Holiday Hopping

February 14th is declared as a day of love (but commonly confused with lust).  Why not put your bunnies together today, so they can celebrate with you?  The great part is that if your doe kindles in 31 days, you'll have a St. Paddy's Day litter!

Due Week

Black otter Rex doe nesting with hay and fur.

I hear people say that their rabbit is "due" some particular day (often "yesterday").  Unfortunately, with rabbits, the term "due date" is poorly used.  Besides the fact that different people express the due "date" as anywhere from 28 to 32 days after breeding (most people say it's 30 days), rabbits can give birth during a rather wide range of time (relative to their total gestation period).  For this reason, I say that a rabbit is due some week, between 28 and 35 days (4 and 5 weeks) after breeding.

A good example which illustrates the due week, is the pattern of birth I'm experiencing with my rabbits this week.  All of the does that were/are due were bred on the exact same day, within the span of an hour.  I gave nestboxes to all of them on day 27 (my standard practice).

Rex litter out of chocolate doe.

On day 30, Mosaic started nesting.  Day 31, she kindled 7 very healthy kits.  That same day, Godiva started nesting.  The afternoon of Day 32, Godiva delivered 6 kits, and Laurel started nesting.  The morning of Day 33, I discovered 6 kits from Laurel, and Iza had started nesting.  By that (this) afternoon, she had kindled her own litter of 6, and Princess had started nesting.  Another doe still has yet to start nesting, but some does wait until they're in active labor before they start nesting.

I have had does kindle as late as 35 days after their last breeding.  I've only had one doe that kindled before day 28 (she kindled on day 25), but have had a number kindle on day 28.  That's why I put the box in on day 27, and leave it in there until day 35.  Of course, if you can train yourself how to palpate (or get lessons from another breeder), you can save yourself some of the wait time.  I've never been very good at it, myself, though.

Sexing Rabbits

I did a quick Google search to see if there was a good reference for people new to rabbits on how to sex a rabbit.  To my surprise, none of the results on the first page seemed like good references; they either seemed to provide an overload of information or only gave general information and not-so-helpful diagrams.  So, my remedy is to provide one here.  Please feel free to share this post around if you find it helpful.

Mature rabbits are by far the easiest to sex.  However, as you can see from the above picture, simply looking at the vent--that's the term we use to refer to all rabbits' private areas, including the anus and vulva or penis--is not enough to determine sex.

Scrotum on a mature buck.

Many mature bucks have very obvious scrota when you flip them over.  Sometimes, especially when it's cold or the buck is stressed out, they suck their testicles inside their bodies, leaving only the scrota external, often hidden in the fur around them.  If you look near the vent, you may be able to find areas of loose flesh, which are the scrota.  Do not mistake a bald area for a scrotum, though--many does will have a bald area in the same place as you would find testicles, but the flesh will be more firm, rather than an empty(ish) sac.

However, a buck that has been neutered, or a buck which hasn't matured to the point of his testicles descending, is still indeterminable from a doe unless you actually expose the vent.  To do this, you'll first have to flip the rabbit over.

Once you have the rabbit on its back, use your free hand to expose the vent.  One finger (or your thumb) should be on the tail, and another finger (or your thumb) should be on the furry mound, such that your fingers frame the vent.

Finger on tail, thumb on mound to frame rabbit's vent.

The anus is the slit that has fur.
The mound is a raised area of fur,
opposite the tail.

With your fingers framing the vent, push the tail gently away from the vent, and press gently into the mound. This will make the genitals pop out so you can see if it is a penis or vulva.

Mature doe - note the slit and
close proximity to the anus

Mature buck - note the pointed-cylindrical protrusion
and distance from the anus.

With younger rabbits it can be a bit trickier.  Not only are they smaller, but their hormones haven't kicked in to bring their genitals into their final form.  As such, it can be very easy to over- or under-expose the genitals, making them look like one gender when they're really the other.  I find that it is best that the tail-holding finger only holds the tail in place, without pulling back on it, and the mound-pressing finger presses gently down into the belly and slightly toward the vent, until a shape becomes apparent.  You may have to readjust your finger placement until you can get it to pop definitively.

