key: cord-0040342-2go6c3ti
authors: Smith, Frances O.
title: Prenatal Care of the Bitch and Queen
date: 2010-09-02
journal: Small Animal Pediatrics
DOI: 10.1016/b978-1-4160-4889-3.00001-2
sha: 023bc09bf4c0ac2b5663d36478631b1e30fc9372
doc_id: 40342
cord_uid: 2go6c3ti

nan

encourage and educate potential breeders on their responsibility to choose healthy, quality bitches and queens for their breeding programs.

Breeding dogs or cats involves tremendous commitment of time, space, knowledge, and financial resources. The practitioner should counsel prospective breeders regarding the ethical considerations involved in breeding, including the difficulty in placing puppies and kittens in permanent homes and the responsibility incurred in creating these new lives.

Bitches selected for breeding should be mature enough to have genetic clearances for their appropriate breed and young enough to produce reasonable litter size and survivability. A bitch is at her peak reproductive potential between 2 and 4 years of age. In at least one study of beagle bitches, conception failure occurred in more than 50% of bitches 5 years of age or older. Similarly, the risk of dystocia increases, neonatal mortality increases, and litter size decreases with increasing maternal age. Average litter size is known for most purebred breeds, with average neonatal losses approaching 30%.

The bitch should be presented to the clinician during proestrus of the anticipated breeding cycle. A complete physical examination should include a rectal examination to evaluate the bony pelvis and a digital vaginal examination to detect any vaginal abnormalities. Brucella canis serology using the rapid-slide agglutination test should be done. An in-house test is available (D-Tec CB, Synbiotics; www.synbiotics. com); this test has high sensitivity and low specificity. Any positive result requires additional testing and should cause a delay in breeding during the cycle in which test results are confirmed. Regardless of previous breeding history, all bitches should be evaluated because the disease is spread orally, as well as venereally. Serologic testing for canine herpes virus should be performed on virgin bitches or in Prenatal care for bitches and queens should begin with the selection of the most desirable members of a potential breeding population. The resources of the important registration bodies and the available databases for evaluation of inherited genetic diseases should be used to select desirable traits. Information is available from the American Kennel Club (AKC), the Cat Fanciers' Association, the United Kennel Club, and many individual breed clubs. The most significant health database is maintained by the Orthopedic Foundation for Animals (OFA). The OFA is a private nonprofit foundation that serves as a central source of information for breeders and owners based on the standards for evaluation established by the experts in each discipline. The Canine Health Information Center (CHIC) is a joint venture of the OFA and the AKC Canine Health Foundation. The focus of CHIC is health consciousness; this focus allows breeders to manage breed-specific genetic disorders. The criteria for acceptance into the CHIC program are established by each of the parent clubs that are involved. Participation in any health database is voluntary but should be encouraged by practitioners (Box 1-1).

More than 400 genetic diseases have been recognized in the dog, and genetic diseases are responsible for 25% of all disease problems affecting dogs. With the exception of inherited renal dysplasia, all of the most commonly diagnosed inherited diseases are seen in mixed breed dogs. Designer dogs have the same prevalence of genetic disease as the purebred breeds. Responsible breeders of dogs and cats, as well as the respected breed registries, make great effort to improve the genetic health of their breeding animals and thus decrease the risk of avoidable inherited disease.

The various competitive venues available to breeders, such as conformation shows for cats and conformation shows, obedience competitions, agility competitions, hunting tests, and field trials for dogs, offer layers of selection in the choice of reproducing animals. Certainly, not every bitch or queen is worthy of reproduction and the practitioner should bitches with a previously negative test. If the bitch has a negative titer, she must be protected from exposure to the virus. More detailed information pertaining to herpes virus can be found in Chapter 16.

Isolation from other canids for 3 weeks before whelping to 3 weeks after whelping should prevent disease. There is no vaccine available in the United States. Vaginal cytology should be obtained and stained to assess the epithelial cells present. The bitch should either have her vaccinations brought up to date or have titers performed to assess her antibody levels. The bitch should be well protected against canine distemper and canine parvovirus to maximize maternal antibody levels.

The bitch has an endotheliochorial placenta. Puppies depend on mammary transfer of antibodies because placental transfer is minimal. With normal ingestion and absorption of colostrum, the antibody level of the puppy will approximate 95% of the dam's measured antibody level. Gut permeability to immunoglobulins begins to decline within 8 hours after birth and is no longer possible after 48 to 72 hours.

