Cats reproduction, breeding and genetics reproduction
Cats reproduction the estrus, commonly called heat, marks the moment from which the fertile period of females begins. It can appear between four and twelve months, depending on the breed.
Activity and sexual cycle
The fertile period, the one in which the female can have a succession of estrus, covers a large part of the year, which is why cats are considered annual polyestrales and whose periods of heat, which last four hundred and ten days, approximate with very often.
In these moments the behavior of the cat changes. She often meows for the male, lays on her stomach, is more affectionate, crawls on her belly, lifting her tail and, unlike the bitch, does not present bleeding. If it is fertilized, these signs diminish at first and then disappear quickly. If not, she returns to heat shortly after, as also happens after delivery. The mount is preceded by a preliminary courtship. The male, who begins puberty between seven and twelve months of age, revolves around the female, who, in turn, walks and exhibits in front of him.
Courtship is very important to achieve the cooperation of the cat during mounting, since the female will have to place the back of her body in a horizontal position and offer the vulva to the male, who will cover it while clinging to his neck with his mouth . Intercourse lasts only about ten seconds, and the female meows loudly as she abruptly separates from the male. This lively reaction is due to the fact that the horny spines of the feline penis, called spicules, cause a painful tear.
The mount can be repeated three times every three or four hours. The female releases from two to eleven eggs, so the probability of pregnancy is very high, since cats are a species with induced ovulation (that is, this only takes place at the time when mating takes place) .
Fertilization, progestation and implantation
We understand by fertilization the moment in which the male and female gametes unite to originate the first cell of the embryo. Two special situations can occur in cats: superfertilization, since the female can be fertilized by different males, and the cubs, therefore, will be children of different parents, and superfetation, since approximately 10% of female cats can go into heat between the twenty-first and twenty-fourth days of gestation, accept the mating and, at the time of delivery, have live puppies and lifeless premature fetuses.
Progestation is the phase in which the eggs migrate towards the uterus before being fertilized.
Implantation is the beginning of the formation of the placenta. It can be done about fourteen days after fertilization.
WHEN IS STERILIZATION OF A CAT NECESSARY?
First, a popular belief should be rebutted: there is no scientific reason why a cat should give birth once before being spayed.
If we decide that our cat has puppies, we must do it for pleasure or to raise them. Therefore, if our intention is the opposite, we have to contact a veterinarian to surgically sterilize her.
Ovariectomy – removal of the ovaries – is a routine operation that is performed under general anesthesia, and involves a few stitches and a couple of days of discomfort for the cat. In compensation, the risk of breast tumors and uterine infections is significantly reduced.
The character of the cat will not change; it is not true that she becomes apathetic, and as far as possible weight gain is concerned, we can avoid the problem by providing her with balanced and slightly hypocaloric foods. Instead, we should avoid suppression of heat and contraception through the administration of drugs and medications. These pharmacological methods can put your health at risk, due to the greater probability of uterine infections, diabetes, and even breast tumors.
Cats reproduction: Gestation
It is the period in which the cat carries her cubs in the womb and lasts between 63 and 68 days. Their diet must be rich and balanced to meet the new energy needs: supplementary foods are often advisable for the proper development of puppies. The pregnancy diagnosis is not made with hormonal tests, since they are not significant for cats, but from the data obtained from the clinical examination, as well as from the radiological and ultrasound evaluation, which also show the number of embryos conceived.
- The veterinary examination is based on palpation of the abdomen and on the perception of the fetuses from the third week of gestation.
- The radiological examination allows to observe the skeleton of the fetuses, visible from the thirty-sixth day, but more evident from the fortieth day.
- On the other hand, the ultrasound examination can be performed from the twentieth day, and fetal movements are appreciated from the fourth week.
Cats reproduction: Birth
Labor is the phase in which the fetuses and the placenta are expelled through the genital canal at the end of gestation.
The signs that indicate the imminence of parturition are the decrease in rectal temperature (the cat goes from 38.5 ºC to almost 37 ºC) and a certain restlessness, which leads the female to withdraw to the place where she has decided to give birth.
It is useless to prepare this site where we want, since she will be the one to choose and we will not make her change her mind. Another symptom is the appearance of milk a few days before delivery. This usually lasts about six hours and the fetuses are expelled with an interval of ten to sixty minutes.
The number of cubs is usually between three and five, and the weight of each of them at the time of birth, between 100 and 130 g. The mother cuts the umbilical cords with her teeth and vigorously licks the little ones to activate circulation, respiration and all organic functions; later, almost an hour later, the puppies begin to drink mother’s milk.
Cats reproduction: Lactation
For forty-eight hours, the mother does not leave the cubs alone, which suck 2 to 3 ml of milk every twenty minutes, so that, in seven days, they practically double their weight. During the first days of life, the little ones move little, and begin to open their eyes between the tenth and fourteenth day. The mother takes care of their cleanliness: she licks them often, and encourages them to eliminate urine and feces, which she ingests to keep the environment clean.
