Milk fever in dogs - causes, symptoms and treatment

The postpartum period is a rather complex process for both the animal and its owner. It is especially difficult for dogs giving birth for the first time. But in addition to the severe psychological condition, serious complications related to the pet’s health may develop in the postpartum period.

A bitch can develop a number of pathologies after giving birth, one of which is milk fever or postpartum eclampsia. The main reason for the development of a dangerous condition is a sharp decrease in the important mineral calcium in the bloodstream.

This leads to serious consequences, including the death of the animal in the absence of timely assistance.

Eclampsia in dogs

Canine eclampsia is a metabolic disorder characterized by a decrease in calcium in the blood. Calcium plays an important biological role in the body. Its active form (ionized calcium) is essential for many cellular processes:(6)

• neuromuscular transmission;
• enzymatic reactions;
• blood clotting;
• vasomotor tone;
• bone metabolism;
• secretion of hormones;
• glycogen metabolism in the liver.

Hypocalcemia is defined as a decrease in ionized calcium in the blood of dogs below 1.2 nmol/L. (6)

Most often, eclampsia occurs in the first three weeks of lactation. At the same time, cases of prenatal eclampsia (2 weeks before birth) have been recorded. This form of the disease is most often described in cats, but can also occur in dogs. Quite rarely, eclampsia develops later than three weeks after birth.

You should not extrapolate data on eclampsia from human medicine to dogs, since eclampsia in women has completely different pathogenetic mechanisms and methods of correction.

Pathogenesis

To understand the causes of hypocalcemia in the postpartum period described below, it is important to remember the normal metabolism of calcium. (6)

Calcium is present in the body of animals in three forms:

• Ionized calcium 50%;
• Protein bound calcium 40%;
• Calcium bound to other compounds (for example, phosphates) 10%.

Calcium metabolism is controlled by parathyroid hormone (PTH), which is produced by the parathyroid glands. Parathyroid hormone is responsible for the synthesis of vitamin D3 (calcitriol) and regulates the constant level of calcium in the intercellular space through a continuous set of reactions.

The table shows the traditional mechanism that maintains normal blood calcium levels under the influence of PTH:

Causes of postpartum eclampsia in dogs

There are four main factors in the development of postpartum eclampsia in dogs. (3)

Nutritional factors

Pregnancy is a period of pronounced dynamic changes in the physiology of the bitch. The fetal period (after 40 days of gestation) is characterized by active growth of embryos and, as a result, an increased need for nutrients. When the increased need for nutrients is not met through the diet, the lactating bitch develops a deficiency of vitamins and minerals.

Bitches who eat so-called homemade food are susceptible to the development of eclampsia - diets of meat, cereals and other products, in the preparation of which a professional nutritionist did not participate, meticulously selecting products and dietary supplements taking into account the characteristics and needs of a particular dog during this difficult period from a physiological point of view.

It is also a mistaken belief that during the gestation period it is useful to give dogs a lot of meat, because it is protein. All meat products contain high levels of phosphorus, which disrupts the calcium-phosphorus ratio and can lead to hyperphosphatemia. This, in turn, plays a role in the development of hypocalcemia.

Decreased albumin

Albumin is a calcium ion carrier protein. With its deficiency, calcium cannot be transported in the amount necessary for homeostasis and perform its required functions. Therefore, if a pregnant bitch has any pathological condition accompanied by hypoalbuminemia, she is likely to show symptoms of eclampsia. In this regard, only animals in ideal health should participate in breeding. It is also important to provide your dog with a diet containing sufficient amounts of high-quality protein.

Lactation

The main cause of hypocalcemia is the loss of calcium in milk. (1) This is why eclampsia will most often develop during peak lactation – 14–21 days after birth. As puppies grow, more and more milk is required for their growth and development, so the loss of calcium in milk increases.

Calcium supplements during pregnancy

The natural solution for the owner is to give the dog extra calcium to prevent postpartum eclampsia. However, this cannot be done when feeding a balanced complete food. Its excess causes negative feedback in the secretion of parathyroid hormone, which regulates calcium metabolism. (2) This effect leads to two important changes in the body of the pregnant bitch:

• the ability to mobilize calcium reserves from bones decreases;
• calcium absorption in the intestine decreases.

