For a lot of Wagyu breeders, the semen tank is the most valuable thing on the place that nobody looks at. A good semen tank inventory tells you what you own, where it sits, and whether you have enough of the right sire before the breeding season starts. A bad one sends you fishing through canisters with the lid open, which is hard on straws and harder on nerves.
Here is a simple system that works whether you have one tank in the shop or several holding semen and embryos for partners.
Where tank records usually go wrong
- Straws used are never taken off the count. The list says 12, the canister holds 7.
- Canes get moved during a busy AI day and nobody updates the map.
- Nitrogen is checked "when someone remembers", which is how a tank runs dry.
- Ownership is fuzzy. Co-owned semen or embryos held for a partner end up mixed in with your own.
- Genetic condition status is not on the inventory, so you only learn a sire is a carrier when you go to plan matings.
What to record for every straw and embryo
Each line in your semen tank inventory should cover:
- Type: semen or embryo
- Sire name, or donor and sire for embryos, plus registration number
- Units on hand
- Semen type (conventional, sexed female, sexed male, reverse-sorted) or embryo type and grade
- Location: tank, canister and cane or goblet
- Straw size, straw color and collection or freeze code
- Source and owner, if it is not all yours
- Cost and value per unit
- Genetic condition results for the sire, such as F11 free or CHS free
Location is the line that saves you time. When you know a straw is in tank 2, canister 3, the green cane, you lift it once, find it, and get the canes back down fast.
Setting up your semen tank inventory in CowSync
CowSync's Semen & embryo tank tool has two tabs: Inventory for straws and embryos, and Tanks & LN2 for your nitrogen readings.
- Click Add straws / embryos and pick Semen or Embryo.
- Type the sire (or donor and sire), the registration number and the units on hand.
- Pick the semen type, or for embryos the embryo type, freeze method and grade.
- Fill in the tank, canister and cane or goblet, plus straw size, color and code.
- Add the optional details that matter to you: Wagyu %, source, owners, cost and value per unit, genetic conditions and export eligibility.
- Click Save.
The summary cards show semen straws and embryos on hand, how many different sires and donors you hold, and the inventory value. Filters let you narrow the list by semen type, embryo type, freeze method or Wagyu %. The CSV button downloads your inventory as a spreadsheet file, which is handy for insurance or a semen sale.
Straws come off when you breed
When you log an AI in the Heat & AI log, or with Log AI on the breeding board, one straw of that sire comes out of the tank by itself. This only works when the sire name matches the inventory line. Capital letters don't matter, but spelling does, so copy the name exactly. You can turn this off in Notifications & automations if you would rather count by hand.
When a sire runs low, the Workspace home shows Low straws under Needs attention. You set how low. If you are using a sire faster than your straws will last, it tells you that too.
Embryos from a flush
If you flush donors, the ET / IVF records have a shortcut to add the frozen embryos from a flush straight into the tank, filled in as donor × sire with the frozen count.
Keeping track of liquid nitrogen
The Tanks & LN2 tab keeps one line per tank with its dipstick readings. Enter the tank name, the reading date, the LN2 level and the full level, plus the last fill date and the tank's static hold time.
- The Level column shows your reading as a percent of full. Over 50% is green. At 50% or below it turns amber and says refill. At 33% or below it turns red and says fill now.
- Next fill due is the last fill date plus half the static hold time.
The screen's own advice is worth repeating: measure weekly with a dipstick, refill at or below half of full depth, and treat a third as an alarm. Never lift canes above the frost line for more than 5 to 10 seconds.
A tank-day checklist
- Dipstick every tank and log the reading.
- Fill any tank that shows amber or red.
- Check the Low straws alert and order more of any sire you plan to use this season.
- After each AI day, make sure every breeding was logged with the exact sire name.
- Once or twice a year, do a full physical count, one canister at a time, and correct the units on hand.
- Download a CSV of the inventory and keep a copy for insurance.
Know what you have
A tank you can trust makes every other breeding decision easier. If you would like to see the full set of tank screens, take a look at the CowSync Guide.
Frequently asked questions
Will logging an AI take a straw off my semen tank inventory?
Yes, as long as the "Use straws automatically" automation is on and the sire name you type matches the inventory line. Spelling has to match; capital letters don't matter.
Can I keep embryos in the same inventory as semen?
Yes. Each line is either semen or embryo. Embryos have their own type, freeze method and grade, and the Embryo tab shows only those.
How often should I check nitrogen levels?
The tool suggests a weekly dipstick reading. It shows each tank's level as a percent of full and the date the next fill is due.