The role of the efferent innervation of cow's udder in the regulation of its blood supply
The experiment was carried out on 3 cows in 3-4<sup>th</sup> lactation with the probes of electromagnetic flow meter implanted on both external pudic artery. During initial 10 d period the blood supply of both udder halfs was studied and then one half udder was fully denervated and aftert 10-12 d after operation the volume mammary blood flow was studied during 20 d. The measurements on both halfs were performed twice a day during 10 min before milking, in the course of milking and during 21 min after milking. In all the periods the volume blood flow through denervated half udder was higher in the average by 11% compared to intact half udder (P<0.001), but the denervation did not exert any influence on daily milk yield. The data obtained suggest that efferent innervation exerts in lactating cows the constant constrictory influence on udder's blood vessels in conditions of various functional state of organ.