As a result of this cascade of reactions, when calcium is needed in large quantities during lactation, the body is not able to quickly adapt to its intense loss in milk and hypocalcemia develops.

It is important to remember that excess calcium in the diet during pregnancy provokes eclampsia in dogs.

Emergency measures

Milk fever progresses quite quickly, and the advanced stage of the disease leads to paralysis, coma and death. The pathology will not go away on its own, and the lack of help almost 100% means the death of the animal.

Attention! When the disease passes into the third stage, only 2-3 hours are allotted for assistance, and in the best case – 20-22 hours. Then it will no longer be possible to save the dog.

First, emergency aid can be provided in the following ways:

1. Administration of 10% calcium gluconate. In case of advanced disease, intramuscular injection is provided alternately into all 4 paws. At the second stage, the drug is diluted with saline (in equal proportions) and injected subcutaneously into the withers. At the beginning of the disease, the solution can be poured into the mouth.
2. Use of calcium chloride. At stages 2 and 3, the drug is administered by intravenous injection. When the disease is detected at stage 1, the solution is diluted with milk in equal proportions and poured into the mouth.
3. In addition to injections, Valocordin solution is used . The concentration is selected from this calculation - small rocks - 4-6 drops, large ones - 12-16 drops per 50 ml of water. The product is poured into the mouth, and a small amount is smeared on the nose.
4. Normalization of the central nervous system is achieved by intramuscular injection of Sulfocamphocaine . It is also advisable to give an injection with Diphenhydramine (0.4-0.6 cc).

Important. When providing first aid, the owner’s nervous state is transferred to the pet. All actions must be carried out calmly, without fuss, with maximum care provided to the animal (stroking, soothing voice).

Risk group

Eclampsia has an increased incidence in small breed dogs, (5) and the disease can develop in bitches of any size.

Also at risk include:

• dogs with multiple pregnancies. However, even with single puppy syndrome, some bitches produce a lot of milk, as a result, the level of calcium in the blood cannot remain within normal limits;
• dogs on natural unbalanced diets;
• dogs that received calcium supplements during pregnancy along with a protein- and Ca:P-balanced diet.

Symptoms of the disease

The dog owner needs to know at least the main signs of eclampsia, which are signals for an urgent visit to a veterinary clinic. These symptoms include:

• Aggression, fearfulness, inappropriate behavior;
• Signs of anxiety, restlessness, expressed in causeless barking, darting around the apartment, frequent carrying of puppies;
• Increased temperature, which can cross 39°C;
• Rapid breathing, shortness of breath, occurring due to fever, heart failure;
• Dry mouth and eyes, which appear due to a critical decrease in the volume of fluid in the body, are accompanied by a deterioration in the condition of the coat;
• Muscle weakness leading to poor coordination of movements. Formed as a result of an acid-base imbalance or insufficient blood supply to the brain;
• Spasms of smooth muscles as a reaction to pain in the abdominal area;
• Convulsions in certain parts or throughout the body can occur in a similar way to epileptic seizures;
• A critical decrease in pressure observed when blood circulation is disrupted. Urgent assistance from a veterinarian is required, otherwise a severe stress reaction of the body will occur and the dog will die.

Symptoms and stages

Eclampsia is a very serious disorder, but owners may not always be able to successfully recognize the early symptoms. At first, the dog may show restlessness and weakness, but later the clinical manifestations of postpartum eclampsia will vary and be observed in different degrees of severity and in different combinations.

List of typical symptoms: (6)

• hyperthermia (body temperature above 39.8 C°) - in connection with this, eclampsia is sometimes called “milk fever”;
• tremor;
• dyspnea;
• tachycardia.

You can also record:

• muscle twitching;
• lethargy;
• itchy muzzle;
• hiccups;
• grinding of teeth;
• pain syndrome;
• ataxia.

In severe forms of the disease, tonic-clonic convulsions develop (therefore, an alternative name for eclampsia, and according to many authors more appropriate, is “puerperal tetany”)

If calcium deficiency is not stopped quickly during convulsive seizures, then the death of the animal occurs.

Picture of the development of the disease

Eclampsia has several stages. Each of them has specific characteristics. At the first stage you may experience:

• increased breathing;
• excessive excitement;
• aggression in behavior.

