Click here to view as a pdf: The Importance of Monitoring Nutrition When Pasturing Pigs

By Darren Zimmerman, D.V.M.

There has been a steady increase in the number of producers choosing to pasture pigs. The reasons can vary: cost of feed savings, aid in tilling soil, spreading manure. When considering if pasturing pigs is right for your operation, there are many things to consider, with one of the most important being how to maintain proper nutrition for the animal.

There has been extensive research on swine nutrition, and nearly all recommendations are for a complete diet. A complete diet is one that is mixed evenly and proportional in all feedings to all desired ingredients to meet the needs of the specific intended animal. This includes calories, protein, fat, vitamins, minerals and other essential nutrients. Swine in different stages of life have different needs.

When considering pasturing pigs, it is essential to understand how pigs process nutrients. Pigs are monogastric. They do not have a rumen and have limited ability to ferment and digest fiber. As we are calling them pasture pigs, there is an expectation that they will get some nutrition from the plants. We should also understand that although they will eat some of the plants on pasture or in the woods, they will not “graze” the pasture evenly. There will be some fermentation in the large intestine and absorption of nutrients. The higher the amount of fiber in a diet, the faster it travels through the intestines. This gives the digestive system less time to ferment and absorb nutrients. Older plants tend to contain more lignin and cellulose (undigestible or insoluble fiber), while the younger, fast-growing plants will have more hemicellulose or pectin (digestible or soluble fiber). They will obviously get more out young growing plants than mature ones.

Aged adults and certain breeds have longer intestines and allow for higher digestion. Over time older pigs can get even more efficient on pasture as their intestine biome changes to accommodate the fiber in their diet. However, this can take months and may not be helpful with a seasonal pasture. Younger pigs have shorter intestines and limited ability to digest nutrients picked up on pasture. For every percentage point of the diet the young pigs are getting from pasture you can expect the same percentage of extra time to get them to a finished weight. It is expected to take15% longer to finish a pig if their diet is supplemented by 15-20 % of pasture. That means an extra month on feed and pasture before finishing.

Nutrients are generally fed at a certain percentage of the diet. With a complete feed, this percentage is easily calculated. When a pig is on pasture, the animal has access to plants, insects and soil. The quality of the pasture or woods can change daily, depending on weather and time of the year. This changes what nutrients are available. It can be difficult to know what or how much the pasture is supplementing the diet. We would recommend they are always provided with adequate vitamins and minerals. How this is provided will depend on each farms management and the needs of the animals by their stage of life. See Figure 1.

What To Expect When Pasturing Pigs:

Young animals will not digest fiber well. The more fiber there is in their diet the longer it will take them to develop.
Mature pigs can digest some fiber.
There is nutrition in bugs, nuts, plants and other things pigs will find when out foraging. It is likely not complete nutrition. It is better to treat the pasture as a supplement to their diet than to treat their feed as a supplement to pasture.
Pigs are not going to graze the pasture like a sheep or a cow.

Pasturing Pig Tips:

When deciding to pasture pigs, there are few tips to help your operation be more successful:

Stick to the basics
Access to clean fresh cool water
Available shelter
Feed balanced for vitamins and minerals
Ensure there is enough space for the animals (approximately ½ acre per pig is a good place to start, every farm is different)
Rotate pasture to allow for recovery. This could by yearly or more frequent.
Consider moving feed and water troughs to reduce flies, odor, soil compaction
Monitor for parasites

What To Look Out For:

A pig on pasture may not be receiving proper nutrition. Symptoms of malnutrition vary depending on the nutrient and the animal. These can include the following: reduced growth, rough hair coat, lethargy or weakness, lameness or difficulty walking, and skin and/or bone problems. Pigs can display different symptoms based on the nutrient they are deficient in. For instance, lethargy could be due to an iron deficiency, while a niacin deficiency could lead to a roughened hair coat and diarrhea. If the animal is displaying any of these symptoms it is important to work with a nutritionist and veterinarian to ensure the pigs are properly cared for.

When deciding to pasture pigs, it is important to consider many factors. Cornell Extension has an informative article as well titled: “The Dirty Truth about Homestead Pigs on Pasture”.

If you would like to speak to a nutritionist about whether pasturing pigs is right for your operation, contact Crystal Creek® at 888-376-6777 or visit the website at www.crystalcreeknatural.com