ADDENDUM THIS IS NOT AN ADVERT I AM SIMPLY SPECULATING ON THE FACT THAT THERE IS A WELL KNOWN SUCCESSFUL JUMPING BLOODLINE WITH FRENCH TROTTER
Since this is the place to learn about different bloodlines with a focus on Olympic/related disciplines, i have a question for everybody concerning genetic differences in equine visual acuity.
My curiosity about vision effect on jumpers, and my interest about whether visual acuity can be selected or culled for in breeding horses led me to these articles. Evidence exists for a link between nose length and visual acuity in dogs and horses. The longer the nose, the sharper the vision say these papers.
" However, the most surprising finding was that the distribution of ganglion cells in the eye varied tremendously from a horizontally aligned visual streak of fairly even density across the retina (as seen in the wolf) to a strong area centralis with virtually no streak (for example, as observed in a pug from the current series). Intriguingly, the ratio of peak ganglion cell density in the area centralis to visual streak was highly negatively correlated with skull length (r = -0.795, n = 22) and positively correlated with cephalic index (r = 0.687, n = 22). The orientation of eyelid aperture was also correlated with cephalic index (r = 0.648, n = 22). Therefore, the genetic manipulation of selective breeding, which has produced an abnormal shortening of the skull and eyelids ..."
"A prominent feature of all wolf retinae was a pronounced "visual streak" of high ganglion cell density, extending from the central area far into both temporal and nasal retina. By contrast, either a pronounced or a moderate visual streak was found in dog retinae. It is hypothesized that a pronounced streak is an archetypal feature of Canis lupus, and that the moderate streak in some dogs is a corollary of breeding during domestication. Irrespective of the differences in streak form and retinal area, the estimated total number of ganglion cells was about 200,000 cells in the wolf and 115,000 in the dog. Ganglion cell density maxima in the central area of the wolf were about 12,000-14,000/mm2, and in the dog they ranged from 6,400/mm2 to 14,400/mm2. This implies individual differences in visual acuity."
"In all species investigated to date, including horses, males
have exhibited superior visuospatial ability compared to
females [45, 46] and this difference in visual ability may
contribute to the relative success of male as compared to
female horses [48, 49] at the highest level of competition.
There is no evidence however as to which of the possible
visual mechanisms responsible for the perception of depth
and distance may be sex-linked. Further investigation is
required in order to determine whether the ability to judge
distance at speed varies between male and female horses, or
indeed between male and female riders."
so does this mean it is the stallion that shows the phenotype for selection of visual acuity in horses?
does the genetics of the long nosed French trotter, related to the Standardbred have a connection with the jumping success of Galoubet line horses (if anyone remembers the blog series by William Micklem where he says Baloubet Du Rouet has a significant amount of French Trotter blood from Galoubet)? i remember reading in several breeding magazine articles that some ppl found Galoubet line horses to pass on a long head/nose, and they thought it was ugly so they selected against it in mares bred to that bloodline.
Also anecdotally i have heard a traditional belief that when a horse has a long upper lip (i do not mean parrot bite just the top lip)it means he can jump. all of the progeny of Galoubet that have what could be called a long head are very successful jumpers- have you seen Baloubet Du Rouet's face? I DO NOT THINK THAT IS UGLY i must say in the strongest possible terms. i am simply illustrating that that type of long face is conventionally selected against in breeding that line currently.
all i want is to find a way to lower the death toll and accident rate in eventing, maybe there is a way to reduce the accidents with genetic selection-