ALABAMA A&M AND AUBURN UNIVERSITIES Canine Breeding and UNP-0052 Reproduction

Introduction

Allowing the female dog (bitch) to have puppies can be a wonderful experience. However, dog owners must understand the responsibility that comes with breeding since overpopulation is a tremendous problem. There are too many abandoned and unwanted mixed and purebred dogs in pounds and shelters all across the country that have to be euthanized (put to sleep) each year. Unless every newborn puppy is guaranteed a loving home, Photo source wikimedia.org dogs should be spayed or neutered before they reach sexual maturity (6 to • Behavioral Problems. Both the bitch 16 months of age, depending on size and the male dog must be of sound and breed). temperament. • Registration. Both dogs should be Factors to Consider Before registered with a national kennel club, especially if the puppies are going to be Breeding registered before they are sold.

• Availability of Good Homes. Owners should identify loving homes for puppies The Reproductive Tract of before breeding decisions are made. the Bitch • Health Status. Prior to breeding, the bitch and the male dog should • Ovaries. These organs produce be in good physical condition. Dogs ova (eggs) and certain reproductive should have up-to-date vaccinations, hormones. The eggs in the ovaries and be free of diseases and physical develop within fluid-filled sacs called abnormalities, including healthy follicles. reproductive tracts.ARCHIVE A canine brucellosis • Oviducts. These tubes move the test should also be conducted before ovulated and released eggs from the breeding occurs even if it is an ovaries to the uterus in approximately uncommon disease among dogs. two days. Moreover, the oviducts are the • Hereditary Disorders. Clearances sites of egg maturation and fertilization. from any hereditary disorders that are • Uterus. This organ consists of two long common to the dog’s breed (e.g. canine horns and a short body. The uterus is hip dysplasia) should be obtained before the site of implantation and placental breeding. and fetal development.

www.aces.edu • Cervix. This structure is a constricted • Penis. The dog’s penis contains two orifice that serves as a channel from the rather unique characteristics: uterus to the vagina. During pregnancy - Os Penis. The objective of this small the cervix closes the birth canal and bone within the free extremity of the serves as a barrier against the entry of penis (glans penis) is to direct the microorganisms into the uterus. male’s non-erect penis into the bitch’s • Vagina. This hollow organ extends from vulva and vagina during the early the cervix to the vulva. The inner lining stages of mating. of the vagina is made up of cells that - Bulbus Glandis. This swelling of undergo particular changes during the the penis is located toward the rear estrous cycle. end of the os penis. As soon as the • Vulva. This structure is composed of the male dog inserts his penis into the external genitalia, which includes the bitch’s vagina and begins to thrust, clitoris (sexual organ) and two vertical the bulbus glandis enlarges to a lips. firm spherical shape, resulting in the so-called “coital tie.” This tie prevents the male dog and the bitch The Reproductive Tract of from separating immediately after the Male Dog ejaculation and may last from 5 to 60 minutes. • Testicles. These masses of • Prepuce. This foreskin or outer covering seminiferous tubules are responsible for is where the external opening of the the production of sperm cells and the penis usually lies. male sex hormone testosterone. Cells • Scrotum. This sac of skin is where the lining the seminiferous tubules produce testicles are suspended outside of the sperm while cells found between peritoneal cavity. the seminiferous tubules produce testosterone. The Estrous Cycle of the Bitch

Bitches become sexually mature when they exhibit their first heat period, usually between 6 and 16 months of age depending on the size and breed. Most bitches come into heat twice a year. The exceptions to this rule are wolves and basenjis, which typically exhibit only one heat cycle per year. The estrous or heat cycle of an intact • Epididymis. These ductules are the (unspayed) and nonpregnant bitch is sites of sperm maturation. divided into four separate phases: • Vas Deferens. This is the ejaculatory sperm duct that is also called ductus ARCHIVE• Proestrus. The most reliable indicator of deferens. the beginning of this phase is the bloody • Prostate. This accessory sex gland is vaginal discharge. This bloody discharge responsible for the production of the is due to the leaking of red blood cells fluid portion of the semen. from capillary vessels lining the uterus • Urethra. This hollow tube originates into the lumen of the uterus. Other at the neck of the bladder and runs indicators are swelling of the vulva and through the penis to transport urine. frequent licking of the external genitalia. During mating, it transports semen. During proestrus the bitch will attract

