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Circulating glucose responses in early lactation dairy cows to dietary restriction and rbST treatment
Dissertation (MSc(Agric))--University of Pretoria, 2008.
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University of Pretoria
2013
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| _version_ | 1867613515829739520 |
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| access_status_str | Open Access |
| author2 | Casey, N.H. (Norman Henry) |
| author_browse | Casey, N.H. (Norman Henry) |
| author_facet | Casey, N.H. (Norman Henry) |
| collection | Thesis |
| dc_rights_str_mv | © 2008, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MSc(Agric))--University of Pretoria, 2008. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/28939 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:37:22.997Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/28939 Circulating glucose responses in early lactation dairy cows to dietary restriction and rbST treatment Casey, N.H. (Norman Henry) annie.basson@up.ac.za Basson, Annelie Insulin resistance Glucose clamp Recombinant bst Early lactation Holstein cows Nutrient restriction UCTD Dissertation (MSc(Agric))--University of Pretoria, 2008. Galactopoietic effects of somatotropin are the result of IGF-I and require high-quality nutrient intake. This study investigated short-term partitioning effects during recombinant bovine somatotropin (bST) administration in high yielding early lactation dairy cows. Administration of recombinant bST has been shown generally to alter results of metabolic tests in the face of unchanged basal glucose and insulin concentrations. Ten multiparous Holstein cows were subjected to rbST (Lactotropin®) and/or feed intake restriction to 80% of predicted ME requirement (80% ME). Responses to insulin challenge (0.1 IU porcine insulin/kg BW. 210 min) and hyperglycaemic clamp (+50 mg/dL whole blood, 120 min) were tested during weeks 8 (control), 9 (rbST ), 11 (80% ME) and 12 (rbST + 80% ME) postpartum. Plasma and whole blood samples were assayed for glucose concentrations. The rbST treatment decreased fasting whole-blood glucose concentration by 9.4% (P<0.0001), which was likely a remnant of control hyperglycaemia. Maximum glucose response was 4.0 mg/dL (21.7%) lower (P<0.0038) and took 6.5 minutes longer to attain (P<0.0037). Steady-state glucose infusion rate (SSGIR) decreased by 8.1 % (P<0.0001). The 80% ME treatment decreased glucose availability by 5 to 6% (P<0.0100), while no glucose responses were affected. Restricted energy intake during treatment with rbST resulted in plasma glucose increase by 5.5% (P<0.0001). Peripheral uptake and utilization of glucose increased by 5.1 % (P<0.0005). Compared to energy restriction, 80%ME + rbST did not alter effects of nutrient restriction on responses to exogenous insulin challenge. Effects were small and inconsistent. SSGIR decreased by 5.0% in the 80% ME + rbST compared to the 80% ME period (P<0.0004) and the change in the hyperglycaemic clamp in the absence of an effect in the insulin challenge may be due to differences in endogenous insulin secretion. The conclusion was that rbST treatment resulted in altered glucose metabolic responses, even with restricted energy intake. Animal and Wildlife Sciences unrestricted 2013-09-07T14:32:14Z 2009-11-03 2013-09-07T14:32:14Z 2009-09-02 2008 2009-10-22 Dissertation Basson, A 2008, Circulating glucose responses in early lactation dairy cows to dietary restriction and rbST treatment, MSc(Agric) dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/28939 > E1488/gm http://hdl.handle.net/2263/28939 http://upetd.up.ac.za/thesis/available/etd-10222009-135500/ © 2008, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf application/pdf University of Pretoria |
| spellingShingle | Insulin resistance Glucose clamp Recombinant bst Early lactation Holstein cows Nutrient restriction UCTD Circulating glucose responses in early lactation dairy cows to dietary restriction and rbST treatment |
| title | Circulating glucose responses in early lactation dairy cows to dietary restriction and rbST treatment |
| title_full | Circulating glucose responses in early lactation dairy cows to dietary restriction and rbST treatment |
| title_fullStr | Circulating glucose responses in early lactation dairy cows to dietary restriction and rbST treatment |
| title_full_unstemmed | Circulating glucose responses in early lactation dairy cows to dietary restriction and rbST treatment |
| title_short | Circulating glucose responses in early lactation dairy cows to dietary restriction and rbST treatment |
| title_sort | circulating glucose responses in early lactation dairy cows to dietary restriction and rbst treatment |
| topic | Insulin resistance Glucose clamp Recombinant bst Early lactation Holstein cows Nutrient restriction UCTD |
| url | http://hdl.handle.net/2263/28939 http://upetd.up.ac.za/thesis/available/etd-10222009-135500/ |