000060657 001__ 60657 000060657 005__ 20170504102051.0 000060657 0247_ $$2doi$$a10.3390/vetsci4010004 000060657 0248_ $$2sideral$$a98040 000060657 037__ $$aART-2017-98040 000060657 041__ $$aeng 000060657 100__ $$0(orcid)0000-0003-2827-3054$$aAbecia, J.A.$$uUniversidad de Zaragoza 000060657 245__ $$aExposure to Photoperiod-Melatonin-Induced, Sexually-Activated Rams after Weaning Advances the Resumption of Sexual Activity in Post-Partum Mediterranean Ewes Lambing in January 000060657 260__ $$c2017 000060657 5060_ $$aAccess copy available to the general public$$fUnrestricted 000060657 5203_ $$aThis study was aimed to determine whether the presence of sexually stimulated rams by photoperiodic and melatonin treatments can advance the resumption of post-partum sexual activity in Mediterranean ewes lambing in January and weaned at the end of the breeding season at 41°N, in March. Rams were exposed to two months of long days (16 h light/day) and given three melatonin implants at the end of the long days (sexually-activated rams; SAR). Control rams (CR) were exposed to the natural photoperiod. Thirty-six ewes weaned on 25 February were assigned to one of two groups. From 1 March to 30 June, one group was housed with four SAR males (SAR-treated; n = 18), and the other group (CR-treated; n = 18) was housed with four unstimulated rams. Ovulation was assessed once per week based on plasma progesterone concentrations. Estrus was monitored daily by marks left on ewes by rams’ harnesses. SAR-treated ewes had a shorter (p < 0.01) weaning–first estrus interval than CR-treated ewes (61 ± 17 days vs. 102 ± 47 days; mean date of first estrus after weaning on April 26 and June 6, respectively). The proportion of the ewes ovulating in April or May was higher (p < 0.05) in the SAR-treated group than in the CR-treated group. SAR-treated ewes resumed estrous activity sooner than CR-treated ewes such that, in April, May, and June, the proportion of females that exhibited estrus was higher (p < 0.01) in the SAR-treated group (72%, 89%, and 100%, respectively) than in the CR-treated group (17%, 44%, and 61%, respectively). In conclusion, the introduction at weaning of sexually activated rams advanced the resumption of estrous activity in ewes in spring. The practical implications of this work could be important in ewes adapted for intensive production and accelerated lambing systems. 000060657 536__ $$9info:eu-repo/grantAgreement/ES/DGA/A26$$9info:eu-repo/grantAgreement/ES/MICINN/AGL2013-41200-P 000060657 540__ $$9info:eu-repo/semantics/openAccess$$aby$$uhttp://creativecommons.org/licenses/by/3.0/es/ 000060657 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion 000060657 700__ $$aChemineau, Philippe 000060657 700__ $$aGómez, Andrea 000060657 700__ $$aPalacios, Carlos 000060657 700__ $$aKeller, Matthieu 000060657 700__ $$aDelgadillo, A.J. 000060657 7102_ $$12008$$2700$$aUniversidad de Zaragoza$$bDepartamento de Producción Animal y Ciencia de los Alimentos$$cProducción Animal 000060657 773__ $$g4, 1 (2017), [9 pp.]$$tVeterinary Sciences$$x2306-7381 000060657 8564_ $$s370938$$uhttps://zaguan.unizar.es/record/60657/files/texto_completo.pdf$$yVersión publicada 000060657 8564_ $$s103055$$uhttps://zaguan.unizar.es/record/60657/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada 000060657 909CO $$ooai:zaguan.unizar.es:60657$$particulos$$pdriver 000060657 951__ $$a2017-05-04-10:19:22 000060657 980__ $$aARTICLE