Dynescan proves to take bull fertility exams to a new level
At the British Cattle Veterinary Association (BCVA) Congress, 18 – 21 October 2023, Dyneval showed a video of a post-thawed conventional semen straw and invited participants to estimate the % progressive motility by eye. This is a similar process farm vets follow when judging the % progressive motility during bull fertility examinations at the farm while using an optical microscope.
A 10 second video was collected with a 20 µm deep Leja channel slide, using a 10x objective, and maintained at 37.5 degrees centigrade with the Dynescan integrated heating stage. The progressive motility was analysed simultaneously with an IVOS II Computer Aided Semen Analyser (CASA) from Hamilton Thorne and a Dynescan from Dyneval Ltd. The results were 28.2% (shown in figure 1 below) for the Dynescan and 24% for the IVOS II using Qualivet settings.
The visual assessments collected from 65 BCVA participants are shown as a histogram in figure 1 where the data is binned in groups of 5% so that bin 30 includes results from 25.1 to 30. Participants were not provided with any guidance or allowed to confer. Results show a surprisingly wide range of values suggested by participants ranging from 11% to over 70%. The average result was 41% with a standard deviation of 15%, in contrast to the previously measured standard deviation of Dynescan devices which is 2%. Recognised experts performing bull semen analysis on farm regularly are shown in black and show a total variation of 42% with values ranging from 18% to 60%.
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Figure 1: Vet visual assessment of the % progressive motility judged by 65 participants from a video of a post-thawed conventional semen straw shown at the British Cattle Veterinary Association Congress in 2023. The top dark part of the bars represent experts in semen assessment who regularly perform visual assessments.
While this experiment was a ‘bit of good fun’ at an exhibition stand, it has revealed the difficulty of assessing a semen sample by eye. The visual assessment of % progressive motility is highly subjective and therefore Dynescan or other computer–aided measurements offer a reliable, objective alternative to judge semen samples. Dynescan enables user-independent, automated analysis on farm on a wide range of concentrations up to 500 million cells/ml allowing vets to concentrate on other jobs such as assessing a bull’s physiological health.
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