VPB 121: Veterinary Physiology - II (2+1)

PINEAL GLAND

• It is the main translator of photoperiodic effect in animals.
• The pineal gland produces a hormone, melatonin in response to darkness. Light passes from the retina to supra chiasmatic nucleus of the hypothalamus, superior cervical ganglia and to pineal gland.
• The melatonin inhibits gonadal activity.
• Cat and horse are positively affected with increasing light period and goat and sheep are positively affected by decreasing photoperiod.
• The pineal gland acts to relay light-dark information to the hypothalamus and regulates seasonal breeding in animals.