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Selection and Use of Commercially Available

Rodent Chow Products

Perspective...

 

Many rehabilitators turn to large online retailers for their rodent chow products, which is perfectly acceptable, but at times make their choice based on limited information, or recommendations made by friends or social media. Here are two popular products with approximately the same protein content commonly purchased and fed to rehab animals.

Product A - Protein 24%.     Fat 4.5%.     Ca:P ratio 1.27.   Cost per ounce $.30.

Product B - Protein 25%.    Fat 33.0%.    Ca:P ratio   ??     Cost per ounce $1.73.

Which would you choose to feed to your rehab animals? The information below should help you make an informed decision. There may be reasons to feed over 7 times more fat at almost 6 times the cost. Or maybe not. These two products are included in the following and are readily available online (pricing as of May 2021). Or consider one of the other 37 products also included and analyzed below.

Introduction

 

A critical choice and challenge facing wildlife rehabilitators of small rodents (e.g., tree, ground and flying squirrels, chipmunks, rats and mice) is the selection of a suitable diet for weaning and post-weaned animals prior to release. Many rehabilitators have turned to one or more of the commercially available rodent chow products to meet this need. Other rehabilitators have chosen not to use these products.

 

This paper discusses some of the reasons that rehabilitators indicate they are attracted to use these products, and why some have avoided them. This paper gives an overview of 39 different rodent chow products available from several different manufacturers, including their recommended uses and applications, and product composition and ingredients for those considering rodent chows. Additionally, it discusses certain criteria that can be helpful in selecting which product or products to use in certain situations.

 

The first decision facing a wildlife rehabilitator that rehabilitates the small rodent species groups listed above is whether to use rodent chow, or some other weaning and post-weaned diet, or some combination of both. The following presents some of the most commonly cited reasons that rehabilitators use rodent chow or why they do not.

 

Reasons Why Rehabilitators Use Rodent Chow Products

 

Many rehabilitators want a reliable and consistent product that provides the proper nutrition to the animal. Some of the higher quality commercially available rodent chow products have been specifically formulated and manufactured for long-term research applications where a complete and balanced nutrition regime must be maintained under very stringent and controlled conditions.

 

Using a purchased product precludes the challenges and uncertainties of trying to create a fully balanced and nutritious diet from other food sources. It also results in much less time and effort (and cost!) in attempting to acquire and prepare a fully “natural” or “wild” diet. While rehabilitators certainly place fresh branches, buds and other natural vegetation in the cages, the use of a high quality rodent chow that the wild rodents willingly eat reduces concern that the animals are getting enough, appropriate and balanced nutrition.

 

Being a dry product, rodent chows are easily transported and stored. They arrive ready to feed, so no daily preparation is required. They are relatively easy to administer and provide to animals in a controlled manner, monitoring how much food is provided and consumed in a given time interval. It is also easy to grind the rodent chow and then moisten and soften with an appropriate formula or water for use with older rodents with mouth or teeth injuries.

 

Being a relatively hard and solid product, it provides a gnawing source for a rodent’s continuously growing incisors.

 

The more commonly used rodent chows manufactured by the larger companies are generally readily and rapidly available by ordering online or mail. Some may be available from local feed stores, though the higher quality rodent chows often require special orders and may take longer to arrive. 

 

The standard products are usually priced in the $.50-$1.75 per pound range when purchased already packaged in quantities of 20-50 pounds, making them a highly cost-effective source of food. Many rehabilitators report that purchasing a high quality rodent chow that the animals eat has reduced the cost of rodent food.

 

In addition to direct cost reduction for many, using a quality rodent chow has reduced time trying to achieve and shop for a properly balanced and nutritious diet. Rehabilitators also report that there is far less food waste when using a quality rodent chow, thus improving cost effectiveness. Some rehabilitators have mentioned that the rodents eat the rodent chow more completely, and it does not readily spoil like fresh vegetables and fruits they previously fed, resulting in far less time spent cleaning up spoiled and unconsumed food (and the insects attracted to decaying produce) -  thus an indirect time and cost savings. 