5-week-old doe: slit very near anus

5-week-old buck: tube protrusion slightly away from anus

3-week-old buck: tube protrusion slightly away from anus

3-week-old doe: slit very near anus

5-week-old buck slightly overstretched,
looking like a slit, but still very far
from anus.

3-week-old buck very overstretched,
looking like a slit, but note the gap
between the slit and the anus.

Many people are unable to sex kits under 6-8 weeks old, so don't worry if you have a hard time: you're not the only one! Just keep practicing.

It is also possible to sex kits that are only a day or two old! (click to read that article)

Rollercoasters of Nests

Nestbox stuffed full of straw.

This weekend marked 28 days after breeding for another four does.  Each of them were given a nest box stuffed full of straw (and I do mean stuffed).

Some of the girls' bellies were getting obviously swollen.  Keep in mind, though, that not all rabbits will show signs of being pregnant.  Some rabbits carry their litters really high up and their bellies don't seem to expand.  Some does maintain the same personality and behavior throughout the entirety of their pregnancy.  Just because a doe doesn't look or act different doesn't mean that she didn't conceive.  On the other hand, a false pregnancy can cause a doe to change her personality, behavior, and even appearance.  My personal rule is that if a doe has been exposed to a buck, she should get a nestbox, no matter what.

Aster's late-term pregnancy belly.

Sweetie's prego belly.

Buck lifts feet as he "falls off"

Of course, not all breedings are successful.  This weekend also marked the 40th day after Mena was bred to Tron.  I was actually surprised to see that her breeding was unsuccessful, given how eager she was to breed.  Then again, her nest only got flatter each day.  In general, a doe that is pregnant (or thinks that she's pregnant) will fluff the nesting material rather than flatten it.  However, that's not a steadfast rule.  Since neither Mena nor Tron is proven, I can't say why the litter didn't take.

Godiva's nest with fur after 24 hours.

Excitingly, Godiva, who was also bred to Tron, made a nice hollow in her nest and even added a bit of fur.  Hopefully, that means that Godiva is really pregnant, and Tron will become proven.  (Meaning that Mena's lack of litter was because of something relating to her, only).

Sweetie's nest after 24 hours.

Rabbits seem to like keeping us on our toes, though.  The very next day, both of the nests with nice hollows had been evened out.  In exchange for that, Aster decided to fill her nest box (and cage) with fur, but no kits just yet.

Godiva's flattened nest

Sweetie's flattened nest.

Aster's cage filled with fur.

Aster's nest box of fur.

Moon Cycle?

So, you've heard about the moon affecting rabbits' breeding habits and results, right?  You haven't?  Well, neither had I until a couple months ago.  Like you, I was definitely skeptical.  What sane, scientifically-minded person wouldn't be?  (And, if you know me, you know that I'm quite scientifically-minded--although I won't say one way or the other on the sanity part.  Give me anything to do with the scientific method, and I'm there, especially if it has to do with rabbits.)

The general points to the moon-phase theory are:

• You get more does than bucks when you breed during the full moon^[1]
• You get more bucks than does when you breed during the new moon^[1]
• You get larger litters when you breed during the full moon than when you breed during the new moon^[2]
• You get larger litters when you breed when the moon is waxing (getting bigger) than when the moon is waning (getting smaller)^[3]

I will be honest, here, and say that I consider myself a Witch, and practice along the lines of Wicca (not completely, but mostly).  In that theology (as well as a number of other ancient culture theologies), the moon plays an important role.  The moon can be a powerful force (it controls the tides, after all!).  However, I've never applied it to my everyday life.  I don't even use it for gardening, which so many people do.  Despite my belief in the power of the moon, spiritually, and knowledge of its effects, geographically, I've never held to the thought that it had any power over biology.

Anyway, the topic has come up frequently in recent days, so I figured I'd take a look at my old records and see if there's any foundation to these [highly improbable] claims.