During this period, the maternal diet should be especially rich, in addition to being supplemented with minerals and vitamins; For this reason, we advise feeding it with the same diet that puppies receive during growth. At three weeks, the little ones begin their explorations. It is advisable that they remain with the mother at least until the second month of life and that they consume as much breast milk as possible, alternating it, from the forty-fifth day, with specific prepared foods for kittens, so that they are gradually weaned. From that moment on, breast milk production will drop rapidly.
WHEN BREAST MILK IS LACK
If we had to urgently nourish the kittens and we did not have the adequate milk, the following recipe will make cow’s milk the most similar to feline, which will allow us to provide the first feedings while we get the baby formula.
- 60 ml of cow’s milk
- 20 g of liquid cream
- 10 g of finely chopped beef
- 2 g of corn oil
- 2 g of raw yolk
- 1 g of vitamin mineral supplement
Add to the milk all the others ingredients. Mix carefully and pour into the bottle. Heat the milk in a bain-marie to 38ºC and feed it to the puppies.
If mother cat cannot breastfeed
It can happen that the mother does not have enough milk and that it is difficult for the little ones to gain weight or that she has a breast condition that prevents her from feeding them. In this case we will have to intervene. We will use specific bottles that we will have to wash and sterilize after each feeding, since newborns are very sensitive to infections and easily have diarrhea problems.
The person who feeds them should wash their hands well and prepare the milk at the time of consumption. The number of feedings is as important as the quality of the milk supplied: it should be passed from the seven bottles every twenty-four hours of the first week to two in the sixth week, at which time they must be interspersed with solid foods.
During feeding, it is advisable to massage the perineal area, that is, the one between the anus and the genitals, with a soft and damp cloth, to stimulate evacuation, just as the cat does by licking them with her tongue. The milk should be as similar as possible to the mother’s. The cow is not suitable because, compared to the cat, it is poor in fat, protein and mineral salts. Feline formula is recommended, powder or liquid, diluted according to the product instructions. It can be bought in pharmacies that have veterinary products or in pet stores.
Breeders continually improve the breeds selected by man and, for this, they always try to fix and enhance the best characteristics, in addition to creating cats that combine beauty and type with a state of health and physical form essential for their well-being. Therefore, if we decide to acquire a puppy, it is advisable that we go to a breeder or a trusted store; For this, we have the possibility to consult the national feline associations in order to provide us with information. It is interesting to contact breeders who are passionate about obtaining puppies with the morphological and behavioral characteristics typical of the breed. To avoid the risk of buying a kitten that does not meet these requirements and taking into account that they are not usually known to the general public, you should only contact qualified breeders. Before giving this important step, it is advisable that you attend some feline shows to get an idea of what the standard of the breed of the cat you intend to buy should be.
Next, we will have to contact different breeders and visit their facilities, to personally verify where and how they keep the cats. A clean and welcoming environment, vaccination records reviewed and updated by veterinarians, tests to verify the absence of contagious viruses – such as viral leukemia, infectious peritonitis and acquired feline immunodeficiency – and the appropriate application of therapies and antiparasitic treatments will offer us a good guarantee regarding the kittens’ state of health.
The kennel must also have a functional room with tiles on the floor and walls, as well as washable plastic cubicles with disposable padded underpads, where the cats can comfortably give birth and suckle the puppies. As far as the characteristics of the breed are concerned, the pedigree, which is the document that attests the origin of the cat, its genealogical tree, and the titles and awards that the two or four preceding generations have obtained, will be of great help. If breeders have a breeder kennel, the name of the cat and its ancestors in the pedigree will be preceded or followed by the name of the kennels from which they come.
If we are owners of a female and, for the pleasure of having a litter, we want to cross it with a breeding male, usually called a stallion, the advice of the breeder will be very useful to choose the most suitable specimen in order to improve the characteristics of the breed . At the right time, we will take the cat to the cattery, with the medical certificates of good health, the vaccination card and the pedigree. We will leave her there for a few days, so that she can interact with the chosen male and mate several times, to be sure of obtaining good results.
NOTIONS OF GENETICS
Genetic factors play a fundamental role in the transmission of the characteristics of any individual and, obviously, this also works for cats.
Every individual is distinguished from another by characters perceptible to the naked eye that, together, form the phenotype. The genetic heritage (not visible) that each cat has is called a genotype. The information is contained in special structures present in each cell: the chromosomes. These are made up of a molecule, DNA (or deoxyribonucleic acid), formed by two filaments that join in a spiral (the double helix) and in which the genes are found, which are responsible for transmitting the information necessary to create a individual. Every gene occupies a precise position on the chromosome, called a locus.
Each feline cell has nineteen pairs of chromosomes, thirty-eight in all. This is so in all the cells of the body, with the sole exception of those that are produced in the ovaries and testes, called gametes, which contain half the chromosomes of the rest (nineteen in each cell). When the male gamete joins the female one, the entire genetic heritage of the individual is recomposed and the first embryonic cell is formed, the zygote, in which thirty-eight chromosomes are found, nineteen from the father and nineteen from the mother: thirty-eight six correspond to all the individual’s traits, while the remaining two are sex chromosomes. Its task is to determine the sex of the offspring: in females the sex chromosome is XX, while in males it is XY. The statistical possibility of having a male or a female is genetically 50%.