 

Some rehabilitators use a rodent chow product simply because they were told or instructed to use it by the individual who helped train them to become a rehabilitator, offered by a rehabilitation center that provides supplies or was easily available from a particular distributor. As such, a rehabilitator may have given much thought about why they use it or why they feed a particular product over another. Or what the other choices might be.

 

Reasons Rodent Chows Are Avoided

 

Some rehabilitators have expressed concerns about the quality of some of the ingredients used in the manufacture of certain rodent chow products (e.g., low-grade agricultural by-products, animal products, and certain ingredients not generally considered to be healthy for rodent consumption). While certainly possible, some manufacturers are working to address this concern and explain specifics to customers.

 

Some report that rodents in rehabilitation have refused or been very slow to accept rodent chow. As mentioned earlier, identifying the reasons for reluctance may resolve this - if the rehabilitator wants to consider using it.

 

Some rehabilitators have expressed concern that a commercially prepared product designed for captive animals (i.e., laboratory or domestic) may not be appropriate for a wild animal. Additionally, being a commercial product, rodent chow is not a food the animal will encounter upon release to the wild. The use of rodent chow as a primary diet does not preclude offering a sample of natural foods from the wild.

Certain specific rodent chow products may not be readily available in all areas. Absolutely true, though ordering online and having products shipped has improved availability. It does, however, require planning to ensure the product is available when needed.

 

Rodent chows are too expensive. While some have mentioned this, a closer look shows that rodent chows are highly costs effective when compared to other foods used to feed wildlife, as mentioned above. For those seeking very specific ingredients or formulations, some boutique rodent chows are priced in the $25-30 per pound range - and definitely consider expensive.

 

While there are probably other factors that may impact a decision, these reasons tend to be more commonly mentioned by rehabilitators discussing weaning and post-weaned diets.

 

Types of Rodent Chow Products

 

Once the decision has been made to use a rodent chow product, it is helpful to understand the different types of products that are available and their intended uses. Many of the larger product lines (e.g., Teklad, LabDiet, Mazuri) are formulated for and targeted for two primary purposes:

 

Laboratory animals. These are typically sold to breeders of rodents for a variety of purposes and research institutions conducting studies involving laboratory rodents. Accordingly, their products generally fall into one of the following three categories:

 

- High performance breeding and reproduction – these products tend to be higher in energy content, containing relatively higher percentages of fat.

 

- Growth or full cycle diets – these products are generally more balanced (protein to fat), intended for normal growth rates and the ability to use the rodent chow in a wider range of applications.

 

- Maintenance – these products tend to be much leaner with a higher ratio of protein to fat, designed for longer-term captive environments, such as laboratory applications.

 

Many of these products are also available in an autoclavable formulation if microorganism content is an issue (i.e., some are irradiated, available in a vacuum sealed package). Some products are certified as to not exceeding specified levels of microorganisms and other contaminants (heavy metals, pesticides).

 

Domestic animals. Some of the smaller manufacturers (e.g., Oxbow, Kaytee) target their rodent chow products more for domestic rodents (hamsters, mice, and rats). Although not a rodent chow nor a product designed or formulated to provide a balanced nutritional diet for rodents, the Primate Diet from Zupreem is included in this article as it is used by some rehabilitators (though the manufacturer cautions that this product is not designed for use with rodent species).

 

Table A below presents the primary ingredients (e.g., corn, wheat, soybean, etc.) in each of the 39 rodent chow products studied as indicated in the package labeling. The table does not itemize the many other supplemental vitamins or other trace nutrients that are included in each product.

 

Table B below presents a comparison of the 39 rodent chow products studied, with the data presented drawn from the guaranteed analysis and typical nutritional analysis for each respective product. The table also indicates the intended use of the product as suggested by the manufacturer.

