Introduction

The high fibre content of oats, which are widely grown in Western Canada, has historically limited their use as an energy source in swine rations. In fact, oats have been shown to have approximately 10% less digestible energy (DE) than barley and 17% and 19% less DE than wheat and corn respectively. However, a recent seminar given at the Western Nutrition Conference in Saskatoon (September, 2007) showed that grower and finisher pigs can be fed diets containing up to 25% oats without compromising growth performance. 

This article will review the nutritional profile of oats and will provide recommendations for how oats can be used in swine diets to reduce feeding costs while maintaining performance.

An overview of oats

Canada is the second largest producer of oats (3.3mt) after Russia (4.6mt), but before the USA (1.7mt), Poland (1.2mt) and Finland (1.2mt). Oats are a common crop in Canada and conditions in Manitoba are thought to be ideal. Oats were the third most important crop in the US but are currently in decline.

In comparison to other cereals, oats have a high fibre content as the hull comprises about 23% of the whole grain. Thus, they are lower in energy value than other cereals, making them a popular cereal for ruminants and horses, but traditionally less so for poultry and pigs. Additionally, the nutritional composition varies widely with variety, climate and fertilization. 

Oats have a high oil level and relatively good protein quality compared with other cereals. The fibre fraction is highly lignified, resulting in reduced digestibility. The soluble fibre in oats is largely due to non-digestible b-glucans located primarily in the endosperm cell wall. In general, oat fibre has a low water holding capacity and is therefore not particularly good at reducing constipation in monogastric animals.

Table 1: Nutritional composition of oats in comparison to barley

                                         Nutrient                                  Barley                Oats

                          Dry matter (%)                      87                    87

                          Crude protein (%)                  9.5                  10.5

                          Crude Fibre (%)                    4.7                  11.6

                          NDF (%)                              17.5                 38.4

                          Oil (%)                                 1.7                   5.2

                          Ash (%)                                2.2                   2.5

                          DE (MJ/kg)                           13                  11.0

                          NE (MJ/kg)                            9.6                   8.2

        Source: Atlas & INRA, 2002

The feeding value of oats

As with other high fibre ingredients, the feeding value of oats is best determined by assessing how inclusion affects the overall diet’s fibre level. This is because, as fibre increases, the transit rate of digesta through the gut of pigs decreases, resulting in a reduction in performance through reduced digestibility and increased mucus production. As a result of this, oats must be limit fed depending on the animal’s stage of development.

Table 2: Potential savings when including oats into various hog rations

Stage of                  No oats           Oats at % limit           Savings           Recommended

animal                    ($/MT)                   ($/MT)                 ($/MT)           maximum oat limit

                                                                                                                        (% of diet)

Grower pigs                $235                         $228                         $7                             25

Finisher pigs                $229                         $222                         $7                             25

Dry sows                    $222                         $217                         $5                             20

Diets assume the following prices/MT: Wheat $215; Barley $205; Soya $300; Oats $170.

Table 2 shows that there is a potential to save on feeding costs but that the highest savings can be realized with growing and finishing pigs. Due to limited research examining the nutritional value of oats within sow diets, a conservative limit of 20% is recommended.  Assuming a herd size of 250 sows, farrow to finish, this could equate to a feed savings of approximately $660 per month or $8000 per year.

Oats and Net Energy

An important point to remember is that higher oat inclusion only works when diets are formulated to net energy (NE) and digestible amino acids. Again, this is because of the high fibre percentage, because diets formulated to ME or DE will decrease in NE as oat levels increase. Reducing NE through inclusion of high fibre ingredients has been shown time and again to reduce performance. 

Table 3: Effect of dietary level of oats on grower and finisher pig growth performance^{1, 2}

                                                                                Level of oats (%)

                                                0                            25                          50                 P-value

Grower (27.5 – 67.5kg)    

      Daily gain (kg)                   0.83                       0.83                       0.85                 0.67

      Daily intake (kg)                1.88                       1.87                       1.89                 0.85

      FCR                                  2.27                       2.26                       2.25                 0.78

      NE                                    2027                      2025                      2041

      NE w/out tallow                 n/a                         1991                      1955

Finisher (67.5 – 80kg)

      Daily gain (kg)                   1.16                       1.16                       1.17                 0.78

      Daily intake (kg)                2.89^a                      2.84^a                      3.08^b                0.01

      FCR                                  2.51                       2.49                       2.70                 0.06

      NE                                    2033                      2058                      2075

      NE w/out tallow                 n/a                         1997                      1960

¹ Source: Zalinko et al., 2007 Proc. W. Nutr. Conf. pp 253

² Values within a row not sharing similar superscripts differ significantly

 One should note that in the study outlined in Table 3, NE levels were balanced by inclusion of tallow. If this had been ignored the amount of energy each pig consumed per kg of gain would have been sub-optimal and growth would have deteriorated. However, if tallow or vegetable oil cannot be handled in a given on-farm mixing system, adequate levels of dietary energy can be obtained by using wheat or corn with similar financial savings being realized.

Some points to consider 

What are the nutrient levels?

 It is generally a good idea to send a sample of your oats for nutrient analysis. This will allow for more accurate formulation and will prevent the feeding of rations containing excess amounts of NDF (Neutral Detergent Fibre).

Will you be pelleting your feed?  

Oats tend to give a poorer pellet quality than other cereals because the fibrous husk tends to give pellets fracture lines. Thus, one should consider limiting oats to 7.5% of the diet and apply a fine grind if pellets are manufactured.

Should you include an enzyme?

 In Europe, where high fibre ingredients such as mill run are commonly used in pig rations, so too are enzymes. However, inclusion costs of enzymes in North America are much higher than in Europe, which typically limits their addition into starter rations.

 So does it make financial sense to use an enzyme? A recent article published by researchers at the University of Saskatchewan examined the effect of supplementing grower and finisher diets containing 40% oats with a mixed β-glucanase / xylanase enzyme product. The study showed that crude protein, dry matter and gross energy digestibilities all increased by 3% as a result of enzyme supplementation. If enzyme inclusion costs approximately $3/tonne, nutrient digestibility would have to improve by around 2% to break even. Based on this study, and many other enzyme focused studies, it would seem likely that enzyme inclusion would make economic sense when diets are formulated to contain high levels of oats. 

Conclusions

 Inclusion of oats at the levels recommended in this article is nutritionally and economically viable. However, in order to reap these benefits, one must be mindful of the method of formulation being applied to their rations. The NE system combined with digestible amino acids currently used by Nutrition Partners is a good way of ensuring the risk of reduced nutrient digestibility and animal performance is minimized.