Viability of Hogging Down Corn and Peas as Swine Feedstock

I ordered Wapsie Valley corn, 4010 forage pea, winter rye, and red clover seeds from Lakeview Organics on 3/14/19.  An NRCS agent collected soil samples on 5/9/19. We set up pig fencing on 5/13/19 and moved (16) 200-lb pigs into first acre on 5/14/19.  We moved the pigs to the second acre on 5/30/19. We moved them out on 6/19/19. During this time they had full access to organic hog grower feed from Green Mountain Feeds.  They consumed 4200 lbs of feed. They grazed the pastures and kept them fairly short, but we were surprised at how little tillage they did. Since so much of the sod was still intact, we decided to plow it up, rather than just disc it, as we had written in our proposal.  This proved much more time consuming than we had hoped, as there were many large stones just under the soil surface. We removed 8 tractor bucket loads of rocks from this 2 acre area, for fear of damaging the corn planter that we were going to borrow. After plowing and removing rocks, we disced the field twice.

We were late moving the pigs into this area because of wet ground and lack of time.  The pigs took longer than expected to dig up the sod. The soil preparation took longer than expected.  And we couldn't get the corn planter as soon as we had hoped because the farmer we were borrowing it from was using it.  So even thought we had hoped to plant the first acre to corn and peas in mid-May and the second acre in early June, but we couldn't plant until late June, so we just planted both acres at the same time.

We borrowed a 2 row corn planter that was set for 30 inch rows and 7 inch spacing between plants.  We did one pass with the corn, and then went back with the peas and planted them in between the corn rows, so essentially the rows alternated between corn and peas with 15 inch spacing between them.  Since the planter had to be lifted out of the ground to turn, and since most of this area was close to perimeter fencing, we had to lift the planter with enough space to turn around. This left an unplanted 60 feet or so at each end.  For curiosities sake, we tried broadcasting the corn and peas, at approximately the same density and then disc harrowed over it to see how well it would germinate in comparison. We were pleasantly surprised that it seemed to germinate and grow just about as well as the corn and peas planted by the planter.  For this reason, and because of potential scheduling conflicts with the planter, we plan to try an earlier broadcast seeding next year instead of using the corn planter. If germination is poor, then we will still have time to disc it and replant with the corn planter.

This year the corn and peas grew very well.  At the suggestion of our technical adviser, we took soil samples again when the corn was about a foot tall and submitted them for pre-sidedress Nitrate testing.  The results came back showing 23 ppm, which we were advised was adequate for good corn growth. There were a few small locations of yellow corn plants with stunted growth, but most of it grew very well, reaching well over 10 feet by October.

A few days before moving the pigs into the corn, we began feeding whole corn plants to the pigs in order to adjust their digestive systems before removing their other feed.  They loved it, and ate nearly the entire plants - stems, leaves, kernels, and cobs. We cut narrow swaths through the corn where we needed to install the temporary electric fencing.  This is where the corn plants came from that we fed to the pigs before the experiment started.

We set up 2-strand polywire electric fencing and an automatic waterer in half an acre of the corn, and then sorted a group of 33 pigs into the corn (17 pigs) and control group (16 pigs).  The control group was in a silvopasture environment, like the rest of our pigs, with full access to Green Mountain organic hog feed. The corn pigs learned within a few hours to knock the corn plants down in order to get to the cobs.  They also ate quite a bit of the leaves and some of the stalks. At this point it was hard to tell how much of the peas they were eating.

One concern from the beginning was that they may not get enough minerals from the plants and soil, so we offered Fertrell's Grazier's Choice mineral just to see if they would like it.  They loved it, and so we ended up feeding them some every day. During the experiment they consumed (2) 50-lb bags of minerals.

About every 8-10 days, the pigs had knocked over every corn plant and eaten nearly every kernel of corn, so we would move them to the next half acre.  The day before moving the pigs, we would broadcast winter rye and red clover seed to allow them time to step it into the soil. We decided on this method rather than broadcasting and disc harrowing because it was so late into the fall and the soil was very wet from regular rain.  We had some germination from the first two areas, but the second two areas were seeded so late, that we did not see any germination.

On the day that the corn pigs were done with the last half acre (11/13/19), we loaded them out and weighed them.  We also weighed the control group.

These costs do not include labor, which was nearly the same for the daily chores of each group.  The main difference in labor was the time spent preparing the soil and planting the corn and peas, which was 19 hours.

2020 Update:

First day in corn - August 26, 2020

Giant Foxtail overtaking corn - August 24, 2020

Peas struggling to keep up with Foxtail - August 24, 2020

Just after pig move from 2nd to 3rd area - September 19, 2020

Tillage and Planting:

I ordered Wapsie Valley corn, 4010 forage pea, winter rye, and red clover seeds from Lakeview Organics on 2/12/20.  We set up fencing and water for the first half acre to be tilled on May 6th.  On May 11th we moved (17) 250-lb pigs into the first area for tillage.  On May 18th we moved the pigs to the second half acre area.  On May 22nd, we disced the first area twice to smooth out the ruts the pigs left and till in the remaining vegetation.  We then broadcast seeded 12 lbs each of corn and peas with a shoulder-mounted Earthway seeder.  Then we disced once more to bury the seed.

We decided on this method, differing from our 2019 approach, because the corn planter we borrowed was not available until the end of June, and we had to return it quickly.  This led to a very late harvest date, and subsequent failure of our fall cover crop because it was planted too late, resulting in bare soil through the winter.  We also were hoping for more staggered corn maturity so that the pigs could always be harvesting the corn at optimum nutrient levels.  In 2019, we had planted the ends of the field (where we had to lift the corn planter in order to turn the tractor) with the "broadcast and disc-in" method.  We had good results at an estimated 80% of the germination rate achieved with the corn planter.

