How to prepare sample for a longer shipping time: 36-48 hours

Sometimes you need to do a longer ship.  For example shipping on a Saturday for a Monday insem, or shipping to the UK or Hawaii from the US. Here's how.

As time passes some sperm will die, but it is possible to ship over a 36 to 48 hour period.  A high initial sperm count and careful prep can get you there.  I know of several successes after 48 hour ships and even one after a 72 hour ship.

Preparing the shipment

1. Use babydust TYB. Anecdotally, it seems to be giving the best rates.
2. After you thaw your TYB, make sure it's room temperature before mixing with the semen.  Sperm are easily killed by at temperatures at or above body temperature, which is why the testes are located in a sac external the body.  TYB at body temperature or above will kill them.
3. When you pour the TYB and semen into the shipping vial, if there is any air space at the top, add more TYB. Oxidation kills sperm and there will be more nutrients and buffers from the extra TYB. As sperm swim they metabolize sugars and produce acid. Eventually they die en masse when their environment becomes too acidic. Buffers in the TYB help counteract this, and cooling slows their metabolism.  More TYB means more nutrients and more buffers.
4. Use two ice packs and wrap them each in three or four plastic grocery bags. Don't be neat, you want to trap air between the layers of the wrap. This will insulate the ice packs inside the shipper, so they will cool more gently, but over a longer period of time. Too cold is as detrimental to sperm survival as too hot. You want a temperature of around 50F (10C) for the duration, and you want to hold that temperature for as long as possible.
5. Styrofoam is good at blocking heat transfer by conduction and convection, but not very good at blocking heat transfer by radiation. Aluminium foil is. If you put aluminium foil (shiny side facing out) on the outside of the styrofoam box (with tape or glue), for a negligible increase in weight and volume you will have a much better shipper that reflects thermal radiation.
6. Find the FedEx with the latest possible drop off time (it's usually the one at the airport).
7. Find a FedEx near the recipient that offers "Express Hold for Pickup". Since it doesn't go out for delivery the recipient can fetch it a few hours earlier. Also the offices are air conditioned, but the delivery trucks likely aren't.
   1. Unfortunately the Express Hold for Pickup service does not seem to be avialalbe in the UK, but your recip can call FedEx there and arrange a pickup add hoc, or so I would think.
8. There will be a reduction in sperm count over a 48 hour transit, so the higher the initial count the better. 

How to tell if the sample is viable

Several successes have been reported over 48 hour ships and even one after a 72 hour ship.  Recipients who own microscopes have confirmed energetic sperm upon receipt.  Any microscope with good optics and 125x magnification will suffice.  It may take a little practice but if you look for movement you should be able to see the sperm swimming.  Perhaps you can invest $150 in one, or arrange to borrow one from a local high school.