Master of Science (MS)


Dairy Science (Animal, Dairy, and Poultry Sciences)

Document Type



The objective of this study was to evaluate two semen collection schedules utilizing the assumed behavioral differences between bovine species. The efficiency was measured by bull behavior and semen quality parameters. Four Holstein and four Brahman bulls were collected each during a morning and a night collection time weekly. Ejaculates (n=64) were obtained via artificial vagina over four-weeks. To avoid masking benefits of night collection, the first collection of the week was alternated between night and day. Two collection teams were employed to reduce the time needed for collection, and the variability in collection method. Sampling order and collection team were randomized throughout the study. Bull behavior parameters included reaction time to first mount, time to ejaculation, a refractory period test, and a thrust intensity test. As a managerial factor, the numbers of handler interruptions were counted. Pre-freeze semen parameters included total volume, initial motility and concentration. These were combined as total motile sperm harvested. Post-freeze semen viability parameters included post thaw motility, percent intact acrosomes, and 3-hour post thaw motility. Semen morphology parameters consisting of primary and secondary abnormalities were also measured. All data were analyzed by least squares methods. The bull within breed interaction was significant for all bull behavior parameters as well as the managerial parameter (P < .05). The bull within breed effect for total motile sperm harvested was not significant, but differed between breeds (P< .05). There was a mixed response due to bull within breed for the post freeze semen viability parameters. Bull within breed was not significant for the semen morphology parameters. The night versus day treatment was significant for the managerial parameter (P = .002). Consideration of a different collection schedule for Bos indicus cattle was not warranted. However, the efficiency of the collection process was impacted by extraneous environmental conditions.



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

John E. Chandler



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Dairy Science Commons