As the pathology develops, the following appear:

• difficulty moving;
• copious secretion of saliva;
• convulsions that appear during sharp sounds or touches;
• tachycardia;
• constriction of the pupils;
• increase in body temperature.

The last stage is accompanied by high temperature, breathing is difficult. The formation of edema in the brain is possible. Therapeutic treatment at this stage is ineffective, and there is a high risk of death of the animal. It should be taken into account that eclampsia during pregnancy can provoke uterine contractions and premature birth.

Diagnosis of eclampsia

The diagnosis of eclampsia is made in a complex manner.

In the typical fulminant form, medical history (recent birth and lactation) correlates with classic symptoms (shortness of breath, fever, tremors, or seizures). However, one should not neglect diagnostic tools to exclude other diseases of the postpartum period of bitches, which may coincide in a number of symptoms with eclampsia.

For example, high fever, pain, and lethargy can accompany postpartum metritis (ultrasound diagnostics of the uterus, a general clinical blood test, and a cytological examination of a vaginal smear can help rule out this disease).

Loss of maternal instinct, anorexia, and shortness of breath may occur with mastitis and/or breast abscess (this diagnosis can be easily confirmed by physical examination).

In this regard, it is important to conduct a general examination, laboratory tests and use visual diagnostic methods to verify the diagnosis and provide effective assistance.

In cases with vague symptoms, a more thorough examination is required, including a detailed interview with the owner, who, in turn, will not always pay attention to some manifestations of the disease. For example, hiccups, teeth grinding, or the urge to rub your face against furniture may not be perceived as abnormal.

Laboratory tests that are carried out if a dog is suspected of having eclampsia:

• general clinical blood test;
• blood chemistry;
• blood glucose level;
• ionized calcium (this test is a specific diagnostic; it will detect hypocalcemia and diagnose eclampsia).

If the dog arrives in serious condition and the history, coupled with characteristic symptoms, strongly suggests eclampsia, the diagnosis can be made based on the therapeutic response to intravenous calcium.

Diagnosis of the disease, examination

When visiting a veterinarian, it is necessary to tell in detail about all the existing symptoms, their intensity, frequency of manifestation, vitamins, supplements included in the pet’s menu, and diet. After studying the symptoms and examining the dog, the specialist prescribes tests to determine the state of internal systems and organs, and assess the effectiveness of metabolic processes.

An important indicator is the calcium content in the bloodstream. When the indicator is determined to be 7 mg per 100 ml or lower, a diagnosis of “eclampsia” is made. During this disease, magnesium and glucose deficiency are often observed. The veterinarian prescribes medications to restore the balance of these microelements.

Therapy

Methods for correcting eclampsia can be divided into two stages:

• emergency treatment;
• long-term treatment.

Emergency treatment

The goal of emergency therapy is to stop abnormalities that are dangerous to the health and life of the animal:

• replenish calcium deficiency;
• eliminate hyperthermia;
• normalize blood glucose levels.

Replenishment of calcium deficiency.

To compensate for calcium deficiency, intravenous solutions are used (calcium gluconate 10% is the drug of choice for clinically significant hypocalcemia). Recommended dose: Calcium gluconate 10% 0.5–1.5 ml/kg/hour (8) (the dose is selected individually according to the therapeutic response). (4)

The infusion is carried out under the supervision of a specialist. The veterinarian monitors vital physiological indicators: temperature, blood pressure, respiratory rate and heart rate, capillary refill rate. Based on monitoring, an ECG may be required during the IV.

Calcium should be given slowly to prevent ventricular fibrillation and cardiac arrest. If bradycardia or arrhythmia develops, the infusion must be stopped.

Elimination of hyperthermia.

Within a few minutes after the onset of seizures, the body temperature becomes critical, which can potentially cause brain damage. It is necessary to use gentle mechanical methods of cooling the animal: (8)

• refrigerants;
• moistening the limbs and abdomen with alcohol;
• infusion with solutions at room temperature.

It is also necessary to check your body temperature regularly (every 15–30 minutes).

Correction of hypoglycemia.

Against the background of convulsive activity, glycogen reserves in the liver, which is a source of glucose, are depleted. Hypoglycemia will also be a trigger for seizures. Dogs of dwarf breeds are especially prone to hypoglycemia.

If the glucose level decreases below normal (less than 3.5 mmol/l), therapy is carried out with a 10–20% dextrose solution intravenously.