Scope of Data
23 does were used, all either purebred Californian, New Zealand, or Rex.  They were all bred to purebred bucks of the same breed.  Does were between the ages of 5 and 49 months. 74 breedings were recorded (where the buck definitely fell off while lined up properly), which resulted in 49 litters.  Kits were sexed at weaning between 6 and 8 weeks old.  Kits which died before weaning were not counted for gender, although they were counted for average litter size.

Comparison of Full Moon vs. New Moon breeding.
Unfortunately, only 5 of the 74 breedings were done on the actual day of the full or new moon (not considered a significant research pool).  Of those, only one resulted in a litter.  That breeding was on a full moon and resulted in 6 kits, all of which died before weaning.  Again, this is not significant data, but I'm providing it anyway.

However, in Wicca, the full- and new-moon phases are considered to be on three-day spans, so I can expand my data to look at the 3-day spans.  When you consider the data that way, there were 22 total breedings (11 each for full and new moon).

	Full Moon	New Moon
Number of breedings	11	11
Number of successes	9	5
Success %	81.8%	45.5%
Average litter size when successful	6.1	7.4
Average Number of Kits Dead Before Weaning	3.4	4.4
Mortality rate	56.4%	59.5%
Average Net Litter Size	2.7	3
Average Number of Bucks Weaned per Litter	1.7	1.6
Average Number of Does Weaned per Litter	1.0	1.4
Weaned Buck:Doe ratio	1.7:1	1.1:1

What this data suggests is that:

• Full-moon breedings are more likely to be successful (almost twice as likely)
• New-moon breedings tend to result in larger litters than full-moon breedings (21.3% larger)
• Mortality rate is marginally increased for new-moon breedings, but not significantly
• Even after mortality, new-moon breedings still result in more kits being weaned, but the difference may not be significant
• Full-moon breedings tend to produce a higher percentage of bucks at weaning

What I want you to note is that my data shows that New Moon breedings resulted in larger litters, which is contrary to the proposed theory.  However, if you look at litter size after mortality, the new moon litter size is not much larger.

I also want you to note that while this data leans toward confirming that you get a higher percentage of bucks with full-moon breedings, but not much more.  Also, if you were to consider the number of kits of unknown gender, there are more than enough to completely reverse the ratio (potentially even quadruple it in favor of the other direction).  Then again, should the gender of the unweaned kits really be considered?

Keep in mind that the above assessment does not take into consideration p-values, which are what researchers use to determine if data is significant.  (I may come back to this, when I'm feeling up to some higher math, and calculate p-values).

Comparison of Waxing vs. Waning
Waxing days include the day immediately following the singular day of the new moon to the day immediately before the singular day of the full moon.  Waning days include the day immediately following the singular day of the full moon to the day immediately before the singular day of the new moon.

	Waxing	Waning
Number of breedings	34	35
Number of successes	25	23
Success %	73.5%	65.7%
Average litter size when successful	6.4	6.5
Average Number of Kits Dead Before Weaning	3.2	2.5
Mortality rate	50.0%	38.8%
Average Net Litter Size	3.2	3.0
Average Number of Bucks Weaned per Litter	1.8	2.4
Average Number of Does Weaned per Litter	1.4	1.6
Weaned Buck:Doe ratio	1.3:1	1.5:1

This data suggests that:

• There is a slightly greater chance of success when breeding while the moon waxes
• There is no significant litter size difference
• There is a slightly greater mortality rate from breedings done while the moon waxes
• There is a slightly higher percentage of bucks when breeding while the moon wanes

I do not consider this data to be significant enough to say that there is indeed a difference between breeding during the waxing or waning moons.  When I'm feeling math-y, I'll come back here and calculate the p-values, which will show more definitively.  (I will probably also add some more litters to the stats, and promise to start trying to document number of bucks/does alive AND dead).

Daily Nest Check

Dead kit on edge of nest.

Sadly, Chesna has lost another kit, leaving her with only three live kits.  It was the one from the second delivery that didn't get completely cleaned off.

This is another reason that it is important to check nests daily. Dead kits usually isolate themselves from their littermates (this one, and the ones that died the day before, had all crawled off to another corner of the box, away from their siblings).  However, sometimes they don't.  Those cold bodies pose a risk to their living littermates.  The cold bodies can draw out the heat of the others, which can cause the others to die.