Genes that determine hair characteristics
We have seen that hair length is conditioned by two alleles: L, dominant for short hair, and l, recessive for long hair. But we must also consider the other characteristics of the mantle, such as color, texture and structure. Let’s look at the most important genes:
- Genes that control hair distribution: A, agouti, which is wild coloring, with hair in light and dark stripes; a, no agouti, no light stripes and a continuous color.
- Genes that control color: among these, for example, are B for black and b for brown or chocolate, ow, which is normal (it can appear together with all color genes), and W, which corresponds to epistatic dominant white (where by dominant it is understood that it is enough that it is present in one of the parents to appear in the children, and by epistatic, that white masks and covers all the color genes that, in its presence, cannot be manifested ). W can also be responsible for deafness.
- Genes that control color intensity: C, intense and uniform; c, not uniform (such as burmese cb or Siamese cs, whose genotype is cscs).
- Genes that determine color density: D, dense; d, diluted.
- Genes that control the distribution of color in the hair: I, color inhibition at the base of the hair; i, colored hair base.
- Genes that control the distribution of white spots: S, more or less extensive white spots; s, normal color distribution on the mantle.
- Genes that determine the brindle: T and ta, tb and other diverse genes that can modify the length, texture and structure of the hair.
Main hair colors
Cats have several hairs on each melanin hair follicle: two to five coarse primary hairs, surrounded by numerous finer hairs called secondary. Each hair is made up of three structures: the innermost, called medullary; the intermediate, known as cortical, and the most superficial, called the cuticle. The set of hairs form the mantle, which is essential for regulating the cat’s temperature, but also for sensory perception, thanks to the modified hairs, the vibrissae, which are distributed on the head and behind the carpus, and that act as tactile organs, very important for the orientation of the animal.
Hair color is given by the interaction of light with the pigment granules, melanin, distributed in the medullary and cortical area of the hair. There are several types: from eumelanins, which give a black-brown color, to pheomelanins, which produce a reddish-yellow color, passing through pigments of intermediate hue. For this reason, depending on the color of the melanin present in the hair and the distribution of its granules, governed by the alleles D (dominant dense) and d (diluted), we will have the colors black, blue, chocolate, lilac, cinnamon, fawn, red and cream . The transmission of the hawksbill color, which depends on the sex chromosomes, represents an exception: in fact, it corresponds to a heterozygous character of orange, present only in X and not in Y, so it occurs only in females, which they have the XX combination, and not in the male, in which a single X is not capable of manifesting it.
In colors with a dense pigmentation, the granules are deposited in a particular and uniform way along the cortical and medullary structure of the hair. The entire surface of the granule absorbs light and gives the hair a dark tone. The density gene (d) acts such that the granules assume a very diverse spatial configuration. The free surface of the granules will be less depending on the degree that it reflects the light, which will give the hair a lighter tone.
Main drawings of the mantle
The drawing that has given rise to all the coats is the tabby. This, in turn, can be:
- blotched, marbled with a pattern of butterfly wings on the shoulders;
- mackerel, with long vertical dark stripes from back to abdomen;
- spotted, mottled with small round or oval dark spots;
- ticket, uniformly marbled without drawing on the body.
The tipped represents another type of drawing characterized by light hair with a darker end. Among the tipped there are different varieties:
- smoke, with the upper two thirds of the hair dark and the lower third light silver at the base, observable only if the hair is parted with the hands;
- silver tabby, where silver stripes alternate with colored stripes; • shaded, in which the upper third of the hair is dark and the lower two thirds are light;
- shell, the top eighth is dark and the rest light. If the light part is silver, they are called silver shaded and silver shell; if it were golden, they would correspond to the golden shaded and the golden shell;
- cameo, equivalent to chinchilla, silver and smoke, but the colored area is red and cream.
The pointed, on the other hand, is a drawing that is characterized by a coat with dark ends (ears, muzzle, tail and legs).
In genetics it is called the Siamese scheme, without referring specifically to this breed.
The varieties are as follows:
- Himalayan: the contrast between the body and the extremities is very marked;
- burmese: the ends are almost the same color as the body, although somewhat darker;
- Tonkinese: the contrast between the body and the extremities is less evident than in the Siamese, but more pronounced than in the Burmese.
Pointed cats, like Siamese cats, can be of many colors:
- seal point: with dark brown ends on a light beige background;
- blue point: with steel colored ends on a snow white background;
- chocolate point: with the ends of milk chocolate color on an ivory background;
- lilac point: with silvery gray ends on a magnolia background;
- red point: with reddish gold ends on a white background with shades of apricot color;
- Burmese: with cream colored ends on a cream-tinged white background;
- cinnamon point: with cinnamon ends on an ivory background;
- fawn point: with fawn-colored ends on a magnolia background;
- tortie point: carey;
- cream blue: with cream blue ends on a snow white background;
- tabby point: with stripes on the legs and tail with the mask striped in all colors. There are also cloaks whose color is mixed with white:
- van: with only two spots of color under the ears and the entire tail; • harlequin: with many colored spots surrounded by white, in five sixths of the body;
- bicolor: with the colored part quite uniform and more extensive than the white.