2 Alabama Cooperative Extension System male dogs but will not allow mounting or to 3 days, and remain viable for a period mating. Proestrus usually lasts between of 12 to 72 hours. Following ovulation 6 to 11 days, but generally lasts for each ruptured follicle changes to corpus nine days. During this phase the follicle- luteum, a yellow body responsible for stimulating hormone (FSH) and the increasing progesterone levels during luteinizing hormone (LH), both secreted estrus. It is worth mentioning at this by the pituitary gland, stimulate growth point that extreme care must be taken and development of follicles within the during the estrus phase in order to ovaries. Furthermore, the levels of the prevent unwanted pregnancies. The hormone estrogen, which is primarily bitch must be supervised when she is produced by the follicles, rise gradually allowed to go out into the yard or taken in the bloodstream causing behavioral out for walks. estrus in the bitch. • Diestrus. This phase, which lasts about two months, begins with the bitch becoming unattractive to the male dog and lasts until the corpora lutea (plural of corpus luteum) regresses. Hence diestrus is under the influence of the hormone progesterone. If the bitch has been bred, this phase is the beginning of pregnancy. However, whether or not the bitch has been bred and becomes pregnant, the corpora lutea are maintained and remain functional secreting progesterone, which is important for the maintenance of pregnancy. • Anestrus. This phase is considered to be a quiet rest stage in the estrous • Estrus. This phase begins when the cycle. Factors such as breed, age, size, bitch allows mounting or mating. To and health condition will influence the indicate sexual receptivity, the bitch duration of anestrus. The length of crouches, elevates the rear quarters anestrus varies, lasting on average toward the male and moves the tail to about 3 to 5 months. During this phase one side. During this phase the vaginal the bitch shows no signs of heat and discharge becomes a straw or light pink no sexual interest in males. Following color. The average duration of estrus is anestrus, the heat cycle begins again. about nine days, but it can last from 2 to 21 days. During this phase estrogen The Reproductive Cycle of levels decrease and progesterone levels increase. Furthermore, it is the Male Dog during estrus that ovulation (release of eggs from ovarian follicles) takes Male dogs, like bitches, reach sexual place. A surge ARCHIVEin LH from the pituitary maturity at varying ages depending gland triggers ovulation, which occurs on the size and breed of the dog. 1 to 3 days after LH levels peak in Most males are sexually mature and the bitch’s bloodstream. All mature capable of producing sperm at about ovarian follicles rupture and release 10 months of age. The hormones FSH their eggs into the oviducts within 24 to and LH, secreted by the pituitary gland, 48 hours. Generally, larger dog breeds stimulate the production of sperm ovulate more eggs than smaller breeds. (spermatogenesis) and testosterone by Released eggs undergo maturation in 2 the testicles. Testosterone is necessary

Canine Breeding and Reproduction 3 for the development and maintenance has regulations concerning the registration of male sex characteristics, male sexual of dogs produced by AI. Therefore, before behavior, and spermatogenesis, which using this technique, check with the AKC or occurs throughout the year and lasts the local kennel club for information about for a period of 62 days. AI and registration of puppies.

Mating Pregnancy

The best rule to follow when breeding The pregnancy or gestation period dogs is to be certain that they are extends from the time of successful physically mature. This means that mating to parturition. Sperm cells will both the bitch and the male dog should reach the eggs in the oviducts of the be 18 to 24 months of age, by which bitch within 30 seconds of ejaculation time the bitch should be in her second and have a viable life span up to seven or third heat period. Since ovulation days. Fertilization (union of sperm and usually occurs on the second day of egg) takes place in the distal portion estrus, it is highly effective to breed of the oviducts and occurs a few days the bitch as soon as she is sexually after mating. receptive to the male dog and again two days later. The resulting zygotes (fertilized eggs) begin cell division growth, and the The bitch is usually brought to the growing organisms are then called male dog for breeding. Courtship embryos. The developing embryos behavior begins with the male dog move from the oviducts into the uterus sniffing at the bitch’s face and flank, 6 to 10 days after conception, and and licking of the vulva. When ready, implant or attach to the uterine walls the bitch presents her hindquarters to 17 to 21 days after fertilization. As they the male dog and stands still with her implant and their placenta develops, tail towards one side. The male dog the embryos are then called fetuses. then clasps the flanks of the bitch with The fetuses are usually evenly spaced his forelegs, inserts his penis into the throughout the two uterine horns. vagina (intromission) and begins to thrust. The enlargement of the bulbus The pregnancy or gestation period glandis occurs at this time, resulting of the bitch lasts between 56 to in the coital tie. With the penis firmly 66 days, with an average length of in place, ejaculation begins. Then with 63 days. As mentioned previously, their genitalia still “locked,” the male during this period the corpora lutea dog will dismount by placing both front feet are maintained and remain functional to one side and lifting one hind leg over secreting progesterone, which is important the bitch’s back so that they are facing in for the maintenance of pregnancy. To opposite directions. The enlarged bulbus confirm pregnancy, palpation of the bitch’s glandis of the male dog prevents separation abdomen for the presence of evenly spaced from the bitch for ARCHIVEabout 5 to 60 minutes. Do swellings can be conducted between 20 not interfere with a coital tie as injury could and 30 days after the last mating by an result. Separation occurs naturally and both experienced person. However, improper dogs usually wash themselves afterwards. procedure or excessive prodding can cause a miscarriage. After confirming that the When artificial insemination (AI) is properly bitch is pregnant, make sure you become performed, conception rates are equal familiar with the basics of prenatal care, to those attained by natural breeding. parturition (whelping) and emergency However, the American Kennel Club (AKC) procedures.

