Swine Ear Notching Laws in Kentucky: What Every Pig Owner Needs to Know

Ear notching has been a cornerstone of swine identification on American farms for generations, and Kentucky producers still rely on it today — but knowing when it satisfies the law is a different matter from simply knowing how to cut the notches. Whether you raise purebred hogs for show, farrow piglets for sale, or move swine across county lines, the rules governing what counts as official identification directly affect your paperwork, your compliance status, and your animals’ traceability.

Kentucky’s swine identification framework is built on both state administrative regulations and federal USDA requirements, and ear notching occupies a specific — and limited — lane within that framework. This guide walks you through exactly how the 1-3-9 system works, when a notch qualifies as official ID under Kentucky law, and how it stacks up against ear tags, tattoos, and electronic identification for every common movement scenario.

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

Ear notching is a permanent physical identification method in which small V-shaped cuts are made at precise locations on a pig’s ears to encode a unique number. It is widely used in the swine industry as a system of animal identification, with all variations identifying a pig by litter number and individual pig number. The method has endured because it requires no electronic reader, no tag inventory, and no ongoing maintenance — the ID is literally cut into the animal at birth.

Ear notching provides a permanent ID system that gives individual identity to all animals and serves as an inexpensive means of identification that enables producers to keep an accurate set of records. In Kentucky, you will encounter ear notching most often in three contexts: purebred herd management, 4-H and FFA show pig enrollment, and interstate movement documentation for registered animals.

If pigs can be notched when their tails are docked, or at 1–3 days old, the task is much easier. Most Kentucky producers perform the procedure at farrowing time, which keeps the piglet stress low and the wounds small. If you allow pigs to become large — around 100 pounds — the task can become considerably demanding mentally and physically, and it may be necessary to house them in separate pens until the notches heal.

Pro Tip: Disinfect your V-notcher between litters using fresh surgical spirit or alcohol. Reusing unclean equipment between litters is one of the most common sources of infection on farrowing operations.

When Ear Notching Qualifies as Official Identification in Kentucky

Not every notch pattern on a pig’s ear constitutes “official identification” under Kentucky or federal law. The distinction matters enormously when you move animals for sale, exhibition, or breeding. Official identification is a device or identification mark approved by the USDA that provides a unique identification number for the individual animal, and official ID devices must be tamper-evident and bear the U.S. shield. A plain farm-management notch does not meet that standard on its own.

Under the USDA’s National Veterinary Accreditation Program (NVAP) guidelines — which Kentucky’s Office of the State Veterinarian (OSV) operates within — ear notching qualifies as official identification only if the ear notching has been recorded in the book of record of a purebred registry association. If your notch pattern is not registered with a recognized purebred breed registry, it functions as a farm management tool, not as a legally recognized official ID for interstate or intrastate movement purposes.

Kentucky’s own administrative regulations reinforce this. Breed registry ear notches on swine are listed as an accepted form of official identification under 302 KAR 20:020, the state’s general requirements for interstate and intrastate animal movement. That same regulation also lists official eartags, USDA back tags (for slaughter animals only), and official tattoos as alternatives. The key phrase throughout is “breed registry” — the notch must be tied to a recorded pedigree to count.

It is unlawful to remove official ID once applied. This applies to ear notches that have been officially recorded just as it does to metal eartags, so you should never re-notch a registered animal in a way that alters or obscures the original pattern.

How the 1-3-9 Ear Notching System Works

The simplest method recommended by most breed associations is ear notching, and the most common notching system is the 1-3-9 system. Understanding this system is not optional for Kentucky producers who want their notch patterns to be readable by veterinarians, show officials, and registry staff.

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 litter mark ear is divided into five sections, and each section has a numerical value — either 1, 3, 9, 27, or 81. Each section, except for 81, can have one or two notches only. The left ear is used for notches to show an individual pig’s number in the litter, and 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 read a pig’s identity, you add up the numerical values of all notches in each ear. To determine the litter number for a pig, the numerical values assigned to each notch are added. For example, notches in the 27, 3, and 1 positions on the right ear give you Litter 31; a notch in the 3 and two notches in the 1 position on the left ear give you Individual Pig 5 — so that animal is read as 31-5.

