Chronological vs. physiological age indicators in beef cattle: Effects of the production system and growth promotants

Abstract

s published in Meat Science from the 2014 CMSA / CMC Abstracts are published in cooperation with the Canadian Meat Science Association / Canadian Meat council and have been subject to the Societies own review process and have not been peer reviewed by the Editorship of the journal In the absence of verifiable chronological age, both dentition and carcass ossification have been used as physiological indicators. Physiological maturity is also important in the determination of meat quality. Changes in production practices may have altered the relationship between chronological age and physiological maturity. A total of 224 steers of known chronological age were allotted to a 2 × 2 factorial arrangement of treatments to determine the effect of production system (calf-fed: CF; yearling-fed: YF) and growth implant (non-implant: NIMP; implant: IMP) on physiological indicators of chronological age. There were significant interactions (P b 0.001) between the production system and the implanting strategies on the frequencies of the carcasses showing ossification in the sacral, lumbar and thoracic vertebral column portions. In the CF, 59% of the NIMP and 2% of the IMP carcasses did not show any evidence of fusion in the sacral portion. In the lumbar portion, none of the NIMP CF showed any ossification (score 0), while most of ⁎ Corresponding author at: Lacombe Research Centre, Agriculture and Agri-Food Canada, 6000 CE fax: 01403 782 6120 E-mail addresses: oscar.lopezcampos@agr.gc.ca, olopezcampos@gmail.com (O. Lopez-Campos). http://dx.doi.org/10.1016/j.meatsci.2014.07.013 0309-1740/© 2014 Elsevier Ltd. All rights reserved. the IMP CF (80%) showed varying degrees of ossification (scores 1–5). In the YF, all the carcasses from the IMP showed advanced ossification ranging from two islands (score 3, 17% and score 4, 15%) to a long fused island on the vertebral cap (score 5, 67%). Sixty six percent of the NIMP YF did not show any osseous formations in the lumbar caps (score 0) and 26% showed a single small island (score 1). The IMP YF (96%) showed ossification in the thoracic portion, while most of the NIMP YF (98%) and both implant groups of the CF (NIMP 100%; IMP 91%), did not show ossification in the thoracic caps. These results support that the physiological maturity of the carcasses might be dramatically impacted depending on the combination of the production system and growth implant strategy. A compendium of descriptors based on dentition and ossification processes at the vertebrae column should be taken into consideration to ensure accurate estimation of chronological age of cattle when birth date is not available.