Matching the nutritional composition to the natural diet

 

While several excellent references provide a description of the types of food small rodents in the wild prefer and actively forage, many of these natural foods are seasonal in nature, prompting a wide variety of food sources during the year. As a result, definitive research is still needed that describes the average or optimal nutritional composition of diets for rodents in the wild. As a default, the nutritional composition of some of the full-cycle, balanced rodent chows can be used as a proxy to estimate the proper balance of protein, fat, fiber, ash and energy content for a wild animal in rehabilitation. While not perfect or exact, many of these rodent chows have produced very satisfactory dietary results for small rodents in a captive setting for decades.

Selection considerations

 

If there are so many commercially available rodent chow products from which to choose, what are some of the key factors that should be considered? While not a comprehensive list, the following criteria can be used to assess the suitability of one product versus another.

 

Consider the animal’s stage of development. As discussed earlier, the manufacturer generally recommends the application for which each product is to be used. As such, animals that are in longer-term recovery care or are being “wintered-over” may not be best matched to a high fat rodent chow formulated for breeding colonies. Weaning juvenile animals will likely benefit most from a product that is formulated for growth or full-cycle use, rather than one designed for long-term maintenance.

Rodent Chow Labdiet 5002.jpg

Compare the ratio of protein to fat. If the manufacturer’s recommendation usage is unclear, a quick way to assess suitability is to calculate the ratio of protein to fat as indicated in the guaranteed analysis, or, if available, the typical nutritional analysis. This ratio is easily calculated by taking the percent of protein divided by the percent of fat. For example, if the analysis indicates 20% protein and 5% fat, the ratio is 4:1. Table C shows the calculated ratio for the 39 rodent chow products, plotted on a continuum from a low ratio (i.e., higher fat on the top of the page) to a high ratio (i.e., less fat on the bottom of the page). 

 

Consider the ingredients and source of nutrients. A quick review of Table A shows which products are totally free from any animal products. For example, while all of the rodent chows have fats, some are sourced from animal ingredients and some are sourced from vegetable ingredients. It also shows which have protein derived from only fish meal, or from fish and meat meal. Also shown are which rodent chows have flavorings added (e.g., Oxbow). Some manufacturers' websites provide considerable product detail and substantial testing results. Other manufacturers provide attractive marketing labels but offer less robust information beyond protein, fat, fiber and total ash content.

 

Evaluate the intended application for the product. All of the rodent chows discussed in this article have been specifically formulated for use with rodents. The Zupreem Primate Diet, according to the manufacturer, is not designed for use with rodents.

 

Cost and availability. Cost is generally considered reasonable for the standard rodent chows produced by larger manufacturers of high quality products. Shipping costs vary based on shipper, volume/amount of the orders and distance to the purchaser/rehabilitator. Availability may be more difficult when buying some of the higher quality rodent chows from local distributor (i.e., an animal feed store) that does not have them in regular inventory. Some local distributors may be willing to order a specific product when given enough advance time. Costs associated with the specialty diets from smaller manufacturers tend to be higher.

 

Palatability. All of these products listed are eaten by either laboratory or domestic small rodents, thus are assumed palatable to rodents in rehabilitation, especially animals that have come into rehabilitation as pre-weaned juveniles. Adult animals may take longer to begin consumption. Some rehabilitators have had difficulty with this, and have switched to Zupreem’s Primate Diet, as some rodents tend to eat it more readily. This is not surprising, as the fourth most prominent ingredient is sugar, and sixth is animal fat. The same holds true with those products from Henry's Healthy Pet Food with very high fat content being attractive to rodents. Other rehabilitators have reported that rodents will not eat the rodent chow, especially when a generous array of “treats” are offered concurrently, such as fruits, hardwood nuts, and seeds.

 

Specific requirements and applications, such as autoclaving prior to use. Some of the products are available in autoclavable form if specific measures of sterilization need to be taken. It should be noted that these products have been manufactured assuming that autoclaving will occur prior to use, such as providing a coating of the chow to accommodate swelling and softening, and the raw composition of the product has been designed to compensate for any nutritional loss that may occur when autoclaved.

