Can Productive Aptitude and Age Affect Circulating Serotonin, Total Thyroid Hormones, and Cortisol Patterns in Cows?

Area of Science:

• Endocrinology
• Animal Science
• Veterinary Medicine

Background:

• Cattle productivity is influenced by complex endocrine regulation.
• Hormones like 5-hydroxytriptamine (5-HT), thyroid hormones (THs), and cortisol impact metabolic pathways crucial for meat and milk yield.
• Understanding these hormonal influences is key to optimizing livestock production.

Purpose of the Study:

• To investigate how milk or meat aptitudes and age affect circulating 5-HT, THs, and cortisol concentrations in cattle.
• To explore potential interactions among these hormones and their relationship with production traits.

Main Methods:

• Analysis of 5-HT, cortisol, and THs (T3, T4) in 46 healthy cows of three breeds.
• Quantification using Enzyme-linked immunosorbent assay (ELISA) for 5-HT and cortisol, and an immunochemiluminescent analyzer for THs.
• Statistical analysis using ANCOVA to assess the influence of age, aptitude, and their interaction.

Main Results:

• Dairy cows exhibited significantly lower triiodothyronine (T3) concentrations compared to meat cows.
• Thyroxine (T4) levels decreased with advancing age in both milk and meat production-oriented cows.
• A positive correlation was observed between T4, T3, and 5-HT in meat production-oriented cows.

Conclusions:

• Age and production aptitude significantly influence key hormone concentrations in cattle.
• Hormonal profiles, particularly T3 and T4 levels, differ between dairy and meat breeds and change with age.
• These findings provide insights into the endocrine regulation of cattle productivity and potential targets for improvement.