Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
Die invloed van 'n geinduseerde kopertekort op die reproduksie van SA vleismerino-ooie
Tesis (M. Sc.) -- Universiteit van Stellenbosch, 1994.
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | Afrikaans |
| Published: |
Stellenbosch : Stellenbosch University
2012
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613862638911488 |
|---|---|
| access_status_str | Open Access |
| author | Du Plessis, Simon Stephanus |
| author2 | Coetzer, W. A. |
| author_browse | Coetzer, W. A. Du Plessis, Simon Stephanus |
| author_facet | Coetzer, W. A. Du Plessis, Simon Stephanus |
| author_sort | Du Plessis, Simon Stephanus |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Tesis (M. Sc.) -- Universiteit van Stellenbosch, 1994. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/58353 |
| institution | Stellenbosch University (South Africa) |
| language | Afrikaans |
| last_indexed | 2026-06-10T12:42:53.367Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2012 |
| publishDateRange | 2012 |
| publishDateSort | 2012 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/58353 Die invloed van 'n geinduseerde kopertekort op die reproduksie van SA vleismerino-ooie Du Plessis, Simon Stephanus Coetzer, W. A. Van Niekerk, F. E. Stellenbosch University. Faculty of Science. Dept. of Physiological Sciences. Merino sheep -- Reproduction Sheep -- Reproduction Trace elements in animal nutrition Sheep -- Feeding and feeds Copper in animal nutrition Dissertations -- Physiology (Human and animal) Tesis (M. Sc.) -- Universiteit van Stellenbosch, 1994. In an attempt to determine at what level a copper deficiency influences the reproduction of ewes a secondary copper deficiency was induced in a number of young (5 months) and adult SA Mutton Merino ewes. Different reproduction parameters were consequently investigated and evaluated. In the first phase of the study, a copper deficiency was induced in the experimental group by means of supplementing their rations with molibdate in combination with sulphur (as sodiumsulphate). A drop in average liver copper concentration in the experimental ewes versus the control ewes (25.0 ± 5.8 µg/g(DM) vs 85.3 ± 10.3 µg/g(DM)) proved the presence of an effective induced copper deficiency in the experimental ewes. In ewes with a copper deficiency, it was found that the course of the normal oestrous cycle ended earlier at the end of the active mating season. Such ewes fell quicker into anestrus (100% experimental ewes vs 66% control ewes in anestrus). There after a FSH and LH blockage was created with the help of exogenous progestagen, by means of progestagen's negative feedback effect (synchronization). In this way estrus and ovulation were induced in the ewes and an attempt was made to determine any underlying endocrine cause of a dysfunction as a result of a copper deficiency. The influence of the copper deficiency on follicular development and ovulation was also investigated after the administering of a progesterone block in combination with high dosages of FSH and LH (superovulation). It was found that if the simultaneous pre-ovulatory FSH and LH peaks were present in the experimental ewes the concentrations were still considerably lower than in the their control ewes. The experimental ewes' average estrogen concentrations was higher while their progesterone concentrations was lower than that of the control ewes' after both hormonal treatments. In spite of the higher estrogen concentrations, the copper shortage had a suppressing effect on the occurrence of estrus as well as follicular development and ovulation. The control ewes had significantly more ovulation points than the experimental ewes (7.25 \(\pm \) 2.217 vs 3.50 \(\pm \) 2.887) after superovulation treatment. Conception (0% vs 66%) and lambing percentage (0% vs 83%) were also totally suppressed by the copper deficiency. From the above results it appears that a copper deficiency exerts an effect on both hypothalamus-hypophysis level as well as ovarian level and in this way effects the whole reproduction process negatively. Masters 2012-08-27T11:38:55Z 2012-08-27T11:38:55Z 1994 Thesis http://hdl.handle.net/10019.1/58353 af Stellenbosch University 189 pages : ill. application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Merino sheep -- Reproduction Sheep -- Reproduction Trace elements in animal nutrition Sheep -- Feeding and feeds Copper in animal nutrition Dissertations -- Physiology (Human and animal) Du Plessis, Simon Stephanus Die invloed van 'n geinduseerde kopertekort op die reproduksie van SA vleismerino-ooie |
| title | Die invloed van 'n geinduseerde kopertekort op die reproduksie van SA vleismerino-ooie |
| title_full | Die invloed van 'n geinduseerde kopertekort op die reproduksie van SA vleismerino-ooie |
| title_fullStr | Die invloed van 'n geinduseerde kopertekort op die reproduksie van SA vleismerino-ooie |
| title_full_unstemmed | Die invloed van 'n geinduseerde kopertekort op die reproduksie van SA vleismerino-ooie |
| title_short | Die invloed van 'n geinduseerde kopertekort op die reproduksie van SA vleismerino-ooie |
| title_sort | die invloed van n geinduseerde kopertekort op die reproduksie van sa vleismerino ooie |
| topic | Merino sheep -- Reproduction Sheep -- Reproduction Trace elements in animal nutrition Sheep -- Feeding and feeds Copper in animal nutrition Dissertations -- Physiology (Human and animal) |
| url | http://hdl.handle.net/10019.1/58353 |
| work_keys_str_mv | AT duplessissimonstephanus dieinvloedvanngeinduseerdekopertekortopdiereproduksievansavleismerinoooie |