Tips to get rodents to eat rodent chow products

 

Many rehabilitators report that when juvenile rodents begin eating solids, they willingly eat the higher quality and fresher rodent chows. This provides a high quality rodent chow product, with minimal preservatives and animal fats which could have become rancid if stored too long. Preferably use the rodent chow within six months or less from the manufacture date. Rodent chows containing high amounts of animal fats, can spoil faster, and then become rancid and less palatable. 

 

Avoid providing other supplemental foods or 'treats' until the rodent chow is fully consumed. Only then supplement with native foods that the species would easily find and eat in the wild, such as twigs, buds, new leaves, pine cones. Remember that while some nuts and seeds may be available in limited amounts during a short time in autumn, they are not available year round in nature.

Storage considerations

 

As a dry product, most rodent chow products have a generous shelf life, usually from 6 to 12 months. Some of the manufacturers indicate that storage of the product at higher temperatures (>70˚F) will tend to cause vitamin loss. For example, the two charts shown in Table D indicate the effect of storage temperature and time on LabDiet’s Certified Rodent Diet 5002 product. The manufacturer of this product recommends storage at temperatures of 72˚F or below, and not beyond six months. Some rehabilitators have expressed concerns regarding the optimum shelf life of those rodent chows containing high amounts of animal fats, with the potential to more quickly spoil, loose vitamin potency or become rancid and less palatable. An easy fix for longer term storage is to place the rodent chow in an airtight bag or container and store in a cooler/colder area such as a cold basement or freezer. 

 

Conclusion

 

The selection of a suitable weaning and post-weaned diet for rodents in rehabilitation is just as critical as the proper selection of a milk-replacer for pre-weaned animals. For juvenile and young adult animals, critical development is still occurring as the animal grows. Correct and balanced nutrition is critical for steady and complete recovery of injured adults.

 

With the availability of many suitable rodent chow products from several manufacturers, the rehabilitator is not forced to “guess at” or conjure up a diet that may or may not produce satisfactory results. Products such as LabDiet’s 5001 and Certified 5002 rodent chows are cited numerous times as the standard products used for long-term critical research studies in a very controlled laboratory setting. Similarly, the Teklad line of products from Envigo is used worldwide and is well known for its high quality and successful products. These products have also proven successful in a wildlife rehabilitation by numerous rehabilitators. There is a wide array of rodent chows that can be used to provide differing levels of proteins and fats, and provide ingredients that are free from certain ingredients, microorganisms and contaminants.

 

The notion that rodent chow products are not palatable or not preferred by rehabilitation rodents seems to be more an issue of husbandry practice. The rodent chow should be the highest quality, as fresh as possible and and stored appropriately. 

 

Offered a steady choice of “treats” containing higher levels of sugar and fat, some rodents will opportunistically seek those and avoid the rodent chow (just as some humans prefer a double bacon cheeseburger, fries and a shake over a green salad and a cup of lentil soup). With proper husbandry, cutting out the unnecessary “treats” and selecting a rodent chow that is properly formulated for rodents, rehabilitation animals will eagerly eat and benefit from the high quality rodent chow. The results will be evident in many metrics, such as good health, steady growth and development, consistent weight gain, alertness, speed, strength, stamina, agility, fullness of coat/fur, and much more.

Just to emphasize the point on minimizing the treats. Which of the following items would you remove from the animal's diet to entice it to eat the rodent chow? Selecting more than one item to remove is okay.

Treats.jpg
Rodent Chow Ingredients Table A 1 .jpg
Rodent Chow Ingredients Table A 2.jpg
Rodent Chow Proximate Analysis 1 REV.jpg
Rodent Chow Proximate Analysis 2 .jpg
Rodent Chow Fat Comparison 1 .jpg
Rodent Chow Fat Comparison 2 .jpg

Table C - Ratio of Protein and Fat in Commercially Available Rodent Chows.

