Improving feed efficiency is a good objective in itself (Patience, 2012) but one of the most important things we need to clarify at the outset when discussing this topic is that improving feed efficiency is not synonymous with cost efficiency.

Every producer has different goals to achieve depending on their particular situation of their operation.

Reducing cost per kilogram gain often translates to feeding more of a less nutrient dense feed for less overall cost, which is of benefit to producers who are not bottlenecked by days in the barn.

For producers who are tight on barn space and days, improving feed efficiency frees up physical and time constraints.

Feed Efficiency

There are many ways in which we can improve feed efficiency nutritionally, most of which have a direct impact on the improvement of overall gut health of the animal that ultimately leads to improving feed conversion.

Some of those include antibiotic growth promoters (AGPs), gut acidifiers, enzymes and probiotics. AGPs show the highest benefit in improving average daily gain and feed conversion but organic acids are a close runner-up and mixed combinations of AGP alternatives can come close to the performance response seen with AGPs (Dansk Slagterier, 2001).

Feed form

Feed form can have a significant impact on feed conversion. Both the type (pelleted versus mash) and the ingredient particle size (particularly for corn) can influence the growth rate of the pig. Pelleted feed improves feed conversion over mash diets (Medel et al., 2004), because the process of pelleting (temperature, heat and pressure) physically breaks down chemical bonds in the feeds, making them more digestible. Changes in ingredient particle size, looking at corn in particular, can have a significant improvement on feed efficiency (Healy et al., 1994). In a healthy herd, a finer particle size has a direct improvement in feed efficiency. We must be cognisant of herd health as a fine particle size may also contribute to incidence of gut ulceration.

Within a nursery barn, the piglet, especially early on in life, has a finite capacity for maximal daily feed intake. Since we cannot significantly change feed intake to improve daily gain in the early nursery feeds, we need to improve feed conversion. We need to make sure that the feed efficiency is also in line with cost per kilo of gain. This is arguably less important in the nursery. Additional gain can come at a higher cost in the nursery because the value of that additional gain multiplies in the grow-finish phase by higher average daily gain and fewer days to market (Primary Diets 2002).

Nutrient density

Another way we can improve feed efficiency is by increasing the nutrient density of the diets. This can either be achieved by feeding additional energy (tallow or vegetable oils) or adding enzymes such as phytase, xylanases and β-glucanases to break down indigestible fractions in the diet. This causes an increase in availability and digestibility of amino acids, energy and carbohydrates (9300.USA.09.38 Purdue University, West Lafayette, USA). The greatest benefit from these enzymes is when you are feeding a diet particularly high in fibre content (Shorts, DDGS, etc.).

Pig response

Today’s lean genetics also respond well to high levels of amino acids. Now that many of the limiting amino acids are synthetically available in the marketplace, we can improve the digestive efficiency of the pig by having a more balanced ideal protein ratio, decreasing the plasma urea nitrogen (PUN) while sparing energy that would have been used to catabolise excess amino acids and use it to improve feed conversion.

Feed cost versus feed efficiency

For a given dietary ingredient composition, increasing the efficiency of pigs to convert feed into growth is an excellent objective. For example, improved health management will reduce the dietary energy and amino acids spent on increased maintenance requirements and increase protein deposition, combined increasing feed efficiency and likely feed cost per unit of gain. However, feed formulation to increase feed efficiency does not automatically reduce feed cost per unit of gain (Woyengo et al., 2014).

Alternative feedstuffs may provide opportunities to reduce feed cost per unit of gain. Such feedstuffs contain in many cases more fibre, hence result in reduced diet nutrient digestibility. Then a reduced feed efficiency would be expected; however, results among experiments with the feeding of corn DDGS to grower-finisher pigs is inconsistent (Stein and Shurson, 2009). Indeed, of the 25 studies listed with grower-finisher pigs, on only five studies with increasing corn DDGS coincide with reduced feed efficiency.

In research with increasing co-product inclusion in diets formulation to equal net energy and standardised digestible amino acids, feed efficiency did not decrease (Jha et al., 2013). Such a lack of response for feed efficiency to increasing dietary co-products is not uncommon, as indicated in the high-fibre diets paper at the 2014 London Swine Conference. Perhaps this should be the target of inclusion of alternative feedstuffs, instead of accepting a reduction of feed efficiency.

Conclusion

In closing, there are many nutritional strategies that can be implemented to improve feed efficiency. The challenge is to identify the areas that can both provide an improvement in feed efficiency and return a lower cost per kg of gain.

Literature Cited

• Dansk Slagterier. 2001. Reproduced in: Feed Mix. 2002. 10(6):34-36.
• Jha, R., J.K. Htoo, M.G. Young, E. Beltranena and R.T. Zijlstra. 2013. Effects of increasing co-product inclusion and reducing dietary protein on growth performance, carcass characteristics, and jowl fatty acid profile of grower-finisher pigs. J. Anim.Sci. 91:2178–2191.
• Medel, P., M.A. Latorre, C. de Blas, R. Lazaro and G.G. Mateos. 2004. Heat processing of cereals in mash or pellet diets for young pigs. Anim. Feed Sci. Technol. 113:127-140.
• Healy, B.J., J.D. Hancock, G.A. Kennedy, P.J. Bramel-Cox, K.C. Behnke and R.H. Hines. 1994. Optimum particle size of corn and hard and soft sorghum for nursery pigs. J. Anim. Sci. 72:2227-2236.
• Patience, J.F. 2012. Feed efficiency in swine. Wageningen Academic Publishers, Wageningen, The Netherlands.
• Primary Diets. 2002. Internal research.
• Stein, H.H. and G.C. Shurson. 2009. Board-invited review: The use and application of distillers dried grains with solubles in swine diets. J. Anim. Sci. 87:1292-1303.
• Woyengo, T.A., E. Beltranena and R.T. Zijlstra. 2014. Controlling feed cost by including alternative ingredients into pig diets: A review. J. Anim. Sci. doi:10.2527/jas2014-7169.9300.USA.09.38 Purdue University, West Lafayette, USA. Sourced via Danisco –Internal presentation.

Reference

Schumann B. and R. Zijlstra. 2014. Improving feed efficiency. Proceedings of the London Swine Conference. London, Ontario, Canada. 26 to 27 March 2014. p131-133.

December 2014