After initial stabilization of the patient, it is necessary to continue therapy.

Long-term treatment

Long-term treatment goals:

• stop calcium loss in milk in case of relapse;
• maintain normal calcium levels with medication.

Types of long-term treatment:

• drug therapy;
• non-drug therapy.

Drug therapy, stopping lactation.

Puppies are transferred to artificial feeding with a bitch milk substitute and are provided with complete care (stimulation of urination, defecation, massage, external hydration, etc.). Weaning is especially important if eclampsia develops in small breed dogs.

Some owners and breeders do not have the opportunity to spend so much time caring for the litter and leave the puppies with the mother. A blanket is put on the dog to prevent natural feeding, and it is engaged in grooming and caring for the offspring. However, it must be remembered that visual and auditory stimuli in the form of puppies also provoke the production of prolactin in the pituitary gland. As a result, drug suppression of lactation may not occur as quickly as necessary.

Today, the drug of choice for stopping lactation is cabergoline. Its advantages:

• high bioavailability;
• conveniently dosed (5 mcg/kg: 0.1 ml/kg veterinary solution forms);
• comfortable regimen (1 day/day);
• Available in veterinary pharmacies in liquid form.

The average duration of cabergoline treatment is one week.

Drug therapy, maintaining normal calcium levels in the blood.

After stabilization of the patient and until cessation of lactation, calcium is administered in the form of intravenous infusions of a solution of calcium gluconate 10% 1-2 times / day in a maintenance dose of 0.25-0.5 ml / kg / hour or in tablet form: calcium gluconate tablets 500 mg - 25–50 mg/kg/day.

Non-drug therapy.

The bitch must be provided with food with the correct Ca:P ratio. For this purpose, PRO PLAN®STARTER food is ideal, which has a number of advantages:

• increased amount of easily digestible protein 30%;
• fats 18–19% (including essential omega-3 fatty acids for brain and vision development);
• Helps strengthen the puppy's natural immunity thanks to the colostrum in its composition. Supplementation with colostrum reduces the risk of developing intestinal infections during pregnancy and lactation;
• contains easily digestible carbohydrates, prebiotics and bentonite to prevent intestinal disorders;
• easily soaks in water and is optimally suited for the first feeding of puppies at 4 weeks, which allows the mother and offspring to have the same diet.

This diet is available in two variations: for puppies of small and medium breeds and for puppies of large breeds. It is important to note that the food is suitable for pregnant and lactating dogs.

Treatment methods

If convulsions and other obvious symptoms of eclampsia occur, specialists give a potassium injection. If the case is severe, a drip with calcium gluconate or glucose is required. The dose is selected according to the age of the animal. The condition improves quickly after this procedure.

After the exacerbation is relieved, medications are prescribed to regulate the functions of the central nervous system. They are administered in the form of intramuscular injections. A decrease in the intensity of symptoms does not indicate a complete cure. A course of taking capsules containing calcium is required. The course lasts about a month. The dog should not feed the puppies during injections or oral medications.

How to give first aid

Eclampsia is an emergency condition, so a dog with suspicious symptoms should be taken to the clinic immediately. However, in some cases it is useful to provide first aid at home:

• measure temperature rectally; at values ​​above 39.8 C°, start cooling on the way to the clinic using a fan/wet compresses on the hairless surface of the body/coolants on the surface of the body through a diaper or blanket (ice/frozen foods);
• if tremors or convulsions are detected, preventively apply a 40% glucose solution or sweet water to the gums/under the tongue;
• In some literary sources you can find information about the administration of calcium gluconate 10% intramuscularly to create a depot from which calcium will be consumed into the blood as first aid.

However, this method is not recommended due to the risk of developing abscesses and muscle necrosis (especially in toy and small breed dogs).

Treatment

First of all, the dog is given anticonvulsants and the temperature is reduced by medication. For this, intravenous diazepam or barbiturates are most often used.

The main treatment is intravenous infusion of 10% calcium gluconate. It is very important to do this under the supervision of a specialist.

Calcium should not be administered quickly. This is done slowly, setting the speed on a special device - an infusion pump. Otherwise, ventricular fibrillation may begin, which will lead to cardiac arrest.

If the tremors are severe and persistent, sedation may be needed to help the muscles relax.

With timely assistance, the condition quickly returns to normal.

