Variation among Beef Bulls in the Ratio of X- to Y-Chromosome Bearing Spermatozoa


A study was conducted to evaluate variation in the ratio of X- to Y-bearing sperm of individual ejaculates and to determine any relationship between skewed sex ratio and either routine morphological evaluation or computer assisted sperm analysis (CASA). Semen was collected from bulls weekly for 6 consecutive weeks, sperm DNA was recovered and quantitative, and real-time PCR was used to determine the ratio of X- to Y-bearing sperm in each ejaculate. The overall mean of X-bearing sperm within ejaculates was 54.7% over the 6 weeks of semen collections. The percentages of X-bearing sperm were similar (P > 0.5) across all collections. Between bulls, there were differences (P < 0.05) in the mean percentage of X-bearing sperm. No significant correlations were found between CASA parameters and percentage of X-bearing sperm across bulls, so analysis was done within each bull. Different combinations of CASA and/or morphological parameters were found to correlate with the percentage of X-bearing sperm but the prediction equations were specific for individual bulls and unlikely to be of use across bulls. These results confirm that the ratio of X- to Y-bearing sperm may be skewed in some ejaculates of bull semen. Some sperm parameters measured by CASA or routine morphological evaluation were associated with semen sex ratio.

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Rorie, R. , Delgado, P. and Lester, T. (2014) Variation among Beef Bulls in the Ratio of X- to Y-Chromosome Bearing Spermatozoa. Advances in Reproductive Sciences, 2, 69-75. doi: 10.4236/arsci.2014.24008.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Clutton-Brock, T H. and Iason, G R. (1986) Sex Ratio Variation in Mammals. The Quarterly Review of Biology, 61, 339-374.
[2] Hardy, I.C.W. (1997) Possible Factors Influencing Vertebrate Sex Ratios: An Introductory Overview. Applied Animal Behaviour Science, 51, 217-241.
[3] Krackow, S. (1995) Potential Mechanisms for Sex Ratio Adjustment in Mammals and Birds. Biological Reviews, 70, 225-241.
[4] Chandler, J.E., Steinholt-Chenervet, H.C., Adkinson, R.W. and Moser, E.B. (1998) Sex Ratio Variation between Ejaculates within Sire Evaluated by Polymerase Chain Reaction, Calving, and Farrowing Records. Journal of Dairy Science, 81, 1855-1867.
[5] Chandler, J.E., Taylor, T.M., Canal, A.L., Cooper, R.K., Moser, E.B., McCormick, M.E., Willard, S.T., Rycroft, H.E. and Gilbert, G.R. (2007) Calving Sex Ratio as Related to the Predicted Y-Chromosome-Bearing Spermatozoa Ratio in Bull Ejaculates. Theriogenology, 67, 563-571.
[6] Checa, M.L., Dunner, S. and Canon, J. (2002) Prediction of X and Y Chromosome Content in Bovine Sperm by Using DNA Pools through Capillary Electrophoresis. Theriogenology, 58, 1579-1586.
[7] Coetzee, K., Kruger, T.F. and Lombard, C.J. (1999) Repeatability and Variance Analysis on Multiple Computer Assisted (IVOS) Sperm Morphology Readings. Andrologia, 31, 163-168.
[8] Gravance, C.G., Garner, D.L., Pitt, C., Vishwanath, R., Sax-Gravance, S.K. and Casey, P.J. (1999) Replicate and Technician Variation Associated with Computer Aided Bull Sperm Head Morphometry Analysis (ASMA). International Journal of Andrology, 22, 77-82.
[9] Campbell, R.C., Dott, H.M. and Glover, T.D. (1956) Nigrosin Eosin as Stain for Differentiating Live and Dead Sperm. The Journal of Agricultural Science, 48, 1-8.
[10] Heyen, D.W., Beever, J.E., Da, Y., Evert, R.E., Green, C., Bates, S.R.E., Ziegle, J.S. and Lewin, H.A. (1997) Exclusion Probabilities of 22 Bovine Microsatelite Markers in Fluorescent Multiplexes for Semi-Automated Parentage Testing. Animal Genetics, 28, 21-27.
[11] Chandler, J.E., Canal, A.M., Paul, J.B. and Moser, E.B. (2002) Collection Frequency Affects Percent Y-Chromosome Bearing Spermatozoa, Sperm Head Area and Quality of Bovine Ejaculates. Theriogenology, 57, 1327-1346.
[12] Navara, K.J. (2010) Programming of Offspring Sex Ratios by Maternal Stress in Humans: Assessment of Physiological Mechanisms Using a Comparative Approach. Journal of Comparative Physiology B, 180, 785-796.
[13] Pérez-Crespo, M., Pintado, B. and Gutiérrez-Adán, A. (2008) Scrotal Heat Stress Effects on Sperm Viability, Sperm DNA Integrity, and the Offspring Sex Ratio in Mice. Molecular Reproduction and Development, 75, 40-47.
[14] Szyda, J., Simianer, H. and Lien, S. (2000) Sex Ratio Distortion in Bovine Sperm Correlates to Recombination in the Pseudoautosomal Region. Genetics Research, 75, 53-59.
[15] Pauciullo, A., Nicodemo, D., Peretti ,V., Marino, G., Iannuzzi, A., Cosenza, G., Di Meo, G.P., Ramunno, L., Iannuzzi, L., Rubes, J. and Di Berardino, D. (2012) X-Y Aneuploidy Rate in Sperm of Two “Minor” Breeds of Cattle (Bos taurus) by Using Dual Color Fluorescent in Situ Hybridization (FISH). Theriogenology, 78, 688-695.
[16] Yan J., Feng, H.L., Chen, Z.J., Hu, J., Gao, X. and Qin, Y. (2006) Influence of Swim-Up Time on the Ratio of X- and Y-Bearing Spermatozoa. European Journal of Obstetrics & Gynecology and Reproductive Biology, 129, 150-154.
[17] Balli, K.S., Patton, W.C., Jacobsen, J.D., Corselli, J., King A. and Chan, P.J. (2004) Sperm Velocity in Seminal Plasma and the Association with Gender of Offspring. Systems Biology in Reproductive Medicine, 50, 37-40.
[18] Maligaya, M.L., Chan, C.A., Jacobson, J.D., Patton, W.C., Corselli, J. and Chan, P.J. (2006) A Follow-Up Expanded Study of the Correlation of Sperm Velocity in Seminal Plasma and Offspring Gender. Archives of Andrology, 52, 39- 44.
[19] Madrid-Bury, N., Fernández, R., Jiménez, A., Pérez-Garnelo, S., Moreira, P.N., Pintado, B., Fuente, J. and Gutiérrez- Adán, A. (2003) Effect of Ejaculate, Bull, and a Double Swim-Up Sperm Processing Method on Sperm Sex Ratio. Zygote, 11, 229-235.

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