Abstract

This work was conducted to study the breeding soundness of semen producing bulls, their semen quality to functional tests and the inter relationship of these functional tests with spermatozoa motility percentage for the semen produced at National Animal Genetic Improvement Institute (NAGII). A total of 14 breeding bulls (Boran = 4, Crosses of 75% Holstein Frisian × 25% Boran = 4 and Holstein Frisian = 6) with respective ejaculates of 35, 33 and 57 for semen quality evaluations were considered. After physical examination of bulls for breeding soundness, semen samples were tested for functional and structural (spermatozoa acrosome integrity, viability and hypo osmotic swelling reactivity) tests and spermatozoa motility percentage using subjective and objective (computer assisted semen analysis; CASA) evaluation methods, to see the correlation of functional tests with spermatozoa motility percentage. And in the study, nevertheless, significant differences between Cross and HF breeds were not recorded for the breeding soundness evaluation parameters and for most of the semen quality parametric test values; significantly (P < 0.05) minimal and highest parametric values of the breeding soundness evaluation and semen quality were recorded in Boran and HF breeds, respectively. All the functional semen quality evaluation tests (HOST, acrosome integrity, sperm morphological defect and viability) were related in one or the other to the objective CASA individual spermatozoa motility evaluation; which were not true with subjective individual spermatozoa motility estimation. Therefore, conducting stringent breeding soundness evaluation for these breeds and evaluating their individual spermatozoa motility percentage using CASA system instead of subjective motility estimation can screen good quality semen and subsequently make possible to predict their fertility potential.

Key words: Boran, correlation, cross-breed, Holstein-Frisian, semen.