4 Alabama Cooperative Extension System A pregnant bitch requires additional food to support the growth of pups inside her and to produce the milk that pups will need after birth. Feed her the same amount of the usual adult maintenance diet for the first four weeks of pregnancy. Then gradually increase the amount of food so that by whelping time she is eating about 1.5 times her maintenance diet. Consider switching to a commercial dog food that is specifically formulated for pregnancy and lactation. However, due to possible whelping problems, make sure that the bitch does not gain any excessive weight during this period.

Very few physical changes occur until the fifth week of pregnancy. By the fifth week Photo source en.wikimedia.org of pregnancy, the nipples and mammary glands swell and darken in color. Between towels, mattress pads, or pieces of carpeting the sixth and seventh week, the bitch’s laid on top of the newspaper for good abdomen is enlarged due to the growth of traction. the pups. At about eight weeks into the pregnancy, the bitch’s mammary glands If necessary, a source of supplemental heat will enlarge considerably and milk may should be placed in the whelping box for the appear on the nipples. puppies, especially after the first few weeks of birth. Supplemental heat can be furnished by using heat bulbs either suspended or Whelping mounted above the floor of the whelping box. However, make sure to leave an area of About a week before the estimated the box without supplemental heat, so the date of parturition, the bitch should bitch and puppies can move away from the be introduced to the whelping area heat if they get too hot. and the whelping box. The whelping area should be a place that is dry, The whelping process usually does not warm, draft-free, secluded, and quiet. require assistance. However, for emergency The whelping or nesting box may be purposes, the following supplies should be constructed of a variety of materials but kept on hand: should be designed to accommodate the bitch fully stretched out on her side and • A clean, small plastic syringe to aspirate have room to spare for the pups. The secretions from the mouth and nose. bitch should be able to step into it, but the • A spool of dental floss to tie the pups should not be able to climb out. The umbilical cords. whelping box shouldARCHIVE include an interior • A pair of sterilized, straight, blunt- shelf around the periphery to prevent tipped scissors, in case it becomes the bitch from smothering or crushing a necessary to cut the umbilical cords. puppy. This shelf should be high enough to • A small bottle of iodine solution to apply accommodate a puppy, but low enough to to the umbilical cords. prevent the bitch from stepping or rolling • Several clean, laundered towels for on a puppy. The bedding of the box should drying the puppies. include fresh, flat newspaper laid at the bottom for fluid absorption, and heavy

Canine Breeding and Reproduction 5 Approximately 12 to 24 hours before labor litter over a period of several hours. The begins, the rectal temperature drops from uterus usually returns to its normal size a normal of 101.5º F (38.6º C) to less than (involution) within 12 weeks of whelping. 100º F (37.7º C). In addition, the bitch loses her appetite, becomes restless and lethargic, and her abdomen becomes more Postpartum and Postnatal distended. An increase in the production Care and secretion of the hormone prostaglandin F-2-alpha by the placenta and uterus Since the bitch’s appetite returns within causes regression of the corpora lutea and 24 hours after whelping, she should be a subsequent decrease in progesterone. fed a highly palatable food, moistened The decrease in progesterone permits with water. Furthermore, at about 20 uterine contractions to occur. The hormone to 30 days after whelping, the bitch relaxin is important for the preparation needs 3 to 4 times more food than she of the uterus for parturition and the normally does. Although the eyelids separation of the pubic bones for passage of the puppies are not open at birth, of the puppies through the birth canal. they can still locate the bitch’s nipples in order to feed. This is of extreme The labor and delivery process in importance since the puppies must dogs usually does not require human consume colostrum (dam’s first milk) intervention, and it entails three stages. within the first 12 to 24 hours after birth. Colostrum contains high levels • Stage I, which lasts about 6 to 12 of antibodies that are absorbed intact hours, is characterized by mild uterine into the bloodstream and provide contractions and dilation of the cervix. At protection against infectious diseases. this time the bitch displays external signs Hence, make sure that each puppy has such as intense nesting and constant access to a nipple and is able to suckle. lying down and standing up. Remember that the most important • Stage II is characterized by intense indicator of puppy health during the uterine contractions, which causes first few days and weeks of life is the expulsion of the puppy. Bitches regular and normal weight gain. If a usually deliver lying down, but some puppy does not gain weight during the may assume a squatting position. Most first 72 hours of life, you should start puppies are born with feet and head supplemental feeding immediately. first. The bitch should instinctively start Commercial milk formulas, which can to lick the fetal membranes away from be obtained from pet supply stores, the puppy’s face, and then sever the should be fed warm in a small bottle umbilical cord with her teeth. with a hole in the nipple. • Stage III is characterized by expulsion of the placenta. The bitch usually expels a placenta within a few minutes after the expulsion of each puppy. It is normal and instinctive for the bitch to eat the placentas. However,ARCHIVE you may want to reach and take some of them from her to avoid undesirable adverse effects. Make sure that the bitch has expelled a placenta for each puppy. If she retains any, she may develop postpartum metritis and need veterinary help. In general, the bitch will deliver her entire

