Blood collection at
exsanguination is a method of collecting samples at abattoirs which itself has no effect on animal welfare, compared with collection prior to stunning. However, there is the potential for artefact to affect measurements. It was hypothesised that, for most blood analytes measured, the differences between lairage and
exsanguination measurements would be minimal, except for
creatine kinase, which was expected be higher in
exsanguination samples. Fifty-nine male dairy calves approximately 5-10 days old were sampled prior to slaughter, and again during
exsanguination after stunning. Each sample was analysed for packed cell volume, serum
urea,
beta-hydroxybutyrate, gamma-glutamyl
transferase, total
protein,
glucose and
creatine kinase concentrations.
Exsanguination and lairage blood results were compared using a paired t-test. There were no significant differences between the measurements taken at
exsanguination compared with lairage for packed cell volume,
urea and
beta-hydroxybutyrate.
Glucose concentrations were higher in
exsanguination samples, and total
protein concentrations were lower, but for both of these analytes the differences were clinically small. Gamma-glutamyl
transferase activity was lower in
exsanguination samples compared with lairage samples.
Creatine kinase activity was higher in
exsanguination samples. It was concluded that collecting blood at
exsanguination is a valid method for collecting samples for measurement of packed cell volume,
urea, and
beta-hydroxybutyrate in calves.
Glucose and total
protein can also yield useful measurements in these samples, though care needs to be taken with interpretation given the minor differences between
exsanguination and lairage measurements.
Exsanguination samples may be unsuitable for
creatine kinase and gamma-glutamyl
transferase measurement.