Effects of melatonin on luteinizing hormone secretion in anestrous ewes following dopamine and opiate receptor blockade

Misztal, Tomasz; Romanowicz, Katarzyna; Barcikowski, B

doi:10.1016/j.anireprosci.2003.08.011

Cited by 4 publications

(3 citation statements)

References 33 publications

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“…Although the extent of this seasonal restriction varies within breeds, geographical location and livestock management, this confirms a well-known fact that goats are seasonally polyestrous (Mio~and Pavi}, 2002;Misztal et al, 2004;Zarazaga et al, 2005). Reproductive traits determined in this study, as well as results of investigated environmental effects were in accordance with some previous reports for dairy goats (Amoah et al, 1996;Mellado et al, 2011).…”

Section: Discussionsupporting

confidence: 93%

Estimation of genetic parameters and genetic trends for reproductive traits in Saanen goats

Kasap¹,

Mioč²,

Škorput³

et al. 2013

ACTA VET-BEOGRAD

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The study was conducted on Saanen goats raised in Croatia. The object of the study was to determine the average litter size (LS), birth weight (BW) and total litter weight (TLW). The study included a total of 2 500 goats among which 1 786 were phenotyped. A total of 6 349 records for BW and 4 256 records for LS and TLW were used in descriptive and inferential statistical analysis. Determined averages for LS, BW and TLW were 1.74 lambs, 3.27 kg and 5.65 kg, respectively. Twinning and tripling rates were 36.9% and 6.2%. Single-trait analysis under repeatability animal model was used in estimation of variance components and prediction of breeding values. Season (as year-month interaction), age at lambing (as quadratic regression) nested within parity and type of birth were treated as fixed, while herd-year, additive genetic, permanent environmental and residual were treated as random effects, respectively. Investigated environmental effects significantly affected all reproductive traits (p<0.001). The largest phenotype variability among investigated traits was determined for TLW. Additive genetic effect accounted for 7%, 5% and 4% in total variability for LS, BW and TLW, respectively. Genetic trends of reproductive traits were estimated for the period from year 2000 to 2010. A positive genetic trend was determined for LS, a negative genetic trend for BW and genetic stagnation for TLW

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Section: Discussionsupporting

confidence: 93%

Estimation of genetic parameters and genetic trends for reproductive traits in Saanen goats

Kasap¹,

Mioč²,

Škorput³

et al. 2013

ACTA VET-BEOGRAD

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“…Kidding year and season also affects some reproduction performances of Boer dam, which effects can be largely attributed to the different forage availability, photoperiod (Misztal et al, 2004), hormones (Zamiri and Khodaei, 2005;deNicolo et al, 2008) and other environments such as temperature and social relationships (Markley et al, 2006). It has been reported that a high level of nutrition may introduce estrus and improve multiple ovulation in goat.…”

Section: Phenotypic Parameters and Fixed Effectsmentioning

confidence: 99%

Genetic and phenotypic parameter estimates for reproduction traits in the Boer dam

Zhang

Chen

et al. 2009

Livestock Science

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“…The photoperiod in seasonally breeding animals e.g. in the short-day breeders (sheep) and/or in the long-day breeders (hamster or mare) is particularly the most important signal affecting many physiological processes, it is associated closely with changes in the concentration of melatonin (Misztal et al 2004). In mature, sexually active sheep, melatonin is a hormone that modulates their sexual activity.…”

Section: Resultsmentioning

confidence: 99%

Profile of gonadotropic hormone secretion in sheep with disturbed rhythm of seasonality

Molik¹,

Błasiak²,

Misztal³

et al. 2017

CZECH J ANIM SCI

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Molik E., Błasiak M., Misztal T., Romanowicz K., Zięba D.A. (2017): Profile of gonadotropic hormone secretion in sheep with disturbed rhythm of seasonality. Czech J. Anim. Sci., 62, 242-248.The effect of artificial conditions of a short daylight period (16 h darkness (D): 8 h light (L)) and exogenous melatonin on milk yield parameters of sheep during spring and summer was examined to determine the impact of using sheep for milk on the secretion level of gonadotrophic hormones. The research was conducted on 60 sheep lambed in February. After raising the lambs, the sheep were divided into 3 groups and assigned for dairy use (May-September). The mothers in the control Group 1 (G1) were maintained under natural daylight conditions. The sheep in Group 2 (G2) were maintained under conditions of an artificial photoperiod (16 h D : 8 h L). Meanwhile, the mothers in Group 3 (G3) were given melatonin implants. A 6-hour collection of blood from 6 sheep of each group was performed every 4 weeks. The concentrations of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) in plasma were measured using radioimmunoassay. The average LH concentration in G1 gradually increased since May (5.32 ± 0.2 ng/ml), reaching the highest value in August (6.70 ± 0.2 ng/ml). In G2, the increase in LH occurred 4 weeks after the introduction of the 16 h D : 8 h L condition (6.26 ± 0.2 ng/ml). The maximum LH concentration in G3 was noted in August (7.31 ± 0.2 ng/ml). The average FSH concentration in G1 gradually increased since May (6.59 ± 0.2 ng/ml), reaching the highest value in August (10.50 ± 2.6 ng/ml). In G2, there was a significant increase in the FSH concentration in June (9.00 ± 0.3 ng/ml). In the final period during lactation, the FSH concentrations in G2 (13.51 ± 1.3 ng/ml) and G3 (13.60 ± 1.9 ng/ml) were higher than in G1. The results indicate that using sheep for milk does not inhibit the secretion of gonadotropic hormones induced by the simulation of short daylight conditions and exogenous melatonin.

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Effects of melatonin on luteinizing hormone secretion in anestrous ewes following dopamine and opiate receptor blockade

Cited by 4 publications

References 33 publications

Estimation of genetic parameters and genetic trends for reproductive traits in Saanen goats

Estimation of genetic parameters and genetic trends for reproductive traits in Saanen goats

Genetic and phenotypic parameter estimates for reproduction traits in the Boer dam

Profile of gonadotropic hormone secretion in sheep with disturbed rhythm of seasonality

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