Even when the dead kits crawl off to another corner, they can get squished, and may attract the attention of flies or other nasties, which can also spell disaster for the littermates.

Undeveloped nest.

Upsettingly, Mena still has yet to kindle.  I had hoped that since she had been so eager to breed that she would conceive, no problem.  Of course, it's only been 33 days since she was bred, so there's still a possibility that she may kindle.  (The record for latest litter at my rabbitry is 35 days, but others have seen as late as 40 days).  Still, the state of her nest (very flat and undeveloped) instills little confidence in the idea that she is actually pregnant.

Both she and the buck were unproven, so I can't really point fingers, if she didn't take.  Both were an estimated 8-1/2 to 9 months old, which is usually a prime breeding age.  But, Tron had taken the winter kind of hard, and Mena has been a pig, so it may have just been their condition.  Tron was also bred to Godiva, who is due in another week or so, so we'll just have to wait and see.

The Waiting Game

Nest 30 days after breeding.

Every rabbit breeder has experienced "the waiting game".  Since rabbit gestation can be so varied--I've seen litters as early as 25 days after breeding, and some people have documented as many as 40 days after breeding--you really can't be sure just when you'll get to see those little wigglers.  Even at the narrowest expectations, the kits could be born on day 30, 31, or 32.

Chesna pulled fur 30 days after breeding.

On the 30th day after breeding, I made my rounds at 8 a.m.  Everything was the same as it had been the night before.  At noon, I decided to go check on the rabbits again (no idea what made me do it).  Chesna, the New Zealand doe, had pulled quite a bit of fur.  Some of it was even flying out of her cage, she had pulled so much.  However, there were no babies in the nest.  Of course, this set me into checking on her nest every few hours to see if she had finally kindled.  Time after time, nothing was changing.  Neither of the other does were doing anything to their nests, either.  Needless to say, I didn't get a whole lot of sleep that night.

Birthing blood in nest.

Finally, the next evening (32 hours after discovering the pulled fur), something changed again.  Some of the hay in Chesna's box had blood on it!  This can alarm many people, but it wasn't a serious amount, and just told me that she had probably at least started giving birth.  (Birth in any mammal species is actually a fairly bloody ordeal.)

Undeveloped kit delivered with litter.

Of course, the first thing that I see in the nest is actually an undeveloped kit, about the diameter of a quarter.  It's not terribly unusual, but disheartening to see.  Something had to have happened to that kit to make it stop developing.  It could have been stress, bad diet, too many other kits in the womb, or any number of things.

Four newborn New Zealand kits.

Nestled in, a little further back, there were four little kits, snuggled in together, under the fur.  They weren't as lively as I'd have liked to see, and one of them was awfully cold (and darker than the others, most likely indicating hypothermia).  The cold one seemed to still be open to curling up with its siblings (which were plenty warm), so I left it with them.

Getting Ready for Kits

Nest box after 1 day with expecting doe. 

If you've been following this blog, you may remember that about a month ago, we got a few does bred.  Rabbit gestation is normally anywhere between 28 and 33 days, with days 31 and 32 being the most common.  However, I've had litters born as early as day 25, and as late as day 35.  I've heard of others who've had litters born on day 40!

It is my policy to give nest boxes to the does 27 days after they've been bred.  Some hutches have built-in nesting areas, so they don't have to worry about when to put in a nest box.  Once upon a time, I used to put boxes in at 2 weeks.  The reason I wait until day 27 anymore is for cost-control and sanitation.  Putting the nest in early often means that the doe will consume or waste more of the nesting material.  Also, does may often choose to use the nest box as a potty box, instead, if given it too early.  Besides that, in my experience, any doe that starts nesting before day 16 is most likely experiencing a false pregnancy.  (A false pregnancy is when the pregnancy hormones are all there, so the doe thinks that she's pregnant, when in fact she is not.)  But, if you feed hay (I don't do it often, myself), and a doe starts nesting after day 16, go ahead and give her a box to put it all in.

Doe scattered nesting material over her cage.

