They're crowded, they don't have much room to disperse, and those first and last puppies are usually the largest, with overcrowding in the center that causes the smallest puppies to come out mid-delivery. There are a couple of reasons that littermates may look different. One relates to how dogs inherit genes. The other has to do with the reproductive system and the mating habits of dogs.
A simple way to predict the size of your puppy is to double its size once it is 16 weeks old. The 16 week by two formula should be a reasonable estimate of your pup's full size. Although there is no science behind this general rule, it seems to work most, if not all of the time. Puppies grow about 5 to 10% per day from the age of 1 week to 8 weeks.
Thereafter, the growth rate will decline, but will grow for another 6 to 18 months. Absolute amount varies due to different birth weights from small to giant breeds. Differential size at birth is largely a function of placental placement and other uterine factors, while final size is almost entirely a genetic function: a “dwarf” often traps or outperforms the rest of the litter, and the largest puppy may end up being the smallest adult. All puppies will grow larger between birth and 8 weeks of age.
Since small breeds don't grow for as long as their larger counterparts, growth will slow down more rapidly. Therefore, your weight at two months can double in four months. I've been seeing several litters of puppies recently. It's quite surprising how puppies in one litter look so much like each other that one has the impression that they were all clones of each other, while other litters contain puppies that show a variety of shapes, sizes, colors and personalities.
This made me wonder why this is so. The answer turns out to be that it's all about genetics. The result of this process, known as genetic recombination or genetic reorganization, is that the actual genetic makeup of puppies in the litter varies. Although all puppies are officially considered adult dogs once they turn one year old, puppies continue to grow in height and size while their bones are still developing, which takes between 6 and 24 months.
Usually, the size of a dog litter is mainly based on the size of the dog's body simply because biologically, larger bodies are capable of carrying a larger litter than smaller bodies. Female dogs produce several eggs at once, which is why they usually give birth to litters instead of individual puppies. This first litter is the smallest isn't it true, my first dorado had 10 beautiful healthy puppies 20 years ago and 3 her last calf. Also having mating at the end of the fruiting period of the female dog and not from the beginning is a factor that leads to having more puppies.
Although the results are relative, it clearly shows that the more inbred the puppies are, the lower the puppy count. You can't put two parents who produced large litters before and expect the puppies to also produce large litters two years later. Let's say that for your breed the average litter size is between 8 and 12 puppies, some breeders want to help their mother reach 11, 12 or even 13 puppies. As is to be expected, the genetic variation between puppies with different parents is greater than that of those who share the same parent.
For example, spaniels and retrievers usually have between four and eight puppies at a time, while smaller dogs, such as terriers, can only have two, maybe three in a litter. Just as human siblings have different physical characteristics, puppies from the same litter often have variations in coat color, coat length, head size, ear shape, and other physical characteristics. If both parents pass on the recessive gene, the offspring will be liver-colored, but the most likely outcome is a litter of black puppies. .
