Australian guidelines in bull sperm morphology examination and reporting (Perry et al., 2002) were originally designed for use within the framework of a new system for Bull Breeding Soundness Evaluation (Fordyce et al., 2006) within which sperm morphology assessment must be carried out by accredited assessor individuals. This morphology scheme has become widely accepted among practitioners and cattle producers, despite some initial opposition, because of the uniformity it offers.
This study was constructed to record the distribution of sperm morphology by breed, age, season and location of 12,272 bulls in 500 herds from more than 90 clinics submitted to QSML during the last 4 years using this single standard where sperm are classified into the 8 categories determined. Australian location was divided into 4 climatic regions based upon temperature, vegetation and parasite exposure. There was a significant effect of location and breed upon both percentage of normal sperm and the individual categories of sperm abnormality (P=<0.001). A significant interaction (P=< 0.01) occurred between 3 locations and breed. Age was significantly correlated (P=<0.01, r2= 0.01) with some abnormalities (e.g. proximal droplets and midpieces, P=<0.01, r2= 0.01) but not others (e.g vacuoles).
This is the first study to comprehensively collect data from this wide geographical area and compare sperm morphology profiles among the Bos indicus and Bos taurus breeds assessed enabling increased accuracy of prognosis by clinicians based on a robust data set established for breed and age within their location. Further, it will enable seedstock producers to measure how their bulls are performing in relation to what is practically achievable in their environment.

Acknowledgements: We are indebted to the clients of QSML for their enthusiasm in providing this data and the funds which enabled this research.