I prefer to use metal nest boxes with removable wooden floors.  Metal boxes are easier to sanitize than wooden boxes, which makes for healthier kits.  The downside is that metal boxes can be deadly in winter, if you don't prepare them right.  When I'm doing winter litters, I line the inner walls of the nest box with corrugated cardboard, which keeps the kits away from the cold metal.  The removable wooden floor allows for drainage around the edges of the flooring, and makes it easier to scrape out leftover nesting material after removing the box.

Another nesting option is all-wire nests, which are particularly good for hot-weather litters, since it avoids trapping heat in.  The flip side to that is that they don't work very well for winter litters, because of an increased likelihood of draft, and less heat being kept by the kits.  Some people like to use wire floors in wooden nest boxes simply because the drainage is the best you can get (no trapped urine), which means less chance of nest box eye.  In a pinch, you can use an empty case of soda or beer, but keep in mind that the urine will eventually break the box down.

Doe collecting straw for her nest.

More important than the material which the nest is made out of is how big the nest is.  A nest box should be only a couple inches wider and longer than the doe.  A nest box which is too big will encourage the doe to hang out in the nest, which puts the kits at risk for being trampled.  Does that hang out in the nest box are also more likely to potty in the nest, which can make sick kits.

You also want to make sure that the nest is deep enough.  In particular, the lowest part of the wall (where the doe will be hopping in and out of the nest) should be no lower than 4 inches.  Six inches may be better.  If the lowest wall is too low, young kits will be more likely to accidentally hop out on their own, and likely catch chill and die.  Some nests are made with an extra lip on the entrance wall, the purpose of which is to scrape off any kits that don't detach from the nipple when the doe decides she's done feeding.  I've never found it necessary to have the scraper lip, and have only lost a couple kits to being dragged out, in all the years I've raised rabbits.

Does will sometimes put anything they can lift into the nest.

My nesting material of choice is plain old straw.  I've tried using hay, but my does always ate all of the hay (even though I always stuff past the brim) within a couple of days.  Some people use wood shavings, but I generally advise against it.  Cedar shavings are an absolute no-no; cedar oil causes serious respiratory issues in rabbits, especially young ones.  Pine shavings are probably the most commonly used, but still puts the kits at an increased risk for nest box eye, because of the oils. (I don't know how many times I've heard people mention that they used to have issues in every litter with nest box eye, until they switched away from using pine shavings).  If you really want to use shavings, I suggest using hardwood shavings, such as aspen.  In a pinch, you can use black-and-white newspaper shreds, but the paper gets soaked quickly, rather than wicking it away, so you should plan on changing out the paper every couple of days after the kits are born.

Doe stuffing her nest with straw.

Always stuff the box as full of nesting material as you possibly can.  The doe will rearrange it as she sees fit. Usually, during summer, a doe will pull most of the nesting material out, but there's no harm in having it scattered across her cage.  If the doe pulls all of the nesting material out, just restuff with a couple more handfuls.

Pay attention to which corner of the cage the doe uses for her potty.  When you put the nest box in, put it in a different corner.  If you put the nest box in the same corner she uses for her potty, chances are that the nest box will become a potty box, which puts the kits at risk for nest box eye and other infections, and will mean that you will have to change out the nesting material frequently.

Tufts of fur added in the first day of having the nest.

Some does will start nesting as soon as they have a nest box, and may even pull a few tufts of fur.  Many does, though, won't start nesting until they're in full labor, and may not pull fur until after the kits have all been born.  Each doe is different.

Line-breeding

Hickory, broken chinchilla Rex, cleaning
white doe, Sweetie, after breeding.

These last two days have been pretty good for breeding, here at Hill Rise.  Yesterday, Godiva (our chocolate Rex doe) was just about as excited to breed as Mena was with Tron (Godiva was also bred to Tron).  Tron got three good fall-offs with Godiva.  I also bred Hickory to his dam, Sweetie, yesterday, but I wasn't too sure about his aim, so I put them together again, today.  Today's breeding seemed much more promising.

Snap and Aster, New Zealands, after breeding.

Aster was bred to her sire, Snap.

Ixis, white Rex, and Princess, otter Rex, after breeding.

