Pedigree Query

I've been reading Boojum's Bonanza and he recently did something on Shuvee and her dam Bourtai.

What's interesting about both these mares is that it appears that they produced good female racehorses almost exclusively and that this pattern continued through several generations of female descendants. This appears to be sex-linked performance, not prowess in the breeding shed.

How common is this? And any speculations on why?

vineyridge wrote:I've been reading Boojum's Bonanza and he recently did something on Shuvee and her dam Bourtai.

What's interesting about both these mares is that it appears that they produced good female racehorses almost exclusively and that this pattern continued through several generations of female descendants. This appears to be sex-linked performance, not prowess in the breeding shed.

How common is this? And any speculations on why?

Bourtai was Shuvee's 2d dam.

Bourtai - 4SW fillies, 1 SW colt, 1 SP colt
| Levee - 3 SW fillies, 1 SW colt
| | Shuvee - 2 SW colts, 1 SP colt, 1 SW filly

Other than the fact that these mares were good producers there's no evidence for a pattern here, especially considering the fact that via other daus. Bourtai has under her male performers such as Aptitude, Big Spruce, Cabildo, Coastal, Dike, Slew O' Gold, Thirty Six Red, et al.