A technique is described for the removal of the seminal vesicles from the boar. The operation was carried out on twelve animals and six of the animals were subsequently trained for semen collection. The seminal plasma from the boars after surgery compared with normal litter mates had a more watery consistency and did not form the characteristic gelduring ejaculation. The sperm concentration was 49% lower while the total reduction of sperm number ejaculate was 78% in the experimental animals, but the ratio of living to dead spermatozoa remained unchanged. The concentrations of citrate and protein were significantly depressed in the seminal plasma of the animals after surgery and the pH increased; the osmolarity remained unchanged. In semination of gilts with the semen from experimental boars revealed no significant loss of fertility compared with the normal controls. Animals slaughtered up to 17 months after surgery showed no regeneration of the seminal vesicles.

Spermatozoa from intact boars and from boars without seminal vesicles were resuspected in diluent and cooled at different rates to 0 degrees C. Glutamic oxaloacetic transaminase and lactate dehydrogenase activities were greater in the diluents which had contained spermatozoa from intact boars than in those which contained spermatozoa from animals without seminal vesicles. The incubation of seminal plasma from an intact boar with spermatozoa from a vesiculectomized animal before cooling also increased the enzyme activity in the diluent. The factors responsible for this effect were associated with the basic protein fractions of boar seminal plasma, in particular the proteins with haemagglutinating activity which may have been adsorbed onto the spermatozoa. Spermatozoa were exposed to colloidal Fe(OH)2+ to determine by electron microscopy the charge on the surface of the plasma membrane of washed epididymal spermatozoa and ejaculated spermatozoa from intact and vesiculectomized boars. Epididymal spermatozoa bound the positively charged particles more readily than the ejaculated spermatozoa from the intact boars, due to the absence of membrane-bound protein.