Let’s be honest. Whenever we eat something, do we always check to see if it’s FDA or USDA approved? No. We may have a quick look if we care and have the time. Maybe we see the marketing labels and check the expiration date and the nutritional content, but that’s about it.
Eaglen sophie
International Program Director / National Association of Animal Breeders Inc./Certified Semen Services Inc.

We usually trust in the quality of the product we buy, especially when it’s from a known brand. We assume there is some organization monitoring our food and products to ensure what we eat and use is safe, even though many of us may not know what organization that is exactly. 

Similarly, I would guess most of us take a quick look at a semen straw on the farm to read the bull’s NAAB (National Association of Animal Breeders) code or name to make sure that we breed the cow with the intended sire and ignore the rest of the coding on the straw. Other than that, we trust the company from which we bought the semen that it is of good quality. 

Thankfully, most of the semen you buy and use in the U.S. is safe and quality controlled, and there is indeed a national organization that monitors the health testing and biosecurity of bulls in A.I. organizations and the quality of the marketed frozen semen. But this doesn’t mean that all circulating semen is safeguarded; unfortunately, this aspect is often taken for granted.  

One of the major advantages of artificial insemination promptly recognized in the early days of the industry was the enhanced biosecurity and reduced disease transmission as compared to a herd bull.  However, in absence of health testing and biosecurity of the donor bulls, A.I. is potentially also a very effective means to spread disease.


For the protection of your herd, it’s therefore important to know how to read the information on your semen straw so you can make sure what you bought is certified. This is not to say that you should read every straw, but knowing the ground rules may keep your business from some pretty grave situations.

What is on your semen straw?

One of the major reasons why the U.S. A.I. industry is world leading is due to the quality of its product. Having high-quality semen is essential for the business of all U.S.-based companies, and poor quality can hurt the reputation of the entire industry. In addition, the industry bears responsibility to you, as the customer, to protect your herd and the data you use for your selection decisions. 

It is not surprising that there are mechanisms in place to ensure the quality of the semen that you breed your cows with. You may not be confronted with these on a day-to-day basis, but it’s all wrapped up in a little summary on each semen straw you purchase. Each straw can tell you if it will be safe to use in terms of disease, if it was checked for viability and fertility, and where and by whom the semen was produced.

The organization that sets the standards for semen quality in the U.S. is called Certified Semen Services, or CSS. CSS is not a government regulatory body like the FDA, but instead is a wholly owned subsidiary of the NAAB and is monitored in turn by the USDA.

CSS sets the minimum requirements for frozen semen with the goal to protect the health of the herd in which the semen is used. If it is CSS certified, you can safely assume the company that sold you the semen is meeting and often exceeding CSS minimum requirements for animal management, semen quality control, sire health testing and laboratories processes. CSS also puts checks and balances in place to ensure that the semen of the bull ID displayed on the straw is also in the straw.

If the semen you bought is CSS certified, the straw will contain the following information (not necessarily in this order):

  1. Collection code – Date of semen collection (Julian or calendar date)
  2. Name of bull – Full registration name 
  3. Bull registration number consisting of:
    • Breed of bull
    • Country of origin
    • Unique herd book number 
  4. Stud code – Codes the semen collection center
  5. NAAB code of bull, which consists of the following:
    • A marketing code (sometimes the same as the stud code) – What kind of semen is in the straw and whose product is it (up to three numbers)
    • A breed code – What breed of bull is the semen from (two letters)?
    • A bull unique number (up to five numbers)
  6. The CSS logo – for CSS certified semen.

The CSS logo is not mandatory. If a purchased semen straw does not contain a logo, then it’s recommendable to ask your semen sales rep if the semen is CSS certified to ensure it’s controlled. The other information is mandatory under CSS regulations.

Here are a few examples of various semen straws and how to read them:

Example 1

This conventional semen (Figure 1) of the American Jersey bull 1080 (c and e), named “JONES {3}” (b) with herd book number 3012659145 (c), was produced on the 213th day in 2019 (a) at the collection center of GENEX in Shawano, Wisconsin (d, stud code 021), and marketed by GENEX ( e, marketing code 001).

Example 2 

This conventional semen (Figure 2) of the American Holstein bull 11669 (c and e), named “AltaJONAH” (b) with herd book number 73752888 (c), was produced on the Feb. 24, 2017 (a), at the collection center of ALTA Genetics in Watertown, Wisconsin (d, stud code 011), and marketed by Alta Genetics (e, marketing code 011).

