Swine Ear Notching Laws in Michigan: What Pig Owners Need to Know

Ear notching has been a cornerstone of swine identification for generations of Michigan pig farmers, 4-H exhibitors, and purebred breeders. Cut a V-shaped notch in the right place, and you can identify every pig in a litter without a single tag, tattoo, or scanner. But Michigan’s identification rules have grown more specific over the years — and knowing exactly where ear notching fits (and where it does not) can save you from a compliance headache at the fair gate or state line.

This guide walks you through what Michigan law and the Michigan Department of Agriculture and Rural Development (MDARD) say about swine ear notching, when a notch qualifies as official identification, how the 1-3-9 system works in practice, and how notching stacks up against tags, tattoos, and RFID for different movement and exhibition scenarios.

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

Swine ear notching is a permanent identification method in which V-shaped cuts are made in specific positions on a piglet’s ears shortly after birth. Each position carries a numerical value, and the combination of notches in both ears creates a unique identifier for every pig in a herd. The procedure is typically performed within the first few days of life, at the same time producers clip needle teeth and treat navel cords.

The simplest identification method recommended by most breed associations is ear notching, and the most common notching system is the 1-3-9 system. Michigan swine producers — from small backyard operations to large commercial farms — have used this system for decades because it requires no equipment to read, never falls out, and links directly to purebred registry records.

In Michigan, ear notching is most commonly used in three situations: on-farm litter and individual pig tracking, purebred registry enrollment, and 4-H project animal documentation. Some fairs may require you to submit photos of your pig’s ear notches by the possession deadline, or your pig could be tagged with a fair-specific tag during check-in. That fair-level documentation role is where notching still has practical value in Michigan — even though, as you will see below, it no longer satisfies the state’s official ID requirement on its own.

If you raise goats or other livestock in Michigan, you will find that identification rules vary by species. Swine carry some of the most specific requirements in the state, shaped largely by disease traceability concerns.

When Ear Notching Qualifies as Official Identification in Michigan

This is the section that trips up most Michigan pig owners: ear notching is not accepted as official identification for exhibition swine in Michigan. Ear notches and tattoos are not accepted as official ID for any pigs at fairs and exhibitions in Michigan. That rule applies whether your pig is heading to the county fair, a jackpot show, a birthing exhibit, or any other public display.

All swine being shown at exhibitions, including fairs, jackpot shows, birthing exhibits, and other events, are required by state law to have official ID in place. The exhibitor is responsible for having official ID in place, and the exhibition is responsible for verifying that all swine have official ID.

So when does ear notching count? At the federal level, the USDA Animal and Plant Health Inspection Service (APHIS) does recognize ear notching as an approved swine identification method — but only under a specific condition. Ear notching qualifies if the ear notching has been recorded in the book of record of a purebred registry association. Outside of that registry context, and specifically for any Michigan exhibition or interstate movement scenario, a physical tag is required.

Important Note: Michigan’s exhibition ID rule is stricter than the federal baseline. Even if your pig’s ear notch is recorded with a purebred registry, you still need an approved physical tag — an 840 RFID tag, a NUES tag, or a PIN tag — before showing at any Michigan fair or exhibition.

For interstate movement into Michigan, pigs must have official identification, and it must be recorded on the interstate Certificate of Veterinary Inspection (CVI). Ear notches alone will not satisfy that CVI requirement. If you are bringing pigs in from another state, check the MDARD pigs identification and movement page before loading the trailer.

How the 1-3-9 Ear Notching System Works

The 1-3-9 system assigns numerical values to specific positions on each ear, allowing producers to encode both a litter number and an individual pig number using nothing more than a V-notcher tool. 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 on 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 will have different notches in the left ear. The left ear is divided into three sections, with values of 1, 3, and 9.

To build a number, you add up the values of the notched positions. The outside bottom quadrant represents the number 1. If there are two notches in that quadrant, the number is 1+1, or 2. There will never be more than two notches in any quadrant. The outside top quadrant represents the number 3, and the inside top quadrant represents the number 9. In the litter ear only, the inside bottom represents the number 27.

A practical example: a pig identified as “7-2” comes from the 7th litter (right ear: one notch at 3, one notch at 3, one notch at 1 = 7) and is the 2nd pig in that litter (left ear: two notches at 1 = 2). By utilizing the “81” notch you can identify up to 161 distinct litters using this system.

Ear	Purpose	Available Zones	Max Value
Right (pig’s right)	Litter number — same for all littermates	1, 3, 9, 27, 81 (tip)	161
Left (pig’s left)	Individual pig number within litter	1, 3, 9	15

For piglets of this size, a small 3/16- to 1/4-inch-deep V-notcher is recommended. Notches placed in the wrong zone — or too close to a zone boundary — create ambiguous reads that can cause registration errors and identification disputes down the line. For proper identification to be made, it is essential that the notches be placed in the appropriate area of the ear so that the mark is clearly a 1 versus a 3, or a 9 versus a 27.

Pro Tip: Always view the pig’s ears from behind the animal or directly face-on when reading notches. Confusion over which ear is the “left ear” can easily occur depending on viewing the pig from the front or the rear. A good way to remember is to always look the pig in the face — read left-to-right for litter number then pig number.

Ear Notching for Purebred Registry Compliance in Michigan

If you raise registered purebred swine (Sus scrofa domesticus) in Michigan, ear notching is not just a management tool — it is often a registry requirement. National breed associations including the National Swine Registry (NSR) and Certified Pedigreed Swine (CPS) have required the 1-3-9 notching system as part of their pedigree registration process for decades.

When using the system of ear notching 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. This standardized approach means that any accredited veterinarian, breed inspector, or registry official can read a pig’s identity without any additional paperwork in hand.

