Pregnancy in dogs and cats, just like humans, is a wonderful time and the pregnant animal experiences changes in hormones, weight, appetite, and behaviour. The time when the dog or cat is pregnant is referred to as the Prenatal or Antenatal period and is the period from conception to parturition, usually 63-65 days. The Perinatal period is a time when puppies or kittens undergo dramatic neural and immune development and sets the stage for every pet's lifetime health, mental stability, and longevity.
Pregnancy may be planned and natural, the result of artificial insemination or accidental (Mesalliance). Prenatal care for bitches and queens begins with the selection of the most healthy desirable members of a potential breeding population as there are more than 400 genetic diseases that have been recognized in the dog, and genetic diseases are responsible for 25% of all disease problems affecting dogs.
Breeding bitches 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. A healthy environment and the provision of good breeding management techniques is necessary for breeding dogs and cats.
What nutritional requirements are there for pregnant bitches and queens?
Pregnant bitches and queens have special dietary requirements that begin before they become pregnant. Care of males and females during growth, development, mating, gestation and lactation is important for successful pregnancy and lactation. Feeding a high-quality and highly digestible diet that meets the increased calories needed during the first half of pregnancy is important. The bitch and queen should be kept in fit condition, and their caloric intake appropriate to allow for a weight gain of approximately 36% over her normal pre-pregnancy weight.
The diet should contain a protein level of 25% to 34% and a fat level of at least 18%, as well as optimum vitamins and minerals. Supplements should be avoided to prevent dietary imbalances and inadvertent toxicity. Calcium supplementation is unnecessary as it can result in decreased parathyroid hormone (PTH) stimulation of bone resorption. Eclampsia (puerperal hypocalcemia) may occur if the bitch depends on intestinal calcium absorption rather than on the PTH-stimulated bone calcium mobilization.
After confirmation of pregnancy, the puppy or kitten's diet is appropriate during the second half of pregnancy as it has highly concentrated nutrients which help with decreasing abdominal space in late pregnancy and has a good Ca:P ratio. Immediately after delivery, the bitch or queen should weigh approximately 5% more than her pre-pregnancy weight. It is nearly impossible to overfeed the bitch or queen during lactation. Both prenatal and postnatal nutrition contributes to metabolic programming. As a rule of thumb, the amount of food should be increased by 10% each week from week 5 of pregnancy.
When bitches or queens experience a period of reduced appetite or inappetence during the second trimester of pregnancy, a period that may be brief or prolonged, they should be encouraged to eat by adding palatable foods to their 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. Queens fed on feline commercial diets do not suffer taurine deficiency but may be seen in situations where dog food is fed to cats. Pregnant and nursing queens have nutritional needs that are four times the maintenance requirements and canned foods prove to be more palatable during pregnancy and should be offered if the queen's appetite wanes.
Pre-breeding care
The male and female must be in good physical condition, well-exercised and of the correct weight. An underweight female may be unable to eat sufficient food to meet her nutritional needs of herself and developing fetuses as low puppy birth weight increases neonatal mortality. On the other hand, overweight females have large fetuses and an increased risk of dystocia (difficult delivery).
What are the signs of pregnancy in dogs and cats?
In bitches, the following are some of the signs that they may exhibit during pregnancy:-
1. Decreased appetite and vomiting are some of the earliest signs of a bitch being pregnant.
2. Sudden Decrease in Activity
3. Breast Development is a good indicator of pregnancy changes. The nipples of an unbred female are usually small, and the area beneath them feels flat.
4. Changes in nipple colour to a rosier one in addition to breast development, especially in the last four or six nipples that are closest to the dog's hind legs.
5. Vaginal discharge during a dog's pregnancy, about four weeks of gestation or even later.
6. Behavioral changes where some females become extra affectionate. These behavioural changes often happen as early as a few days after successful breeding.
In queens, the following are some of the signs that they may exhibit during pregnancy:-
Nausea/vomiting
Initial loss of appetite
Increased appetite as pregnancy continues
Increased need for affection and attention from her owner
Irritability toward other pets, regardless of prior relationship
Increased restlessness and discomfort during later pregnancy
Occasional incontinence due to growing pressure on the bladder
and bowels
Hunting for a secluded place to nest prior to delivery
How is Pregnancy diagnosed in cats and dogs?
