Swine Ear Notching Laws in Minnesota: What Producers Need to Know

Minnesota is one of the top pork-producing states in the country. According to the Minnesota Pork Board, the state ranks second nationally in the number of hogs raised and second in the value of animals sold for meat processing. With that level of production comes a detailed web of identification requirements that every swine producer — from small hobby farms to large commercial operations — needs to understand.

Ear notching is one of the oldest and most recognizable methods of swine identification, but its legal standing in Minnesota depends heavily on context. Whether it qualifies as official ID, how it interacts with federal traceability rules, and when you need something more are questions that affect your compliance status every time you move, sell, or register an animal.

This guide walks you through everything you need to know about swine ear notching laws in Minnesota, including how the 1-3-9 system works, when ear notches satisfy official ID requirements, and how they stack up against ear tags, tattoos, and RFID devices.

What Is Swine Ear Notching and When It Is Used in Minnesota

Ear notching is a permanent identification method that involves cutting small V-shaped notches into specific zones of a pig’s ears. It helps identify a pig’s litter and which individual within that litter it is, giving each pig a unique identity number. Notches are placed in one of five locations in the pig’s right ear to show the litter number, and in one of three locations in the left ear to show the individual pig number.

Ear notches are typically made within the first few days of birth. They help breeders maintain accurate records regarding registration and health records on the farm, such as vaccination records. Because the marks are permanent — they grow with the pig and cannot be lost like a tag — they remain readable throughout the animal’s life.

In Minnesota, ear notching is used primarily in two contexts: purebred swine operations where registry associations require it for pedigree documentation, and 4-H and youth exhibition programs where producers must record and report individual pig identity. The University of Minnesota Extension provides a “How to Read Ear Notches of Pigs” resource and a Swine ID worksheet specifically for 4-H participants. Outside of those contexts, most commercial and feeder swine operations rely on ear tags or tattoos rather than notching.

Pro Tip: Notch piglets at one to three days old when processing other newborn tasks like tail docking and navel care. The procedure is far easier on young piglets, and combining tasks reduces handling stress on the litter.

When Ear Notching Qualifies as Official Identification in Minnesota

Not every ear notch counts as official identification under Minnesota or federal rules. The Minnesota Board of Animal Health (BAH) sets the standards for what qualifies as official ID for swine moving within or out of the state, and ear notching occupies a narrow — but real — place in that framework.

Under USDA guidelines, ear notching qualifies as official identification when the ear notching has been recorded in the book of record of a purebred registry association. That condition is critical. A notch alone, without a corresponding registry record, does not satisfy the official ID requirement for interstate movement or disease traceability purposes.

Swine imported into Minnesota must be officially identified and accompanied by a certificate of veterinary inspection issued by an accredited veterinarian, except for swine consigned to a state-federal approved livestock market that move directly from a farm of origin. If you are moving purebred swine whose notches are recorded with a recognized breed association, those notches can serve as official ID — but you still need the paperwork to prove it.

Breeding swine and feeding swine moved from a premises to another location in the state must also be officially identified, subject to certain exceptions. For most producers, this means ear tags or tattoos are the practical default. Ear notching as official ID is the exception, not the rule, and applies only when registry documentation is in order.

Important Note: A certificate of veterinary inspection (CVI) is required for most interstate swine movements in Minnesota. Even when ear notching qualifies as official ID, you still need a CVI from an accredited veterinarian listing the notch and registration numbers. Confirm current requirements with the Minnesota Board of Animal Health before any movement.

How the 1-3-9 Ear Notching System Works

The simplest method and the one recommended by most breed associations is ear notching. The most common notching system is the 1-3-9 system. Understanding how it works lets you read any pig’s identity directly from its ears without any additional equipment.

The universal ear notching system is based on the fact that a pig has two ears. The pig’s right ear, as viewed from the rear of the pig, is designated as the “litter” ear. The right ear is used for the litter mark, and all pigs in the same litter must have the same notches in this ear. The right ear is the pig’s own right. The litter mark ear is divided into five sections, and each section has a numerical value: either 1, 3, 9, 27, or 81.

The left ear is used for notches to show an individual pig’s number in the litter. Each pig has different notches in the left ear. The left ear is divided into three sections, with values of 1, 3, and 9. You add up the values of all notches in each ear to get the litter number and the individual pig number.