Example 3

The sexed semen (Figure 3) of this Dutch Holstein bull 128 (c and e), named “XAVI-RED” (b) with herd book number 539346589 (c), was produced on the 329th day in the year 2014 (a) by Sexing Technologies Benelux in The Netherlands (d, stud code 266) and marketed by A.I. Total (e, marketing code 515). Foreign straws may also have a local stud code listed instead of the U.S. version. For example, this straw may have NL01 printed on the straw as the EU equivalent of as U.S. stud code. 

The bigger picture

The information that is on your semen straw is the most accurate representation of the product that you use to breed the next generation of cows. It’s listed on the straw for the purpose of traceability. It allows you to trace by who, where and when the semen was produced. However, the information on your straw is also part of the U.S. genetic evaluation system, and you, as the producer, play an important role in ensuring that the PTAs on sires remain accurate.

The NAAB code listed on your straw represents the bull you use for breeding. However, it also represents the type of semen you use, indicated by the first three digits of an NAAB code or the so-called marketing code.

If you breed with conventional semen by Select Sires, the marketing code of this bull will likely be 007 or simply 7, for example 7HO12837, for ZAMBONI. If you purchased sex-sorted semen of ZAMBONI, the NAAB code on the straw will be different. The marketing code for sex-sorted semen sold by Select Sires is 507 and the NAAB code for ZAMBONI on your sexed straw will be 507HO12837. Same bull, different code.

Does that matter? Yes, it does. Firstly, the different code obviously tells you it’s a different product, but secondly, if you are on DHI, this code will also feed into the genetic evaluation system. 

When you enter the breeding by this bull in your herd management system, this information is sent to the Council of Dairy Cattle Breeding (CDCB) by DHI and the Dairy Record Processing Centers (DRPC). CDCB collects all the breeding information from this bull and returns PTAs for fertility traits back to you through the national evaluations. 

Due to the many breedings on the farm, and the many available A.I. sires, most bulls are simply known and remembered by the short name or the conventional NAAB code. For that reason, it’s often either the short name or conventional NAAB code that gets entered in herd management software. When a breeding was indeed with conventional semen, that works perfectly. But when the breeding was in fact with sexed-sorted semen, we now have an inaccurate record and a problem. 

Errors in the NAAB code like these are impossible to detect by the genetic evaluation system. Because there are differences between sexed-sorted and conventional semen, these errors will affect the accuracy of the fertility PTAs on A.I. marketed bulls. This affects all fertility traits but is especially the case for sire conception rate (SCR).  

Therefore, for herds on DHI, it’s important to realize you are an essential part of the U.S. genetic evaluation system and directly contribute to the accuracy of our national proofs. 

Management decisions will have considerably different economic consequences if the conception occurred to a 507 versus an 007 insemination. Consequently, when entering your breedings, it is of significance for your own herd management as well as the entire industry to enter the NAAB code displayed on your semen straw. This will ensure that the genetic merit for fertility of both your cow and the bull get calculated properly and returned to you. Sex-sorted straws are often colored pink or blue for your convenience. 

So, if you breed with a pink or blue straw, or simply use a considerable amount of sex-sorted semen, please pay extra attention to the NAAB code when breeding data is entered into your farm software. 

So why should you care?

The U.S. has long been recognized as the world leader in dairy genetics, and this is largely due to our meticulous system that measures and tracks animal performance. Several unique codes connect the A.I. industry to what happens on the farm and to the national genetic evaluation system. 

As a dairy farmer, you are in the epicenter of this system, and it’s therefore in the interest of your business, your herd and the entire industry that you understand what is on your semen straw.  

You are given traceable information on each straw that informs you if the semen you are about to use is disease-free and fertile. And in return, with your help, the information on how that semen performs on your farm is fed back into the genetic evaluation system, and updated PTAs on available A.I. bulls are returned. 

It has worked for decades and will work for decades more, with your contribution and ours.  end mark

Sophie Eaglen
  • Sophie Eaglen

  • International Program Director
  • National Association of Animal Breeders Inc.
  • Certified Semen Services Inc.
  • Email Sophie Eaglen

To look up stud codes, click here

To look up marketing codes, click here.

To look up breed codes, click here.

To check which companies are CSS certified, click here.