Yesterday while getting ready to post Isla's Warlander registration papers I noticed the registry has added something new.
There is a sentence below the Warlander logo saying "Notes: If used for breeding, this horse should be tested for dwarfism & hydrocephalus"
When seeing that sentence it infers that one or both of the parents may be carriers but this is NOT the case. I understand why the registry would encourage people to do this but to be honest the cost involved ($65.00) each horse tested doesn't make sense to a breeder unless that cost is passed on to the buyer. Now I know why Dixie, the lady that bought Ayanna's 2018 colt sent me the message, "the dna results came back and he is all clear." I thought it was weird that she was making sure this really was Ayanna's colt by Evan but because she did send it in and had it done I know Raven and Lily are clear as those are Ayanna's parents which means Rosalie, Ayanna's full sister is clear and all of their offspring are clear.as long as these mares are bred to Evan. Evan is clear as that is the colt's sire. SO do I really need to spend $65.00 EXTRA on each horse when I KNOW they can't possibly be a carrier? We have around 20 foals a year and that is an EXTRA $1300.00 over and above the registering and DNA testing we already do, and that EXTRA money would buy a lot of hay, grain or bedding.
I quit FHANA as the cost of registering a foal was just too high. I really like the Friesian Heritage Horse Registry however (isn't there always a however) I'm not sure I like THAT sentence on the registration papers.
So, because that colt is negative- it does not guarantee the parents are clear as well. It just means that they have one clear gene to pass on—- they could be clear or could be heterozygous (carrying one copy) carriers.
ReplyDeleteA horse carries two copies and so will pass on each gene 50% of the time.
So...
Let’s pretend that the mare is a carrier of one of the genes and the stallion is clear.
Stallion. 0 0
Mare X //. X0. XO
0 //. OO. OO
This would mean 50% of offspring would be carriers and 50% of offspring would be clear. The stallion always passes the clear on. And the mare would pass carrier status 1/2 time. The goals would be unaffected, but could pass on carrier status 50% of the time.
Next example. Clear stallion- clear mare
Stallion. 0 0
Mare O //. O0. OO
O//. OO. OO
This would mean 100% of offspring will be clear. The stallion always passes the clear on. And the mare would pass the clear on. All goals unaffected and clear.
Last example- carrier stallion - carrier mare.
Stallion. X. O
Mare X //. XX. XO
O//. XO. OO
This would mean 25% of offspring with be AFFECTED!!! 50% of offspring would be carriers and 25% of offspring would be clear. The stallion always passes the carrier on 50%. And the mare would pass carrier status 50% time.
Because the Friesian breed has such a small gene pool, it is recommended to not eliminate all carriers all at once, but to make the goal of breeding it out in a few generations. And to NEVER have an affected foal again.
Knowing the status of a breeding stallion is vital, and if he is a carriers of a disease then all mares bred to him MUST be negative.
If you know parents status are clear... then the goals are clear by parentage. And that would be on the paperwork.
ReplyDeleteFHANA does not have dna results written on the paperwork, though the stallions results are kept public.
I am,however, being required to test my mares status’ starting in 2019 in order to register my foal next year.