Stress in Dairy Animals | Management Induced Stress in Dairy Cattle: Effects on Reproduction
| Autor: | H.A. Garverick, Matthew C. Lucy, D.E. Spiers |
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| Rok vydání: | 2011 |
| Předmět: |
Estrous cycle
endocrine system medicine.medical_specialty Adrenal gland media_common.quotation_subject Biology Endocrinology medicine.anatomical_structure Hypothalamus Internal medicine Follicular phase medicine Endocrine system Luteinizing hormone Ovulation hormones hormone substitutes and hormone antagonists Hormone media_common |
| Popis: | During stress, the hypothalamic-pituitary-adrenal (HPA) axis is activated. Hypothalamic neurons within the HPA axis secrete corticotropin-releasing hormone that causes the release of adrenocorticotrophic hormone (ACTH) from the pituitary. The ACTH causes the adrenal gland to secrete cortisol (a stress hormone). Cortisol will initially improve an animal's ability to cope with stress. Long-term increases in cortisol, however, are unhealthy. The hormone responsible for reproduction is gonadotropin-releasing hormone (GnRH). GnRH is released from the hypothalamus and causes the release of luteinizing hormone (LH) from the pituitary. The release of LH stimulates ovarian follicular growth and ovulation (essential processes for reproduction). Physiological and psychological stressors will typically inhibit GnRH and LH release. Some stressors activate the HPA axis (i.e., increase cortisol) and inhibit GnRH and LH through an HPA-dependent mechanism. Other stressors including postpartum negative energy balance have inhibitory effects on GnRH and LH but act through pathways that do not involve the HPA axis. A certain amount of management-induced stress is unavoidable. The best reproductive performance will be achieved when stress is minimized so that the endocrine components of the reproductive axis can function at their maximal level. |
| Databáze: | OpenAIRE |
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