Abstract
Thirty-six gilts which had not shown oestrus at about 8 months of age or more were transported from the pig research station to the clinic, a journey of 12 km. The gilts were examined by laparoscopy and those which had only small follicles in the ovaries were catheterized and placed in pens, with sexually mature boars kept in adjacent pens. Oestrus detection was done twice daily and blood was sampled three times a day. After 7 days the laparoscopy was repeated and gilts which still had only small follicles in their ovaries were given 250 μg GnRH intravenously the following day. Blood samples were taken frequently before and after GnRH treatment. One week. after administration of GnRH the ovaries were inspected by laparoscopy once more.
The first laparoscopic examination showed that 42 % of the gilts were sexually mature. One gilt had no uterus or ovaries. Twenty gilts had only small follicles in the ovaries and fourteen of these gilts showed ovulatory oestrus 5.5 days (4-7.5 days) after arrival. In these fourteen gilts a rise in the oestradiol-17B level (>30 pmol/1) was seen at an average time of 1.9 days and a rise in LH (preovulatory peak) was seen at an averaged 4.5 days after the start of blood sampling. Six gilts were given 250 ug GnRH. An immediate rise in LH could be seen in all the gilts (mean peak level was 6.18 μg/l) and the elevated levels had a duration of 4 hours. None of the GnRH-treated gilts responded with oestrus symptoms or increased ovarian activity.
Sammanfattning
Trettiosex gyltor som inte hade visat brunst vid ca 8 månaders ålder transporterades 12 km från en försöksstation till kliniken. Gyltorna undersöktes med laparoskopi. På gyltor som bara hade små folliklar i äggstockarne opererades en kateter in för blodprovstagning och därefter placerades gyltorna i boxar med könsmogna galtar i närheten. Brunstkontroll utfördes 2 gånger och blodprov togs 3 gånger per dag. Efter 7 dagar upprepades laparoskopi-undersökningen och gyltor som fortfarande bara hade små folliklar i äggstockarna behandlades med 250 μg GnRH i.v. följande dag. Frekvent blodprovstagning utfördes i anslutning till GnRH-behandlingen och 5 ggr per dag därefter. En vecka efter GnRH-behandlingen undersöktes gyltorna på nytt med laparoskopi. Den första laparoskopi-undersökningen visade att 42 % av gyltorna var könsmogna. En gylta saknade livmoder och äggstockar. Tjugo gyltor hade små folliklar i äggstockarna och av dessa visade 14 brunst 5,5 dagar (4–7,5 dagar) efter ankomsten till kliniken. Hos dessa 14 gyltor sågs en östradiol-17ß stegring (>30 pmol/1) efter i medeltal 1.9 dagar och en stegring av LH (preovulatorisk stegring) efter i medeltal 4.5 dagar från blodprovstagningens början. Hos de 6 gyltorna som behandlades med GnRH sågs omedelbart en LH-stegring. Medelvärdet för maximumnivåen var 6.18 μg/l och LH-stegringen hade en duration på 4 timmar. Ingen av gyltorna svarade med brunst eller ökad äggstocksaktivitet efter GnRH-behandlingen.
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Acknowledgment
This investigation was supported by grants from the Swedish Council for Forestry and Agricultural Research. The Department of Animal Breeding and Genetics is gratefully acknowledged for supplying the gilts. Thanks are also due to Prof. Stig Einarsson for valuable advice and to Marianne Carlsson, Eva Hedberg, Mari Wallbring and Carina Ahlstedt for their excellent technical assistance.
Antiserum to ovine LH was kindly donated by Dr. G. D. Niswender, Colorado State University, Fort Collins, USA. The authors are indebted to Dr. L. E. Reichert for supplying porcine LH for iodination and as standard.
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Dalin, AM., Eliasson, L. Clinical, Morphological and Endocrinological Studies in Gilts with Delayed Puberty. Acta Vet Scand 28, 263–269 (1987). https://doi.org/10.1186/BF03548592
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DOI: https://doi.org/10.1186/BF03548592