My job requires a lot of scientific reading and occasionally that will spark an idea for a newsletter article. The April issue of Animal Frontiers has a literature review article titled “Swine convert co-products from food and biofuel industries into animal protein for food.” (R.T. Zijlstra & E. Beltranena. Animal Frontiers. April 2013. 3:48-53.)
Alternative feed for cattle is a common topic of conversation locally. Especially with the current drought limiting feed supplies and the rising cost of traditional feeds. However, we don’t hear much about alternative swine feeds around here. This is likely due to there being few swine producers in the area. Still, there are many hogs in northeastern Colorado and they contribute greatly to an active feed ingredient market. Nationally, more than seventy-two percent of the costs associated with swine production are related to feed.
When the term alternative feed or co-product comes up in today’s society, people will often correlate that with distillers grains (dry or wet). Yet, there are many other things that will fit within those descriptors. Beet pulp, citrus pulp, whey, bakery waste, and flour millings are all common co-products that are fed to swine. Even left over table scraps constitute co-products on some small scale swine operations. One of my former students works for a company in Georgia that collects unsold produce from grocery stores that they then process and sell as livestock feed. As stated by the authors of the previously mentioned article, “Behind every food product in the supermarket, there is a co-product.” In many cases these co-products can be used as a feed source to create high-value/quality animal protein. In doing so we can often reduce feed costs in the livestock industry and improve what scientists refer to as the Human-Edible Protein Balance (H-EPB).
The H-EPB is an index value that represents the edible protein output that is produced per unit of edible protein input that was required to produce it. Researchers report that the H-EPB for the US livestock industry in 2005 to 2007 was 0.53, on diets relying heavily on cereal grains. During the same time, the Netherlands, relying heavily on co-products, had a livestock feeding H-EPB of 1.02. The researchers suggest that improving the US H-EPB through the use of co-products in swine feeds will help contribute to both a more sustainable swine industry and less societal pressure against pork producers.
Traditional swine diets made with cereal grains and soybean meal are very consistent and are easy to create and feed. Feeding co-products in place of these can create a wide variety of challenges; however, with proper management and attention to detail many of these challenges can be alleviated. Following are some of the management items to be aware of and monitor when you do feed co-products to swine.
The nutritive quality of co-products can lack consistency. Producers using co-products need to be aware of this and closely monitor nutrient quality. Additionally, co-products tend to be higher in fiber than the original feed that it was derived from. This is especially true when wet fractionation was used in the process. High fiber content in swine diets can lead to lower digestibility, poorer feed efficiency, and greater excretion of nutrients. Therefore, when utilizing these alternative feeds the producer needs to be certain that the lowered cost of production makes up for the decreased efficiency.
A co-product that was made using a wet fractionation process may be sold as a wet product, like wet distillers grain. This can be very good for feeding to swine in a liquid feeding system and can improve responses to some enzymes. However, it can add feed transportation costs and shorten shelf life of the feedstuffs. Many places will dry the product. This has both advantages and disadvantages. Beyond shipping and storage advantages, positive responses may be increased mineral availability and the inactivation of some anti-nutritional factors. However, overheating or heating for too long of period can also damage proteins and the ever important amino acid called lysine.
When swine producers feed co-products in the diet, they need to carefully consider how they develop rations. As mentioned previously, the co-products tend to be higher in fiber than did the original cereal grain. They also are usually higher in non-starch polysaccharides and protein. Due to these differences, the digestible energy (DE) and metabolizable energy (ME) systems that many swine producers use to formulate rations will overestimate the energy contribution of the co-product diet. As a result, growth performance is reduced when co-product rations are formulated using the DE or the ME systems. The net energy (NE) system is more successful at formulating co-product diets.
Many mycotoxins can form naturally on crops. We often use a “solution by dilution” approach to feeding grains that have an active mycotoxin issue. However, we want to be extra diligent when feeding co-products made from affected grains. As an example, ethanol production will actually concentrate some mycotoxins within the co-product. This is readily seen with aflatoxins, deoxynivalenol, fumonisins, and zearalenone. When this occurs, pig growth and reproduction rates can be severely affected. It is important to note that it is rare that this becomes a problem, but if mycotoxins are an issue in a particular year or location you may want to be aware of it. Some residues in the crop can be similarly concentrated when a co-product is produced from contaminated grains.
Potential lower feed efficiency as a result of feeding some co-products has already been mentioned. High fiber and polyunsaturated fatty acids (PUFA) in some co-products, like distillers grains and canola meal, can also effect the carcass. In particular, dressing percentage can be lowered and the hardness quality of the pork fat can be negatively affected. Some researchers suggest that distillers grains or canola meal should be removed from swine diets at least three weeks prior to harvest to alleviate these concerns. On the other hand, it has been suggested that the inclusion of co-products in the swine diet that are high in omega-3 PUFA may deposit greater amounts of omega-3 into fat and yield a carcass with health advantages.
As you can see, there are a lot of things that need to be monitored and managed when feeding co-products to swine. However, with strong management practices in place, this may be a rewarding way to increase sustainability of the swine industry, reduce societal concerns, and increase profitability on the hog farm. Co-product feeding will not be for everyone but it definitely can have the potential to be a management asset on many swine operations. The key is to make certain that lowered feed costs outweigh lowered production results.