Seeing that the pigs were not tilling as thoroughly as we had hoped, on May 22nd we added a group of (8) gestating sows to half of the fourth area for experimentation with a different class of pigs and to increase overall impact.

On June 8th we moved the pigs into the third area.  We disced and planted the second area on June 12th using the same method as the first.  On June 15th we moved the pigs into the remaining half of the fourth area.  On June 22nd we disced and planted the third section again with the same method. On July 2nd we moved all of the pigs out of the corn area.  Over this entire tillage period, the pigs consumed 7200 lbs of feed.

By this point we could observe the germination of the first two areas.  In the first area about 50% of the area had germinated well, but the other 50% was just weeds.  In the second area, very little corn or peas germinated at all, and weeds quickly took over.  So we decided to alter our planting method for the fourth area, as an experiment.  We disced the area twice on July 6th, and then dropped the seeds by hand into the furrows, at roughly 24" row spacing and 8" plant spacing.  Thinking that the seeds may have been buried too deep by the disc harrow, we instead dragged a 12 foot long, 4x4 post behind the tractor that just knocked the ridges of soil into the furrows.  This seemed to result in a more consistent planting depth around 2" deep.  However, it was much more time consuming than simply broadcasting.  And unfortunately, it did not result in any better germination than the "broadcast and disc-in" method.

By early August, the few corn plants that had germinated in the 4th section were about a foot tall, so we submitted a soil sample again for pre-sidedress Nitrate testing.  We were curious if low nitrogen levels were contributing to poor growth and yellowing plants.  The results came back at 52 ppm, which is more than double the previous years results, negating nitrogen levels as a contributing factor to crop failure.

By late August we had a beautiful patch of giant foxtail (with dotting of corn and pea plants) in the vegetative state, and we considered grazing it with our cattle, who had been transitioned to hay, as our pastures were all brown from drought.  But we still wanted to see the results of the soil analysis at the end of two years grazing it with pigs, so we let it go and stayed on schedule to put the pigs in just as the few ears of corn matured.  However, recognizing that there was not enough feed value in the corn to properly nourish the pigs, we decided to keep the pigs in the corn area on full feed.  Instead of measuring the difference in cost between fully corn fed pigs versus fully grain fed pigs, we decided we would measure the difference in feed consumption between the control group of pigs raised in the woods and the "corn" pigs that got to graze (mostly on giant foxtail and other summer annuals).

It's worth noting that between planting and harvesting in 2019 we received 13.6" of total rainfall with 8 rainfall events of an inch or more, and in 2020 we received 6.2" of rainfall with no rainfall events of greater than 0.6".  We had to feed hay to our cattle from July 20th to August 24th, because the pastures were all brown and dormant.  This may have contributed significantly to the corn crop failure.

Harvesting:

On August 26th (96 days after planting), we weighed 36 pigs and divided them evenly into a control group and "corn" group.  Each group had roughly even numbers from each of the four litters that made up the whole group.  Each group had full access to Green Mountain's organic hog grower feed and water.  Given the amount of crop residue left behind after the 2019 experiment, we knew discing would not adequately incorporate the plant residue or the cover crop seeds (winter rye and red clover).  In other areas of our farm, we have enjoyed very good success with broadcasting cover crop seeds the day before we move pigs out of an area, in order to give them a chance to "plant" the seeds with their hooves.  So we decided to use this method instead of discing in the seeds.  Even so, there was so much standing crop and weed residue after the pigs left that we decided to brush-hog much of the area to give the cover crop a better advantage.  All four areas needed some level of brush-hogging.  We moved the pigs to the second area on September 8th; the third area on the 17th; and the fourth area on the 28th.  The pigs were moved out, weighed, and recombined with the control group on October 12th.

The cover crop germinated well in all 4 areas and grew 2-4 inches tall before the end of the growing season. This was much more successful than the 2019 cover crop establishment.

During the experiment period, the corn pigs consumed 6340 lbs of feed and the control pigs consumed 5700 lbs of feed.

To complicate our calculations, the timing of the 2020 corn harvest was such that we had to take 6 pigs from the control group to harvest on September 28th.  So we had to figure out average daily weight gains based on the number of pigs in each group on each day, multiplied by the number of days they were in the experiment, rather than weight gained over the entire course of the experiment.  We also added the calculation of feed conversion (lbs of feed consumed divided by lbs of weight gained), since we altered the experiment by giving full feed to both groups, as a result of poor corn production.

2020 Calculations

Given that this doesn't compare apples to apples with our 2019 Calculation Table, we have gone back and made additional calculations for 2019 in order to make direct comparisons and to help us analyze the very unusual and unexpected results from 2020.

2019 and 2020 Calculations

These costs do not include labor.  Daily chore time was similar for the two groups. The main difference in labor was the time spent moving the corn pigs (11 hours) and preparing the soil and planting the corn and peas (17 hours).  I chose not to include these in the above tables as these numbers could vary significantly from one farm to another, based on pay rate, scale of farm, and available cultivation and planting equipment.

I was hoping to minimize variables in the soil analysis by having the same NRCS technician sample and submit our soil for testing.  However, after several requests to several different people at NRCS in October, November, and December, we could not get them to come back out to test our soils.  So I ultimately sampled and submitted the soil myself on December 29th to the same lab as the first test, as well as a second lab that we have used in the past and that returns results much more quickly.