The bitch should have baseline laboratory tests performed to assess her suitability for pregnancy and lactation. A bitch with total plasma protein levels of less than 5.0 gm/dl is unlikely to whelp a litter of strong, healthy puppies. Bitches with significant renal or hepatic dysfunction are not successful brood bitches. If the bitch has a history of infertility or pregnancy loss, a vaginal culture should be performed during the first 5 days of proestrus. Although the value of vaginal cultures is controversial, most clinicians consider a pure culture in significant numbers of a known pathogen to be worthy of treatment. The vaginal culture should be interpreted within the context of patient history, physical examination findings, and vaginal cytology. Both B. canis and Salmonella sp. are always considered pathogens. B. canis is rarely treated in any kennel or colony situation. In kennel situations, B. canis is managed in a test and cull manner because it is highly contagious and nearly impossible to eradicate with therapy. Antibiotic choice and duration of treatment should be based on safety and efficacy in pregnancy. Bitches that have sustained pregnancy loss may be monitored weekly for hypoluteoidism, which is a poorly documented condition.

BOX 1-2 Prevention of neonatal isoerythrolysis in the feline During normal pregnancy, progesterone reaches peak levels of 15 to 90 ng/ml. During the last trimester of pregnancy, progesterone decreases until it drops below 2 ng/ml approximately 1 day before whelping. A progesterone level above 2 ng/ml is required for the maintenance of pregnancy in the bitch. If the progesterone drops to 10 ng/ml, frequent monitoring of the progesterone levels is recommended. Progesterone values of 5 ng/ml may warrant intervention with an exogenous progestogen supplementation. Exogenous progestogen administration is an extralabel use of any of the available preparations and should always be accompanied by careful client education and a signed release form outlining the risks. Prolactin and luteinizing hormone (LH) are also luteotrophic in the bitch.

The queen should also be examined before breeding. When presented, the queen should have a complete physical examination, including baseline laboratory work, and a fecal examination should be performed. Serology for feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) should be obtained. Only queens testing negative for these two viruses should be used for breeding. Neonatal isoerythrolysis occurs in purebred cats. This condition may be avoided by blood typing the queen and breeding to a tom of an appropriate blood type (Box 1-2). The blood types of domestic felids are A, B, and AB. The breeds with the highest frequency of type B blood are the British Shorthair, the Devon Rex, and the Cornish Rex. Cats are unusual in that unlike dogs, they have naturally occurring antibodies to other blood types. The A allele (A) is dominant to the B (B) allele so only the cats with homozygous recessive condition (BB) express the type B antigen on their erythrocytes. Type A cats are either homozygous AA or heterozygous AB. The AB blood type is rare and inherited separately as a third allele recessive to A and co-dominant with B. Feline neonatal isoerythrolysis occurs when maternal anti-A alloantibody gains access to the fetal circulation after colostrum ingestion and destroys type A and type AB erythrocytes. Type A and type AB kittens from a type B queen bred to a type A or AB tom are at risk. Specifics pertaining to the clinical manifestations of the disease in neonates are discussed in Chapter 2.

In the case of breedings within catteries, the status of all cats with respect to feline coronavirus (FCOR) should be evaluated (Table 1 -1). To prevent the spread of coronavirus, the tom and the queen should have the same serologic status. The Chlamydia status of cattery members should also be determined using serology. The queen should be vaccinated for feline panleukopenia (FPL), feline herpes virus (FHV), and feline calicivirus (FCV) to prevent clinical disease within the cattery (Table  1 -2). However, vaccination alone may not prevent the spread of infection. Higher levels of maternal antibody may be achieved by boostering the vaccinations just before or at the time of breeding.

The queen has an endotheliochorial placenta. Colostral antibodies are the main source of immunoglobulins in the kitten. Progesterone produced by the corpus luteum is necessary for maintenance of pregnancy in the cat since placental production of progesterone is minor. The corpora lutea remains functional throughout pregnancy and regresses after delivery. The queen typically has a progesterone level of 1.0 to 1.6 ng/ml at day 60 of pregnancy. Thus pregnancy likely involves pregnancy-specific secretion of luteotrophic hormones of placental or pituitary origin. Several studies indicate that prolactin is a major luteotrophic factor in pregnant queens after implantation has occurred. Hypoluteoidism has not been reported in the queen. Progesterone therapy to prevent recurrent pregnancy loss should only be considered when infectious causes of pregnancy loss in the queen have been ruled out.

