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

If you raise hogs in Illinois, ear notching is one of the oldest and most practical ways to keep individual animals traceable from birth. A simple V-cut made with a notching tool at the right time can satisfy breed registry requirements, support disease traceability, and travel with an animal for its entire life — no batteries, no scanners required.

But ear notching does not operate in a vacuum. Illinois law, federal animal disease traceability rules, and individual breed registry standards each place specific conditions on when a notch qualifies as official identification and when it does not. Getting those conditions right protects your herd records, your movement paperwork, and your standing with any registry association you work with.

This guide walks you through every layer — from the mechanics of the 1-3-9 system to how the Illinois Department of Agriculture (IDOA) treats notching relative to ear tags and electronic ID — so you know exactly where notching fits in your operation.

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

Ear notching is a permanent identification method in which small V-shaped cuts are made in specific positions along a pig’s ear using a specialized notching tool. Each position carries a numeric value, and the combination of notches encodes both a litter number and an individual pig number into the animal’s ear tissue. Because the notch heals as scar tissue, it cannot fall off or be accidentally removed the way a plastic tag can.

Illinois producers use ear notching in two main contexts. The first is on-farm record-keeping — notching lets you track performance data, vaccination histories, and parentage without relying on tags that can tear out during group housing. Ear notches help breeders maintain accurate records regarding registration and health records on the farm, including vaccination records. The second context is purebred registry compliance, where notching is the identification method required or preferred by most major swine breed associations operating in Illinois.

Timing matters. 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 can become considerably more demanding. Most Illinois producers who notch do so within the first 24 to 72 hours after farrowing, combining the procedure with tail docking and needle teeth clipping to minimize stress on the litter.

Pro Tip: Dip your notching tool in disinfectant between each piglet to prevent cross-contamination. A spray-on wound dressing applied immediately after notching reduces infection risk, especially in warm-weather farrowing seasons.

When Ear Notching Qualifies as Official Identification in Illinois

Not every ear notch automatically counts as official identification under Illinois or federal rules. The distinction matters because official ID is what gets recorded on a Certificate of Veterinary Inspection (CVI), satisfies movement requirements, and supports disease traceability investigations.

Ear notching qualifies as official identification when the ear notching has been recorded in the book of record of a purebred registry association, according to USDA APHIS. This is the federal standard, and Illinois applies it consistently. If a notch is not tied to a registry record, it does not rise to the level of official ID for interstate or intrastate movement purposes.

Illinois’s own administrative code reinforces this. Any purebred animal, or any inbred or hybrid animal registered with a livestock registry association, shall be identified by registration number, registry association approved individual tattoo, ear notch, or an ear tag. Any grade animal shall be identified by an ear tag or tattoo. In plain terms: if your pig is registered with a breed association and the notch matches the registry record, the notch is valid official ID. If your pig is a commercial grade animal, a notch alone is not enough — you need an ear tag or tattoo.

For swine entering Illinois from out of state, the IDOA’s import rules list acceptable identification methods explicitly. Swine must be accompanied by an entry permit issued by the Department and Certificate of Veterinary Inspection and identified thereon by approved official ear tag, breed registry tattoo, or ear notch approved by the respective breed registry. That phrase — “approved by the respective breed registry” — is the key qualifier. Your notch must match what the registry has on file for that animal.

For feeder and breeding swine entering Illinois, all feeder and breeding swine shall be accompanied by an entry permit issued by the Department and a Certificate of Veterinary Inspection showing ear tag number or other approved, official identification. If you are moving purebred animals with registry-recorded notches, those notches satisfy the “other approved, official identification” standard. If you are moving commercial feeders, plan on using an official ear tag instead. You can review transporting livestock laws in Illinois for a broader look at movement documentation requirements.

Important Note: Illinois requires an entry permit for all swine entering the state. All swine entering Illinois must be accompanied by an entry permit from the Department. Contact IDOA at 217-782-4944 Monday through Friday, 8:00 AM to 4:30 PM, to obtain a permit before movement.

How the 1-3-9 Ear Notching System Works

The 1-3-9 system is the standard used by virtually every major swine breed registry in the United States, including those with members in Illinois. 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 it is essential whether you are registering a Duroc, a Hampshire, or any other purebred breed.

The system works by assigning numeric values to specific positions on each ear. 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 carries the litter identification, and the left ear carries the individual pig identification within that litter.

