Ear notching is one of the oldest and most cost-effective ways to identify swine, but in Ohio, its legal standing depends entirely on context. Whether you raise purebred Berkshires for a breed registry, show pigs at the county fair, or move feeder hogs across state lines, the rules governing when an ear notch is legally sufficient — and when it is not — differ significantly.
Ohio’s swine identification framework is shaped by both state administrative code and federal USDA traceability requirements. Understanding where ear notching fits within that framework helps you stay compliant, protect your herd’s records, and avoid costly paperwork problems at the sale barn or the show ring. If you also raise other livestock or keep animals under Ohio’s various regulations, you may find our guide on goat ownership laws in Ohio a useful companion read.
What Is Swine Ear Notching and When It Is Used in Ohio
Ear notching is a permanent identification method in which small V-shaped cuts are made into specific locations on a pig’s ears shortly after birth. The task is much easier if pigs are notched when their tails are docked, or at one to three days old; if you allow pigs to become large, the task becomes considerably more demanding mentally and physically. Because the notches are placed in cartilage, they remain readable for the animal’s entire life — no tag to lose, no ink to fade.
In Ohio, ear notching is used in three main scenarios: purebred herd management and breed registry compliance, 4-H and fair exhibition enrollment, and as one of several accepted forms of official identification for interstate movement under specific conditions. Ear notches help breeders maintain accurate records for registration and health records on the farm, including vaccination records. For commercial operations running large numbers of market hogs, ear notching is rarely the primary identification tool, but it remains standard practice on purebred and seedstock farms across Ohio.
Pro Tip: Notch piglets at one to three days old when the cartilage is soft and the process is quick. Waiting until pigs reach even 50 pounds makes the procedure significantly harder and increases stress on the animal.
Notching equipment must be kept clean at all times, cleaned with a clean toothbrush between litters, and dipped in fresh surgical spirit or alcohol. Fresh alcohol must be used each day the notching equipment is in use. Keeping your tools sanitized is not just good practice — it directly affects the health of the litter and the readability of the notches over time.
When Ear Notching Qualifies as Official Identification in Ohio
Ohio Administrative Code Rule 901:1-11-02 defines what counts as “official identification” for swine subject to pseudorabies testing and disease control programs. Under that rule, official identification includes an official eartag bearing the U.S. shield, an animal identification number (fifteen-digit number), a group or lot number, a premises number used in conjunction with the producer’s livestock production numbering system, an official identification device or method, or an ear notch or tattoo if the animal is registered with a breed association.
That final clause is the key condition: an ear notch only qualifies as official identification in Ohio when the animal is registered with a recognized breed association. A notch alone on a commercial market hog does not meet the official ID threshold under state or federal rules. According to the USDA’s National Veterinary Accreditation Program reference guide (as of January 2026), ear notching qualifies as official swine identification only if the ear notching has been recorded in the book of record of a purebred registry association.
For swine being imported into Ohio, swine imported or brought into Ohio must be accompanied by a certificate of veterinary inspection, have identification, and meet disease requirements. The certificate of veterinary inspection must be signed by an accredited veterinarian and issued within 30 days prior to entry. Accepted individual identification methods include an ear notch or tattoo recognized by a breed association in purebred registered swine, or an ear tag firmly affixed by an approved method.
Important Note: Ohio Administrative Code Rule 901:1-11-02 also states that no person shall remove, alter, or deface any identification — permanent or temporary — applied to any animal being tested or examined for pseudorabies. Tampering with ear notches on tested animals carries legal consequences under Ohio law.
How the 1-3-9 Ear Notching System Works
The universal ear notching system used across U.S. swine registries is a numeric code built from notch positions in four quadrants of each ear. Each ear is divided into four quadrants, and each quadrant represents a number. The outside bottom quadrant represents the number 1. 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.
The pig’s right ear carries the litter number; the left ear carries the individual pig number within that litter. Notches in the right ear tell the producer which litter the pig was born to. Producers may start with litter number 1 on the first of the year, or restart litter numbers several times per year depending on the number of sows. All pigs born to the same sow have the same litter number and thus identical notches in the right ear.
