Randy,
Thanks for the reply. I'm a statistician at heart, and it sounds like you are too. I'm always looking for correlations.
Unfortunately, in my quest, I've come across some things that make me go "hmmm"....
Like the female who consistently produced large clutches when bred with Male a, and have half the eggs when bred to male b. Now at first glance, people would knee jerk react and say it was the male's fault, but the female has to ovulate X amount of follicles in order for the male's sperm to do it's thing. So the only thing I can come up with is that male a is a better courtier than male b, and stimulates the female to ovulate more follicles. But then, so many factors effect if and what a female ovulates already, that would be presumptious.
That said, I like your ratios, they do work for me. You wouldn't happen to have data on food intake vs. # of eggs or weight of eggs laid would you? For next season, I plan to chart the weight of food intake by my breeding females prior to breeding and see if that makes a difference. Not all females convert that food into weight, but "knowing" that food is around is a universal breeding indicator, so I figure it's worth looking into.
I'm rambling.
thanks Randy, as usual, you gave a well thought out and intriguing response. It's much appreciated.
K. Royer
>>I remember that girl from last year and she was one of the ones that got me hoping that it might be possible to selectively breed for clutches with lots of small eggs. It's rather disappointing to see her produce a lot less and bigger eggs this year. Perhaps chance or conditioning play a bigger roll in egg size than genetics.
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>>I would go for more smaller babies. I've had very small twins that did fine and really haven't noticed a trend for smaller hatchlings to be more problematic. A few extra weeks feeding and they are caught up on size. I'm thinking that captive bred baby balls don't need to be as big as nature has selected most wild ones to be.
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>>I guess I’ll have to start collecting data for years and years to see if I can find a genetic line that tends to throw more and smaller eggs. I’ve been thinking about ways to quantify this tendency with a Maternal Efficiency Rating (MER). I was thinking of dividing the post lay weight by the average egg weight but this doesn’t take into account the occasional variations in percentage of body weight going to the clutch (usually very close to 1/3 pre lay weight) or infertile eggs. Now I’m thinking of using the number of fertile eggs divided by pre-lay weight in kilograms (so as to make the MER have less leading decimal zeros). Now you have to weigh in kilograms (or just divide grams by 1,000) but at least it will factor down females that have problems and lay slugs or much less than 1/3 of their weight. I’m also thinking that pre-lay rather than post lay is the weight to use because then the MER can be multiplied by next years pre-lay weight in kg to guess how many babies you might get. I’m thinking it’s easier to get a post lay weight because you know when to weigh her but you can always weigh the eggs and add them up to get pre-lay.
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>>So, your female’s numbers would look like this:
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>>2003: MER = 6 eggs / 1.2 kg = 5 eggs/kg
>>2004: MER = 3 eggs / 1.75 kg = 1.7 eggs/kg
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>>Anyone have lots of records of both numbers of good eggs and pre-lay weights so we can calculate MERs and get a feeling for the normal range (I’m thinking this example female is an anomaly)? It would be especially interesting to see the MER for the same female over many years to see if they tend to be consistent or not.