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 left ear identifies individual pigs in the same litter. All littermates must have different notches in the left ear. Think of the right ear as the family name and the left ear as the given name — every pig in the litter shares the same right-ear pattern, but each one has a unique left-ear pattern.

To read a notch, you add up the values of all notch positions on each ear. For example, a pig with one notch in the “9” zone and one in the “3” zone of the right ear comes from litter 12. A pig with one notch in the “1” zone of the left ear is individual pig number 1 from that litter — written as 12-1. With this system, every number from 1 through 161 can be created on each ear.

For larger operations with more than 80 litters per farrowing season, the system includes an extension. When those positions are filled in the right ear, an 81-notch placed in the tip doubles the system. Only one notch may be at the 81 position. January 1 and July 1 of each year are the starts of each farrowing season, according to Certified Pedigreed Swine (CPS), which means litter numbering resets twice annually for registry purposes.

A quick orientation tip when reading notches in the field: since 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 which is the left ear is to always look the pig in the face — then, if read left-to-right, it would always be litter number then pig number.

Ear	Function	Zones Available	Max Notches Per Zone	Maximum Number
Right Ear	Litter identification	1, 3, 9, 27, 81 (tip)	2 (1 at tip)	161
Left Ear	Individual pig ID within litter	1, 3, 9	2	27

Ear Notching for Purebred Registry Compliance in Illinois

If you raise registered purebred swine in Illinois, ear notching is not just a farm management habit — it is a registry obligation. The major breed registries that Illinois producers work with, including the Certified Pedigreed Swine (CPS) organization and the National Swine Registry (NSR), require notches to be applied correctly and submitted with registration paperwork.

The connection between notching and official ID status runs directly through the registry record. Once you submit a litter registration with the correct notch pattern documented, that notch becomes the animal’s traceable identifier in the breed association’s book of record. That record is exactly what USDA APHIS and Illinois law require before a notch can substitute for an official ear tag on a CVI or movement permit.

For Illinois producers showing purebreds at county fairs or the Illinois State Fair, registry compliance is especially important. Exhibition swine are subject to IDOA’s livestock exhibition requirements, and official identification must appear on all paperwork. A registry-recorded notch satisfies that requirement for purebred animals. However, keep in mind that all cattle and swine exhibited at Illinois county fairs are required to have an electronic 840 tag, which is an approved official animal identification number that allows for visual and electronic identification of each animal. For exhibition purposes, the 840 tag requirement layers on top of — not in place of — any registry notch your animal already carries.

Grade or commercial pigs shown at Illinois exhibitions do not qualify for notch-only identification. Those animals need an official ear tag regardless of whether they have been notched on the farm. The rule is consistent with the broader Illinois administrative code position: notching counts as official ID only when a registry record backs it up.

Pro Tip: Keep a physical copy of your litter registration confirmation from your breed association on file at the farm. If an IDOA inspector or accredited veterinarian needs to verify that a notch is registry-recorded, that document is your fastest proof of compliance.

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

Illinois recognizes multiple official swine identification methods, and each one fits a different operational scenario. Choosing the right method — or the right combination — depends on your production type, whether you move animals interstate, and whether you show at exhibitions.

The current list of APHIS-approved swine identification devices and methods includes official ear tags; USDA backtags only when used on swine moving in slaughter channels; official swine tattoos issued and authorized by state or federal animal health officials on swine moving in slaughter channels; and ear notching if the ear notching has been recorded in the book of record of a purebred registry association.

ID Method	Official ID Status	Best Use Case	Illinois Exhibition Valid?	Registry Requirement?
Ear Notch	Yes — purebreds only, registry-recorded	Purebred farms, 4-H projects, breed shows	Supplemental only (840 tag also required)	Yes
Official Ear Tag (840)	Yes	All swine, including commercial and grade	Yes — required for all exhibition swine	No
Tattoo	Yes — slaughter channels and registry use	Slaughter swine, some breed registries	Supplemental	Depends on registry
RFID / EID	Yes — when part of 840 tag system	Electronic traceability, large operations	Yes — 840 EID tags accepted	No
USDA Backtag	Yes — slaughter channels only	Slaughter-bound swine in transit	No	No

Ear tags are the most versatile option for commercial producers. Once a tag is applied, its status is permanent. Once a tag is applied to an animal, it is the official ID that remains with the animal for its lifetime. You are not to remove an official ID and should not apply a second official ID. If a tag is lost, the official retag must be recorded and reported with both the old number and the replacement number.

