Comments on: Dexter Bulldogs and Waterbabies

By: Gabriella

Gabriella — Fri, 25 Oct 2019 03:15:36 +0000

No. For two reasons.

1. An animal that is homozygous for chondrodysplasia is dead. It’s a bulldog calf.

2. Let’s say chondrodysplasia is not lethal in its homozygous form. So your heifer is homozygous. She has two copies of the gene. She can only pass on one copy to each offspring. This is how DNA works. If a cow has six feet of DNA in her cells, she passes on three feet to her offspring, and the bull passes on three feet. The calf has sex feet of DNA and a fresh combination of genes.

By: Jonnie

Jonnie — Wed, 14 Feb 2018 16:08:11 +0000

I have a related question. Could a dwarf heifer be homozygous for chondroplasia and give birth to a stillborn bulldog calf even if she was bred to a non carrier bull?

By: Gabriella

Gabriella — Fri, 29 Aug 2014 10:09:37 +0000

Most mini cow strains are influenced by the process of selecting extremely small animals that randomly appeared either within their own breed or within other breeds. This means something happened to that small calf that did not happen to his or her sire or dam. For a new mini cow project, I suppose the best case scenario is that the calf has a fresh mutation for something that made it small.* The problem with a fresh mutation is the animal is heterozygous (has one genetic copy) for the trait, because the odds of two mutations at the same location in the same animal is infinitesimal. So, if the animal shows effect of the mutation, it is clinically dominant or co-dominant in nature, meaning two animals bred together that have this new “small size gene” or even two similar new “small size genes” will have a 25% chance of producing a homozygous animal with a double dose of this trait. There are many genetic lethals known in full size cattle, and it is possible that you are experiencing one from the Jersey breed. But, since productivity and growth are selected for in commercial herds, the mutations that cause growth retardation are culled, so any sort of co-dominant dwarfism is usually selected against. In these new mini breeds, the random dwarfs are gathered up from anywhere they can be found, and bred together. So, it is not uncommon for these animals, when bred together, to produce some strange lethals. There are even cases where the sire and dam are quite unrelated and the concept of “compound heterozygote” comes into play, since they may not have the exact same mutation, but the mutations are similar enough that a calf who receives one bad gene/allele from each parent is still born dead. This concept could also result in an extremely small animal that carries two types of dwarfism, which would then be bred extensively because its size is favored.

* Another scenario in new mini cow breeds can be animals that pop out and do not have the smallness of their parents, either because:
1. A randomly small animal used as a mini cow or bull in a breeding program was small for reasons that were not genetic, such as placental insufficiency or nutritional factors during growth of the calf.
2. Two animals that had mutations for some sort of smallness factor were bred together and produced a non-affected animal (also a 25% chance), and this animal reached full size.

These concepts may be a contributing factor when calving difficulties that are reported due to an unusually large calf for the miniature strain.

By: Deb

Deb — Mon, 28 Jul 2014 03:47:54 +0000

I have two tested NON CARRIER miniature Jerseys which just produced a presumed BD calf. Both sire (semen) and dam (live) were tested for BD1 at UCD. Is there a mutation of this gene or possibly a BD2 gene out there? I am sending a tail hair sample to UCD tomorrow and kept the dead calf in the freezer just in case they want to do a necropsy. This is the first time that we have had this and especially from tested animals. This concerns me to know that there is another gene out there that can cause this.

In this case, the calf is a heifer, legs about 6″ long, very hard curled, front and rear, bulldog face and swollen head, normal ears and tail, tongue protruding, and 5 days away from her expected due date. I have pictures if you could tell me more…thank you!
~Deb…

By: Gabriella

Gabriella — Mon, 17 Mar 2014 16:44:15 +0000

Her non-carrier offspring do not carry hidden bulldog alleles. The allele is lost from their genome forever. They cannot produce a bulldog calf. The only way they can produce a carrier calf is to be bred to a bulldog carrier, (meaning the bulldog allele came from the other parent).

By: Gabriella

Gabriella — Thu, 06 Feb 2014 05:14:40 +0000

A dead bulldog calf has two bulldog genes, A dwarf/chondro carrier has one bulldog gene and one normal gene. If your cow is a dwarf, 1/2 the time her calf will get her normal gene, and 1/2 the time her calf will get the bulldog gene. So, even if bred to a non-dwarf/non-carrier, 1/2 of the calves from your dwarf cow will be dwarfs themselves. They will look somewhat different than the normal calves and will have one bulldog gene.

By: Victoria McCutcheon

Victoria McCutcheon — Wed, 01 Jan 2014 05:18:00 +0000

To add more to my question above…………
Would this cow WITH BDG have calves that ALSO have the gene even though bred to a NON CARRIER BULL.
Would THOSE CALVES then ALWAYS have the BDG in them and be nown as a “CARRIER” of such?
With THEM also having the possibility of HAVING a BDG calf “EVEN WHEN BRED TO A NON CARRIER” bull in the future?

By: Victoria McCutcheon

Victoria McCutcheon — Wed, 01 Jan 2014 05:12:01 +0000

I understand that breeding a cow that IS positive for the Bulldog Gene will NOT produce a BULLDOG CALF.
However, MY QUESTION IS THIS……………..
Even though this calf IS NOT A BULLDOG calf, would THIS calf ALWAYS CARRY the BD Gene? “Would it be a carrier” so to speak? IF So,,, “IF” that calf were bred to a CARRIER BULL in “IT’S” adult life time, would it “THEN HAVE A BULLDOG CALF” as the results of “being a CARRIER” AND being bred to the carrier bull?