Industry averages suggest that the replacement rate in a sow herd is near 50%. With that in mind, it is essential to source replacement gilts that are built to last. Whether you are purchasing replacements or raising your own, there are a few key factors that help identify which females should be kept and finding those that should be culled.
The primary factor to evaluate is underline correctness. Replacement females must have at least 7 functional teats on each side. The main issues to consider are proper spacing and proper size. Teats that are bunched up or are spaced too far apart cause difficulty for young pigs to find ample space while nursing. Having a consistent size is key as well, as small, “pin” teats are often non-functional, while large, blunt teats are difficult for young piglets to latch-on to while nursing. Additionally, evaluating the proper size and set to a gilt’s vulva is important. The main concern in considering to cull females is small, tipped or upward pointing vulvas.
Evaluating the structural build of a replacement gilt definitely requires some practice or experience to perform quickly. However, a well-built female will prove to be durable and offer longevity in your sow herd. An easy exercise is to simply evaluate each gilt walking across the pen. The freedom in her movement tells a story about her structural build. It is important to watch her topline, as a gilt that is well-built will often be consistently level topped. Gilts that break behind their shoulder or roach in their topline usually have structural issues. Evaluating a gilt’s structural correctness piece by piece starts at the ground. A good replacement female will offer big, evenly-sized toes, has a comfortable set to their pasterns, and proper set to their knee and hock. Gilts that should be culled are simply the opposite. Producers can quickly spot small or uneven toe size, soft/weak pastern set, being upright or stiff in the set to their knee, straight and stiff in the set to her hock, or there is too much set to the hock. An additional indicator is a gilt’s base width. A gilt’s foot placement should be as wide as the width of her shoulders or hips. Gilts that offer excessive base width or stand too narrow at the ground will tend to breakdown over time. As you study a gilt from the ground up, these tell-tale signs often indicate if she is built to last. Although a gilt’s structural build does not dictate how many pigs she will wean for you, it is clear that a gilt that is sound from the ground-up should last for a longer period in your sow herd.
There are a few other factors to consider when evaluating your replacement gilts. It is important to consider her overall growth or rate of gain, body conformation, if she has an adequate amount of muscling, and the presence of any abnormalities. Although we do not prefer to grow our replacement gilts like finishing pigs, a gilt that shows adequate and consistent growth is very appealing as you would expect her offspring to do the same. Also, a gilt’s body confirmation is important. Ideally, a replacement gilt offers a robust rib cage and a productive look. Gilts that are smaller framed or are more quick to mature are often carrying extra fat and can be a challenge to manage her condition later in life. The same is true at the opposite end of the spectrum with an extraordinarily long, narrow gilt that never shows much flesh or fill through her center body, and become sows that wither away. We still want our gilts to offer some muscling over their top and from behind, since they do pass half of the genetic potential to their market hog offspring. The final factor to consider is usually the easiest to spot. A gilt that has experienced a belly rupture, a wound or permanent damage to their vulva or underline, or has any other abnormality that deems her unacceptable should be culled.
Raising and producing replacement gilts is a challenging task. Investing money into every female and then being asked to cull some of them can be even tougher. In order to replace aging sows, maintain your production standards and to continue moving forward, replacement gilts are a key piece in the effort. However, all replacement females are not created equal. Staying grounded in your approach and taking your time to study each and every gilt will allow you to identify those gilts that are built to provide longevity in the sow herd.
At Sioux Nation Ag Center, we actively play a role assisting in the gilt selection area for our customers and would be thrilled to help you in any way.