Here is a quick breakdown of how the values work in practice:

Ear	Purpose	Zone Values Available	Max Notches per Zone
Right ear (pig’s right)	Litter number	1, 3, 9, 27, 81 (tip)	2 per zone (1 at tip)
Left ear (pig’s left)	Individual pig number	1, 3, 9	2 per zone

After notching, an individual pig’s identification would be read as something like 14-6. The 14 represents a pig from the 14th litter and the 6 represents the 6th pig within that litter. By using the “81” notch at the ear tip, you can identify up to 161 distinct litters using this system.

Remember, the reference to left and right ear refers to the pig’s left or right ear as viewed from the rear of the pig. Left and right does not refer to the viewer’s left or right when the pig is facing the viewer. Getting this orientation wrong is one of the most common mistakes beginners make.

When it comes to technique, for piglets of this size, a small 3/16- to 1/4-inch-deep V-notcher is recommended. Avoid making notches too shallow, as they may become hard to read or possibly heal shut. A notch that is too deep, especially one toward the ear tip, may result in a torn ear. Leave at least 1/4 inch between notches to ensure easy reading.

Pro Tip: Always disinfect your notching tool between litters. Notching equipment must be kept clean at all times and cleaned with a clean toothbrush between litters, then dipped in fresh surgical spirit or alcohol.

Ear Notching for Purebred Registry Compliance in Minnesota

If you raise purebred swine in Minnesota, ear notching is not just a management tool — it is a registry requirement. As required by the purebred swine associations of the United States, the litter number is notched in the pig’s right ear, and the individual pig number is notched in the pig’s left ear. Without proper notches recorded in the association’s book of record, you cannot register the animal.

Domestic swine, known scientifically as Sus scrofa, are recognized under Minnesota administrative rules by that genus and species name. Minnesota rules define swine as animals that are members of the genus and species Sus scrofa, and the terms swine, pigs, and hogs may be used interchangeably.

Several major breed associations — including those for Duroc, Hampshire, Yorkshire, Berkshire, Chester White, and Spotted breeds — use the universal ear notching system as their standard. The National Swine Registry and Certified Pedigreed Swine both publish ear notching guides and require notch data on registration applications. All littermates must have different notches in the left ear, and no more than two notches may be made at any position.

For Minnesota producers, the practical compliance checklist for purebred registry ear notching looks like this:

• Notch piglets within the first few days of birth using the correct 1-3-9 zone values
• Record each animal’s litter number (right ear) and individual pig number (left ear)
• Submit notch data along with the registration application to the appropriate breed association
• Retain a copy of the registration certificate or pending registration documentation
• When moving the animal, accompany it with documentation listing the breed registration number

The notch is acceptable as official ID if accompanied by documentation listing the breed registration number — pending registrations are not acceptable. Make sure registration is finalized before you move the animal if you intend to use the notch as official ID.

Ear Notching vs. Ear Tags, Tattoos, and RFID in Minnesota

Ear notching is one of several identification methods available to Minnesota swine producers, but it is not interchangeable with all of them. Each method has different legal standing, different use cases, and different practical limitations. Knowing when each applies helps you stay compliant without over-identifying your animals.

Method	Official ID Status in MN	Primary Use	Interstate Movement
Ear notching	Only if recorded in purebred registry book of record	Purebred registry, 4-H, farm records	Limited; requires registry documentation
Ear tag (NUES/PIN)	Yes, for sows/boars in slaughter channels	Slaughter, commercial movement	Yes, with unique within-herd number
Tattoo (premises/herd number)	Yes, if legible and properly recorded	Feeding swine, monitored herds	Yes, with CVI and registry documentation
RFID (AIN 840)	Yes — federally required as of Nov. 5, 2024	Disease traceability, interstate movement	Yes, primary method for official ID

The USDA made a federal rule requiring the use of RFID for official identification, effective November 5, 2024. Radio Frequency Identification (RFID) using the Animal Identification Number (AIN) system meets this requirement and consists of 15 digits beginning with the official country code — ‘840’ for the United States. This federal shift means RFID has become the primary official ID method for animals moving interstate, including swine.

