+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

Influence of exogenous melatonin and altered day length on reproductive performance of Polypay ewes

, : Influence of exogenous melatonin and altered day length on reproductive performance of Polypay ewes. Theriogenology 29(2): 535-543

Two experiments were designed to evaluate postlight treatment use of melatonin as a method of overcoming photorefractory response by measuring the lambing percentage of early-postpartum Polypay ewes bred either late in the breeding season or during anestrus. In Trial 1, pregnant ewes (n = 140) were assigned to one of three groups: 1) ambient photoperiod (control), 2) extended light (20 h) from October 21 to December 27, and 3) extended light as in Group 2, followed by supplemental feeding of 10 mg melatonin/head (hd) daily until April 6. Breeding started on February 3 and ended April 9. A greater percentage of ewes given extended light plus melatonin (54%) and extended light alone (45%) lambed than controls (24%) (P = 0.06). In Trial 2, pregnant ewes (n = 158) were assigned to groups as in Trial 1, except extended light was given to Groups 2 and 3 from January 1 to March 11, and Group 3 ewes were supplemented with 10 mg melatonin daily from March 12 to June 10. Breeding started April 18 and ended June 10. Lambing percentage was increased (P < 0.01) by extended light plus melatonin (54%) compared to controls (6%) or ewes given only extended light (10%). The shift from artificially extended light to the shorter ambient light with or without melatonin enhanced the lambing percentage of early postpartum ewes on an accelerated lambing program during breeding late in the season. However, only the more pronounced shift from long days to short days, accomplished with extended light plus melatonin, was effective in inducing out-of-season breeding in Polypay ewes.


PMID: 16726377

DOI: 10.1016/0093-691x(88)90256-7

Other references

Smirnova, G.; Samoilova, Z.; Muzyka, N.; Oktyabrsky, O., 2013: Influence of plant polyphenols and medicinal plant extracts on antibiotic susceptibility of Escherichia coli.   To investigate the influence of polyphenols and plant extracts on the susceptibility of Escherichia coli to antibiotics.   Susceptibility of E. coli to antibiotics in the presence of extracts and polyphenols was estimated by the determinatio...

Davey, G., C.L.; Craigie, P., 1997: Manipulation of dangerousness judgements to fear-relevant stimuli: Effects on a priori UCS expectancy and a posterior covariation assessment. Using a covariation assessment procedure, the present study pre-experimentally manipulated subjects' assessments of the dangerousness of fear-relevant stimuli. The results demonstrated that this manipulation subsequently influenced both a pri...

Pelayo, M.; Vargas, V.; Gonzales, A.; Vallano, A.; Esteban, R.; Guardia, J., 1993: Drug-induced lupus-like reaction and captopril. Annals of PharmacoTherapy 27(12): 1541-1542

Gwazdauskas, F.; Peery, D.; Paape, M.; Mcgilliard, M., 1979: Plasma glucocorticoid alterations following sequential injections of adrenocorticotropin. Program: ADSA annual meeting and divisional abstracts2(1): 212

Leeds A.R., 1975: Lithospheric thickness in the western Pacific. Rayleigh wave phase velocities were determined by the single-station method for ten paths in the western Pacific. The data show that even 100 m.y. after formation, the phase velocity and upper-mantle structure are still dependent upon age. Inversi...

Emery, K.J.; Tuttle, T.; Murphy, J.A., 2017: Evidence of single electron transfer from the enolate anion of an N,N'-dialkyldiketopiperazine additive in BHAS coupling reactions. A designed N,N'-dialkyldiketopiperazine (DKP) provides evidence for the role of DKP additives as initiators that act by electron transfer in base-induced homolytic aromatic substitution reactions, involving coupling of haloarenes to arenes.

Kozarovich, L.Hurt., 2004: Fit to be tied. New gowns provide higher patient satisfaction. Materials Management in Health Care 12(11): 37-37

Micheli, L.J.; Jupiter, J., 1978: Osteoid osteoma as a cause of knee pain in the young athlete: a case study. Knee problems are frequently seen in young athletes. It is important for the examining physician to be mindful of the complex differential diagnosis of knee pain in the adolescent, and not presume a traumatic origin of this pain. A case of osteoid...

Freire E., 1984: Thermotropic behavior and dynamics of cholera toxin and cholera toxin subunits bound to phospho lipid vesicles containing ganglioside gm 1. Biophysical Journalpart 2: 359a

A.T.hir, O.A.; Makki, Y.M.; Mustafa, A.M.I., 1991: Growth, productivity, and miling qualities of commercial cultivars and advanced lines of wheat (Triticum aestivum L.) grown at different sites in Saudi Arabia. The agronomic and milling performance of 4 King Faisal University (KFU) advanced lines, developed from a cross of indigenous variety Madina with commercially introduced Probred, were compared with 6 commonly grown cultivars at 4 locations and over...