Factors affecting pre-ovulatory follicle diameter in the mare: the effect of mare age, season and presence of other ovulatory follicles (multiple ovulation)

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dc.contributor.author Davies-Morel, M. C. G.
dc.contributor.author Newcombe, J. R.
dc.contributor.author Hayward, K.
dc.date.accessioned 2011-06-01T10:42:43Z
dc.date.available 2011-06-01T10:42:43Z
dc.date.issued 2010-10-15
dc.identifier.citation Davies-Morel , M C G , Newcombe , J R & Hayward , K 2010 , ' Factors affecting pre-ovulatory follicle diameter in the mare: the effect of mare age, season and presence of other ovulatory follicles (multiple ovulation) ' Theriogenology , vol 74 , no. 7 , pp. 1241-1247 . , 10.1016/j.theriogenology.2010.05.027 en
dc.identifier.issn 0093-691X
dc.identifier.other PURE: 162937
dc.identifier.other dspace: 2160/6870
dc.identifier.uri http://hdl.handle.net/2160/6870
dc.description Davies Morel, M. C. G., Newcombe, J. R., Hayward, K. (2010). Factors affecting pre-ovulatory follicle diameter in the mare: the effect of mare age, season and presence of other ovulatory follicles (multiple ovulation.   Theriogenology, 74, (7), 1241-1247. IMPF: 02.04 RONO: 00 en
dc.description.abstract The importance of elucidating factors affecting reproductive performance and efficiency is of paramount concern to the equine industry. Oocyte viability is known to be one of the determinants of reproductive success and evidence suggests that it may be linked to follicle size. The aims of this study were, therefore, to ascertain: i) the average diameter and range of pre-ovulatory follicles in thoroughbred mares; ii) whether this is affected by either mare age, time within the breeding season, or the presence of multiple pre-ovulatory follicles (MO). One thousand, four hundred and ninety two thoroughbred mares, aged 2-26 years, were examined with ultrasound to ascertain ovulation date to within 24h, and pre-ovulatory follicle(s) (F1) diameter. Mares were divided into groups according to age (7 groups, 2-4 yr, 5-7 yr, 8-10 yr, 11-13 yr, 14-16 yr, 17-19 yr, >19 yr), time within the season (16 half-month groups, from Feb 1(st) to Sept 30(th)), and pre-ovulatory follicles (single, (SO) or multiple (MO)). Overall average F1 diameter was 39.95 +/- 4.84 mm (range 22-50 mm). Mare age had a significant (P <0.001) negative effect on F1 diameter (largest F1 38.95 +/- 5.61 mm, mares 2-4 yrs; smallest F1 33.30 +/- 4.66 mm, mares > 19 yrs) as did season (largest F1 44.20 +/- 3.95 mm, Feb 1(st)-14(th); smallest F1 33.74 +/- 4.87 mm, Aug 15(th)-31(st)) and the presence of more than one pre-ovulatory follicle (MO F1 35.45 +/- 4.53 mm; SO F1 37.44 +/- 4.84 mm). In conclusion, older mares, bred towards the end of the breeding season, especially if MO were present, were more likely to ovulate from smaller follicles, If, as suggested, small pre-ovulatory follicle size is associated with low oocyte viability, then this may account, at least in part, for the poor fertility rates characteristic of older MO mares, bred later in the season and so justify increased monitoring and careful reproductive management of such mares. (C) 2010 Elsevier Inc. All rights reserved. en
dc.format.extent 7 en
dc.language.iso eng
dc.relation.ispartof Theriogenology en
dc.subject pre-ovulatory en
dc.subject follicle en
dc.subject multiple ovulation en
dc.subject mare en
dc.subject age en
dc.subject season en
dc.title Factors affecting pre-ovulatory follicle diameter in the mare: the effect of mare age, season and presence of other ovulatory follicles (multiple ovulation) en
dc.type Text en
dc.type.publicationtype Article (Journal) en
dc.identifier.doi http://dx.doi.org/10.1016/j.theriogenology.2010.05.027
dc.contributor.institution Institute of Biological, Environmental and Rural Sciences en
dc.description.status Peer reviewed en


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