Murdoch MSA Long Distance Transport

Summary

Proposed indicators of pre-slaughter stress due to time from dispatch to slaughter and transport distance were measured in 294 yearling cattle and 130 export cows harvested in 5 and 4 separate lots respectively. Plasma lactate, urine specific gravity (Usg), D-3-hydroxybutyrate (BHB), carcass weight, meat colour and pHu measurements were taken on all animals with muscle glycogen, muscle lactate and all MSA measurements also recorded in all yearlings.
There was a strong effect of kill group on plasma lactate, BHB and Usg but none of these measures had a strong linear relationship (positive or negative) with distance travelled or time from despatch to slaughter. The variation between and across killgroups was also large for all parameters. This indicates that blood lactate or BHB and Usg can’t be accurately used as a predictor of long term stress or time in transit. Increased "flightiness" in the yearling cattle was associated with increased muscle and plasma lactate concentration, but more glycogen in the longissimus thoracis et lumborum.
It is concluded that cattle with increased flight speed have a stronger acute stress response immediately preslaughter but that this response is so short term that it does not affect the final ultimate pH at grading.