Every cattle breeding company in the world receives a steady trickle of complaints from farmers saying that the bull semen sold to them is faulty – it’s a fact of life in Artificial Insemination. However, what the farmer forgets is that every single batch of bull semen produced is subjected to a rigorous Quality Control programme both before AND after freezing, otherwise it’s discarded.
Once the post thaw check is completed on a sample from each batch of straws in the semen processing lab, the remaining straws can be moved to the main semen store where they are quarantined for 30 days before release for distribution or sale.
At the point of despatch from the main store, the straws have spent their entire life submerged in liquid nitrogen at -196C since freezing. It is incredibly rare for semen to deteriorate whilst stored in liquid nitrogen and there is no published evidence to explain such a phenomenon. However, anecdotal evidence from the AI industry does suggest that frozen semen from some bulls can deteriorate to a degree in storage, but this is extremely rare and there is no logical explanation for it.
Semen from individual bulls is delivered to the farm and stored on the farm in small goblets. If one of these goblets is dropped by the courier at any time during delivery, or is dropped on farm by the inseminator (be it a technician service or the farmer himself managing the farm flask ), then all the straws in that goblet will be compromised. The nitrogen is lost from the goblet, the straws thaw or partially thaw, they are quickly picked up and plunged back into nitrogen. This is likely to result in significant sperm cell damage which in turn will reduce conception rates, and often affects the stock from a single bull.
It is therefore very easy and quite logical to blame the bull, when it is in fact the semen handling which has been at fault. This is probably one of the most common causes of reduced conception rates to a single AI bull at the farm level.