This is a metabolic disease, which is commonly found in cattle (particularly dairy, as the cows are frequently calving), or female dogs who are pregnant or have recently had a litter (in which case it is also known as Eclampsia). In this I will mainly focus on cows.
Causes
This typically occurs within the first 72 hours after the animal has given birth (parturition), with some being affected several days to weeks before or after the birth. The main cause is a deficiency of calcium, caused by a production of milk for the baby - therefore depriving the mother of the calcium that is used up. The low levels of calcium present in the blood may cause problems for the animal, developing into clinical symptoms in the cases where the animal is unable to replace the lost calcium. Some kinds of cow (for example, Jersey cows) are more susceptible to the disease. Age is also an important factor, with older cows being more likely to be affected due to producing more milk than heifers (a younger cow, before she has had her first calf), as they produce more milk and are less able to replace calcium quickly. The diet of the cow can also cause this. Cows that receive excess calcium have a decreased efficiency in both absorbing calcium in the intestine and transferring the calcium from the skeleton, making them more susceptible to milk fever. Fat cows are also more likely to get milk fever, due to their increased calcium intake and milk production (prior to and following, respectively) calving being higher than in normal cows.
Symptoms & Diagnosis
Initial symptoms may include agitation or a tremor in the muscles (particularly in the triceps and flanks), with the animal being weak or trembling. The condition of the animal deteriorates, with the cow eventually lying down, likely being unable to stand without motivation, if at all.
“Since calcium is required for the release of acetylcholine at the neuromuscular junction, affected animals will begin to experience muscle weakness.” [1]
At this point, they may have a dry muzzle, cold legs and ears, staring eyes and drowsiness. Heart beat becomes weaker and faster, and body temperature drops. It will finally become comatose and unresponsive, head lain on the floor, increasing the likelihood of bloating. If left untreated, cows which have progressed to this stage may only survive for a few hours.
An older cow that is near to calving or has calved recently showing these symptoms is likely to have milk fever. While it is possible to confirm with laboratory results by checking calcium levels, this is often diagnosed based on the clinical signs, due to the fast acting nature of the illness. Early treatment is preferable to delayed, as it improves the animal’s chance of survival.
Treatments
Early treatment means injecting the cow with a calcium supplement, either through the veins (intravenous) or muscle (intramuscular). This is often done by the farmer upon noticing abnormal behaviour of the cow or the above symptoms (since this disease is common among dairy cows that have recently calved), with injection sites being under the skin at the neck or behind the shoulder. Injection into the vein (which could potentially be to the milk vein or jugular) should be left to the veterinary surgeon due to the potential risk, as high levels of calcium is dangerous because calcium is cardiotoxic (damaging to the heart) and so has to be applied slowly. The calcium supplement may be using 300ml or more of a 40% solution of calcium borogluconate.
“A general rule for dosing is 1 g calcium/45 kg (100 lb) body weight.” [2]
Oral calcium may also be administered, as it avoids the risks to the heart, but is not recommended as the sole treatment (cows with hypocalcaemia may also have difficulty swallowing, making oral treatments more difficult to administer if this is the case with a particular cow). As well as calcium this provides magnesium, which may also be at low levels, which protects against myocardial irritation (irritation of the muscular tissue of the heart) caused by the administration of calcium, and to produce the appropriate hormone (parathyroid hormone, PTH) in response to hypocalcaemia.
If a cow is lying on it’s side it should be sat up, and stood up if possible. This is to relieve bloating, as gas in the rumen may build up, being unable to escape. As well as this, the longer a cow lays on it's side, the less likely it is to stand up, making sitting it up as soon as possible important.
The response to treatment with calcium to the vein should be immediate, with tremors appearing (muscular function returning) and the heart rate slowing and becoming stronger.