Princess was paired up with Ixis.  Both are very sizable Rex, so we should be seeing some big babies from these two!

Diagram of one line-breeding system.

In case you're wondering about the closeness of the breedings, I can assure you that inbreeding (or in this case, line-breeding) is not as detrimental to rabbits as it is to many other species.  There have been a number of studies on the subject--at least three that I have read--and they conclude that as long as you start with healthy stock with no known genetic defects, rabbits can withstand sibling to sibling pairings for 9 to 20 generations before you will see ill effects.

Line-breeding is a specific type of inbreeding where you breed son to mother or daughter to father, take the offspring of that pairing and breed it back to the mother-grandmother or father-grandfather.  It can be repeated for several generations.  It can also involve crossing cousins, but not always.  Basically, the difference between line-breeding and just inbreeding is that line-breeding is systematic, whereas inbreeding can be haphazard.

Vulvar Indicator?

There are a number of breeders out there who check their does' vulvas before putting them in with bucks for breeding.  They do this because rabbits don't have an estrus (or heat) cycle like most other familiar mammal species.  Instead, rabbits are induced ovulators.  In other words, the act of mating causes the does to release their eggs into their uteri.  However, they do still have hormones which affect them, and there are times when does are more or less willing to mate. The theory behind checking the vulva is that a doe that has the right hormone levels and is going to be willing to breed will have a moist, dark-colored vulva.

Vulvas of does not interested in breeding.

The first time I even heard about this theory was only a couple years ago--a decade after I first started raising rabbits.  Out of curiosity, I started checking, but I don't put much reliance on it.  Today was one of those days that didn't offer much support for the idea, in my mind.

This picture is a compilation of the vulvas of the does which refused, today.  Some are kind of pale, but I've seen paler (and drier).  Some people might even consider some of these vulvas rather red, or even purple (which is supposed to be really interested).

I probably should have gotten some pictures of the does that were willing, but the thought didn't occur to me at the time.  Maybe when I get these does to breed, I'll offer contrast photos.

Interestingly enough, all four of these does are related--a mother/aunt, her daughter, and two nieces.  If these gals don't change their minds, I may not be having red and tricolor Rex for a while. *sigh*

Breeding Successfully

Very-ready doe, lifting for buck.

Finally!  The weather has been decent for long enough that the rabbits actually agree with me that it is time to start making kits!  (In case you didn't know: rabbit fertility can be affected by light; they are much more likely to be in the mood when they get 12-16 hours of light a day than when they only get 8-10 hours.)

Doe rolled over, she was so excited to breed!

Our blue otter doe, Mena, was so into it, that she had her hind end up on stilts, and her tail lifted as high as it possibly could go, as soon as she was in Tron's cage.  She even rolled over onto her side at one point.  (In talking with others online, this is a common behavior in does that really want bred).

(Tip for beginners: always bring the doe to the buck's cage, or both of them to a neutral territory.  Bucks can be too interested in sniffing around a new area to do their job.  Does can get very territorial, and have been known to castrate bucks.  Also, watch them the whole time they are together.  Breeding can happen in a split second, and one or the other could decide to hurt the other one at any time.)

Circling each other as part of the mating dance.

Of course, there was also some of the usual horny-doe behavior, including chasing each other around in circles, and she riding him (backwards, of course, to keep it more interesting).  He also did sideways and backwards mounts a couple of times, but we still got a good couple of fall-offs from him.

Doe riding buck, backwards.

Buck holds a tuft of doe's fur after breeding.

Mena and Tron weren't the only ones to breed successfully today (although certainly the most entertaining).  BamBam pulled a few tufts of fur out of Lisi's shoulders.  At least he's not as bad as some bucks I've had, which have pulled fur until the doe starts bleeding!

Doe keeps hocks firmly planted to thwart buck.

But, not every story is a success story.  Poor Gem was trying so hard, but Razzle was just not interested.  I checked her vent afterward, and it was a nice red, which just goes to show that checking the vent really doesn't indicate much of anything.  (I've never relied on it--in fact, I only just heard about it maybe a couple years ago.)