Ear	Purpose	Zone Values Available	Max Notches per Zone
Right Ear	Litter Number	1, 3, 9, 27, 81	2 (except 81: max 1)
Left Ear	Individual Pig Number	1, 3, 9	2 per zone

In zones 1, 3, 9, and 27, there can only be two notches — so two notches in all four zones would represent Litter 80. A notch in zone 81 basically doubles the system. This means a single producer can track well over 160 litters before needing to recycle numbers, making the system practical for mid-size Kentucky farrow-to-finish operations.

Since confusion over which ear is the “left ear” can easily occur depending on whether you are viewing the pig from the front or the rear, a good way to remember is to always look the pig in the face — then, reading left to right, it is always litter number then pig number.

Avoid placing a notch midway in the outside edge of either ear, because such marks can easily be mistaken for either a 1 or a 3 or a 9 or a 27. Precision matters — a misread notch on a registered animal can cause a mismatch between the physical pig and its pedigree record.

Pro Tip: Use a V-ear notcher for piglets weighing less than about 25 pounds. These notchers typically make a notch that is 3/16 to 1/4 inch deep. For larger animals, step up to a notcher rated for 1/2-inch depth to ensure the notch remains readable as the ear grows.

Ear Notching for Purebred Registry Compliance in Kentucky

If you raise registered swine in Kentucky — Berkshire, Duroc, Hampshire, Yorkshire, or any other recognized breed — ear notching is not just a management convenience; it is the foundation of your pedigree documentation. 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.

Ear notches are typically made within the first few days of birth. They help breeders maintain accurate records with regard to registration and health records on the farm, including vaccination records. When you submit a litter registration application to your breed association — such as the National Swine Registry — the notch pattern you record on that application must exactly match the physical notches on each pig’s ears. Any discrepancy can result in a rejected registration.

Ear notching of any swine qualifies as an APHIS-approved identification method if the ear notching has been recorded in a purebred registry association’s book of record. This is the federal standard that Kentucky’s OSV enforces when reviewing CVIs for registered animals entering or leaving the state. Without that recorded entry in the breed registry, the notch is invisible to the official identification system.

Kentucky 4-H and FFA members showing purebred project pigs face the same requirement. Understanding the ear notching system and being able to read the ear notches of their pigs is necessary to properly enroll 4-H swine projects. County Extension agents across Kentucky routinely help first-time exhibitors verify their notch patterns before county fair deadlines. If you are new to the process, reach out to your local University of Kentucky Cooperative Extension office well before show season.

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

Kentucky producers have several official identification options, and choosing the right one depends on how and where you move your animals. Each method has specific use cases, strengths, and limitations under 302 KAR 20:020 and the USDA’s interstate movement rules.

Official swine tattoos — issued and authorized by state or federal animal health officials — apply to swine moving in slaughter channels. Tattoos on the ear or inner flank of any swine also qualify as official ID if the tattoos have been recorded in the book of record of a swine registry association. Registry tattoos work similarly to registry notches: the record in the breed association’s database is what gives the mark its official status.

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 the standard identification method. This PIN-based system is what most commercial Kentucky hog operations use, since it does not require purebred registry enrollment.

ID Method	Approved Use Cases	Registry Required?	Tamper-Evident?
Ear Notching	Breeding, exhibition, registered animals	Yes — purebred registry	No (permanent but not tamper-evident)
Official Ear Tag (AIN 840)	Any swine, all movement types	No	Yes
Official Tattoo (PIN-based)	Slaughter and feeder swine	No	Permanent but not removable
Registry Tattoo	Breeding and exhibition	Yes — swine registry	Permanent but not removable
USDA Back Tag	Slaughter animals from state-federal stockyard to slaughter facility only	No	Yes (temporary)
RFID Implant (ISO 840)	Any swine; supports electronic traceability	No	Yes

RFID microchip implants compliant with ISO 11784/11785 and bearing an AIN 840 number are increasingly common on larger Kentucky operations. Implants must be compliant with ISO 11784/11785 and must be an AIN (“840”); implant placement is between the skin and cartilage of the backside of the ear. Unlike ear notches, RFID implants can be scanned at livestock markets without handling the animal, which speeds up processing considerably.