The pig’s left ear designates the pig number within the litter, so the first piglet is pig number one, the second piglet is pig number two, and so on. These individual numbers are randomly assigned to piglets and are not associated with birth order. To read a pig’s full identity, you combine both ears. After notching, an individual pig’s identification would be read as something like 14-6, where 14 represents a pig from the 14th litter and 6 represents the sixth pig within the 14th litter.
Adding up the values is straightforward arithmetic. There will never be more than two notches in any quadrant. There are five designated zones — 1, 3, 9, 27, and 81 — in the litter ear, and three designated zones — 1, 3, and 9 — in the individual pig ear. In zones 1, 3, 9, and 27, there can only be two notches, so if there are two notches in all four zones, that represents litter 80. A notch in zone 81 at the tip of the right ear doubles the system.
| Ear | Purpose | Zones Available | Maximum Value |
|---|---|---|---|
| Right ear | Litter number | 1, 3, 9, 27, 81 (tip) | 161+ |
| Left ear | Individual pig number | 1, 3, 9 | Up to 15 |
Avoid making notches too shallow, as they may become hard to read or possibly heal shut. Leave at least one-quarter inch between notches, and avoid making notches too close to the head. Clean, well-placed notches are readable at a glance for the life of the animal — a significant advantage over tags that can tear out or numbers that can smear.
Ear Notching for Purebred Registry Compliance in Ohio
If you register purebred swine with a national breed association — such as the National Swine Registry or Certified Pedigreed Swine — ear notching is a required step in the registration process. The notch pattern must be recorded in the association’s book of record before the animal’s identification carries any official weight under Ohio or federal rules.
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. The notches from the right and left ear combine to give each pig a unique identification. This combination is what gets transcribed onto the registration certificate, linking the physical animal to its pedigree records permanently.
Each ear is divided into four parts, with each area representing the numbers 1, 3, 9, or 27. In each of the four areas, you can have up to two notches. The right ear is used for litter mark, and all pigs in the same litter must have the same notches in the right ear. Consistency within a litter is what allows the registry to verify parentage and confirm that the registered pig matches the physical animal being presented.
Ohio producers showing purebred swine at state or county fairs also rely on registry-recorded ear notches to confirm ownership and breed eligibility. Ohio’s Exhibition Rules, including Ohio Administrative Code 901:1-18 and Ohio Administrative Code 901-19, were updated as of May 23, 2024. Staying current with those exhibition rules matters, especially given upcoming changes to official ID requirements described in the next section. You may also find it helpful to review backyard chicken laws in Ohio if you raise multiple species on the same property, since exhibition and movement rules vary by animal.
Pro Tip: Submit your litter registration paperwork to your breed association promptly after notching. The ear notch only becomes official identification once it is recorded in the association’s book of record — the physical notch alone is not enough without that paper trail.
Ear Notching vs. Ear Tags, Tattoos, and RFID in Ohio
Ohio and federal rules recognize several methods of swine identification, and each has a different legal standing depending on the purpose — disease traceability, interstate movement, or exhibition. Understanding how ear notching compares to the alternatives helps you choose the right method for your operation.
| ID Method | Permanent | Official ID Eligible | Registry Use | Required for Exhibition (post-2027) |
|---|---|---|---|---|
| Ear notch | Yes | Only if registry-recorded | Yes (purebred) | No |
| Ear tag (visual) | No (can tear out) | Yes (USDA-approved) | No | Transitional |
| Tattoo | Yes | Yes (if registry-recorded or official) | Yes | No |
| RFID/EID tag | No (device) | Yes | No | Yes (beginning Jan. 1, 2027) |
| Premises ID number | N/A | Yes | No | Transitional |
Tattoos on the ear or inner flank of any swine qualify as official identification if they have been recorded in the book of record of a swine registry association. For slaughter swine and feeder swine, an eartag or tattoo bearing the Premises Identification Number assigned by the State Animal Health Official to the premises on which the swine originated is accepted.
