The relationship between postmortem urinary catecholamines, meat ultimate pH, and shear force in bulls and cows

Area of Science:

• Animal Science
• Food Science
• Meat Science

Background:

• Investigating the link between pre-slaughter stress and meat quality is crucial for the beef industry.
• Understanding how stress indicators like catecholamines influence meat characteristics informs animal handling and processing protocols.

Purpose of the Study:

• To determine the relationship between stress responsiveness, measured by urinary catecholamines, and meat quality parameters in cattle.
• To assess how factors like age, breed, nutritional status, and mixing affect stress levels and subsequent meat tenderness.

Main Methods:

• Analyzed muscle samples (m. longissimus lumborum) and urinary catecholamines (noradrenaline, adrenaline) from Friesian bulls and cull cows.
• Measured ultimate pH (pH(u)), lactate, glycogen, glycolytic potential, sarcomere length, and shear force (meat tenderness).
• Classified animals based on age, mixing status (bulls), and nutritional finish (cows) prior to slaughter.

Main Results:

• Unfinished cows exhibited higher urinary noradrenaline than bulls and finished cows.
• Mixed bulls and both cow groups had elevated urinary adrenaline compared to non-mixed bulls.
• In well-fed bulls, pre-slaughter stress (high adrenaline) negatively impacted meat tenderness via glycogen depletion and lower pH(u).
• In cows, adrenaline response was not directly linked to glycogen depletion, and meat tenderization capacity was reduced in nutritionally compromised (unfinished) animals.

Conclusions:

• Pre-slaughter stress, particularly elevated urinary adrenaline, significantly affects meat tenderness in bulls, especially when muscle glycogen is depleted.
• Nutritional status is a key factor in meat quality and tenderization potential, with underfed cows showing reduced meat quality.
• The impact of stress hormones on meat quality differs between bulls and cows, necessitating distinct management strategies.