Proper diet for gestation begins before the bitch becomes pregnant. The bitch should be fed a quality, name-brand diet labeled complete for all life stages by the Association of American Feed Control Officials (AAFCO) standards using feeding trials or suitable for pregnancy and lactation. There is minimal need for increased calories during the first half of pregnancy. The bitch should be kept in fit condition, and her caloric intake should be appropriate to allow for a weight gain of approximately 36% over her normal prepregnancy weight. The diet should contain a protein level of 25% to 34% and a fat level of at least 18% with a balanced supply of n-6 and n-3 fatty acids, as well as optimum vitamins and minerals. Supplements should be avoided to prevent dietary imbalances and inadvertent toxicity.

Calcium supplementation is unnecessary and can result in decreased parathyroid hormone (PTH) stimulation of bone resorption. Eclampsia (puerperal hypocalcemia) can occur when the bitch depends on intestinal calcium absorption rather than on the PTH-stimulated bone calcium mobilization. After confirmation of pregnancy, the puppy or kitten diet is appropriate during the second half of pregnancy. Immediately after delivery, the bitch or queen should weigh approximately 5% more than her prepregnancy weight. It is nearly impossible to overfeed the bitch or queen during lactation. Recently, it has been established that nutrients may influence maternal or fetal gene expression, thereby influencing the metabolic status of an animal for life. It has been established that both prenatal and postnatal nutrition contribute to metabolic programming.

Many bitches experience a period of reduced appetite or inappetence during the second trimester of pregnancy. This period may be brief or prolonged. The bitch should be encouraged to eat by adding palatable foods to her diet (cooked meat or canned food). If inappetence persists, force feeding may be necessary.

Nutritional insufficiency of taurine may result in resorption, abortion, and stillbirth of kittens. Effects of a taurine deficient diet may persist beyond an individual lost pregnancy. This effect is unlikely to be seen in queens who are fed feline commercial diets but may be seen in situations where dog food is fed to cats. Dietary supplements are not recommended. Pregnant and nursing queens may have nutritional needs that are four times maintenance requirements. Canned foods may prove to be more palatable during pregnancy and should be offered if the queen's appetite wanes.

It is possible and recommended to treat bitches to prevent transplacental and transmammary transmission of somatic Toxocara canis and Ancylostoma caninum larvae. There are no anthelmintics that are completely effective against the somatic and larval stages. The somatic larva of T. canis are encysted in muscle tissue but reactivated during the last trimester of pregnancy and migrate transplacentally. Transmammary transmission of T. canis occurs, whereas A. caninum is transmitted only transplacentally. The Centers for Disease Control (CDC) and the Companion Animal Parasite Council (CAPC) recommend aggressive deworming protocols of pregnant bitches, pregnant queens, and their offspring to prevent environmental contamination with parasite eggs and the potential zoonotic risk. A number of different protocols have been suggested using multiple doses of fenbendazole and ivermectin orally in bitches (Table 1 -3). In both bitches and queens, topical selamectin 6 mg/kg has been shown to greatly reduce worm burdens in both puppies (98%) and kittens (100%) up to 6 and 7 weeks old.

External parasites must be controlled using products approved for pregnant bitches and queens. Frontline Plus and Revolution are approved for safety when used in pregnant animals. Products containing carbaryl should not be used because it may cause brachygnathia, taillessness, extra digits, failure of skeletal formation, and dystocia in bitches caused by uterine inertia. Heartworm preventive should be continued throughout pregnancy and has been proved to have a high margin of safety even in pregnant bitches and queens.

A birth defect is a deviation from normal morphology or function that occurs during pregnancy and is severe enough to interfere with viability or the physical well-being of the offspring. Teratology is the science of studying the etiology of birth defects. There are three critical periods in the development of the fetus. The first period is preimplantation (pregastrulation), which occurs from fertilization to implantation. The second is the embryonic period, which is when organogenesis occurs, and is an important period when birth defects develop. The third is the fetal period, which roughly encompasses the last 3 weeks of pregnancy, during which growth and maturation of organ systems occur. Serious insult during the preimplantation phase may result in an all-or-none phenomenon in which implantation does not occur or the cells survive and continue development. Most serious defects occur during the embryonic period (days 22 to 44 from the LH surge) in the dog. During the fetal stage, gross structural defects seldom occur except in structures undergoing rapid growth and maturation such as the palate, the cerebellum, and parts of the cardiovascular and urogenital system.