For ear tags specifically, a sow or boar tag identifies the animal to the premises where it was kept immediately prior to entering slaughter channels, and swine must remain in slaughter channels. If the tag includes a unique within-herd management number imprinted by the manufacturer, the tag qualifies as an official ear tag for interstate movement and swine do not need to be in slaughter channels.

Tattoos also have a role. For any tattoo to be considered official identification, it must be legible. Ear notching is acceptable for feeding swine, and a tattoo or tag with a monitored herd number or state/national assigned premises number is also acceptable. For small-scale producers raising feeder pigs that stay on-farm until slaughter, a legible premises tattoo may be the most practical option.

The bottom line: ear notching fills a specific niche for purebred and exhibition animals, but for commercial operations moving swine between premises or across state lines, ear tags with premises identification numbers and RFID devices carry far more legal weight in Minnesota today.

State-Specific Swine Identification Rules That Affect Ear Notching in Minnesota

Minnesota’s swine identification framework sits at the intersection of state Board of Animal Health rules and federal USDA traceability requirements. Understanding both layers is essential if you raise swine in the state.

At the state level, the Minnesota Administrative Rules Chapter 1721 governs livestock identification and movement. The board requires official identification of livestock when it is necessary to control or eradicate disease, follow the movement of livestock between locations, or determine which animals have been exposed to disease. Swine are not exempt from this framework simply because they are small-scale or locally raised.

Minnesota livestock producers and the Board have worked together over the years to eliminate diseases like pseudorabies, swine brucellosis, and bovine tuberculosis. The Board continues working to increase the efficiency and speed at which animals can be traced in Minnesota. That disease history is part of why the state takes animal ID seriously — and why ear notching alone is rarely sufficient for regulated movement.

Premises registration is another layer that directly affects how identification — including ear notching — functions in practice. One of the most fundamental steps you can take as a Minnesota livestock producer is registering your premises to obtain an official Premises Identification Number (PIN). All animal production or processing facilities in Minnesota are highly encouraged to register their site to obtain a PIN. The PIN is a location-based official identification number for each animal production site or animal product processing facility, and this permanent number does not change even if the premises is sold.

When an emergency occurs, animal and product movement may be restricted by location to control a disease or outbreak. The USDA requires farms to have a PIN for animal disease traceability and emergency response in the event of a Foreign Animal Disease such as African swine fever, avian influenza, or foot and mouth disease. A registered PIN ties your physical location to your animals’ identification records — making it a foundation for any ID method you use, including ear notching.

Local ordinances can add another layer on top of state rules. The Minnesota Department of Agriculture’s Animal Ordinance Map provides information about local ordinances that regulate animal agriculture in Minnesota, including the most common kinds of regulations such as setbacks and separation distances, conditional use permits, feedlot size limitations, and minimum acreage requirements. There may be local regulations the MDA is not aware of, so you should also check with your county, township, or city officials.

If you raise swine alongside other livestock or operate a mixed-species farm, Minnesota’s identification rules apply species by species. You may also want to review brucellosis laws in Minnesota, which have historically intersected with swine herd management requirements, and goat ownership laws in Minnesota if you run a multi-species operation. Producers who also keep poultry should check backyard chicken laws in Minnesota for separate identification and permitting requirements that apply to those animals.

Key Insight: If you plan to exhibit swine at a Minnesota county fair or state fair through 4-H, the University of Minnesota Extension’s 4-H Animal ID program requires you to record ear notch data in the 4-H Online system by the species deadline. The 2026 deadline for swine was May 15, 2026. Missing that deadline affects your eligibility to show.

For questions about official ID requirements specific to your operation, you can consult the Minnesota Board of Animal Health’s Find Field Staff Nearby map to locate the closest BAH field personnel who can assist with answering questions on the requirements for official identification and movement of livestock. You can reach the Board directly at 651-296-2942 or through bah.state.mn.us/swine.

Ear notching remains a practical, low-cost identification tool for Minnesota swine producers — especially those raising purebred or exhibition animals. But it works best as part of a broader identification strategy that includes premises registration, proper documentation, and, where required, RFID or approved ear tags. Staying current with both state BAH rules and federal USDA traceability requirements is the most reliable way to keep your operation compliant and your animals traceable when it matters most.