There are 4 formulations used in age ranges of guinea pig baby:

Infant (up to 4 days of baby age)

Intermediate (day 5 through 7)

Baby 1 (day 7 through day 9)

Baby 2 (baby age 9+ days)

If the baby is losing interest in one version, jumping to the next can resolve this.

Materials (inclusive for all versions):

1.5% fat milk (only).
Unsalted butter
Magnesium citrate
Vitamin C powder or non chewable pills that you can pulverize into a powder (no sweetener needed)
Casein - milk-based protein powder, unflavored, containing 83.9 grams of protein per 100g of powder.
Whey - milk-based protein powder, unflavored, containing 80 grams of protein per 100g of powder.
Off-the-shelf liquid multivitamin syrup, flavored with Sorbitol.
Natural fiber type herbivore recovery feed (crucial: not soy-based)

Important note: All of the stated ingredients are required - do not significantly change it - the percentages are all related. Doing this wrong (such as skipping an ingredient) can cause the rehabilitation to fail.

Equipment:

Precision scale, 1-100 grams
Regular kitchen scale, if making batches 200g or larger.

Regular 1.5L stainless steel pot, no lid needed
Spoon

Syringes (without needles):

• 100 ml syringe with cap (large one for storage of finished formula).
  
• Plunger must have an O-ring, not a solid rubber stopper.
• Optional: other syringes (for storage) 50ml for example.
  
• Plunger should have an O-ring, not a solid rubber stopper.
• Modified 1 ml syringe (for herbivore recovery feed),
• Plunger must have an O-ring, not a solid rubber stopper.
  
• Cut off the tip/hub of the syringe, allowing the plunger to still work normally, and no sharp edges facing outward.
• 1 ml syringe (for milk formula feeding), unmodified,
  
• plunger must have an O-ring, not a solid rubber stopper.
• Optional: 2 or 2.5 ml syringe (for milk formula feeding older babies), unmodified,
  
• plunger must have an O-ring, not a solid rubber stopper.

Syringes for feeding: wrap the barrel with a piece of clear packing tape to preserve the markings.

Instructions are for when starting with 100g of 1.5% milk, but is possible to make larger amounts by multiplying the numbers. I don't recommend attempting to make smaller batches where you would need to reduce 50g of milk to 35g on stovetop.

The Infant formula is straightforward to adjust into Intermediate by estimating the remaining volume of Infant formula and adding the correct measure of protein powders based upon that. For example, if you have roughly 50% of one batch of Infant formula left (starting as 100g milk as in these directions) and want to transform it into Intermediate, you could add .6g casein powder and .1425g whey powder.

The lower-protein formulas become less-palatable to the babies over time, and they can have more enthusiasm for feeding when they are switched to the next higher-protein formula.

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Infant formulation (babies up to 4 days old):

Weigh 100g of the 1.5% milk.

In the 1.5L pot, carefully reduce the 100g milk over stovetop, stirring constantly, to 70g. Pour the milk out of the pot as needed to check its weight. Be careful not to use too much heat.

• If any skim begins to form on top, or solidification of milk products forms on the inside of the pot, the milk cannot be used and must be discarded (too much heat was used and/or not stirred consistently enough).

Remove pot from heat when done.

Use precision scale to accurately measure 20mg magnesium citrate. Pulverize into powder, add to milk, mix gently.

Use precision scale to accurately measure 2.62g of unsalted butter. Gently mix into milk until dissolved (milk should still be warm).

Separately, make a small batch of herbivore recovery feed by mixing with water in a separate container. Herbivore recovery feed should be allowed to age for at least half an hour while refrigerated. Consistency is checked before feeding. It does not need to be very runny.

Note that herbivore recovery feed is never mixed directly into the milk formula.

At this point, Infant Formula is finished in its storable form (not its feeding form).

Infant Formula is stored in the large syringe, refrigerated, with air eliminated from the syringe. Before taking small amounts out for feeding, vigorously shake the syringe. It can not be stored in its final prepared form. The final prepared form for all 4 formulations is at the bottom of this page.

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Intermediate formulation (baby age 5 - 7 days)

Weigh 100g of the 1.5% milk.

In the 1.5L pot, carefully reduce the 100g milk over stovetop, stirring constantly, to 70g. Pour the milk out of the pot as needed to check its weight. Be careful not to use too much heat.

• If any skim begins to form on top, or solidification of milk products forms on the inside of the pot, the milk cannot be used and must be discarded (too much heat was used and/or not stirred consistently enough).