In humans, 60% of congenital malformations have no identifiable cause, 20% are a combination of hereditable and -3 and 1-4) . Certain breeds of dogs have increased incidence of birth defects. The English bulldog, the pug, the Boston Terrier, and the French bulldog all have increased incidence of fetal anasarca resulting in increased fetal loss and a greatly increased rate of cesarean sections. Anasarca or lethal BOX 1-3 Diseases causing pregnancy loss in the bitch Nutritional components have caused congenital defects. Excessive vitamin A between days 17 and 22 has been reported to result in cleft palates, kinked tails, and deformed auricles in kittens. Excess vitamin D has been linked with tissue calcinosis, premature closure of fontanelles, enamel hypoplasia, and supravalvular stenosis.

Congenital malformations can best be evaluated by careful necropsy of all nonsurviving puppies or kittens with the goal of eliminating the cause of such defects (see Chapter 31). There are several drugs that are contraindicated during pregnancy because they are known to cause birth defects (Box 1-5). For an explanation of the reproductive effect or for a complete list of drugs that are safe for use during pregnancy, see Chapter 27 (Table 27 -4). Clinicians should obtain a good drug history, including the use of topical, herbal, and other alternative modalities (Box 1-6).

The bitch should have her pregnancy confirmed 25 to 30 days after her first breeding (Table 1-4). In lean relaxed bitches, it may be possible to detect discrete swellings in the uterus as early as 21 days after breeding. However, it is not possible to use palpation to differentiate uterine swellings congenital edema involves generalized subcutaneous edema and varying amounts of fluid in other body cavities ( Figure  1-1) . The condition is known to be heritable likely as a recessive trait. Many of the anasarcous puppies also are afflicted with congenital heart defects.

Cleft palates are common in all of the brachycephalic breeds (Figures 1-2 and 1-3) . Cleft palates can be caused by genetic traits or by teratogenetic agents. Both griseofulvin and corticosteroids have been implicated as teratogens that can cause cleft palate. Even aspirin has been demonstrated to cause cleft palates. In general, all drugs should be avoided in the pregnant bitch or queen, including all live virus vaccines, unless they are necessary to maintain the welfare of the mother and the drug is reported to be safe during pregnancy. associated with uterine pathology (Figures 1-4 and 1-5) from normal uterine development associated with pregnancy. After day 35, the uterine swellings enlarge, resulting in a confluence, making pregnancy palpation even more unreliable.

Real-time ultrasonography is valuable in early pregnancy diagnosis, as well as throughout the second half of gestation whenever there is a question of fetal viability or fetal loss. Ultrasonography in the bitch is accurate for pregnancy diagnosis in the hands of an experienced ultrasonographer using quality equipment as early as 19 to 21 days post-LH peak in the bitch. When the LH peak is known, pregnancy diagnosis in the bitch is very accurate after days 21 to 23. If the LH peak is unknown, ultrasonography for pregnancy detection should be performed at approximately 30 days after the last known breeding (see Figure 1-4) . Fetal heartbeats are first detected 23 to 25 days after the LH peak or 16 days after the onset of cytologic diestrus. In addition to pregnancy diagnosis, ultrasonography can be used to identify fetal loss. This author has observed disparity between the sizes of gestational sacs in some pregnancies. This size disparity appears to be accompanied by low volume of embryonic fluid, cessation of fetal heart beat in the smaller sacs, shrinkage, and ultimately resorption. Ultrasound has not been proved reliable for determination of litter size. Determination of fetal age involves multiple measurements of the biparietal or trunk diameter and must take into consideration differences relative to breed and litter size.

Embryonic vesicles may be detected earlier in the queen than in the bitch (Table 1-5). Ultrasonographic pregnancy diagnosis is accurate in the queen as early as 11 to 16 days after breeding. Fetal heartbeats may be detected as early as day 16. Embryonic vesicles closest to the uterine bifurcation are detected earliest, and early examination may miss some fetuses. The ultrasound should be repeated 5 to 7 days later if no fetal vesicles are seen. Ultrasound in the queen can be used to detect fetal loss and may be used in an attempt to estimate fetal age.

