Postpartum hypocalcemia in female dogs should not be ignored, and dog owners need to take it seriously

Postpartum hypocalcemia in female dogs, also known as postpartum eclampsia, postpartum tetany or lactation eclampsia, is a serious metabolic disorder in female dogs after giving birth. This disease is mainly characterized by hypocalcemia and muscle tonic spasms caused by abnormal excitation of motor nerves, accompanied by symptoms such as increased respiratory rate. This disease is paroxysmal and mostly occurs in small dogs or medium-sized high-yielding female dogs 10 to 20 days after delivery. At present, domestic techniques for diagnosing and treating this disease are relatively mature, and the treatment results are also relatively satisfactory. The basic approach is symptomatic treatment and calcium supplementation. During the treatment of 5 cases, the author monitored blood calcium ion concentration in order to determine the relationship between blood calcium ion concentration and the severity of clinical symptoms, and to provide a reference basis for clinical work.

1 Clinical symptoms

Postpartum hypocalcemia mostly occurs in high-yielding female dogs 10 to 25 days after delivery, and affected dogs often develop the disease suddenly without warning. In the early stage of the disease, the affected dog shows restlessness, reduced appetite, sensitivity to external stimuli, repeated chewing and swallowing, and abnormal consciousness, but still responds during breathing, and body temperature rises above 40°C. Subsequently, it shows accelerated heartbeat, rapid breathing, enhanced heart sounds, upward rolling of the eyeballs, hesitant movement, stiff gait, generalized trembling, and muscular tonic, intermittent or continuous spasms. In severe late stages, the dog lies on the ground unable to stand or even shows opisthotonus, with excessive salivation at the corners of the mouth, and body temperature continuously rising above 43°C.

2 Determination of whole blood calcium ion concentration

Add 2.5 ml of whole blood from dogs I, II and III to 0.2 ml of sodium hydroxide respectively, add 2 drops of calcium indicator, mix, titrate with EDTANa2 until pale blue, and record the consumption of EDTANa2 concentration respectively. According to the laboratory determination of calcium ions using 1 ml of EDTANa2, the blood calcium ion concentrations of case dogs I, II and III were 5.4 mg/100 ml, 5.9 mg/100 ml and 6.8 mg/100 ml respectively.

3 Treatment

3.1 Calcium supplementation

For affected dogs with relatively severe spastic symptoms (such as dog I), add 20 ml of 10% calcium gluconate to 200 ml of 5% glucose injection and inject slowly intravenously at a speed of 1 to 3 ml/minute (or administer by intravenous drip). At the same time, add 2 to 3 ml each of vitamin B1 and vitamin C to the injection, inject vitamin D3 200,000 Iu intramuscularly, and draw 2 ml of whole blood at 15 minutes and 25 minutes respectively, then determine the concentration in the laboratory according to the whole blood calcium ion concentration determination method. Usually, after the infusion is completed, the dog can stand and walk, and all other conditions return to normal. On the second day, infuse 10 ml of 10% calcium gluconate and 100 ml of 5% glucose injection again until recovery.

For affected dogs with milder spastic symptoms and longer intervals (5 to 6 minutes) (dog II), add 10 ml of 10% calcium gluconate to 100 ml of 5% glucose solution for injection. On the same day, inject 2 to 3 ml each of vitamin B1 and vitamin C, and inject vitamin D3 200,000 lu intramuscularly. After 15 minutes, the spastic symptoms disappeared. On the second day, supplement with 5 ml of calcium again until recovery.

3.2 Symptomatic and auxiliary therapy

① For dogs with relatively severe convulsions and spasms (dog 1), inject the sedative chlorpromazine intramuscularly at 2 to 4 mg/kg body weight. ② Appropriately supplement magnesium ions, such as intravenous injection of 2.5% magnesium sulfate 2 to 5 ml (dissolved in 200 ml of normal saline or Ringer's solution) to maintain the balance of calcium ion and magnesium ion concentrations in the dog's body and to alleviate convulsions and spasms in the dog. ③ For those with excessively high body temperature, inject 2 to 4 ml of aminopyrine intramuscularly. ④ After the condition is relieved, orally administer vitamin D 500 to 1000 Iu daily.

3.3 Prevention of secondary infection

Use ampicillin 1 to 3 g intravenously or intramuscularly, but attention should be paid to allergy.

4 Results

After treatment by the above methods, all 5 affected dogs were cured.