Electronic identification (RFID embedded in 840 tags) is growing in use for Illinois swine operations, particularly for producers who submit diagnostic samples to laboratories or who participate in continuity of business programs. The National Pork Board’s premises validation system allows producers to print barcode labels from their Premises Identification Number (PIN) for use on all diagnostic sample submissions, which pairs well with electronic ear tags for end-to-end traceability.

For a broader look at how Illinois animal identification rules interact with other livestock regulations on your property, the animal cruelty laws in Illinois and backyard chicken laws in Illinois pages cover related livestock management obligations.

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

Illinois’s swine identification framework draws from several overlapping authorities: the Illinois Swine Disease Control and Eradication Act (510 ILCS 100), the Illinois Swine Brucellosis Eradication Act (510 ILCS 95), the Illinois Pseudorabies Control Act (510 ILCS 90), and IDOA administrative rules at Title 8 of the Illinois Administrative Code. Understanding which rules apply to your specific situation keeps you on the right side of both state and federal requirements.

Premises Registration: Before any identification method — notch, tag, or tattoo — carries legal weight in Illinois’s traceability system, your farm needs a Premises Identification Number (PIN). Premises registration is the first step you can take to protect your investment in Illinois’ livestock industry, and a database of locations where livestock are produced, raised, and kept also aids animal health officials in responding quickly during a disease outbreak or emergency. Registering your premises is easy to do and is absolutely free. Contact IDOA or visit the IDOA Animal Disease Traceability page to register.

Interstate Movement: Swine, except for slaughter channels or those on commuter herd agreements, must have an official interstate Certificate of Veterinary Inspection (CVI) completed by a USDA-accredited veterinarian from the state of origin, including the name and physical address of both origin and destination. CVIs are valid for 30 days from the date of animal inspection listed on the CVI. A copy of the CVI must be filed with the Department within 30 days of issue. For purebred swine with registry-recorded notches, the notch number must appear on that CVI as the animal’s official ID.

Feral Swine: Ear notching does not apply to feral swine entering Illinois. All feral swine that enter Illinois must be individually identified by an approved, official ear tag, and that identification listed on the Certificate of Veterinary Inspection. All feral swine must be negative to an official test for pseudorabies and brucellosis within 30 days prior to entry.

Brucellosis and Pseudorabies Herd Validation: If you maintain a validated brucellosis-free herd in Illinois, identification rules tighten further. Any purebred animal or any inbred or hybrid animal registered with a livestock registry association shall be identified by registration number, registry association approved individual tattoo, ear notch, or an ear tag. Any grade animal shall be identified by an ear tag or tattoo. Reactor animals in a brucellosis investigation are handled differently — the reactor shall be tagged in the left ear with a reactor identification tag and shipped direct to slaughter within 15 days. A notch does not substitute for the required reactor tag in that situation.

Slaughter Swine: Before being mixed with swine from any other source, all breeding animals consigned to slaughter or offered for sale for slaughter shall be identified to the herd of origin by an approved identification tag in accordance with the Swine Identification Program (9 CFR 78.33, 2002). This means that even purebred animals with registry notches need an approved identification tag when moving to slaughter — the notch alone does not satisfy the slaughter-channel rule.

Exhibition Swine: As noted above, all swine exhibited at Illinois county fairs require an electronic 840 tag regardless of breed or registry status. If you are preparing 4-H market hogs or purebred show pigs for county fair season, plan to apply the 840 tag well before the exhibition date. The ear notch and the 840 tag can coexist on the same animal without conflict.

Important Note: Illinois does not require brucellosis or pseudorabies testing for in-state swine movement. Brucellosis testing is not required for Illinois swine. Pseudorabies testing is not required for Illinois swine. These testing exemptions apply to animals already within Illinois; out-of-state swine entering Illinois face different requirements depending on their state of origin’s pseudorabies status.

If you have questions about how identification rules intersect with other animal law topics in Illinois — from premises liability to livestock transport — the following resources cover related ground: pet import laws in Illinois, kennel zoning laws in Illinois, and roadkill laws in Illinois.

For the most current IDOA guidance on swine identification requirements, contact the Illinois Department of Agriculture directly at 217-782-4944 or visit the IDOA Animal Health and Welfare Laws page. Rules governing official identification methods can change as federal animal disease traceability regulations are updated, so verifying requirements with IDOA before each movement season is always the right call.