HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Weisgold, A. D. Articles by Almquist, J. O. Search for Related Content PubMed PubMed Citation Articles by Weisgold, A. D. Articles by Almquist, J. O.

Reproductive Capacity of Beef Bulls. VI. Daily Spermatozoal Production, Spermatozoal Reserves and Dimensions and Weight of Reproductive Organs^{1 ,2,}

The Pennsylvania State University³, University Park 16802

Abstract

Daily testicular spermatozoal production (DSP) and extragonadal spermatozoal reserves (EGR) were determined hemacytometrically using tissue homogenates from beef bulls. The first experiment involved 7-year-old Angus (N = 7) and Hereford (N = 7) bulls and the second involved one group of 3-year-old Charolais (N = 8) and another group of 5- to 6-year-old Charolais (N = 11). Each bull was sexually rested 29 days prior to slaughter. Breeds differed widely in testicular weight, DSP and EGR. Testicular weight of Angus exceeded (P<.05) that of Herefords (363 vs 323 g), as did DSP (6.9 vs 5.9 x 10⁹) and EGR (55.3 vs 39.4 x 10⁹). Characteristics of the two groups of Charolais did not differ significantly; testicular weight, DSP and EGR for the 19 bulls averaged 386 g, 8.9 x 10⁹ and 63.5 x 10⁹. Thus, Charolais bulls attained sexual maturity by 3 years of age. Correlations between testicular weight and DSP per testis for Angus and Charolais bulls of .70 and .81 were significant (P<.01), but that of .41 for Herefords was not. Efficiency of spermatozoal production was higher (P<.01) for 3-year-old than 5- to 6-year-old Charolais bulls (14 vs 12 x 10⁶ spermatozoa daily/g testicular parenchyma), but did not differ significantly between Angus and Hereford bulls (10 x 10⁶ spermatozoa daily/g testicular parenchyma for each breed). For mature beef bulls, paired testicular weight and body weight were not significantly correlated. Reproductive organ dimensions and weights were summarized by breeds and ages.

¹ Authorized for publication as Paper No. 5518, Journal Series, The Pennsylvania Agricultural Experiment Station on June 2, 1978.

² Partially supported by Atlantic Breeders Cooperative, Lancaster, PA, Northeastern Breeders Association and Sire Power, Inc., Tunkhannock, PA, and the American-International Charolais Association, Houston, TX. The technical assistance of Mrs. A. Keene and Mrs. H. Homan is gratefully acknowledged.

³ Dairy Breeding Research Center, Department of Dairy and Animal Science.