CONGENITAL DEFECTS – A WOLF’S WOLF, WHEN AND WHY (part 1)
I hope that you will never have a litter of puppies with wolf’s mouth. But if this happens, there are a number of reasons that can explain the appearance of this defect, at least in some cases.
Let’s start from the beginning. A sperm with the half set of chromosomes necessary for a new puppy penetrates the egg and causes the cell to divide into more and more multiplying cells that have the correct number of chromosomes and features from both parents. After some time, these cells begin to unite in different groups, some of which will later become the intestines, others – the heart tissues, and some will finish their formation in the form of reproductive organs. Some chromosomes in any of these groups remain inactive, while others do the work of forming DNA and RNA, which determine whether certain cells will be skin or hair cells, whether they determine pigment, and many other features. Chromosomes, which, for example, determine how a dog will bark, do not function in the cells that make up the skin, although all chromosomes with their genes are found in all somatic cells of the body. After the first few divisions of a fertilized egg, the resulting mass is called an embryo. Like an acorn that “contains” leaves, bark, roots, size, disease resistance, etc., the embryo can be considered as an adult and its future descendants.
In some lower animals, tissue segregation in the embryonic urogenital tract never ends with what we observe in mammals, i.e. the reproductive and urinary organs are nearby, but differ from each other. You can assume that this is the result of interrupted or stopped embryonic development compared to higher animals. However, the closer the time of conception and early cell division, the smaller the differences between embryos of worms, frogs, chihuahuas, water buffaloes and pterodactyls. The differences become apparent when groups of cells continue to “specialize” and this process continues before, and even after, birth.
Sometimes, during the embryonic development of structures on the way to their completion, something goes wrong. If the development is stopped or impaired, the part of the body formed at this time will be defective in the future. An example that we will consider is the development of the central dorsal line of the body. Early embryos are a bit like flatworms or pancakes and, as they develop, their edges bend and should connect at the top. Have you ever made ravioli or apple pies? You must fold the edges of the dough and then pinch them so that the filling does not leak when baking. The spinal cord is the filling of ravioli, and the fully formed vertebral column is the finished product. If you get a call before you pinch the edges of the dough, and your beloved granddaughter decides to help you and puts the cake in the oven, then after an interesting conversation, you will find that the whole filling is anywhere, but not in the cake! A similar thing can happen to the body if the development of the embryo has been impaired. Premature babies are at risk because some of them have not completed the “pinching” process before being placed in the “oven”, known as the world outside the uterus. The overgrown frontal bones of the skull, spina bifida and hemivertebra are examples of defects that can occur with the central dorsal line.
Defects in the midline closure can manifest themselves in different ways; In German Shepherds, I observed incomplete fusion of the midline of the scalp, incompletely formed tails, defects of the skull, spina bifida, and cleft palate. Sometimes other types of midline deviations appear, for example, umbilical hernias, although they are for other reasons. The cleft lip is the result of midline deviations likely to have occurred at a time other than the time when a cleft palate can form.
The cleft palate is a condition in which the hard surface of the sky and softer tissues behind it, for genetic and / or environmental reasons, are not able to completely close. The first sign when the puppy has a similar disorder (if you do not examine the puppies immediately after birth) is the milk bubbling around the nostrils when the puppy tries to suck. In addition to purely genetic reasons, cleft palate may be due to environmental influences. Often this defect is observed in the offspring of diabetics. It was experimentally established that the appearance of a defect is affected by an imbalance of vitamin A (both excess and deficiency) and steroids obtained or produced by the bitch during the first three weeks of pregnancy. Such an increase in corticosteroid production can often be due to unbalanced temperament and / or severe consternation. In dogs, vitamin B12 deficiency can also be identified as the cause of the appearance of a cleft palate. Antihistamines obtained at the beginning of pregnancy are also suspected of causing this defect, as are other chemicals and viral infections.