Remove pot from heat when done.

Use precision scale to accurately measure 20mg magnesium citrate. Pulverize into powder, add to milk, mix gently.

Use precision scale to accurately measure 1.2 grams of the casein protein powder.

Use precision scale to accurately measure the much smaller amount, .28 grams (point two eight), of the whey protein powder.

Stir the protein powders into the milk until completely dissolved. Electric mixer is generally not recommended because it creates too much aeration and the formula must sit for a few hours if mixed that way.

Use precision scale to accurately measure 2.62g of unsalted butter. Gently mix into milk until dissolved (milk should still be warm). Always do the butter after the protein powder, not the other way around.


Separately, make a small batch of herbivore recovery feed by mixing with water in a separate container. Herbivore recovery feed should be allowed to age for at least half an hour while refrigerated. Consistency is checked before feeding. It does not need to be very runny.

Note that herbivore recovery feed is never mixed directly into the milk formula.

At this point, Intermediate Formula is finished in its storable form (not its feeding form).

Intermediate Formula is stored in the large syringe, refrigerated, with air eliminated from the syringe. Before taking small amounts out for feeding, vigorously shake the syringe. It can not be stored in its final prepared form. The final prepared form for all 4 formulations is at the bottom of this page.

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Baby 1 formulation (baby age 7 - 9 days)

Weigh 100g of the 1.5% milk.

In the 1.5L pot, carefully reduce the 100g milk over stovetop, stirring constantly, to 70g. Pour the milk out of the pot as needed to check its weight. Be careful not to use too much heat.

• If any skim begins to form on top, or solidification of milk products forms on the inside of the pot, the milk cannot be used and must be discarded (too much heat was used and/or not stirred consistently enough).

Remove pot from heat when done.

Use precision scale to accurately measure 20mg magnesium citrate. Pulverize into powder, add to milk, mix gently.

Use precision scale to accurately measure 2.4 grams of the casein protein powder.

Use precision scale to accurately measure the much smaller amount, .57 grams (point five seven), of the whey protein powder.

Stir the protein powders into the milk until completely dissolved. Electric mixer is generally not recommended because it creates too much aeration and the formula must sit for a few hours if mixed that way.

Use precision scale to accurately measure 2.62g of unsalted butter. Gently mix into milk until dissolved (milk should still be warm). Always do the butter after the protein powder, not the other way around.


Separately, make a small batch of herbivore recovery feed by mixing with water in a separate container. Herbivore recovery feed should be allowed to age for at least half an hour while refrigerated. Consistency is checked before feeding. It does not need to be very runny.

Note that herbivore recovery feed is never mixed directly into the milk formula.

At this point, Baby 1 Formula is finished in its storable form (not its feeding form).

Baby 1 Formula is stored in the large syringe, refrigerated, with air eliminated from the syringe. Before taking small amounts out for feeding, vigorously shake the syringe. It can not be stored in its final prepared form. The final prepared form for all 4 formulations is at the bottom of this page.

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Baby 2 formulation (baby age 9+ days)

Weigh 100g of the 1.5% milk.

In the 1.5L pot, carefully reduce the 100g milk over stovetop, stirring constantly, to 70g. Pour the milk out of the pot as needed to check its weight. Be careful not to use too much heat.

• If any skim begins to form on top, or solidification of milk products forms on the inside of the pot, the milk cannot be used and must be discarded (too much heat was used and/or not stirred consistently enough).

Remove pot from heat when done.

Use precision scale to accurately measure 20mg magnesium citrate. Pulverize into powder, add to milk, mix gently.

Use precision scale to accurately measure 3.09 grams of the casein protein powder.

Use precision scale to accurately measure the much smaller amount, .71 grams (point seven one), of the whey protein powder.

Stir the protein powders into the milk until completely dissolved. Electric mixer is generally not recommended because it creates too much aeration and the formula must sit for a few hours if mixed that way.

Use precision scale to accurately measure 2.62g of unsalted butter. Gently mix into milk until dissolved (milk should still be warm). Always do the butter after the protein powder, not the other way around.


Separately, make a small batch of herbivore recovery feed by mixing with water in a separate container. Herbivore recovery feed should be allowed to age for at least half an hour while refrigerated. Consistency is checked before feeding. It does not need to be very runny.

Note that herbivore recovery feed is never mixed directly into the milk formula.

At this point, Baby 2 Formula is finished in its storable form (not its feeding form).