Hormonal diagnosis of pregnancy varies with species. In the bitch, progesterone elevations are not different whether a bitch is or is not pregnant. Progesterone levels, however, can be used to confirm ovulation failure. In the queen, progesterone levels may be used 40 days after breeding to differentiate pseudopregnancy from pregnancy. In the pseudopregnant queen, progesterone declines to baseline levels by day 40 after breeding but remains at 1 ng/ml or above in pregnant queens. Prolactin levels increase in both the pregnant bitch and the pregnant queen; however, a commercial test is not available. Relaxin is the only reported hormone that is pregnancy-specific in carnivores and is produced by the fetoplacental unit. Relaxin is best measured by radioimmunoassay or enzyme-linked immunosorbent assay (ELISA) techniques. An in-clinic test (ReproCHEK, Synbiotics; www.synbiotics.com) has been developed but is not as reliable as ultrasonography. At this visit, the physical examination should be repeated. The body condition of the bitch or queen should be assessed, and recommendations made for adjustments as needed. If the bitch or queen has previously been on a maintenance diet, she should be switched to a ration suitable for pregnancy and lactation. In cases where the bitch or queen is underweight and anorectic, a balanced multivitamin, such as Pet-Tabs, should be considered. There are hematologic changes throughout pregnancy, and both the bitch and the queen will experience a gradual decline in hematocrit associated with increased plasma volume (Tables 1-6 and 1-7) . Pregnancy may be accompanied by toxemia in bitches carrying large litters. Ketosis can develop in bitches not meeting the nutritional demands of pregnancy, and a negative energy balance can develop. Anorexia in late pregnancy must be corrected by force feeding or parenteral nutrition.

The owner should be questioned about any changes in behavior or appetite, increases or decreases in water consumption, extent of mammary development, and the presence of any vaginal discharge. If the bitch or queen is found to be nonpregnant at this visit, a diagnostic workup for conception failure should be discussed. This is a good time to remind the owner to avoid exposure to any infectious disease. The bitch or queen should remain in the home, kennel, or cattery environment and should not share housing or exercise areas with animals still in competition or training. This includes shared areas for exercise even if direct contact is prevented.

There are numerous viral and bacterial diseases that have potential risks for the pregnant animal. Training classes and competitive field events should be discontinued because the effect of stress on the bitch can be significant. With maternal stress, there is increased adrenaline secretion, decreased uterine and placental blood flow, decreased oxygen to the fetus, and increased fetal adrenocorticotropic hormone (ACTH).

Before term the bitch or queen should be introduced to her delivery area. This area should be safe and quiet and provide the privacy and comfort needed for the dam to become acclimated and ready for parturition. The bitch should be Figure 1-6 The lateral abdominal radiograph can be used to assess number of fetuses. Six puppies can be seen on this film of a Labrador retriever bitch taken 6 days before whelping.

Figure 1-7 Ultrasound is the best tool for assessing fetal status and viability. It can be used to assess fetal heart beats, as well as movement of the fetus. This ultrasound captured a near-term puppy yawning. introduced to the whelping area and confined to the area where she will whelp at least 1 week before the anticipated parturition. The queen will often seek a small confined area for parturition.

The bitch or queen should have a lateral abdominal radiograph (Figure 1-6 ) taken 5 to 10 days before the expected delivery date to assess the number of fetuses. Radiography is an accurate method for determination of fetal numbers but can underestimate the litter size in very large litters. Radiography will also allow the assessment of the fetal skeleton for signs of fetal death (i.e., collapse of the fetal skeleton or gas within the uterus). Radiography does not truly assess the presentation of the fetus because of the mobility of the uterine horns. Ultrasonography is a better diagnostic tool for the assessment of fetal health since it allows examination of the fetal heart rate, the amount of allantoic fluid, fetal movement, and some fetal abnormalities such as abdominal wall defects (Figure 1-7) . Fetal heart rates that are below 130 beats per minute indicate poor puppy viability, and the pregnancy requires intensive monitoring. Normal fetal heart rates at term are often greater than 200 beats per minute.

