Investing in gilt care: How development drives lifetime sow productivity

11 February 2026

4 minute read

By: Zoetis

Why gilt development matters

Gilts represent the future of your breeding herd, so being equipped to care for them at key life phases is critical. There’s a lot that goes into developing robust gilts — from their growth, body condition, and structural soundness to reproductive potential and health.

Gilts live in distinct production phases in a relatively short period of time. Because of this, gilt development is not a single step, but it’s a complex program that leads gilts through several key stages — growing, selection and acclimation, breeding and farrowing — with distinct needs at each step.

The gilt development process requires significant investment in resources, including feed, genetics, management, etc. However, gilts are often the most frequently culled female from the swine breeding herd, with between 38.5% and 51.1% of gilts not being retained in the herd.1 Culled gilts are not able to contribute to breeding herd performance, so the investment is lost and doubly costs more to bring in yet another gilt.

The gilt development process sets the foundation for everything that happens downstream as she enters the breeding herd. She needs to be provided everything possible for her to meet her full potential and become a successful sow.

From gilt to sow: Laying the foundation for success

Gilt development can be divided into three phases — the developing gilt, the selected/bred gilt and the farrowing/lactating gilt — each with its own requirements and management practices.

During the growth phase, the gilt needs to develop the physical and skeletal framework to not only carry herself but also carry and care for her progeny, either in utero or during lactation.

Skeletal development should be robust to support the gilt and litter. Her feet and legs are also key, so she can get up and move around, which is especially important in pen-based gestation systems.

During growth, the gilt must maintain good body condition, which needs to be adequate to supply her energy needs but not so much as to impede the farrowing process. The gilt continues to grow and develop through her first lactation, so her body fat reserves need to help her maintain her growth pattern and nourish the group of piglets she’s carrying and feeding.

Mammary development is also important — not only the uniformity of the underline and proper teat anatomy but also the glandular tissue that produces milk and duct development. A sow’s total milk production can rival that of a dairy cow, because she’s letting milk down every hour for her piglets.

Once pregnancy occurs, the mammary gland will see a great deal of glandular development because of pregnancy-related hormones, but its potential is preset during the gilt’s growth phase.

From a health standpoint, there can be short-term impacts of disease on developing gilts. To overcome the challenge, a gilt will divert body resources toward resolving the infection and clinical disease, which can limit her growth or future performance.

The other health impact is the colonization or establishment of certain bacterial or viral diseases. Some diseases need a certain amount of time to be cleared before the gilt stops shedding. For example, if a mycoplasma-negative gilt is going into a mycoplasma-positive sow farm, she needs to be exposed to mycoplasma by about 80 days of age, so she has time to clear the pathogen and not infect her first litter.

This acclimation period varies by pathogen, but it is an important step in gilt development to stabilize herd disease status.

Successfully transitioning a gilt through her first gestation and first lactation and remaining in the herd for another parity can be a pretty big feat, which is why producers should focus more on the gilt during growth and development.

Understanding profitability and parity

A fully developed gilt is not profitable with her first litter. On average, she will not break even until she’s had over 3 litters (parities) whether she was raised on farm or if she was purchased from a genetics company.2

There are management practices that can help set up a gilt for breeding herd success, such as boar exposure and heat/no service (HNS). Boar exposure stimulates gilt reproduction by inducing puberty and estrus through a combination of olfactory (smell), visual, auditory and tactile stimuli that activates the gilt’s hormonal system to advance sexual maturity.

With HNS, after a gilt has her first confirmed heat cycle, she is typically bred on her second heat cycle, which can lead to higher farrowing rates and more pigs born over her lifetime. This means she may become profitable sooner.

Optimizing the wean-to-rebreed interval

Gilt development doesn’t stop when she becomes a parity 1 sow. She will continue to grow through her first lactation, possibly leading to metabolic stress if she loses body condition while growing. These parity 1 sows may require extra attention and monitoring before they return to the breeding herd. As this is her first time in the farrowing house, she may also need to adjust to a new type of feeder or water drinker.

Throughout the gilt development process, gilts have unique needs that caregivers should provide to ensure gilts’ success in the breeding herd. Caregivers working with gilts should be trained on specific management practices, such as boar exposure and monitoring for puberty. Spending extra time caring for gilts and putting specific management practices in place will ensure longevity of the gilt in the herd and, ultimately, profitability from investing in her.