A 2 x 2 factorial trial with 2 phases was conducted to evaluate the effects of weaning age (6 wk vs 12 wk) and anthelmintic treatment (non vs dewormed) on average daily weight gain (ADG) in 36 Holstein and Jersey X Holstein crossbred steers born in fall (Oct - Nov) and winter (Dec ? Feb) 2003 ? 2004. Steers were blocked into 4 treatment groups by birth weight and breed. Calves of similar age were managed together in pastures regardless of treatment and group-fed 3.8 to 7.6 L of whole milk/d until weaning. Phase 1 extended from birth until July 15, 2004. Phase 2 started on July 15 and ended on Nov 18, 2004. Dewormed calves received 1 mL ivermectin pour-on formulation/ 10 kg body weight (BW) at 12 and 20 wk of age, and again on July 15 and Sept 23. Fecal samples and BW (birth to Nov 18, 2004) were taken from each calf at 4-wk intervals. Fecal egg counts (FEC), BW, and ADG (during Phase 1, Phase 2, and Phases 1 & 2 combined) were compared among deworm, wean age, % Holstein, birth season, and their interactions. Parasite eggs were not detected until April and were lower in dewormed calves after July and Sept treatments. Fall-born calves usually had lower FEC than winter-born calves. Gains during Phase 1 were higher for fall-born calves. In Phase 2, dewormed calves actually had faster ADG than non-dewormed calves. Gain across Phase 1 and Phase 2 were higher in fall-born calves and tended to be higher in calves weaned at 6 wk. Gains and BW generally were higher with increasing % Holstein. Although steers that were not dewormed had higher FEC and differing ADG during parts of the trial, their overall performance was similar to those that received 4 doses of ivermectin.
| Identifer | oai:union.ndltd.org:NCSU/oai:NCSU:etd-07232005-183914 |
| Date | 27 July 2005 |
| Creators | Thompson, Bianca Merrick |
| Contributors | Brinton A. Hopkins, Steven P. Washburn, Jean Marie Luginbuhl |
| Publisher | NCSU |
| Source Sets | North Carolina State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://www.lib.ncsu.edu/theses/available/etd-07232005-183914/ |
| 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 NC State University 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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