Blog > May 2020 > Reducing Gains on Market Hogs

Reducing Gains on Market Hogs

May 26, 2020

By Steve Jones

The swine industry is in a tough situation now. Slaughter plants are closing due to the COVID-19 virus impacting the line workers. Producers are being told that the planned deliveries of market-weight pigs are going to be drastically delayed, and some producers simply don’t have anywhere else to send pigs that are already at market weight. Only time will tell us how all of this is going to shake out. There are too many unknown factors.
I wanted to pass on some information that may be of limited help. We know that packers severely discount pigs over their target weights. Producers are looking for ways to slow pigs down in their gains so that they can get those pigs closer to their packer’s window and reduce weight discounts.
I want to say upfront, that there is very limited information on doing this. For decades, swine research had been geared toward improving performance, not decreasing it. Nutritionists simply don’t have all the answers we are looking for. We also need to keep in mind that any practices we employ must maintain solid animal welfare practices. Methods of reducing gain that increase morbidity, mortality, or worsens social habits such as tail-biting, are of little value.
Lower Energy Levels
We have a pretty good handle on the pig’s relationship between energy levels and growth rate. We can definitely reduce gains by lowering the calories available to the pig. The way that the industry is going to achieve reduced calories is by adding high fiber ingredients. Today, the best choice we have is soybean hulls, followed by wheat midds. Iowa State University is in the third week of a trial right now using three levels of soy hulls to reduce gains, and the first two weeks data showed that they can achieve up to a 25% reduction in gain when they approached 25% NDF (Non-Detergent Fiber) in the diet. So far, this seems to be the most popular approach toward reducing gains and is the program I am implementing with those producers who have needed to hold down gains. 
Producers are going to need to watch current feeder adjustments to see how this is feeding through whatever model of feeder they are using. Adding large amounts of soy hulls to rations will also reduce the amounts of feed that can be delivered, by merely being less dense by volume. Higher fiber diets will reduce yields by up to 1% simply due to additional gut fill.  
Using soy hulls also gives a producer more time to use a slow-growth program than some of the other alternatives I will discuss. I had a producer wishing to hit a market two weeks later than his usual market date on a group of pigs. We fed 200 pounds of soy hulls for the last two months, and we did delay those pigs by two weeks. 
A 25% reduction in gain may not be enough reduction in gain, that we need in this market scenario, but that’s 7-8 pounds over a two week time period.
Calcium Chloride
The Iowa State Trial also is looking at adding calcium chloride to their trial at two levels. Calcium chloride increases the acid load on the pig’s digestive system and causes them to eat less. The more you use, the less they eat. It also can lead to severe problems if there is any type of water restriction. The lower level is showing a reduction in gain, similar to that of the high-fiber diet. The higher level so far has had a huge impact on gains. It is reducing gains from a 2.8 ADG for the control pigs, to a .15 ADG on the higher calcium chloride pigs, through week 2 of the trial. It seems the pigs are adjusting to the calcium chloride somewhat, since the week two reduction in gain was not as high as week 1, compared to the control pigs.
Producers need to ask themselves if, during planting season, they are going to get off the tractor twice a day to walk this barn and check every waterer because that is what you need to do to use this type of program. The Iowa State researchers that were discussing this were nervous about using this for more than 2-3 weeks.
Rations also need to be formulated carefully, because using this much additional calcium in the diet really widens the calcium to phosphorus ratio. I recommend that you employ this program only when you are working in conjunction with a skilled swine nutritionist. The traditional phosphorus sources such as mono-calcium phosphate just add more calcium and worsen the problem. CVA’s swine nutrition staff can guide you through this.
Again, you need to absolutely ensure adequate water supply for pigs on any additional calcium chloride.
Low Amino Acid Diets