6 Alabama Cooperative Extension System • Prolonged Heat. This term refers to a bitch that remains in estrus for more than 21 days. This condition is usually the result of excessive levels of estrogen due to ovarian tumors or follicular cysts. • Vaginitis. This infectious disease occurs when pathogenic bacteria invade the vagina and cause infection. • Pyometra. This disease occurs when the uterus has been under the sustained effect of high levels of progesterone and ideal conditions for bacterial growth. • Cryptorchidism. This inherited trait is the failure of one or both testicles to descend. Dogs with both testicles Handle the puppies daily to get them undescended are sterile. used to human contact and change the • Orchitis. This is an infection of the bedding often to prevent urine burn. As testicles. you handle them, inspect for cleft palates, • Balanoposthitis. This is an infection of umbilical hernias, Atresia ani (absence of the penis and prepuce. an anal opening), and any other abnormal • False Pregnancy. This condition refers conditions. to a nonpregnant bitch acting as if she was pregnant. The condition is caused by At about three weeks of age, puppies should progesterone produced by corpora luteal be given access to dry dog food mixed with cysts in the ovaries. warm water (gruel) in a large bowl several • Dystocia. This term refers to prolonged times a day. Gradually, the water content or difficult labor caused by a physical should be reduced so that by 4 to 6 weeks blockage or uterine inertia. of age the puppies are meeting most of • Mastitis. This refers to an infection and their requirements with the dry food. By inflammation of the bitch’s mammary this time there is less demand on the bitch’s glands (normally five pairs). milk and her food intake should be reduced. • Brucellosis. This disease, which is This initiates the process of stopping milk caused by the bacterium Brucella canis, is production and helps to normalize the bitch’s a well-recognized cause of abortions and food intake. After about 6 or 7 weeks of stillbirths. age, puppies are ready to be weaned and placed into new homes. Before sending them off, make sure they have been treated Conclusion for parasites and vaccinated for distemper, hepatitis, leptospirosis, parvovirus, It is advantageous to have knowledge coronavirus, and kennel cough. of canine reproductive anatomy and physiology, the estrous cycle of the bitch, mating, pregnancy, whelping, Some CommonARCHIVE and postnatal care of pups if you are Reproductive Problems planning to breed dogs. Furthermore, your objective should be to improve • Silent Heat. This term refers to a bitch the standard of the breed. Remember, that is in estrus but is not exhibiting pounds and shelters all across this vulvar swelling and vaginal bleeding. country are already full of unwanted dogs.

Canine Breeding and Reproduction 7 References Case, L.P. (1999). The Dog: Its Behavior, Nutrition, and Health. Ames, Iowa: Iowa State University Press.

Currie, W.B. (1988). Structure and Function of Domestic Animals. Stoneham, MA: Butterworth Publishers.

Giffin, J.M. and L. Carlson. (2000).Dog Owner’s Home Veterinary Handbook. New York, NY: Hungry Minds, Incorporated.

Marder, A. (1997). The Iams Company Complete Dog Owner’s Manual. Australia: Weldon Owen Private Limited Company.

Pond, W.G. and K.R. Pond. (2000). Introduction to Animal Science. New York, NY: John Wiley & Sons, Incorporated.

Rice, D. (1996). The Complete Book of Dog Breeding. Hauppauge, NY: Barron’s Educational Series.

Whitehead, S. (1999). Dog: The Complete Guide. London, UK: Team Media, Limited.

Julio E. Correa, Extension Animal Scientist and Associate Professor, Food and Animal Sciences, Alabama A&M University ARCHIVEReference to a company or produce name does not imply approval or recommendation of the product by the Alabama Cooperative Extension System or the United States Department of Agriculture to the exclusion of others that may also be suitable.

For more information, call your county Extension office. Look in your telephone directory under your county’s name to find the number. UNP-0052 The Alabama Cooperative Extension System (Alabama A&M University and Auburn University), is an equal opportunity educator and employer. Everyone is welcome! Revised, February 2016; UNP-0052 © 2016 by Alabama Cooperative Extension System. All rights reserved.