategy ◽  
Breeding Season ◽  
Reproductive Performance ◽  
Body Condition Score ◽  
Pregnancy Rates ◽  
Fescue Toxicosis ◽  
Soybean Hulls ◽  
Randomized Design ◽  
Condition Score ◽  
Calf Performance

Abstract This study evaluated the effect of heifer development system on body weight (BW), body condition score (BCS), fescue toxicosis symptoms, reproductive performance, and subsequent calf growth of fall-calving beef heifers. Angus × Simmental heifers [n = 399; 240 ± 20.0 kg initial BW; age = 252 ± 20 d] were stratified by BW and BCS and assigned to 1 of 12 groups in each of the 2 production years. The study utilized a stratified randomized design. Pens were randomly assigned to 4 treatments: drylot (DL) development (fed ad-libitum diet consisting of 90% hay and 10% DDGS on a dry matter basis), grazing endophyte-infected fescue supplemented daily (2.3 kg as-fed/heifer/d; 50:50 mix of soybean hulls and DDGS; E+/S), grazing endophyte-infected fescue and supplemented from the midpoint of treatment period until breeding (4.5 kg as-fed/heifer/d; 50:50 mix of soybean hulls and DDGS; E+/LS), and grazing novel endophyte-infected fescue with no supplement (NE+/NS). Treatments ceased on d 168 [time of artificial insemination (AI)] and heifers were commingled and managed as a group through second breeding season. Heifers in DL had greatest (P ≤ 0.05) BW and BCS from d 28 until d 254. Furthermore, E+/S heifers had greater (P ≤ 0.05) BW and BCS than both E+/LS and NE+/NS from d 28 until d 168. On d 56 and 84, E+/LS heifers had lower (P ≤ 0.05) BW and BCS compared to NE+/NS, but on d 148 treatments reranked and E+/LS remained at a greater (P ≤ 0.05) BW and BCS compared to NE+/NS through the first breeding season. Drylot heifers had greatest (P ≤ 0.05) percentage cycling and percentage of mature BW at AI (66.6%) and had greater (P ≤ 0.05) AI and overall pregnancy rates compared to E+/LS and NE+/NS. The E+/S (55%) and E+/LS (53.7%) heifers were developed to a greater (P &lt; 0.01) percentage of mature BW than NE+/NS (49.3%). A greater (P ≤ 0.02) percentage of DL and E+/S heifers were pregnant at the end of the first breeding season (89.3 and 85.1%; respectively) compared to NE+/NS (61.5%). In summary, DL heifers had the greatest BW and BCS at AI, percentage cycling, and AI pregnancy rate. However, this strategy did not result in differing overall pregnancy rates between DL, E+/S, and E+/LS and there were no differences in milk production, rebreeding reproductive performance, and calf performance between all treatments. Finally, the poorest AI and overall pregnancy rates of the NE+/NS heifers suggests this is not a viable development strategy for fall-born heifers.

Breeding biology and movements of Australian sea-lions, Neophoca cinerea, off the west coasst of Western Australia

1992 ◽  
Vol 19 (4) ◽  
pp. 405 ◽  
Author(s):  
NJ Gales ◽  
AJ Cheal ◽  
GJ Pobar ◽  
P Williamson
Keyword(s):  
Breeding Season ◽  
Western Australia ◽  
West Coast ◽  
Metropolitan Region ◽  
Breeding Cycle ◽  
Sea Lion ◽  
The West ◽  
Breeding Sites ◽  
Sea Lions ◽  
Neophoca Cinerea

The Australian sea-lion, Neophoca cinerea, has a 17-18-month breeding cycle on islands off the west coast of Western Australia. Buller, North Fisherman and Beagle Is are the main pupping sites, with several very small colonies (n> 3) at the Abrolhos Is. The 4-5-month pupping seasons are synchronised at North Fisherman and Beagle Is, but the sea-lions from Buller I. breed one month later and those from the Abrolhos Is two months earlier. Pup production and pup mortality were highly variable between seasons over which observations were recorded: 129 pups were born at the main breeding sites in early 1988, the mortality in the first five months was 7.1%, whereas 181 pups were born in late 1989 of which 24.3% died. Pups remain in the vicinity of their natal islands for the first 4-5 months of life before leaving, perhaps on foraging trips, with their mothers. Most return to their natal island, although others haulout on islands up to 27 km away. Some male N. cinerea congregate in bachelor colonies on islands adjacent to the Perth metropolitan region during the non-breeding season and migrate up to 280 km north each breeding season. The status of the isolated, west-coast N. cinerea population is unknown. The current high level of human pressure on sea-lion terrestrial habitats and their food resources indicate a need for further monitoring of this species.

scholarly journals Linking oceanographic conditions, migratory schedules and foraging behaviour during the non‐breeding season to reproductive performance in a long‐lived seabird

2018 ◽  
Vol 32 (8) ◽  
pp. 2040-2053 ◽  
Author(s):  
Marine Desprez ◽  
Stéphanie Jenouvrier ◽  
Christophe Barbraud ◽  
Karine Delord ◽  
Henri Weimerskirch
Keyword(s):  
Breeding Season ◽  
Reproductive Performance ◽  
Foraging Behaviour ◽  
Oceanographic Conditions

Pineal Apoplexy: A Case Series and Review of the Literature

2021 ◽  
Author(s):  
Martin Majovsky ◽  
David Netuka ◽  
Radim Lipina ◽  
Jan Mraček ◽  
Vladimír Beneš
Keyword(s):  
Surgical Treatment ◽  
Pineal Gland ◽  
Clinical Significance ◽  
Obstructive Hydrocephalus ◽  
Case Series ◽  
Surgical Removal ◽  
Pineal Tumor ◽  
Review Of The Literature ◽  
Melatonin Secretion ◽  
Pubmed Database

Abstract Background Pineal apoplexy is a rare condition, with unknown incidence and clinical significance. To elucidate this clinical condition, we analyzed our own case series and performed a review of the literature. Methods We enrolled all patients with a hemorrhagic pineal apoplexy who were referred to our department between January 2000 and January 2020. Hemorrhagic pineal apoplexy was defined as the presence of fluid–fluid levels inside the pineal cyst (PC) on an axial or sagittal magnetic resonance scan. In one patient, after PC apoplexy, we performed a circadian melatonin sampling from peripheral blood to determine the function of the pineal gland. The PubMed database was searched for publications using the terms “pineal” and “apoplexy.” Results Eight patients were enrolled, of which three patients underwent surgical treatment and five patients were managed conservatively. One patient was tested for circadian melatonin secretion. Results confirmed melatonin secretion with preserved physiologic circadian rhythm.Our search of the literature led us to 31 studies that comprised 30 patients with apoplectic PC, 9 with apoplectic pineal tumor, and 1 with bleeding into the normal pineal gland. Most patients presented with headache, nausea, and vomiting, less frequently with acute hydrocephalus and gaze palsy. Twenty patients with a PC underwent resection or aspiration. Two patients underwent shunt placement as the only procedure and five received both shunt and surgical removal. Six patients with a PC were observed without surgical treatment. All the nine patients with a pineal tumor were operated on. In indicated cases, four patients received radiation therapy and one received chemotherapy. Conclusion Clinical significance of hemorrhagic pineal apoplexy ranges from an asymptomatic course to rapid deterioration and death. In patients with mild symptoms, observation is indicated, whereas surgical treatment is reserved for severe cases presenting with obstructive hydrocephalus and includes cerebrospinal fluid diversion, resection of apoplectic pineal lesions, or both.

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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