Intradermal Vaccination Is Now on U.S. Sow Farms. Here's What a Year of Field Data Looks Like.

U.S. pork producers have always taken a protocol-by-protocol approach to herd health. What works for one operation doesn't automatically translate to the next, and the variables, housing, staffing, health status, welfare commitments, mean the best toolbox is a flexible one. In 2025, that toolbox got a new addition.

Merck Animal Health obtained the first U.S. license for an Intradermal Application of Liquids device, known as the IDAL, with SEQUIVITY prescription vaccines becoming the first intradermal vaccines approved for swine using the technology. After a year of field evaluations across commercial sow farms, early data is starting to paint a picture of how the technology performs in real-world conditions.

How the Device Works

The IDAL device delivers a 0.2 mL intradermal dose and can be administered at multiple soft-skin sites on adult breeding animals, including the neck, perianal area, and skin above the mammary tissue. The expanded site options matter practically. More viable injection locations on mature animals means the vaccination process becomes easier to execute and safer for caretakers, particularly on operations where animal handling during mass vaccination events creates workflow and safety challenges.

What the Field Evaluations Found

Two controlled field evaluations assessed the intradermal vaccination experience on commercial sow farms. Pipestone Veterinary Services conducted one study across two farms, vaccinating more than 2,500 gilts and sows with SEQUIVITY PPV1 during a mass vaccination event. The University of Pennsylvania conducted the other.

The behavioral data from Pipestone is the headline finding. During IDAL vaccination, 63% of animals did not change their position or react at all when the vaccine was administered. Additionally, 64% did not vocalize during the intradermal procedure. For anyone who has managed or observed mass sow vaccination events, those numbers represent a meaningful departure from what traditional intramuscular injection typically produces.

The University of Pennsylvania study observed consistent patterns. Sows vaccinated with the IDAL device showed fewer stress behaviors and vocalizations and spent more time lying calmly after vaccination, behavioral indicators that align with the welfare metrics the industry has been increasingly tracking and reporting against.

The Worker Side of the Equation

Animal welfare data gets attention, but the vaccinator experience data from these evaluations is equally worth noting. All vaccinators surveyed at both Pipestone farms found the IDAL device easy and comfortable to operate. All reported feeling safer during the vaccination process compared to conventional injection methods. Top-rated features included speed of dose delivery, ease of preparation, and the hose-free design.

That last point connects to a documented industry problem. A 2017 University of Minnesota report found that 5.2% of injuries across four swine operations were related to needle sticks and 37.5% stemmed from animal interaction during handling. Any route of administration that reduces both categories of risk is worth serious evaluation, especially on operations managing lean labor pools where a single injury has outsized operational impact.

What This Means for Swine Veterinary Practice

Intradermal delivery is not a replacement for existing protocols. It's an addition to them. The value proposition is optionality: another viable route for operations where welfare commitments, worker safety goals, or workflow constraints make a needle-free or needle-reduced approach worth building into the vaccination program.

For veterinarians advising sow operations, the first year of IDAL data provides a foundation for that conversation. The field evaluations were conducted on commercial farms under real production conditions, not controlled laboratory settings, which gives the behavioral and workflow findings more direct relevance to the operations where these decisions get made.

More evaluation data is expected to emerge in the months ahead. For now, the U.S. swine industry has a new route of administration backed by early field evidence and a year of producer experience. In a production system where vaccination compliance, animal handling efficiency, and worker safety are all in play simultaneously, that kind of flexibility has real value.

TAGS: swine, vaccination, sow farm, animal welfare, IDAL, intradermal, Merck Animal Health, SEQUIVITY, food animal, worker safety, herd health