Rodent Chow Storage Time Effects .jpg

References:

 

Casey, Shirley and Allan M. Casey. 2003. Squirrel Rehabilitation Handbook. WildAgain Wildlife Rehabilitation, Inc., Evergreen, CO.

 

Casey, A. M. 2001. “Mammal Nutrition – How Cookbooks can be Harmful,” Wildlife Rehabilitation, Vol 19 (Proceedings from Nineteenth Annual Symposium, Lake Tahoe, NV). National Wildlife Rehabilitators Association, St. Cloud, MN.

 

Casey, S. J. 2001. “Utilizing Squirrel Natural History in Rehabilitation Decisions,” Wildlife Rehabilitation, Vol 19 (Proceedings from Nineteenth Annual Symposium, Lake Tahoe, NV). National Wildlife Rehabilitators Association, St. Cloud, MN.

 

Chapman, J. A., and G. A. Feldhamer. 1992. Wild Mammals of North America. The Johns Hopkins University Press, Baltimore, MD and London, England.

 

Fitzgerald, J. P., C. A. Meaney, and D. M. Armstrong. 1994. Mammals of Colorado. Denver Museum of Natural History and University of Colorado Press, Niwot, CO.

 

Gurnell, J. 1987. The Natural History of Squirrels. Facts on File Publications, New York, NY and Oxford, England.

 

Hartson, T. 1999. Squirrels of the West. Lone Pine Publishing, Renton, WA.

 

Hofve, J., DVM. Personal conversation. 2002.

 

Holm, J. 1994. Squirrels. Whittet Books, Ltd, London, England.

 

Long, K. 1995. Squirrels: a Wildlife Handbook. Johnson Books, Boulder, CO.

 

Moore, A. T., and S. Joosten. 2002. NWRA Principles of Wildlife Rehabilitation. National Wildlife Rehabilitators Association, St. Cloud, MN.

 

Murie, J. O., and G. R. Michener, editors. 1984. The Biology of Ground-Dwelling Squirrels. University of Nebraska Press, Lincoln, Nebraska and London, England.

 

Steele, M. A., and J. L. Koprowski. 2001. North American Tree Squirrels. Smithsonian Institution Press, Washington, D. C.

White, J. 2000. Basic Wildlife Rehabilitation 1AB. International Wildlife Rehabilitation Council, Suisun, CA.

 

Wilson, D. E., and S. Ruff, editors. 1999. The Smithsonian Book of North American Mammals. Smithsonian Institution Press (in association with the American Society of Mammalogists), Washington, D.C. and London, England.

 

Information sources for the products and manufacturers (updated as of May 2021):

 

PMI Nutrition International (a wholly owned subsidiary of Loans o'Lakes Inc.) is the manufacturer of both the LabDiet and Mazuri product lines. Website and contact addresses are as follows. All of the Purina, PMI, LabDiet and Mazuri locations can be reached at (800) 227-8941.

 

Purina Mills, LLC 

4001 Lexington Ave N

Arden Hills, MN 55126

(314) 768-4100, Fax (314) 768-4894

 

PMI Nutrition International

P.O.Box 66812

St. Louis, MO 63166-6812

(765) 966-1855

 

LabDiet (www.labdiet.com)

PO Box 19798

St. Louis, MO 63144

(800) 227-8941

 

Mazuri (www.mazuri.com)

PO Box 66812

St. Louis, MO 63166

(833) 462-9874

 

Harlan Teklad (www.envigo.com)

Online chat available

Corporate Office

Indianapolis, IN

(800) 793-7287

 

Oxbow Pet Products (www.oxbowanimalhealth.com)

11902 South 150th Street

Omaha, NE 68138

(800) 249-0366

(531) 721-2300

 

Kaytee Products, Inc. (www.kaytee.com)

521 Clay Street, P.O.Box 230

Chilton, WI 53014

(800) KAYTEE-1

Henry's Healthy Pet Foods, Inc. (www.henryspets.com)

158 Pioneer Way NE, Suite 1

Floyd, VA 24091

(540) 745-3334