The third segment of the Iowa State trial is looking at using high corn diets. They used a 97% corn ration, and one that split the difference between the all-corn diet and a normal diet. The all-corn diet resulted in a 40% reduction in gain, while the 50/50 diet showed a 19% reduction compared to the control. A 40% reduction in gain seems attractive, but again, it made the Iowa State nutritionists nervous if it was fed for more than 2-3 weeks. Soybean meal is an important source of potassium, which plays a major role in the body’s fluid management. Feed efficiency for the all-corn diet went up drastically. The control pigs converted at a 2.5 FCR, vs. a 6.0 FCR for the all corn diet. Muscle deposition would fall off drastically without a protein source in the diet, and fat deposition would significantly increase. Feed cost of gain would be significantly higher. Their recommendation was to limit lysine reductions.
Restricted Feed Access
I would recommend that most producers take a very gradual approach to tightening feeders. Our current recommendations, under normal times, is that we want to be able to see 40-50% of the steel in the bottom of a feed pan, to maximize gain, but reduce feed efficiency. I believe we can reduce feed consumption by tightening them down some, but because of the changes in our ingredients, we need to do so carefully. The Iowa State nutritionists felt we could go down to a 10-20% pan coverage, but if we go that far, we need to do so gradually. The man looking at the feeders and pig behavior is going to be the one to decide the limits of this practice.
Increasing Barn Temperatures
Pigs eat less feed when they are warmer than when they are cooler. I have always recommended that pigs approaching market weight have 62 degrees as a target temperature for those pigs to maximize their intakes. We can reduce gains by raising the target temperature some. I am comfortable with a 4-5 degree bump in the target temperature. But, again, the man in the barn is going to have to be the one to decide how, what he sees, relates to the welfare of the pig.
There are several other practices that you may wonder about. I have been asked about increasing micron size on the corn. Reducing micron size has a significant impact on feed efficiency, but not really much of an impact on gain. I don’t think we want to do anything that impacts feed efficiency.
I have also been asked about adding salt. Additional salt over normal rates will reduce intake. But again, it is critical that water availability be unrestricted. I have gone up to 20 pounds/ton, compared to the 7-8 pounds in normal formulation for finishing pigs, and got along just fine. But again, will you climb off the tractor twice a day to check waterers?
Feed additives play an important role in pork production. If you are using a feed additive to manage a health situation, continue doing so. If you are using one that promotes improved feed efficiency, continue doing so. If you are using a feed additive that has increasing daily gain as it’s main role, you may need to consider pulling it.  
Keep in mind that some of the things we have discussed may change the social habits and vices in your barn. Things like tail-biting, ear-nipping, or fighting may occur. Restricting feeder flow, raising barn temperatures, or adding to stocking densities definitely will upset their routines. Animal welfare needs to remain a priority during this period.
This is a good time to be talking to your nutritionist. I assure you that he understands your problems, but you need to make sure he understands your goals for reduced gains. Let him explain the limitations of what he can do and can’t do. These rations need to be formulated carefully and keep in mind that reducing gain is a new territory for him, without a lot of guideposts.
Don’t wait until the pigs are 285 pounds to implement these programs. Shackle space is going to be very limited for quite a while. Give yourself some lead time on slower gains. Do the math on when it is realistic for your pigs to get harvested, and calculate the gain they need to stay within the packer’s window. Give yourself a little extra margin of error. It is better to be on the bottom side of his window, than past the top end of it.
As nutritionists, this subject is foreign to us. We have never focused at all on reducing performance. On the Iowa State webinar, Jason Ross made the statement that in theory, practice always works, but that theories don’t always work in practice. This is going to truly be a learning experience. One where I hope, we never again, need to apply what we learn.  
You can view the Iowa State webinar in its entirety on YouTube.  Here is a direct link to “Nutritional Strategies to Managing Pork Market Disruptions Webinar”

Iowa State Pork Industry Center has other information relevant to COVID-19, view their additional resources here:
Posted: 5/26/2020 7:53:07 PM by Kelli Reznicek | with 0 comments

Blog post currently doesn't have any comments.