How to Use Freeze Dried Liver Instead of Fresh

When first introducing organs during the transition, many of us find that our cats do not like or cannot keep down fresh, raw liver. Clearly if there are issues, the rate of introduction should be very slow with the fresh, sometimes they can manage just a sliver. But we still want them to get the benefit from the 5% liver they need in their diet. There are three options:

1. If possible, offer a different kind of liver (for instance, beef or pork instead of chicken or turkey. Do bear in mind that many cats are especially sensitive to red meats. This carries through to their organs).
2. Cook the liver. Sometimes cooking helps keep it down; sometimes a touch of (unsalted) butter (from grass-fed cows if possible) for cooking helps make it more palatable.
3. Use freeze-dried liver. Most cats do enjoy freeze dried liver. In the U.S. and Canada, there are many brands and proteins.   In the U.S. brands include Fresh is Best, PureBites, Whole Life, Stewart’s ProTreat, Etta Says, Northwest Naturals, Bravo – and many more.

While fresh is best, freeze-dried liver is a healthy alternative as it retains virtually all of the nutrients of fresh intact.
 
 
How Much Freeze Dried Liver to Feed
 
www.rawcalc.org makes it easy to determine how much freeze dried liver to use. You do need to know some basic information, outlined here.

If you want to understand the math, or to use the automatic calculator that does the math for you, in order to calculate how much freeze dried liver to feed, you need to know:

1. The moisture content of the brand you feed. This is listed in the guaranteed analysis on the package;
2. Whether the brand of freeze-dried liver you are using is cooked or raw. To my knowledge, the only freeze-dried raw liver is Stewart’s ProTreat. If you are not sure, contact the manufacturer.
3. The moisture content of the type of liver (beef, pork, turkey, chicken, duck, etc.). This is data from the USDA Nutrient Database (http://ndb.nal.usda.gov/ndb/search/list)

Moisture Content of:
Raw Beef Liver                                    70.8%
Raw Chicken Liver                               76.5%
Raw Duck Liver                                   71.8%
Raw Lamb Liver                                   71.4%
Raw Pork Liver                                    71.1%
Raw Turkey Liver                                75.5%
 
Moisture Content of:
Cooked Beef Liver                               58.8%
Cooked Chicken Liver                         66.8%
Cooked Duck Liver                              58.0% (estimated, the USDA does not have a value)
Cooked Lamb Liver                             56.7%
Cooked Pork Liver                               64.3%
Cooked Turkey Liver                           64.0%

Finally, you need to know how much fresh liver your cat needs to eat each day. This is usually 5% to 10% of the diet: 5% if feeding another organ, 10% if not. Alnutrin with eggshell recipes recommend 7%. There is no "right" or "wrong" answer. Prey model raw feeding uses the guideline of 5% liver, 5% second secreting organ. We recommend 10% liver if not using another organ - this will not provide too much vitamin A. Please see the table, below, to determine how much fresh liver you would feed daily for the basis of how much freeze dried liver to use.

Converting Freeze-dried Liver into Fresh Equivalent
 
The formula to determine how much freeze-dried liver is the equivalent to fresh:
 
(The % of fresh solids / The % of freeze-dried solids) * Fresh Weight = Freeze-dried Weight
 
This is: the percent of fresh liver solids divided by the percent of freeze-dried liver solids, multiplied by the fresh weight of liver you need to feed.
 
Fresh solids:  100% - moisture % of fresh liver
Freeze dried solids: 100% - moisture % of the freeze dried liver you are using
 
 
Example: freeze-dried raw chicken liver. Brand: Stewart’s ProTreat
 
Fresh Solids % = (100% - 76.5% as per USDA data for raw chicken liver) = 23.5%
Freeze-dried Solids % = (100% - 6.5% as per guaranteed analysis on the package) = 93.5%
 
(Fresh Liver Solids % / Freeze-dried Liver Solids %):  (23.5% / 93.5%) = 25.2%
 
25.2% * (Insert amount of liver needed. In this example, we will convert to one pound of fresh, so 16 ounces: 25.2% * 16) = 4 ounces of Stewart’s ProTreat freeze dried raw chicken liver is equivalent to one pound of fresh raw liver.
 
How Much Fresh Liver Does My Cat Need?
 
When introducing organs, some feed liver to 10% of the diet until they introduce another secreting organ. So how much fresh liver depends on whether you are feeding 5% of the total diet, or 10% (or somewhere between).
 
If you are targeting 5% liver and feed a total of 4.5 ounces of food per day, your kitty needs 0.225 ounces of FRESH liver daily.
 
In the above example using Stewart’s ProTreat raw, freeze dried chicken liver, to calculate how much liver to use at 5% liver, feeding 4.5 ounces of total food daily, 0.225 ounces of fresh liver is needed. To convert to a freeze dried quantity:
 
Example: freeze-dried raw chicken liver. Brand: Stewart’s ProTreat
 
Following the steps already detailed, above:
 
Fresh Liver Solids % = (100% - 76.5% as per USDA data) = 23.5%
Freeze-dried Liver Solids % = (100% - 6.5% as per guaranteed analysis) = 93.5%
 
(Fresh Solids % / Freeze-dried solids %):  (23.5% / 93.5%) = 25.2%
 
25.2% * 0.225 ounces of fresh raw liver  = 0.06 ounces of Stewart’s ProTreat freeze dried raw chicken liver is the equivalent to 0.225 ounces of fresh raw chicken liver. Because the amounts of freeze dried liver are usually so small, I find it easier to weigh grams.
 
There are 28.35 grams to one ounce. To convert, multiply the number of ounces by grams per ounce:
 
0.06 ounces of freeze dried liver * 28.35 grams =  1.7 grams
 
In this example, 1.7 grams of Stewart’s ProTreat freeze dried chicken liver is needed daily.
 
Of course, if you need assistance, please just ask in the group.