Baby 2 Formula is stored in the large syringe, refrigerated, with air eliminated from the syringe. Before taking small amounts out for feeding, vigorously shake the syringe. It can not be stored in its final prepared form. The final prepared form for all 4 formulations is at the bottom of this page.

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Final preparation for feeding - all formulas:

Before taking some of the milk formula out of the refrigerated 100ml storage syringe, draw some air into it, and with the top covered firmly, shake the syringe vigorously, especially when using Intermediate, Baby 1 or Baby 2 formulations. The protein supplement tends to settle during storage and must be mixed back in.

Baby guinea pigs that are being hand fed should be gently stimulated to urinate and defecate. The sow may not be doing this to non-nursing babies, so you need to be sure it is happening. Doing this every few hours, before feeding, is a good idea.

Milk formula is fed to the baby warm or at room-temperature, but not hot.

Syringe (non-modified) you are using to feed the milk formula: remove the plunger completely from the syringe by drawing out all the way out of the back.

Put a very small amount of powdered vitamin C directly into the empty syringe through the open back. The correct amount is too small to be weighed on a 0.01g precision scale. You will need to experiment to learn the right vitamin C amounts for your syringes. You can judge if you added too much in the next step. Replace the plunger into the syringe afterward.

If you are still learning how much vitamin C to use, you can evaluate the vitamin C amount this way:

Draw milk formula into the syringe:

• 1ml syringe: .8 ml

Cover the top of the syringe with your thumb and shake.

If the vitamin C amount was correct, virtually all of the milk will still be liquid.
If you put in way too much, all of the milk will have turned into white sludge (clean out completely and redo)
If you put in a bit too much, the milk will be partially white sludge (clean out completely and redo).

Make milk/vitamin C solution in the unmodified syringe, such as:

• 1.0 ml milk formula +C, if syringe is 1ml size and not offsetting with multivitamin as below
  
• .8 ml milk formula + C, if syringe is 1ml size and offsetting with multivitamin as below
  
• 1.6ml milk formula + C, if syringe is 2 - 2.5ml size (multivitamin offset assumed)
  

Liquid multivitamin:

Infant formulation:

3x daily, cause the baby to take .1 multivitamin regardless of the milk portion size at the time, unless you estimate that the baby is dehydrated, in which case skip the multivitamin. Wait until the hydration has likely been corrected (maybe 12h after feeding start in a complete non-nursing case).

Intermediate and higher formulation:

After the baby is acclimated to Intermediate formulation, begin offsetting the milk formulation with 20% liquid multivitamin.

draw liquid multivitamin in:

• 1ml syringe: .2 ml (making 1 ml total solution)
• 2 - 2.5mi syringe: .4ml (making 2 ml total solution)

Cover the top of the syringe with your thumb and shake.

Feeding to the baby guinea pig:

• Can skip the herbivore recovery feed in situations where the baby has not eaten before and is still so young that it is expelling meconium (newborn poop). Can begin the herbivore recovery feed accompaniment a few hours after this.
  

• Can skip the herbivore recovery feed if the baby is eating an equivalent amount of grass in its place
  

Draw pre-made herbivore recovery feed into the modified 1ml syringe.

If the baby is expected to take .5 ml or less during this feeding:

• Feed .1ml of the herbivore recovery formula (or skip this step depending on case).
• Then, feed the milk formula

If the baby is expected to take more than .5 of the milk formula:

• If amount of formula fed is expected to be above .5 but less than 1ml, feed .15ml of the herbivore recovery formula.
• If amount of formula fed is expected to be 1ml or more, feed .2 of the herbivore recovery formula.
  
• Then, feed up to 1.5 ml of the milk formula.
• For total feed amounts over 1.5 ml, keep stopping the milk feeding at [1 ml - 1.5ml] intervals, feeding .2 ml of the herbivore recovery formula before each [1 ml - 1.5ml] of milk formula.
  
• During each feeding, cap the amount of herbivore recovery formula at a maximum of .6 ml per feeding.
•  such as:
  
• baby takes 1.0 ml of milk formula = .2 herbivore recovery formula
• baby takes 2.0 ml of milk formula = .4 herbivore recovery formula
• baby takes 3.0 ml of milk formula = .6 herbivore recovery formula
• baby takes 4.0 ml of milk formula = .6 herbivore recovery formula *
  
• baby takes 5.0 ml of milk formula = .6 herbivore recovery formula *
  
• * = babies taking these quantities are expected to be consuming significant roughage in the cage environment