One important limitation of ear notching relative to all tag-based systems: official ID devices must be tamper-evident and bear the U.S. shield. A notch pattern, by definition, cannot be tamper-evident the way a sealed metal tag can. This is why notches are not accepted as official ID for commercial slaughter or feeder pig channels in Kentucky unless paired with a breed registry record — the registry record provides the accountability layer the notch itself cannot.

Important Note: USDA back tags are accepted for slaughter animals moving from a state-federal approved stockyard directly to a slaughter facility, but back tags shall not be used for animals entering into Kentucky. Do not rely on back tags for any inbound shipment.

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

Kentucky’s swine identification requirements are governed primarily by 302 KAR 20:020 (general movement requirements), 302 KAR 20:040 (interstate movement), and 302 KAR 20:065 (intrastate movement). Understanding which regulation applies to your situation determines what paperwork you need alongside any ear notch identification.

For intrastate movement — moving swine between farms or to a sale within Kentucky — swine moving intrastate for sale, change of ownership, or exhibition shall meet the requirements established in the relevant subsections of 302 KAR 20:065. All swine moving intrastate for sale, exhibition, or change of ownership shall be accompanied by a valid Certificate of Veterinary Inspection (CVI) as required by 302 KAR 20:020, and a CVI for change of ownership and sale shall be valid for thirty (30) days.

There is one meaningful exemption for small Kentucky producers. Swine sold or bartered by private treaty and moving directly from farm to farm shall be exempt from the CVI requirement if the seller’s or barterer’s name and premises of origin information are recorded and maintained for two (2) years by the recipient of the animal. This farm-to-farm private treaty exemption is widely used by small Kentucky hog producers, but it does not eliminate the need for official identification — it only removes the CVI paperwork requirement for that specific transaction.

For interstate movement into Kentucky, the rules are more demanding. All swine entering the state for sale, exhibition, breeding, or feeding purposes shall be accompanied by a valid CVI, and an entry permit shall be required prior to entry for all swine entering for sale, breeding, or feeding purposes. If an entry permit is required, it shall be obtained by calling the OSV at (502) 564-3956, Monday through Friday, 8 a.m. to 4:30 p.m. EST.

Wild and feral swine are categorically excluded from standard identification pathways. Wild, captive wild, or feral swine — including Russian wild boars and Eurasian wild boars — shall not be moved for any purpose except under the jurisdiction of the OSV or USDA APHIS VS. If you are dealing with any Sus scrofa variant outside a domestic breed registry, standard ear notching rules do not apply, and you need direct OSV authorization before any movement.

Exhibition swine face an additional layer of disease-related requirements. An entry permit shall be required for exhibition purposes from states with less than Stage 5 Pseudorabies status. When you bring registered show pigs into Kentucky from out of state, confirm the origin state’s Pseudorabies status with the OSV before the animals load — a missing permit can bar your animals from entering the fairgrounds. You can also review Kentucky’s broader transporting livestock laws to understand the full documentation chain for any multi-species haul.

Kentucky’s livestock identification framework also connects to how you manage other farm animals. If you raise goats alongside your hogs, the scrapie identification requirements for small ruminants operate under a parallel but separate system — see our overview of goat ownership laws in Kentucky for details. Producers who keep poultry on the same property may also find the rules around backyard chicken laws in Kentucky relevant to their overall compliance picture.

Key Insight: Kentucky’s OSV is your single most important resource for swine ID compliance questions. The office can confirm current Pseudorabies status for origin states, issue entry permits, and clarify which identification methods are accepted for any specific movement scenario. Contact them at (502) 564-3956 before any interstate shipment, not after.

Ear notching remains a legitimate and practical identification tool for Kentucky swine producers — but only within its proper legal lane. For purebred and registered animals with notch patterns recorded in a breed registry, it satisfies both state and federal official ID requirements for breeding and exhibition movement. For commercial slaughter, feeder pig, or unregistered animals, you need an official eartag or PIN-based tattoo instead. Knowing the difference keeps your operation compliant, your paperwork clean, and your animals traceable from the farrowing crate to their final destination. For related animal law topics on your Kentucky farm, explore our guides on pet import laws in Kentucky and beekeeping laws in Kentucky.