During the prenatal visit, it is prudent to evaluate the dam's blood glucose and serum calcium (ionized calcium preferred) levels and packed cell volume. The physical examination should include a digital vaginal examination to detect any soft tissue obstructions (stricture or masses) and to evaluate the vaginal area for excessive edema. Any vaginal discharge warrants vaginoscopy, using either a human sigmoidoscope (Figure 1-8) or a rigid endoscope (Figure 1-9) with a video monitor to assess cervical patency and the presence of fetal membranes. The client should be given verbal and written instructions on the management of parturition and should be encouraged to inform the clinician of any change in rectal temperature (Boxes 1-7 and 1-8 

Begin preparations for delivery of puppies before the female gives birth. Provide a whelping box for the mother to begin sleeping in to ensure the puppies are born in the area you have chosen. This box should be only slightly bigger than the mother, with sides 6 to 8 inches high to keep the pups from crawling out of the nest. Place the box in a secluded yet familiar area of the home, away from the family traffic, to allow the mother solitude. Newspapers make excellent bedding because they can be changed easily, are absorbent, and can be shredded by the mother as she makes her "nest. " If materials such as old quilts, blankets, rugs, or towels are used, they must be washed frequently.

If you want to know precisely when delivery is near, check the rectal temperature of the mother twice daily from the 58th day of pregnancy until labor begins. Normal rectal temperature is between 100.5° F (38° C) and 102° F (38.9° C). Within 24 hours before the onset of labor, the rectal temperature drops nearly 2 degrees to 99° F (37.2° C) or below.

Labor in the female dog (bitch) can be divided into three stages. The second and third stages are repeated with the birth of each puppy. During the first stage, the mother seems extremely restless and very nervous and often seeks seclusion. She may refuse food even if offered her favorite treats. This stage may last 6 to 24 hours. This is a good time to exercise the mother to allow her to urinate and defecate. In the second stage, uterine contractions and expulsion of the puppies begin. Usually, a small greenish sac of fluid protrudes from the vulva, followed by the puppy and its attached placenta. The normal presentation of the puppy is nose first, stomach down ("diving" position). About one-third of all puppies, however, are born hindquarters first. This presentation is considered normal in the dog. After delivery, the mother opens the sac, cleans off the pup, and severs the umbilical cord. You may have to perform these functions for the mother (see Obstetric Care). Make sure the sac is removed from the puppy immediately if it is unbroken during delivery. The third stage of labor is the resting stage, which follows delivery of each puppy. Mild contractions and delivery of the afterbirth occur in this phase. This stage usually lasts 10 to 30 minutes, but it may range from a few seconds to an hour.

After a pup is delivered, remove all membranes covering the puppy, clean the face, and remove mucus from the mouth and nose. Rub the puppy with a clean towel to dry it and to stimulate respiration and circulation. After a few minutes of rubbing, the puppy should begin to squirm and cry loudly. The umbilical cord should be tied about an inch from the puppy's body with fine thread and then cut on the side of the knot away from the puppy. Apply a drop of Betadine to the cord end after it is cut.

If a puppy seems to be lodged in the birth canal and the mother cannot expel it, rapid assistance is necessary. There may not be time to call the veterinarian and drive to the hospital. Grasp the puppy with a clean towel and exert steady, firm traction. Do not jerk or pull suddenly. Traction may have to be applied for as long as 5 minutes. If you cannot remove the puppy, call the doctor.

• A puppy is lodged in the birth canal and cannot be removed. • There is strong, persistent labor for 30 minutes without delivery of a pup. • There is weak, intermittent labor for 3 hours without delivery of any puppies. • It has been more than 3 hours since the delivery of the last pup, and it is probable that more puppies are still inside. • There is a greenish-black vaginal discharge and no labor or puppies within 3 to 4 hours. The greenish-black color is normal, but the discharge should be followed very soon by delivery of the pups. • The pregnancy lasts more than 65 days. • It has been 24 hours since the drop in rectal temperature and there are no signs of labor.

temperature commonly drops to below 99° F (37.2° C) within 24 hours of initiation of parturition. The queen may experience a similar decrease in rectal temperature, although it is seldom reported by the owner. The temperature drop follows the decrease in progesterone at the end of pregnancy. During late pregnancy, the pattern of uterine electrical activity changes, which correlates with the decrease in plasma progesterone. This suggests that progesterone plays an important role in the process of parturition in the bitch. The client should be counseled to seek veterinary attention if labor is not initiated within 24 hours of the decrease in rectal temperature. The client should be given after-hours contact information if the clinician will be providing after-hours care or contact information for appropriate emergency care.

Reproduction and periparturient care

Canine and feline theriogenology

The whelping and rearing of puppies: a complete and practical guide

Manual of small animal reproduction and neonatology