A significant change is coming for Ohio exhibition swine. Beginning January 1, 2027, all cattle and swine will be required to have official ear tags at exhibitions in Ohio. Official ear tags are USDA-approved electronic identification devices that are both visibly and electronically readable. This means that ear notching alone — even for registered purebred pigs — will not satisfy the exhibition identification requirement starting in 2027. You will need an approved RFID/EID tag in addition to any notches already applied.
For producers concerned about the cost of RFID tags, the Ohio Agricultural Law Blog notes that Ohio producers can contact the State Veterinarian’s office at the Ohio Department of Agriculture for information about the availability of free EID tags that comply with official identification requirements. This is worth doing before the 2027 deadline to budget and plan accordingly.
Ear tags have one practical disadvantage compared to notches and tattoos: they can be torn out. A pig that loses its tag in a pen or pasture has no traceable identification until a replacement is applied. Ear notches and tattoos, being permanent and part of the animal’s tissue, do not carry that risk — which is one reason purebred registries continue to require them even as electronic identification expands.
State-Specific Swine Identification Rules That Affect Ear Notching in Ohio
Several Ohio-specific rules directly affect when and how ear notching must be used or supplemented with other identification. These rules come from the Ohio Department of Agriculture (ODA) and interact with federal USDA traceability standards.
Interstate movement: Swine imported or brought into Ohio must be accompanied by a certificate of veterinary inspection (CVI), have identification, and meet disease requirements. The CVI must contain the statement that all swine in the shipment have not been fed raw garbage, and must have the breed, age, sex, and state of origin of the shipment. For purebred swine with registry-recorded ear notches, the notch serves as the individual identification on that CVI. For all other swine, an approved ear tag or premises tattoo is required.
Disease control programs: Ohio’s pseudorabies control program under Ohio Administrative Code Chapter 901:1-11 requires official identification on any swine being tested. Unless authorized by the department, no person shall remove, alter, or deface any identification — either permanent or temporary — applied to any animal being tested or examined for pseudorabies. This rule protects the integrity of test records and applies to ear notches just as it does to ear tags.
Brucellosis requirements for breeding swine: Swine imported into Ohio for breeding purposes must also meet brucellosis requirements, and animals must originate from a validated brucellosis-free herd, state, or country. Ear notching does not exempt breeding swine from these disease status requirements — identification and disease compliance are separate obligations.
Swine at approved livestock markets: Swine imported into Ohio that have been consigned from a herd of origin to a livestock market approved pursuant to 9 C.F.R. 71.20 to handle any class of swine are not required to be accompanied by a certificate of veterinary inspection. However, identification requirements still apply at the point of origin and must be documented in the market’s records.
Ohio also maintains rules specific to feral swine. Under Ohio Administrative Code, “feral swine” means any swine that has lived any part of its life free roaming. Feral swine are subject to separate movement and control regulations, and standard ear notching or registry documentation does not apply to animals classified as feral under state law.
If you raise other regulated animals alongside your swine operation, Ohio’s broader animal law framework is worth understanding. Our guides on rooster laws in Ohio, pet import laws in Ohio, and wildlife removal laws in Ohio cover related state regulations that may affect multi-species operations. For producers who also keep cattle, the hunting laws in Ohio page addresses some relevant land-use and animal-control intersections worth reviewing.
Key Takeaway: In Ohio, ear notching is a legally recognized form of official swine identification — but only when the notch pattern has been recorded in the book of record of a recognized purebred breed association. For commercial, feeder, and slaughter swine, an approved ear tag or premises tattoo is required instead. Beginning January 1, 2027, all swine exhibited at Ohio fairs must also carry an official USDA-approved electronic identification tag regardless of registry status.
The rules around swine identification in Ohio are not static. The ODA updates its exhibition and movement regulations on a rolling basis, and federal USDA traceability standards continue to evolve. Contact the Ohio Department of Agriculture’s Animal Health Division directly for the most current guidance before moving animals across state lines or enrolling pigs in a new exhibition program. Consulting with an accredited veterinarian before any interstate shipment is also required by law — and is your best protection against compliance gaps that ear notching alone cannot cover.