Prevention

To minimize the risk of developing eclampsia in dogs, it is necessary to examine animals before mating and use only healthy representatives of the breed for breeding. Not all diseases cause noticeable symptoms, so it is important to ensure that the animal has normal blood chemistry, is regularly treated for parasites, is vaccinated annually, eats a balanced diet throughout its life, and receives puppy food for the last 3 weeks of the gestation period. All this provides the dog with a resource for successful pregnancy and lactation.

It is important to remember that stress contributes to the development of hypocalcemia, so it is necessary to prevent stressful situations. The bitch needs to create the most comfortable conditions for childbirth and the lactation period. It must have its own place in which the following requirements are met:

• the presence of a birth box of optimal size with sides of such a height that the puppies could not get out or get injured, but the mother could, if necessary, leave the “nest” without stepping on the offspring;
• restriction of visiting people (except the owner);
• maintaining an optimal ambient temperature of 24 C°;
• maintaining optimal indoor humidity (60% or more);
• ensuring constant access to clean water (for normal lactation a dog needs a lot of fluid);
• introduction of a calcium supplement into the diet of dogs at risk during lactation.

Dog care

Since food is the source of calcium, it is important to take a responsible approach to choosing a diet for your dog.

In the embryonic period (up to 40 days of gestation), the growth of puppies is approximately 30%, (7) therefore the needs of the bitch will be effectively covered by a regular diet, for example, PRO PLAN® OPTIBALANCE® for adult dogs of small and toy breeds, medium breeds, large athletic breeds or powerful build.

The main increase in maternal body weight and fetal growth occurs in the last 3 weeks of pregnancy, (7) which is why it is recommended to change the diet to PRO PLAN®STARTER only after 35–40 days of pregnancy. By the time of birth, a dog normally increases its weight by 30–40%.

The feeding regimen should also be reconsidered: make portions smaller, increasing the number of meals to 4 times a day. This need in the later stages arises due to compression of the pregnant uterus on the stomach, reducing its capacity.

The need for calcium increases after the 40th day of pregnancy (due to the mineralization of fetal skeletons), so it is critical to maintain an adequate calcium-phosphorus ratio in the diet (Ca:P = 1.2:1).

Eclampsia is an unpredictable metabolic disorder caused by a deficiency of calcium in the blood. It is potentially fatal and requires immediate veterinary attention. A number of preventive measures on the part of the breeder will help reduce the incidence of the disease in the nursery:

• examination of the stud bitch before mating;
• feeding with balanced food;
• avoiding calcium supplements when feeding a prepared diet during pregnancy;
• preventive calcium supplements in the diet of high-risk dogs immediately after birth;
• stress prevention;
• exclusion from breeding work of dogs systematically suffering from hypocalcemia (subject to compliance with the above conditions).

Bibliography:

1. Severity of Ionized Hypercalcemia and Hypocalcemia Is Associated With Etiology in Dogs and Cats / Michelle Coady, Daniel J. Fletcher and Robert Goggs*. Department of Clinical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY, United States.
2. A CASE REPORT OF ECLAMPSY IN DOG / Dimiter Dimitrov, Nikolay Mehandzhiysky, Iliya Peev, Georgy Georgiev. University of Forestry, Faculty of Veterinary Medicine, Sofia, Bulgaria.
3. Eclampsia in a Dog: An Overview / M. M. Pathan*, G. M. Siddiquee, A. Latif, H. Das, Md. JZ Khan and MK Shukla, Dept. of Animal Physiology & Biochemistry. College of Veterinary Science & A.H. Sardarkrushinagar Dantiwada Agricultural University, Sardarkrushinagar – 385 506, India.
4. Acute Management of Calcium Disorders / Reid P. Groman, DVM, Diplomate ACVIM, ACVECC.
5. Calcium and phosphorus metabolism in peripartal dogs / Stephanie Schmitt, Britta Dobenecker.
6. Canine and Feline Endocrinology, 4th Edition / Edward Feldman Richard Nelson Claudia Reusch J. Catharine Scott-Moncrief.
7. BSAVA Manual of Canine and Feline Reproduction and Neonatology, 2nd Edition / Gary England (Editor), Angelika von Heimendahl (Editor).
8. Monitoring and intensive care of dogs and cats / R. Kirby, E. Linklater.