Baby Rabbit not gaining weight

Question
I do not know if you got my personal message or not so I will restate here. I cannot thank you enough for this advice. The bunny now weighs 3.2 ounces. It is 24 days old.  It turns out that the mothers milk had dried up.  The little bunny is doing great. I do put the Mom occasionally together with the baby so she can give it its bath. Thank yo so much for your recipe. The bunny loves the formula and is very cooperative when it is fed. How many more weeks do I feed him this?

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Followup To

Question -
How much do I give and how often? The mother is now refusing to nurse. I am fighting with her.
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Followup To

Question -
We had a mother who gave a litter of 3 kits on September 18th.  Two of them died because they were peanuts.  The mothers milk did not come in for 2 days so we decided to give the baby some kitten milk. We did that to supplement the mothers milk.  We are now on day 17. The bunny is very small and weighing it on a postal scale it has lost weight this week from 2.3oz to 1.9oz. She still nurses from her mom BUT the mom will only let it nurse on one side. We have it still in its nest with a heating pad. Is there anything we can do at this point to help it gain weight. Could we supplement once again and if so how much would we give the bunny?

Answer -
Dear Corinne,

My first suspicion in a case like this is that the bunny has a congenital defect that is causing this failure to thrive.  The fact that its two littermates were "peanuts"--if you're using the term in its true, genetic sense--means that both parents carry the dwarfing gene, which in homozygous condition (i.e., the babies received one from each parent, so had two copies of the dwarfing gene) is lethal.  

Some peanuts survive for a short time before succumbing to the lethal genetic condition.  Others die almost immediately after birth, others before birth.  The condition shows variable expressivity (i.e., it's expressed differently in different individuals, depending on what else is in the genome.  It's possible that the little one you're trying to save is, indeed, a peanut, and that other genes in its genome are interacting, allowing it to survive longer than its siblings.  But perhaps not for long.

Size in rabbits, despite the obvious involvement of the lethal gene in dwarf rabbits, is polygenic (controlled by more than one gene).  It's also possible that the baby you're trying to save has inherited some other deleterious/harmful genes that are preventing it from developing and growing normally.  This is even more likely if the parents are genetically related to one another.

To try to get some size on the baby, it might help to increase the caloric content of his food without increasing volume too much.  I feed orphaned hares the following formula

1 cup Pasteurized goat milk
1 teaspoon heavy cream
1 teaspoon whey powder (protein)
1 teaspoon lyophilized (freeze-dried) colostrum

The latter can be bought at large health food outlets such as Wild Oats or Natural Foods.

The extra cream provides more calories.  The extra protein provides more amino acids so the baby can manufacture more of his own, if he's genetically capable of doing so (which he might not be).  The colostrum provides antibodies against intestinal pathogens.  But if you're fighting against bad genes, then it might not help.  Only time will tell.

Please read:

www.bio.miami.edu/hare/breeding.html

Good luck.

Dana

Answer -
Dear Corinne,

You can find instructions for feeding an orphan rabbit here:

http://www.rabbit.org/faq/sections/orphan.html

and specifically here:

http://www.rabbit.org/faq/sections/orphan.html#The%20Bunny%20is%20Domestic%20and

Good luck!  I hope he makes it!

Dana

Answer
Dear Corinne,

I'm so glad the baby is doing well!  :)

He should continue receiving formula until he's 8 weeks old.  You can gradually decrease the amount of cream and colostrum, but it won't hurt to keep up the colostrum until he's 4-6 weeks old, or so.

To wean him, you can gradually dilute the formula with clean drinking water, a little bit at a time over several feedings.  When the formula doesn't taste as creamy, he'll gradually lose interest.

Good luck with the wee one!

Dana