“Approximately 75% of cows stand within 2 hr of treatment. Animals not responding by 4–8 hr should be reevaluated and retreated if necessary.” [3]
References - provided general understanding of the disease; including symptoms, causes and treatments
Bovine Postparturient Paresis
http://www.vetmedclinic.com/?p=279
- Quoted, explains the muscle tremors and inability to stand in a cow with milk fever, [1]
Parturient Paresis in Cows: Disorders of Calcum Metabolism: Merck Veterinary Manual
http://www.merckmanuals.com/vet/metabolic_disorders/disorders_of_calcium_metabolism/parturient_paresis_in_cows.html
- Quoted, general rule for dosage of calcium solution, [2]
- Quoted, approximation on treatment responses, [3]
DEPI - Milk Fever (Hypocalcaemia)
http://www.depi.vic.gov.au/agriculture-and-food/pests-diseases-and-weeds/animal-diseases/beef-and-dairy-cows/milk-fever-hypocalcaemia-in-cows
Charlotte O'Connor
Causes
This typically occurs within the first 72 hours after the animal has given birth (parturition), with some being affected several days to weeks before or after the birth. The main cause is a deficiency of calcium, caused by a production of milk for the baby - therefore depriving the mother of the calcium that is used up. The low levels of calcium present in the blood may cause problems for the animal, developing into clinical symptoms in the cases where the animal is unable to replace the lost calcium. Some kinds of cow (for example, Jersey cows) are more susceptible to the disease. Age is also an important factor, with older cows being more likely to be affected due to producing more milk than heifers (a younger cow, before she has had her first calf), as they produce more milk and are less able to replace calcium quickly. The diet of the cow can also cause this. Cows that receive excess calcium have a decreased efficiency in both absorbing calcium in the intestine and transferring the calcium from the skeleton, making them more susceptible to milk fever. Fat cows are also more likely to get milk fever, due to their increased calcium intake and milk production (prior to and following, respectively) calving being higher than in normal cows.
Symptoms & Diagnosis
Initial symptoms may include agitation or a tremor in the muscles (particularly in the triceps and flanks), with the animal being weak or trembling. The condition of the animal deteriorates, with the cow eventually lying down, likely being unable to stand without motivation, if at all.
“Since calcium is required for the release of acetylcholine at the neuromuscular junction, affected animals will begin to experience muscle weakness.” [1]
At this point, they may have a dry muzzle, cold legs and ears, staring eyes and drowsiness. Heart beat becomes weaker and faster, and body temperature drops. It will finally become comatose and unresponsive, head lain on the floor, increasing the likelihood of bloating. If left untreated, cows which have progressed to this stage may only survive for a few hours.
An older cow that is near to calving or has calved recently showing these symptoms is likely to have milk fever. While it is possible to confirm with laboratory results by checking calcium levels, this is often diagnosed based on the clinical signs, due to the fast acting nature of the illness. Early treatment is preferable to delayed, as it improves the animal’s chance of survival.
Treatments
Early treatment means injecting the cow with a calcium supplement, either through the veins (intravenous) or muscle (intramuscular). This is often done by the farmer upon noticing abnormal behaviour of the cow or the above symptoms (since this disease is common among dairy cows that have recently calved), with injection sites being under the skin at the neck or behind the shoulder. Injection into the vein (which could potentially be to the milk vein or jugular) should be left to the veterinary surgeon due to the potential risk, as high levels of calcium is dangerous because calcium is cardiotoxic (damaging to the heart) and so has to be applied slowly. The calcium supplement may be using 300ml or more of a 40% solution of calcium borogluconate.
“A general rule for dosing is 1 g calcium/45 kg (100 lb) body weight.” [2]
Oral calcium may also be administered, as it avoids the risks to the heart, but is not recommended as the sole treatment (cows with hypocalcaemia may also have difficulty swallowing, making oral treatments more difficult to administer if this is the case with a particular cow). As well as calcium this provides magnesium, which may also be at low levels, which protects against myocardial irritation (irritation of the muscular tissue of the heart) caused by the administration of calcium, and to produce the appropriate hormone (parathyroid hormone, PTH) in response to hypocalcaemia.
If a cow is lying on it’s side it should be sat up, and stood up if possible. This is to relieve bloating, as gas in the rumen may build up, being unable to escape. As well as this, the longer a cow lays on it's side, the less likely it is to stand up, making sitting it up as soon as possible important.
The response to treatment with calcium to the vein should be immediate, with tremors appearing (muscular function returning) and the heart rate slowing and becoming stronger.
“Approximately 75% of cows stand within 2 hr of treatment. Animals not responding by 4–8 hr should be reevaluated and retreated if necessary.” [3]
References - provided general understanding of the disease; including symptoms, causes and treatments
Bovine Postparturient Paresis
http://www.vetmedclinic.com/?p=279
- Quoted, explains the muscle tremors and inability to stand in a cow with milk fever, [1]
Parturient Paresis in Cows: Disorders of Calcum Metabolism: Merck Veterinary Manual
http://www.merckmanuals.com/vet/metabolic_disorders/disorders_of_calcium_metabolism/parturient_paresis_in_cows.html
- Quoted, general rule for dosage of calcium solution, [2]
- Quoted, approximation on treatment responses, [3]
DEPI - Milk Fever (Hypocalcaemia)
http://www.depi.vic.gov.au/agriculture-and-food/pests-diseases-and-weeds/animal-diseases/beef-and-dairy-cows/milk-fever-hypocalcaemia-in-cows
Charlotte O'Connor