Nervous system:

• The udder is supplied with two types of nervous fibers:

a) Afferent (sensory) fibers, originate from the dorsal root of spinal cord and

b) efferent or motor (sympathetic) fibers which is originate from the ventral root of the spinal cord

• The motor nerve to the udder regulate blood flow and innervate the smooth muscles.
• Excitation of the cow causes the sympathetic system to discharge epinephrine which constricts the blood vessels of the udder and if prolonged reduce milk production.