The methods of Pregnancy Diagnosis include the following:-
1. Abdominal palpation: Traditionally, this method is used in bitches and queens as the first method. It is accurate between 24- to 35-day post-breeding, and the accuracy is high at 87% between 30-35 days.
2. Radiography (X-ray): Radiography is done after 45 days of mating and is 100% accurate in the last 15 days of pregnancy. Mineralization of bones starts from 44 days of pregnancy onwards.
The radiograph is preferably done in lateral recumbency than dorsal or dorso-ventral at a voltage of50 KVp and a current of 0.5 – 1 mA. X-rays are good in evaluating foetal numbers and the foetuses can be differentiated easily from abdominal contents due to the mineralization of bones after 45 days. The position of the foetuses can also be easily determined and the number of foetuses can be easily counted too. The whelping date can also be predicted in a radiograph.
3. Ultrasonography (Ultrasound): Transabdominal ultrasonography is a safe and accurate modality for early pregnancy diagnosis. There are 3 types of diagnostic ultrasound for canine and feline pregnancy diagnosis: A-mode, Doppler and B-mode.
The B-mode or real-time ultrasound is mostly used for pregnancy diagnosis as it allows assessment of pregnancy status, foetal numbers and viability. The frequency of the transducer is set between 3.5 – 5 MHz and for early Pregnancy Diagnosis, a 7.5 – 10 MHz transducer is used. Ultrasonography is 94 – 95 % accurate between 24 – 25 days, 99% accurate at 28 days and best accuracy at 25 – 30 days after mating.
4. Relaxin assay: Hormonal assay of relaxin, a pregnancy-specific hormone in dogs that is secreted by the placenta only, is a differential hormone between pregnancy & pseudo pregnancy. It is at a peak concentration 20–30 days after successful mating but relaxin assay cannot be used to estimate litter size
5. Acute phase proteins: Acute phase proteins include haptoglobin, ceruloplasmin, alpha-globulin, C-reactive protein and fibrinogen. These proteins increase after day 20 of gestation and they are released during pregnancy and inflammatory diseases. Serum fibrinogen as a pregnancy confirmatory test is 98% accurate, with a value >280 mg/dL and 100% accurate with a value >300 mg/ dL.
Are there disease risks in pregnant dogs and cats?
Infections can cause abortion or stillbirth in both pregnant bitches and queens and the following are some of the causal organisms.
Diseases causing pregnancy loss in the bitch
Canine herpes virus
Canine parvovirus type 2
Canine distemper
Canine adenovirus
Campylobacter sp.
Escherichia coli
Mycoplasma sp.
Ureaplasma sp.
Salmonella sp.
Brucella canis
Canine minute virus (CPV-1)
Diseases causing pregnancy loss in queen
Feline leukaemia virus (FeLV)
Feline herpes virus (FHV)
Feline panleukopenia virus (FPV)
Feline infectious peritonitis (FIP; feline coronavirus)
Feline immunodeficiency virus (FIV)
Toxoplasma
Chlamydia
Pseudopregnancy (pseudocyesis/false pregnancy) may mimic pregnancy.
Are there treatment risks in pregnant dogs and cats?
The following drugs are known to cause congenital malformations or embryotoxicity in pregnant cats and dogs:-
Altrenogest
Aspirin
Ciprofloxacin
Corticosteroids
Diethylstilbestrol
Doxycycline
Enrofloxacin
Estradiol cypionate
Excess vitamin A
Excess vitamin D
Gold
Griseofulvin
Misoprostol
Mitotane
Oxytetracycline
Pentobarbital
Stanozolol
Streptomycin
Testosterone
Tetracycline
Warfarin
The following topical therapies should be avoided during pregnancy
Carbaryl
Dexamethasone sodium phosphate ophthalmic
Ophthalmics containing corticosteroids
Panolog cream which contains nystatin 100,000 units, neomycin sulfate 2.5 mg, thiostrepton 2,500 units and Triamcinolone acetonide 1.0mg.
Rotenone is a naturally occurring compound found in the roots of several plant species and has been extensively used as an insecticide and to kill fish. Rotenone is toxic not only to insects and fish but also to humans and animals
St. John's Wort is a plant with yellow, star-shaped flowers. It's often used for depression but can cause serious interactions with some drugs.
