If you've been following the blog recently, you know that I've been doing a lot of thinking about ways to feed my pigs more economically. In a previous post, I discussed feeding hay as a potential solution. The entire topic can be a bit controversial, so I wanted to give it some more thought in this post.
Back to the grass clumps. Why are the pigs spitting out the grass instead of swallowing it? Obviously, I can't ask them, so here's my best guess: The pigs have a finite amount of stomach and intestinal space. The only way they can extract nutrition from the fibrous parts of the grass is to let it get through their digestive tract and into their large intestine, where microorganisms can go to work on breaking down the cellulose, pectins, etc. They're not particularly efficient at extracting the energy from the fiber, and thus are better served by ingesting more digestible material. By grinding the plant matter in their mouths, they extract the easily digestible juices, then spit out the hard to digest parts. Of course, I don't think they make this a conscious calculation, but rather rely on instinct. An example from just a few feet away of something the pigs eat and swallow in the pasture are these blackberry roots. I caught them a few days before this picture was taken rooting out the tender roots and eating them.
The difficulty in assessing the ability and degree to which pasture can provide feed to pigs is that it very hard to quantify how much food they're getting from it. Since they will eat commercial feed first, I can't just measure their pasture ingestion by the amount of feed they eat. All I can really do is observe them eating, look at existing scientific research, read what other farms have done in the past, think about the pig digestive tract, and perhaps most importantly, look at what feral pigs and wild boar eat.
So without further ado, here's the state of my thinking on pasture (and hay):
1. Pigs can extract nutrition from grass, but it is far less than what a ruminant, horse, or rabbit can extract. The maturity of the grass probably has a big effect (young leaves tend to have more easily digestible nutrients).
2. Increasing the amount of legumes, brassicas, or other higher protein plants will provide higher nutrition than grass alone. In general, higher protein is better, but this is especially important for lactating sows and young pigs.
3. Roots are really important. The pig's best tool is its snout. Roots make up a huge amount of the diet of wild pigs.
4. Invertebrates (insects, spiders, slugs, snails, etc) are the best food of all.
5. Pigs can and will eat hay. I've seen it. All hays are not the same. The hay that I bale here on the farm is high fiber, low protein. Eastern Washington alfalfa is high protein, lower fiber. I don't know if pigs can survive and grow on hay alone, but if they can, they would probably need the very best hay. My homegrown hay is not going to cut it.
6. Optimizing my pasture for pigs would require me to plant foodstuffs that are more digestible by pigs. An example might be a mix of field peas, camelina, and turnips.
7. Last but not least, I don't know if planting such an optimized pasture would be worth it economically. Since it's so hard to quantify how much nutrition the pigs are getting from the pasture, it's hard to measure the benefit of the cost of seed, equipment, and man hours. It certainly would be a lot less expensive than trying to grow my own grain.
In the spirit of experimentation and because I just can't stop myself from constantly trying to do new things, I'm going to plant an acre of improved pasture and put the pigs out on it in the late spring. I will keep you posted!