Is it true that a mare's first foal is usually not a nice as later offspring?
Is this a myth? Also, that the first foal is usually smaller? I know my horse's full sibling (she's first he's second) is a full hand shorter than he is, and he is only three! So is this an example of the saying or just chance? From a genetics standpoint it makes no sense. Also they have studies showing TB's transfered into ponies, although born smaller, grow to their genetic potential, so I don't think a tight uterus can be blaimed.
The reason I ask is because someone wants to have a foal from my mare. They don't care about size (and I do). Would it be better if I have the second foal?
Got two full brothers here....3 and 4 year olds. Sire has some speed breeding behind him (is grandson of winner of All American Futurity...the QH version of the Kentucky Derby) as well as a lot of cowhorse and stands just a hair under 15 hands. Dam is big, deep bodied mare also right at 15 hands with a ton of cowhorse in her background. Both tobiano Paints...not that that matters.
First foal a solid bay with only a star...is now a 4 year old and about 13.3 or maybe pushing 14 hands (is going to be gelded in March and become my grandsons horse in a couple years).
Second foal a brown tobiano...now three year old and about 14.3 and butt high. Will likely remain ungelded and possibly replace his sire in the program here (sire is 19),
I read an article once that said it was historically common thinking that the mare's earlier offspring would be higher quality because the mare was in better physical condition, and the odds of the egg being better quality earlier in her life were greater.
The article did not present it as scientific fact, and I don't believe this has ever been statistically verified. But I can see where the belief stems from. If a mare produced an exceptional individual, anything she produced after would always be compared against that standard. The mares who produce all exceptional offspring are very few and far between.
People are crazy and times are strange.
I used to care but, things have changed.
I agree that they are occasionally smaller at birth, but mature just the same. I've also had a couple HUGE foals out of maiden mares. There are so many variables in breeding, and how many foals are mare has had, is not one I take into consideration when breeding a mare/choosing a stallion.