Two experiments were conducted. In experiment 1, the objectives were: 1) to develop and evaluate the accuracy and precision of a new continuous ruminal pH measurement system 2) to determine the required frequency for pH electrode standardization and 3) to determine the effect of additional pre-partum concentrate when compared to NRC (2001) recommendations on post-partum ruminal acidosis in primiparous cows. Accuracy and precision of the Lethbridge Research Centre Ruminal pH measurement system (LRCpH) was determined by comparing LRCpH derived values against manual measurement. To determine the required frequency of electrode standardization, three treatments were imposed (24, 48, or 72 h of continuous measurement) and arranged in a repeated 3×3 Latin square design. The LRCpH accurately and precisely measured ruminal pH (repeated measures correlation coefficient = 0.97 and concordance correlation coefficient = 0.97 for 5-min averages). Changes in baseline mV readings for pH readings after 24, 48 or 72 h of ruminal incubation were not significantly different than zero, indicating that daily standardization of new electrodes was not essential. Using the LRCpH to measure ruminal pH overcomes animal mobility restrictions of previous systems. <p>In experiment 2, the effect of additional concentrate allocation during the pre-partum period was evaluated using 14 ruminally cannulated Holstein heifers. The heifers were assigned to one of two feeding regimes pre-calving: 1) control treatment or 2) an intensive high concentrate feeding treatment (HC). All cows received the same lactation diet post-partum. Ruminal pH was measured continuously from d -5 to d +5, and for 3-consecutive days starting on d +17 ± 1.2, d +37 ± 1.4, and d +58 ± 1.5 relative to parturition. Feeding additional concentrate pre-partum did not reduce post-partum ruminal acidosis. In fact, animals fed the HC treatment had more daily episodes of acute acidosis and lower dry matter intake and body condition score than animals fed the control treatment. Day relative to parturition affected the occurrence and severity of ruminal acidosis with a dramatic increase in ruminal acidosis after parturition. This study demonstrates that feeding addition concentrate pre-partum did not reduce post-partum acidosis which emphasized the need to develop and implement feeding strategies that reduce this risk.
| Identifer | oai:union.ndltd.org:USASK/oai:usask.ca:etd-08312006-062719 |
| Date | 31 August 2006 |
| Creators | Penner, Gregory Brent |
| Contributors | Van Kessel, Andrew G., Mutsvangwa, Tim, Christensen, David A., Buchanan, Fiona C., Beauchemin, Karen A. |
| Publisher | University of Saskatchewan |
| Source Sets | University of Saskatchewan Library |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://library.usask.ca/theses/available/etd-08312006-062719/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Saskatchewan or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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