5 Prevention

5.1 In daily feeding, provide more foods containing relatively high calcium ions and vitamins, such as bone soup and green vegetables. Especially for dogs fed mainly meat after pregnancy, an appropriate amount of calcium ions should be added to the food. According to available data, for every 1.00 g of meat fed, 0.5 to 1 g of calcium carbonate should be added.

5.2 After the female dog develops the disease, the puppies should be isolated as much as possible and artificially nursed in order to improve the female dog's nutrition and promote recovery of body condition.

5.3 On the day of onset, inject vitamin D3 300,000 lu intramuscularly, and repeat the injection once at an interval of 2 weeks.

5.4 Orally administer vitamin D calcium gelatin tablets, once daily, 2 tablets each time, for 7 consecutive days.

6 Discussion

6.1 The prominent feature of hypocalcemia in female dogs is elevated body temperature (this was true in all 5 cases). Clinical observation shows that when convulsions and spasms occur, body temperature mostly rises to 41 to 42.5°C, with the highest reaching 43.5°C. This is clearly different from the symptoms of postpartum calcium deficiency in other animals, and is determined by the physiological characteristics of dogs. In addition to participating in skeletal muscle metabolism, calcium ions in the blood also participate in the normal conduction of nerve impulses. When blood calcium decreases, the excitability of nerves and muscles increases, causing convulsions and spasms, which produce a large amount of heat. However, because dogs have poorly developed sweat glands, they can only dissipate heat through respiration and evaporation of saliva, causing heat to accumulate in large amounts within the body in a short time, thereby producing symptoms of high fever and excessive salivation.

6.2 This disease often occurs in high-yielding female dogs 10 to 20 days after delivery, and affected dogs develop the disease suddenly. This is often easily confused with hypoglycemia in female dogs, nervous-type canine distemper and vitamin B1 deficiency. To confirm the diagnosis and ensure treatment safety, blood calcium ion determination can be carried out along with supportive therapy, and calcium preparations can be injected intravenously until whole blood calcium is normal. For mild cases, an appropriate amount of calcium preparation can be injected or vitamin D and calcium preparations can be injected intramuscularly, and during intravenous injection attention should be paid to observing cardiac changes. If symptoms of arrhythmia appear, calcium tablets can be given instead, while orally administering vitamin D 3,000,000 Iu/kg body weight for 10 consecutive days.

6.3 Direct calcium supplementation in the blood can quickly control the condition, but because its metabolism is fast and it is continuously absorbed and utilized, continuous calcium supplementation for several days is needed. To ensure sufficient absorption and utilization of calcium ions, vitamin D3 should be supplemented at the same time. Although calcium supplementation can increase blood calcium ion concentration, calcium obtained from food may not necessarily be fully absorbed and utilized. If lactation continues after the condition is controlled once, the female dog will develop calcium deficiency again, while vitamin D3 can effectively help the body absorb and utilize calcium. However, when supplementing vitamin D3, attention should be paid not to supplement in large doses within a short period, so as to avoid poisoning.

6.4 A sharp drop in postpartum blood calcium concentration in female dogs is the direct cause of this disease. According to surveys, the feed of affected female dogs is mostly meat-based. Relevant data show that the calcium content in both raw and cooked meat is relatively low, with a calcium-to-phosphorus ratio of 1:20. The optimal calcium-to-phosphorus ratio in food is (1.2 to 1.4):1. Because the calcium-to-phosphorus ratio in meat is imbalanced, dogs remain in a calcium-deficient state for a long time. At the same time, because the gastrointestinal digestive and absorptive function of female dogs decreases after delivery, the amount of calcium absorbed by the intestines is significantly reduced. Especially in late pregnancy, the increased consumption for fetal development and the weakened gastrointestinal absorption capacity reduce the calcium reserve in the bones, making it impossible to compensate for the large postpartum calcium consumption (or certain pathological factors such as decreased thyroid function may make it impossible for the female dog to mobilize calcium ions from the bones to restore blood calcium ion levels). Therefore, in order to prevent the occurrence of this disease, it is recommended to appropriately add calcium ions to the feed of female dogs during pregnancy and lactation. For every 100 g of fresh meat fed to dogs, add 0.5 g of calcium carbonate; for every 100 ml of milk fed, add 0.15 g of calcium carbonate, while orally administering vitamin D 3,000,000 lu/kg body weight. In this way, the dog's calcium needs can be met.