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Feed Conversion Efficiency and Clover Finishing

9/22/2014

4 Comments

 
Now that this year's pigs have gone to the butcher, I've had a chance to compare the hanging weights of this year to last year. We raised the pigs for either 2 or 4 weeks longer than last year, but we kept the pig feed ration the same (5 pounds per pig a day (after a ramp up period during the first two months). The only other thing I changed was tilling up the pasture to plant more palatable clover. Here are the results:


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I'm trying my best to make objective sense of these numbers. Since I fed basically the same ration both years, I have one important variable controlled. In 2013, I fed 4200 lbs of feed to produce 712 of pork, which gives a feed conversion ratio of 5.90 (most published ratios compare to live weight, but I don't really care about live weight and don't have a good way to measure it. We get paid based on hanging weight.) In 2014, I fed 8062 lbs of feed to produce 1416 lbs of pork, for a ratio of 5.69. While it's good to have a smaller ratio this year, the feed savings works out to about $6/pig. I spent $240 on seed last year to plant about 4 acres, plus fuel, depreciation, and my labor. I was hoping that 4 acres of clover would replace about 2000 lbs of pig feed per acre, but the math suggests that I only replaced about 290 lbs of feed for the 10 pigs (I had sows and weaner pigs on this pasture too, as well as two steers for the last month, so that complicates things a bit). So, what happened?

The first question might be to ask whether the pigs were eating the clover. They clearly were, and lots of it. The were mowing through a paddock in a few days in the last month.
I opened up the gut of one of the pigs at slaughter and took the picture below. Full of clover.

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The second question might be to ask if they were converting much of the energy in the clover to muscle. This one is harder to tell. This type of clover is supposed to be the most palatable and digestible of all the potential forages. It's high in protein and reasonably low in indigestible fiber.

Another question is to wonder if I'm feeding too much or too little feed ration. My first year, I fed free choice and the pigs were too fatty for the average home cook's tastes. I chose 5 lbs as the ration last year and continued it this year essentially at random. The quality of the pigs and that fat/meat ratio was really good both this year and last year, so I'm hesitant to change it up.

There are lots of other questions, such as "is the benefit of the clover somewhat minimized by the increased exercise they get in foraging (I have a hard time believing that )", "Did improving the pasture not actually make that much of a significant improvement in the nutrition the pigs were getting from it (in other words, perhaps the pigs ate and converted just as much energy from last year's pasture), "Is there a specific age in which they start to convert pasture better because their gut has developed, and should I keep them longer to take advantage of this," "will continued selection for the best animals improve the feed conversion over time?" Some of these questions will be difficult to answer without rigorous controlled studies--studies I would like to do, but need to have sufficient herd numbers to be able to replicate my treatments (I am a scientist after all).

In the end, even though I didn't get the full benefit of the clover planting that I had hoped, I'm still pleased with how it turned out. My pasture is much improved from last year, and it should stay that way for several years with minimal management (white and ladino clovers tend to reseed and stick around, as compared to red clover). The pigs clearly ate a lot of clover, and I suspect the same nutritional benefits that come from eating grass fed beef are present in the meat of these pigs. I would really like to do a full nutritional comparison to supermarket pork--especially to look at things like omega3s.


One thing that I now have a much better handle on it the actual feed cost of raising pigs in my system. This year, it is about $170/pig. Hopefully, I'll find ways to nudge that down little by little over the upcoming years.



4 Comments
bruce king link
9/22/2014 10:28:02 am

Another way to look at your results is to figure out the average gain per day. so in 2013 you had 180 days of feed and in 2014 you had 202 days. In 2013 you had 1.51 lbs / day gain, in 2014 you had 1.42lbs of gain per day.

Industry feeds a different ration for several stages of the pigs life, based on nutritional needs. The clover is a good ground cover, and the pigs do find it palatable (mine like it and alfalfa about the same) but it's not as high a calorie by volume as a standard corn/soy pig feed. That means that if it's offered as part of their diet they may be unable to eat as much feed in a sitting because of the clover bulk as they would if they were just given a complete ration. It also may be making the complete ration less effective than it otherwise might be -- the clover has different dietary contributions than the feed, so it may be oversupplying protein and making carbs harder to get into the pig. or something. I'm not sure what clover looks like as far as nutrition for a mono-gastric critter like a pig.

One thing that I've found is that the better the housing for the pigs, the less I spend on feed, and good housing is the cheapest way to reduce my input costs. A bale of straw for $4 and a simple 3-sided shelter means that more of the feed goes into meat and less into keeping the pig warm. They are less sensitive to heat as they get bigger (surface to mass ratio, body fat) and so this effect is less as they get towards slaughter but it's particularly effective on younger, leaner hogs. So I bed the weaners with enough straw that they can bury themselves in it and often come out to see a row of noses sticking out, with the rest of the snoozing pigs in their warm straw blanket.

there is a widely disseminated myth that you can raise pigs on pasture and have them get most or all of their nutrition from that pasture that's been popularized by walter jefferies. He's also been stating that larger pigs use pasture or hay more effectively. Neither claim stands up to scrutiny as you are finding. I offered walter $10,000 to prove to me he could do it, with pigs of his choice and he declined. Don't believe everything you read on the internet, particularly claims of miraculous results that cannot be replicated by anyone else. Walter puts weight on his hogs using cheese, butter, whey and milk. The pasture is just where he keeps them.

http://ebeyfarm.blogspot.com/2009/11/10000-sugar-mountain-farm-challenge.html

Reply
Cathy
9/29/2014 06:43:19 am

I am somewhat surprised that the average hanging weight would not be higher just because os the increase ratio of male to female this year.

Are you at a point in age where you expect the feed efficiency to decrease.

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Jeff
9/29/2014 08:05:44 am

I'm working off the assumption that barrows put on more weight (eat more) but aren't necessarily more efficient than females. Not sure if that is correct or not.

It's a tricky thing to try to figure out the conversion efficiency curve. In general, feed conversion efficiency decreases with increasing age, but there is usually an inflection point where efficiency begins to drop faster. I'd like to do some studies that measure weight gain over time, but I'd probably need to use the tape method, which is somewhat imprecise.

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Brad link
3/27/2017 03:30:16 pm

White clover isn't really an energy source for pigs as much as its a protein source. The way to save money with clover would be to cut back on the soy (or whatever protein supplement you're using) in your ration. Of course, you'd have to know what you're doing and have a mill that would make you custom feed. With a small number of pigs on a handful of acres, you could feed the pigs a limit feed of corn and minerals with a lysine supplement and get very good growth. Replacing soy with clover is where the value of the clover lies.

Brad

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