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Semen and Testis Characteristics in Young Yorkshire and Lacombe Boars

Canada Department of Agriculture, Brandon, Manitoba, Canada

Abstract

Twenty-two Yorkshire boars (average age 9.2 months) and 22 Lacombe boars (average age 9.2 months) were ejaculated at 48-hr, intervals for an 8-week period. For the York-shire boars the average values for the different semen components were: semen volume, 225 ml.; strained volume,178 ml.; gel volume, 47 ml.; sperm concentration, 143x10⁶ per ml.; total sperm per ejaculate, 23.1 xlO⁹; and motile sperm per ejaculate, 17.3x10⁹. Corresponding values for the Lacombe boars were 228, 176, 52, 138x10⁶, 21.7x10⁹ and 15.0xlO⁹. No significant differences were observed between the two breeds in regard to the previously listed semen components, but significant differences were found among boars within a breed with respect to these components. Also, there was considerable variation among ejaculates in the same boar. Initial ejaculates were of poorer quality than ejaculates obtained during final weeks of the semen collection period. Generally, there was a high positive correlation between total volume and gel volume, and between sperm concentration and total sperm per ejaculate. There appeared to be no direct relationship between total volume and total sperm per ejaculate, or between strained volume and total sperm per ejaculate. In most boars sperm concentration decreased when total volume of the ejaculate increased.

The two breeds differed significantly (P<.01) with respect to duration of ejaculation. The average ejaculation time of the Yorkshire boars was 5.7 min. and of the Lacombe boars, 7.2 min.

The collection equipment, cheesecloth (used for removing the gel fraction) and gel retained 1.49, 1.44 and 0.35%, respectively, of the total sperm counted in the collection bottle.

In both breeds the combined testis weight comprised 0.46% of total body weight. The sperm output per gram of testis per 48-hr. was on the average 44.4xlO⁶ sperm for the Yorkshire boars and 40.4x10⁶ sperm for the Lacombe boars. The two breeds did not differ significantly in sperm output per gram of testis. Sperm output was correlated (0.51, P<.01) with combined testis weight.

¹ The authors are indebted to T. H. Anstey and his staff, Research Station, Canada Department of Agriculture, Lethbridge, Alberta, for carrying out the computer analyses. The technical assistance of H. H. S. Bell is gratefully acknowledged.