Eighteen neonatal Holstein bull calves (38.85 ± 4.71 kg) were assigned to one of two treatments at birth to determine the effect of feeding time on growth, nutrient intake, metabolic hormone secretion, and energy metabolism. Regularly fed calves (n = 9) were fed MR daily at 0630 h, and irregularly fed calves (n = 9) at 1030, 0800, 0630, 0830, 0530, 0930, and 0730 Monday through Sunday. Body weights were measured weekly from birth to 9 weeks. Water intake, fecal scores, and starter intake were measured daily. Serial blood collections were conducted at 2, 4, 6, and 8 weeks for ghrelin and GH concentrations. Blood sample collection began one hour prior to regular feeding time (0530 h) and ended one hour post regular feeding time (0730 h), at time points 0, 15, 30, 45, 50, 55, 60, 65, 70, 75, 90, 105, and 120 minutes. An IVGTT was performed at weeks 3, 6, and 9 to assess glucose metabolism. Water intake increased (P < 0.05) in irregularly fed calves at weeks 1 and 3. A treatment by week interaction and a main effect of week were observed for ghrelin concentrations (P < 0.05), and regularly fed calves exhibited increased ghrelin concentrations at week 4 (P < 0.10). Plasma ghrelin concentrations increased with age until weaning at week 6 then decreased at week 8. An increase in GH concentrations were observed at time points t= 75 (P < 0.05), 90 (P < 0.10), and 120 (P < 0.10) min. A treatment by week interaction and a main effect of week were observed for GH concentrations (P < 0.0001). Regularly fed calves had higher GH concentrations at weeks 2 and 4 (P < 0.05). No differences were observed (P > 0.10) for glucose concentrations. Peak insulin concentrations (P < 0.05) and AUC for insulin (P < 0.10) increased as calves aged, indicating that calves become less sensitive to insulin as they develop. Results indicated that feeding time does not have an overall effect on growth, feed intake, and glucose metabolism, but does affect growth hormone concentrations.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-08192013-113334 |
| Date | 29 August 2013 |
| Creators | Chartier, Erica Lynn |
| Contributors | Williams, Cathleen, Jenny, Bruce, Thompson, Donald, Hutchison, Charles |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-08192013-113334/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein 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 LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, 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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