Alternative Feeds: Is Variety the Spice of Life?

When it comes to sheep feed…it depends. With staggering increases in feed costs due to inflation, supply chain disruptions, impacts of international conflicts affecting energy, grain and fertilizer production along with regional weather events, now might be a good time to investigate alternative feeds. Alternative feeds are those that are not commonly used on a regular basis as part of the usual livestock feed ration and are often cheaper than typical feed, such as corn and soybeans. Availability and cost of certain alternative feeds will vary based on geographic region so it pays to do some research on what might or might not be available in your area. Most alternative feeds are by-products or residuals, and so the energy, protein and mineral content, as well as the costs can vary widely. As with any feed, there are potential concerns with some alternative feedstuffs that producers should be aware of prior to incorporating them into their sheep feeding program.

Dried Distiller’s Grains: DDGs are a by-product of bioethanol production from grains, usually corn. It can be an inexpensive source of protein and energy when fed to growing/finishing lambs resulting in good weight gain and improved carcass traits. The high nutritional value of DDGs could also temporarily boost parasite resistance when fed to lambs on pasture. DDGs can be used to supplement crude protein to dry or early gestation ewes on low quality forage. Feeding DDGs to lactating ewes has been shown to increase milk fat and result in better body condition scores during lactation and at weaning. However, there are potential drawbacks to feeding DDGs.

There can be considerable variation in the nutrient content, digestibility and availability of DDGs due to differences in processing. DDGs contain high levels of sulfur, phosphorus and nitrogen. Excess nutrients will be excreted by the animal and can negatively affect the environment and create mineral imbalances in the soil. The high levels of sulfur can also increase the risk of polio, especially when combined with other sources of dietary sulfur such as well water, fish meal and/or sulfur based coccidiostats. High levels of phosphorus can significantly increase the risk of urinary calculi in male sheep. A low calcium to phosphorus ratio (<2:1) in the feed can exacerbate subclinical hypocalcemia in ewes, especially during late pregnancy and parturition. Hypocalcemia increases a ewe’s risk for milk fever, dystocia, retained placenta and prolapses, although the incidence is low. Adding calcium to the ration can help mitigate deficiencies. For those producers evaluating fecal egg counts, feeding DDGs could delay or prevent adequate fecal egg count averages for FEC EBV submission.

Mycotoxins are almost always present in corn (and other grains) used for animal feed. The most concerning of these are the Fusarium fungi: aflatoxin and zearalenone. Zearalenone is a potent estrogen-like hormone that can reduce fertility in ewes and rams. In ewes, zearalenone causes decreased ovulation and conception rates. In rams, zearalenone can cause permanent changes to the testes and decreased spermatozoa production, a serious concern for any breeding program. The mechanism for these changes is unknown.

Studies evaluating the effects of DDGs in sheep are extremely limited, so be aware of the potential consequences, especially to breeding animals. The current recommendation is to limit DDGs to < 15% of total feed ration in breeding animals, and significantly less if sheep are exposed to other sources of sulfur in the diet or water. Studies have shown that feeder and castrated lambs can be fed a ration containing up to 40% DDGs, with adequate thiamine supplementation, without affecting performance or meat quality. Like DDGs, corn gluten byproducts can be an excellent protein source, but can have high sulfur and/or phosphorus levels as well.

Soybean Hulls (or soyhulls): Soyhulls, are a byproduct of soybean processing for meal or oil. They are commonly used in sheep rations and are easy to handle and feed when pelleted. Similar to DDGs, they are high fiber/low starch and have lower rumen acidosis potential compared to grain-based diets. The most common use of soyhulls is as an energy supplement for sheep consuming a low to moderate quality forage-based diet. When feeding soyhulls to hungry sheep, choking can be a problem if sheep eat too fast. This can be minimized by mixing the hulls with other feeds or feeding hay first.

Crop Residues: Grazing is the most efficient way to feed residues after crops have been harvested. Sheep will typically consume grain and leaves first, before grazing stalks. This can be an excellent way to extend the grazing season. However, fields with excess grain residue, such as crops damaged by weather prior to harvest, can significantly increase the risk of overeating disease (ruminal acidosis). When low quality stalks are the dominant residue, feed performance may decline. Depending on the stage of production, crop residues may not meet the animals’ nutrient needs. Provide a good mineral supplement while grazing low quality residues. Adequate fencing and access to water are also important considerations when grazing sheep on harvested crops.

Beet Pulp or Beet By-products: Beet pulp is typically available in pelleted form or as shreds/flakes and can provide an economical source of energy and fiber but is low in protein. It can be used as a good supplemental feed alternative during maintenance or mid pregnancy when protein requirements are low. Sugar beet processing usually occurs in September so wet sugar beet byproducts are typically only available in fall. Beet pellets can pose a choking hazard to sheep, especially with aggressive feeders. The pelleting process is variable. Large pellets should be soaked in water before feeding to reduce choking hazards, adding yet another step in the feeding process for producers.

Canola Meal Pellets/Screenings: Canola meal is a byproduct of canola oil processing and is high in both protein and energy. When available, canola meal can serve as an economical substitute for soybean meal. Canola meal contains about 80% of the energy and protein of soybean meal, so feed rates may need to be adjusted upward by as much as twenty percent. Studies have shown that feeding canola meal increases milk production compared to soybean meal in lactating cattle. The availability, price and quality of canola screenings can vary. Grade 1 canola is of higher quality and contains less weed seeds, chaff, dust or other unwanted plant material.

With “by-product” feeds, the energy, protein and mineral content of the feed can vary widely. Wet chemistry analysis is recommended for accurate feed value determination. Sheep are often reluctant to consume novel feeds, so start low and go slow when acclimating sheep to a new diet. Concentrated feeds like DDGs, when fed at higher rates to finish lambs on feedlot, should always be accompanied by good quality hay/roughage as a buffer to prevent overeating and to keep ruminal pH levels normal. Fresh water and a good mineral should always be offered.

Rations containing alternative feed products can often be cost effective. But each farm is unique. Availability and prices of feedstuffs vary by location, year and season, as do delivery, storage and feeding options. Keep in mind that mineral imbalances in the soil and plants can exacerbate mineral imbalances in sheep grazing on or eating hay cut from those fields. High stocking rates or application of fertilizer like chicken manure or gypsum can have an cumulative effect on phosphorus and sulfur levels in grazing sheep that are also being supplemented with certain alternative feeds. Testing of feed, forage and hay allows producers to mitigate these potential problems before they occur.

By: EAPK Communications Committee

References:

Dried Distillers Grains

https://www.extension.purdue.edu/extmedia/AS/AS-603-W.pdf

https://www.proquest.com/openview/dc537bcbb356c4f2cd416891f326ba5b/1?pq-origsite=gscholar&cbl=49113

https://pubmed.ncbi.nlm.nih.gov/24146156/

https://www.sheepusa.org/wp-content/uploads/2022/07/2021-Combined-SGRJ.pdf

https://katahdins.org/wp/wp-content/uploads/2022/10/Katahdin_Hairald_2017_Spring.pdf page 12

https://extension.psu.edu/opportunities-and-challenges-of-feeding-distillers-grains

https://pubmed.ncbi.nlm.nih.gov/32704982/

Soybean Hulls

https://openprairie.sdstate.edu/cgi/viewcontent.cgi?article=1074&context=extension_extra