Hormonal growth-promotant effects on grain-fed cattle maintained under different environments

Area of Science:

• Animal Science
• Physiology
• Environmental Science

Background:

• Climatic conditions and hormone growth promotants (HGP) influence cattle physiological responses.
• Understanding these interactions is crucial for animal welfare and productivity.

Purpose of the Study:

• To investigate the effects of thermoneutral, hot, and cold climatic conditions on cattle physiology.
• To evaluate the impact of different HGPs (estrogenic, trenbolone acetate, or both) on these physiological responses.

Main Methods:

• Six steers and six heifers were exposed to thermoneutral, hot, and cold conditions before and after HGP implantation.
• Respiration rate (RR), pulse rate, rectal temperature (RT), and heat production (HP) were measured.
• Implant types included estrogenic (E), trenbolone acetate (TBA), or both (ET).

Main Results:

• Respiration rates were higher in hot conditions and lower in cold conditions compared to thermoneutral conditions.
• Rectal temperatures increased in hot conditions post-implantation and were higher with E implants compared to TBA or ET implants.
• Heat production was higher in hot conditions than in cold conditions, with ET cattle showing the lowest HP and highest feed intake under thermoneutral conditions.

Conclusions:

• HGP and climate significantly affect cattle physiological parameters, including respiration rate, rectal temperature, and heat production.
• Trenbolone acetate (TBA) or combined (ET) implants may offer advantages in managing heat stress, potentially reducing risks associated with extreme heat.
• Further research into optimal HGP use under varying climatic conditions is warranted for improved cattle management.