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Slaughtered hogs with discoloured bones and the relationship with tetracycline medication in the grower-finisher stage

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dc.contributor.advisor Friendship, Robert Varela, Norma P. 2012-05-15T19:09:33Z 2012-05-15T19:09:33Z 2012-05 2012-05-03 2012-05-15
dc.description.abstract Bone discolouration of pig carcasses is a quality concern that has been observed in Ontario slaughter plants. The objectives of this study were to establish the prevalence of pig carcasses showing bone discolouration, its relationship with residues of tetracyclines in bones, and to investigate the use of tetracyclines in feeding programs for grower-finisher pigs as the main risk factor for discolouration. Abattoir data were examined to determine the extent of the problem and the prevalence of bone discolouration during 2006, 2008, 2009, and 2010 was found to be 0.13%, 0.22%, 0.26%, and 0.28%, respectively, indicating that the issue of bone discolouration was present at low levels over the entire period of the study. A controlled trial using feed, water, and injectable tetracycline products to investigate the effect of tetracyclines on residue and bone colour was conducted. Bones were assessed visually for signs of discolouration, and high performance liquid chromatography (HPLC) was used to measure the levels of tetracycline residues in the bones. Results from this trial demonstrated that discolouration could be produced with 660ppm of chlortetracycline (CTC) in feed for 12 weeks even when 33 days of withdrawal time was observed. It was also found that residues of tetracyclines can be present in bones in the absence of discolouration. A retrospective study was conducted to investigate tetracycline use in herds identified as having discoloured bones at slaughter. Positive shipments were associated with dosage and duration of CTC use as well as with length of withdrawal. In conclusion, discoloured bones of pig carcasses were identified at low levels in one large Ontario abattoir; however, further investigation is needed in order to determine the impact it may have on the swine industry. en_US
dc.description.sponsorship Ontario Pork and the University of Guelph - Ontario Ministry of Agriculture (OMAFRA) Sustainable Production System Program en_US
dc.language.iso en en_US
dc.subject Swine en_US
dc.subject Tetracycline en_US
dc.subject Bone discolouration en_US
dc.subject Discoloured bones en_US
dc.subject Residues in bones en_US
dc.subject Tetracycline Residues en_US
dc.subject Chlortetracycline en_US
dc.subject Tetracycline en_US
dc.subject Oxytetracycline en_US
dc.subject Pig en_US
dc.subject Hog carcasses en_US
dc.subject Medicated feeding programs en_US
dc.title Slaughtered hogs with discoloured bones and the relationship with tetracycline medication in the grower-finisher stage en_US
dc.type Thesis en_US Population Medicine en_US Doctor of Philosophy en_US Population Medicine en_US
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