TriTop ointment contains in each gram the potent anti-inflammatory agent isoflupredone acetate 1 mg (0.1%); the antibiotic neomycin sulfate, 5 mg (0.5%) (equivalent to 3.5 mg neomycin); and the topical anaesthetic tetracaine hydrochloride, 5 mg (0.5%).
What parasites need to be controlled?
It is recommended to treat bitches and queens against parasites to prevent transplacental and transmammary transmission of worms, e.g. Toxocara canis (roundworms) and Ancylostoma caninum (hookworms) larvae. There are no dewormers that are completely effective against all the worm stages. The somatic larva of Toxocara canis are encysted in muscle tissue but reactivated during the last trimester of pregnancy and migrate transplacentally. Transmammary transmission of Toxocara canis occurs, whereas Ancylostoma caninum is transmitted only transplacentally. Aggressive deworming protocols are recommended for pregnant bitches, pregnant queens, and their offspring to prevent environmental contamination with parasite eggs and the potential zoonotic risk.
External parasites must be controlled using products approved for pregnant bitches and queens. Frontline Plus is approved for safe use in pregnant animals. Products containing carbaryl should not be used because they may cause brachygnathia, taillessness, extra digits, failure of skeletal formation, and dystocia in bitches caused by uterine inertia. Heartworm prevention for dogs and cats living along the coastal line should be continued throughout pregnancy as it has been proven to have a high margin of safety even in pregnant bitches and queens.
Any behaviour changes in pregnant bitches and queens?
Behavioural changes occur during pregnancy, becoming most evident towards parturition because of changes in hormones and the instinctive need of the dam to protect herself and her puppies. The pregnant cat or dog may become more irritable, aggressive, and territorial as she prepares for her puppies to come or become much more affectionate than normal. Behavioural changes of pseudopregnancy mimic those of pregnancy.
Gestation and parturition
Normal gestation ranges from 57 to 72 days post breeding in the dog and 52 to 74 days post breeding in the cat, depending on the breed (cat and dog) and litter size (dog only). More accurate measurements of gestational length in the dog are based on the Luteinizing Hormone (LH) surge, with whelping occurring 64 to 66 days post LH surge.
Foetal growth
During the first 5 weeks of pregnancy, less than 30% of puppy growth occurs with only a slight increase in maternal nutritional requirements. Beginning from the sixth week to birth (8th or 9th week), there is 75% increase of puppy weight and 50% increase of puppy length hence optimal maternal nutrition is essential.
Pregnant bitches' and queens' weight
For the first five weeks there is no extra feeding that is required if the pregnant dog or cat was at the optimum weight at breeding. A transient decrease in appetite occurs at around three weeks of pregnancy which increases again around weeks four and five. At this point, the daily food intake should be gradually increased for maintenance to 25-50% at parturition (when body weight should have increased 15-25%). From between the sixth and the ninth week, several small feeds should be provided daily because abdominal space decreases as puppy size increases. Underfeeding may lead to a decrease in body weight leading to poor lactation, whereas overfeeding leads to heavier foetuses that can possibly cause complications at parturition.
Parturition
Mammary development and lactation begin 1-5 days before delivery and food may be refused within 12 hours. before parturition. Afterwards, once the placentae are expelled and puppies are resting, fresh food and water should be offered to ensure that adequate fluid is consumed to assist lactation. Adding warm water to food stimulates appetite. Post-partum weight should be about 5 - 10% above normal. Sometimes parturition may not occur spontaneously and may require induction
References
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Peterson, M. E., & Kutzler, M. (2010). Small animal paediatrics: the first 12 months of life. Elsevier Health Sciences.
Johnston, S. D., Root Kustritz, M. V., & Olson, P. S. (2001). Canine and feline theriogenology. Saunders.
Johnson, C. A. (1986). Reproduction and Periparturient Care - Forward. Veterinary Clinics Of North America - Small Animal Practice, 16(3), 417-417.
Aziz, Dhafer. (2018). Canine and Feline Pregnancy Diagnosis. 10.13140/RG.2.2.30133.12003.
Lamm, C. G., & Makloski, C. L. (2012). Current advances in gestation and parturition in cats and dogs. Veterinary Clinics: Small Animal Practice, 42(3), 445-456.