At this time of the year, many of you are still looking to finalize your winter feeding program and are searching for competitively priced ingredients. Typically producers are looking for alternatives to high-priced cereal grains or protein supplements. In such cases, many producers look at grain screening pellets (GSP). Grain screening pellets are by no means new to the market but judging by the number of questions I get, their nutritional value is not widely understood or appreciated. Part of this confusion is due to the fact that there are a wide variety of products on the market, each differing in ingredient makeup, nutrient composition and pricing. With this column, I will discuss the nutritional merits of the various GSP products and the feeding situations for which they are best suited.
Grain screenings are a byproduct of the grain-cleaning sector. When grain is cleaned, the material that is removed is referred to as dockage. Dockage includes chaff, other grain, weed or inseparable seeds, and pieces of stem. When this dockage is cleaned, three products are generated. These include No. 1 and No. 2 feed screenings. These products are relatively high in value and do not typically find their way into ruminant rations. Refuse screenings are the third product. They consist of the residual material that remains after the No. 1 and No. 2 feed screenings have been removed from the dockage. Refuse screenings consist of chaff, small weed seeds and dust and up to 15 per cent of the parent grain. They form the basis of most of the GSP products on the market.
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Grain screening pellets were a focus of a considerable amount of research in the mid-1990s at the University of Saskatchewan. This work showed that refuse screenings were a good source of protein, averaging 13 to 15 per cent (DM basis). The research also showed that GSP derived from refuse screenings were about 85 per cent of the energy value of barley grain, averaging 75 per cent total digestible nutrients (TDN; DM basis). A key finding of the research was that in order to realize full feeding value, the refuse screenings needed to be processed (ground and pelleted) prior to feeding. This is because a significant amount of the energy in GSP is derived from the oil content of weed seeds which if not processed, simply passes through the animal undigested.
One of the knocks against GSP has been the perception that they are highly variable in nutrient content. For example in our research, the starch content of 18 loads of GSP averaged 26.2 per cent with a standard deviation of 6.2 per cent. In a similar sampling of barley grain, the starch content averaged 57.8 per cent with a standard deviation of 3.5 per cent (T. Marx, M.Sc. Thesis University of Saskatchewan). This variation has been one of the factors that limited the widespread use of GSP within the feed industry. To minimize issues with nutrient variation, the feed industry created an enhanced or fortified version of GSP. These pellets are a mix of refuse screenings, pulse (i.e. lentil) screenings and barley grain. Lentil screenings are added as a source of protein while barley grain is used as a consistent energy source. As well, GSP can be fortified with major minerals such as calcium and phosphorus, trace minerals (i.e. copper, zinc and manganese) and vitamins (A, D and E). Feed additives such as monensin sodium can also be added to the mix. While adding to cost, these fortified pellets are a convenient method of supplementing energy, protein, minerals and vitamins to cattle.
How do GSP fit into your feeding program? The answer to this question depends to a large extent on the type of animal you are feeding and your performance expectations. From the perspective of a cow-calf operator, GSP, particularly fortified GSP are a good fit for wintering beef cows. When fed with a medium- to good-quality forage, they will help meet energy and protein requirements of pregnant beef cows. Relative to barley grain, it will be necessary to increase the intake of GSP by approximately 15 per cent in order to supply an equal amount of energy. As indicated above, fortified GSP can also be used to ensure adequate mineral and vitamin intake.
With respect to feeding operations, GSP, even the fortified products do not contain sufficient energy to efficiently finish cattle. However, for backgrounding operations where target gains of 2.0 to 2.25 pounds per day are required, GSP are a good fit. In such cases, GSP inclusion rates will typically range from 35 to 45 per cent of the diet dry matter depending on forage quality.
There are some issues feeding GSP. For example bloat can be a concern, particularly when GSP are fed in combination with alfalfa or alfalfa/grass hay. In such situations, feeding an ionophore is recommended. Ergot contamination can also be an issue, particularly in years where there has been a wet spring. If you have a concern, consult with your supplier to determine if they have tested ingredients for mycotoxins.
In summary, GSP when competitively priced can be a key component of your winter feeding program. Knowledge of ingredient and nutrient composition and appropriate feeding rates are keys to successful utilization.