23/06/2025
𝐇𝐨𝐫𝐦𝐨𝐧𝐞𝐬 𝐚𝐧𝐝 𝐀𝐧𝐢𝐦𝐚𝐥 𝐋𝐢𝐟𝐞: 𝐅𝐫𝐨𝐦 𝐆𝐫𝐨𝐰𝐭𝐡 𝐭𝐨 𝐑𝐞𝐩𝐫𝐨𝐝𝐮𝐜𝐭𝐢𝐨𝐧
Hormones play a vital role in every stage of an animal's life - from growth and development to reproduction and survival. These chemical messengers are produced by endocrine glands and travel through the bloodstream to regulate body functions.
1. Growth and Development
Growth hormone (GH), secreted by the pituitary gland, is essential for the growth of bones and tissues in young animals. It stimulates protein synthesis and helps in the utilization of fat for energy. Thyroid hormones (T3 and T4) also regulate metabolism, ensuring proper development of the nervous system and body temperature regulation.
Example: Calves with GH deficiency may show stunted growth and poor muscle development.
2. Metabolism and Homeostasis
Insulin and glucagon, produced by the pancreas, maintain blood glucose balance. Cortisol, a steroid hormone from the adrenal gland, helps animals cope with stress and regulates energy metabolism.
Example: In diabetic animals, insulin imbalance can lead to lethargy, weight loss, and excessive thirst.
3. Reproductive Hormones
Reproduction in animals is controlled by a complex hormonal system. Gonadotropin-releasing hormone (GnRH) from the hypothalamus triggers the release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary gland. These hormones regulate ovarian and testicular functions.
In females: Estrogen and progesterone control the estrous cycle, ovulation, and pregnancy.
In males: Testosterone regulates s***m production and secondary sexual characteristics.
Example: A deficiency in progesterone may lead to early embryonic loss in cattle.
4. Maternal Behavior and Lactation
Prolactin and oxytocin are key hormones involved in maternal behavior and milk production. Prolactin stimulates milk synthesis, while oxytocin causes milk let-down in response to suckling.
Example: Oxytocin injections are often used in veterinary practice to assist with milk let-down in animals that are stressed or uncooperative.
Conclusion
Hormones are fundamental to the health, reproduction, and productivity of animals. Understanding their roles helps veterinarians diagnose disorders and improve animal management and welfare.
Scientific Reference
Sjaastad, Ø.V., Hove, K., & Sand, O. (2010). Physiology of Domestic Animals (2nd ed.). Scandinavian Veterinary Press.
National Research Council. (1996). Nutrient Requirements of Domestic Animals. National Academies Press.
Figure 1. Oxytocin action on the smooth muscle cells in the myometrium.
