Question about kit size?

[rtower]

Just curious and hoping to learn a bit more...

I have two pedigreed Florida White does who each kindled recently (July 9 and July 10). Both does are from the same breeder but different lines. Both does are about the same age (right at one year old) and are the same size. (Probably right at 5 lbs, but I haven't actually put them on the scale to confirm.)

Both does were bred on the same day, June 8, but to different bucks.

The first doe delivered six live, fat, healthy kits.
[album]3366[/album]

The second doe delivered one day later and had seven live, healthy but much smaller kits.
[album]3367[/album]

This is not the first litter for either doe. The breeder advised both does are proven, good mothers and that has proven to be true. Both kindled without any complication with all kits delivered in the nest box. They've built good nests and fed and cared for their kits with no difficulties of any kind.

At kindling, it appeared the kits in the second litter were, at best, perhaps 2/3 the size of the kits in the first litter. (Possibly even less... They looked really small compared to the size of the kits in the first litter immediately after kindling.) The larger kits seem to be growing and developing much faster than the smaller kits.

I feed the does alfalfa-based pellets (free-choice) and high-quality timothy hay. I also give them about 1 tablespoon of old-fashioned oats at each feeding.

I started both does on BOSS the day after kindling as I had read in other posts that would help milk production. Started them with less than 1/2 teaspoon each at first, now up to perhaps 1 1/2 teaspoon each per feeding.

I want to develop the best herd I can with highest priorities on overall heath and vigor, heat-tolerance, good mothering instincts and good growth rate.

Now the questions...

Could the difference in kit size be attributable to the buck, or the doe? (Or something else?)

If the doe that produced the smaller-sized kits shows the same results in the next litter (with the senior buck I now have) should I replace her? She seems to be a very good mother.

Just based on these two litters (a very small sample, I realize) I would be tempted to perhaps keep a couple of does from the litter with the larger-sized kits for future breeding. Or am I making a judgement call too early in the process with too little information?

Thanks for any help you can provide. As I said, just trying to learn a bit about how to develop a quality herd.

Randy

 

[Zass]

I actually don't pay much attention to birth weights, figuring rabbits can regulate that for themselves. Larger kits isn't necessarily better, especially in a smaller breed.

The general trend is that kits will be born a little smaller in larger litters, but it's not 1/3 smaller for the difference of just one kit.
Sometimes they catch up if a doe has a nice milk supply.

And yeah, The buck might have made the difference.

I'd weigh the kits at 4 weeks old, and expect the kits in the smaller sized litter to still be a bit larger since she has one less mouth to feed.

Then I'd breed them both to the same buck, and compare.

 

[Dood]

Too early to judge

The smaller kits might be more muscular and hence have a better meat to bone ratio

They might have a better growth once weaned

Consider Flemish Giant kits - they are big but gangly and slow to turn food into muscle

I'd wait until after 4 weeks to start deciding who's "best" bigger is not always better - especially in a small meat breed - you want the most muscle and least bone on your fryers

 

[rtower]

I'd weigh the kits at 4 weeks old, and expect the kits in the smaller sized litter to still be a bit larger since she has one less mouth to feed.

Then I'd breed them both to the same buck, and compare.

I'd wait until after 4 weeks to start deciding who's "best" bigger is not always better - especially in a small meat breed - you want the most muscle and least bone on your fryers

Thank you both! That's the kind of thing I need to learn.

 

[Rainey]

Thanks, Zass and Dood, (and rtower for asking the question) It's something I've wondered but hadn't asked--whether the size of kits at birth matters. Noticed that most mention weighing at 4 or 5 weeks to get an idea of how they're doing. <br /><br /> -- Sat Jul 18, 2015 5:54 pm -- <br /><br /> Thanks, Zass and Dood, (and rtower for asking the question) It's something I've wondered but hadn't asked--whether the size of kits at birth matters. Noticed that most mention weighing at 4 or 5 weeks to get an idea of how they're doing.

 

[TF3]

Great questions and answers!
To tag in-- what about the difference in size in small litters vs. larger litters...
Does it even out at some age?
I'm not sure how to fairly judge the out one of a specific breeding if the litter is small so the kits are bigger, faster?

When my FG cross for had 10 kits, they were smaller over 8 weeks than her current litter of 7 has been so far. But the kits out of my small mutt doe (7 lbs) of which there are only two are measuring about a week ahead of the litter of seven 3/4 FG kits... Will kits from small litters continue to have an advantage over their lives? But there is no way to know if it is innate or luck?

 

[Zass]

TF3 The kits from the small litters will usually only retain their advantage so long as they are taking milk.

The weaning age the doe prefers matters too.
I certainly saw a size different when bucklings were weaned at 6 weeks, and the doelings were left with a late weaning doe until 9 weeks.

The doelings who ended up taking all the milk were always larger and more robust at processing time, but those later weaning brood does always did tend to be heavy milkers..

(Note, my rabbits have always started on solid food at a normal age and eat normal amounts of it even while still taking supplementary milk.
But, I don't think most does will feed that late.)

I think,
there is absolutely no way to judge a doe's ability from one litter.
Which brings the three strikes rule to mind.

I think three litters would be about right to get a feel for her abilities, unless the doe is just plain a failure.
I've never let a doe lose three litters, and I don't regret it.

I don't prefer small litters even though they tend to grow a bit faster.

I'd still much rather have 9 or 10, 5 lb fryers in the 9-12 week range than 4, 5 lb fryers at 8.

I can then give the doe a break for a few weeks if I want and still have lots of meat.

Does who have smaller litters are still useful to have around. They make great fosters.

Hmm..Some like to wean earlier and breed back more often though, and I could see a bigger small litter advantage to that.

 

[Dood]

My rabbitry is pretty standardized as I was quick to cull does who had less than 7 kits. All my girls feed 8 kits and they are weaned at 5 weeks - so I cannot really comment on litters of 2 vs 10 and the effect on older weaning ages :shrug:

 

[TF3]

Thanks!
Very interesting re the weaning.
I can see advantages to both routes-- smaller faster litters or larger longer litters.
I've got a ways to go to get a feel and to get to consistency!

 

[wamplercathy]

I would switch bucks next time and then see what the results show. Then compare both sets of litters at there 4 wk mark. Maybe the buck did matter, or maybe not. Only time will tell.