At the federal level, APHIS recognizes this registry-backed notching as an approved identification method. Swine identification methods approved by APHIS’ Administrator include ear notching of any swine if the ear notching has been recorded in a purebred registry association’s book of record. That federal recognition matters for interstate movement documentation — but remember that Michigan’s exhibition rules layer additional requirements on top of it.

Pigs being kept as replacement breeding stock and for exhibition purposes need to be ear notched. Ear tags are often used in conjunction with ear notches in a breeding herd. Running both systems in parallel is the practical approach for Michigan purebred producers: notch for registry records and herd management, tag with an 840 RFID for any movement or exhibition that triggers state law.

For context on how Michigan regulates other disease-sensitive livestock activities, see the state’s brucellosis laws in Michigan — brucellosis testing requirements directly intersect with swine movement rules under MDARD.

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

Michigan recognizes several forms of official swine identification, and each has a different role depending on whether you are managing a breeding herd on-farm, heading to a county fair, or crossing state lines. Understanding the differences keeps you compliant without over-investing in ID hardware you do not need.

USDA 840 tags are the most common form of official ID tag. They have a unique 15-digit number beginning with 840, which is the United States country code. These tags are tamper-resistant and bear the U.S. shield. They are available with or without radio frequency identification (RFID); it is suggested to use a tag with an RFID option so fairs and exhibitions can use RFID tag readers during their event to easily record animal ID numbers.

Premise Identification Number (PIN) tags and National Uniform Eartagging System (NUES) tags are also acceptable forms of official identification according to MDARD. NUES tags carry a unique nine-character number beginning with a two-digit state code and come in metal or plastic versions.

ID Method	Accepted for Michigan Exhibition	Accepted for Interstate Movement (CVI)	Purebred Registry Use	Permanent / Tamper-Proof
840 RFID / Visual Tag	Yes	Yes	Supplemental	Yes (tamper-resistant)
NUES Ear Tag	Yes	Yes	Supplemental	Yes
PIN Tag	Yes	Yes	Supplemental	Yes
Ear Notch	No	Only if registry-recorded	Primary (required by most breed associations)	Yes (permanent)
Tattoo	No	Only if registry-recorded	Accepted by some registries	Yes (permanent)

As of December 2025, 840 RFID tags are available to order at www.840swinetags.com at no cost as a part of a national effort to strengthen swine disease traceability. That makes the cost barrier for official tagging essentially zero for Michigan exhibitors who plan ahead. Individual swine exhibitors are able to order official 840 RFID tags, with a minimum order of 20, at no cost when ordered at www.840swinetags.com.

One important restriction to keep in mind: official ID may not be shared with or transferred to another premises. It is illegal to remove official ID or to apply more than one official ID. If a tag is lost, contact the breeder or obtain a replacement through MDARD before the animal moves or is exhibited again.

Pro Tip: Need tags quickly before a fair? Official 840 RFID tags may be purchased from local retailers and livestock markets across Michigan — visit www.mi.gov/animalimport to find a location near you.

Michigan’s backyard chicken laws and beekeeping regulations show how MDARD applies different identification and premises-registration frameworks to different livestock species — swine rules are among the most detailed because of the disease traceability stakes involved.

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

Michigan’s swine ID framework sits at the intersection of state law and federal traceability requirements. MDARD administers the rules under the Michigan Animal Industry Act, and those rules align with — but sometimes exceed — the federal baseline set by USDA APHIS under Title 9, Part 71.19 of the Code of Federal Regulations.

All swine being shown at exhibitions, including fairs and jackpot shows, must have official identification tags in accordance with Michigan state law. This requirement has not changed, but there are some updates to the process for obtaining tags in Michigan. The 2026 fair season brought changes to how tags are ordered and distributed, so producers and 4-H families should verify their sourcing method early in the season.

Michigan classifies pigs by risk level for disease purposes, and that classification affects movement documentation requirements. High-risk pigs include pigs with management practices that allow possible exposure, directly or indirectly, to feral pigs, causing increased risk of infection with PRV and brucellosis. This includes pigs that are pasture-raised, free-range, and/or use other outdoor swine farming systems. Low-risk pigs are those continuously managed and housed in facilities with practices that prevent exposure to high-risk or feral pigs. High-risk pigs face additional testing requirements beyond just ID.

For 4-H participants specifically, the Michigan State University Extension program provides detailed guidance on ID requirements. Livestock are subject to state and federal laws regarding identification practices, and 4-H project animals are no exception. In addition to state and federal identification requirements, each fair may have its own requirements. Always check with your specific county fair well before the possession deadline.

To obtain a Premises Identification Number — required before you can purchase 840 tags — contact MDARD at 888-565-8626. Your PIN is tied to the physical property where your pigs are housed, not to you personally, so each location where pigs are kept needs its own PIN registered with MDARD.

According to USDA APHIS, “traceability does not prevent disease, but it significantly reduces the time needed to respond to outbreaks, helping to limit the number of affected farms and animals.” That is the underlying rationale behind Michigan’s strict exhibition ID rules — ear notches, however permanent and precise, cannot be scanned at a gate or traced in a disease investigation the way an 840 RFID tag can.

Michigan producers who move animals across state lines should also review Michigan’s pet and animal import laws for the broader regulatory context, and those dealing with wildlife interactions on their property may find the state’s wildlife removal laws relevant when feral pigs are a concern in their area.

For questions about specific movement scenarios, disease testing requirements, or how to register your premises, contact MDARD’s Animal Industry Division directly. The rules are detailed, but the compliance path is straightforward once you know which ID method applies to your situation.