Milk fever, postparturient hypocalcemia, or parturient paresis is a disease, primarily in

dairy cattle Dairy cattle (also called dairy cows) are cattle bred for the ability to produce large quantities of milk, from which dairy products are made. Dairy cattle generally are of the species ''Bos taurus''. Historically, little distinction was mad ...

but also seen in

beef cattle Beef cattle are cattle raised for meat production (as distinguished from dairy cattle, used for milk production). The meat of mature or almost mature cattle is mostly known as beef. In beef production there are three main stages: cow-calf operat ...

and non-bovine

domesticated animals This page gives a list of domesticated animals, also including a list of animals which are or may be currently undergoing the process of domestication and animals that have an extensive relationship with humans beyond simple predation. This includ ...

, characterized by reduced blood

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...

levels (

hypocalcemia Hypocalcemia is a medical condition characterized by low calcium levels in the blood serum. The normal range of blood calcium is typically between 2.1–2.6 mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L) while levels less than 2.1 mm ...

). It occurs following

parturition Birth is the act or process of bearing or bringing forth offspring, also referred to in technical contexts as parturition. In mammals, the process is initiated by hormones which cause the muscular walls of the uterus to contract, expelling the f ...

, at onset of

lactation Lactation describes the secretion of milk from the mammary glands and the period of time that a mother lactates to feed her young. The process naturally occurs with all sexually mature female mammals, although it may predate mammals. The proces ...

, when demand for calcium for

colostrum Colostrum, also known as beestings or first milk, is the first form of milk produced by the mammary glands of mammals (including humans) immediately following delivery of the newborn. Colostrum powder is rich in high protein and low in sugar and ...

and

milk Milk is a white liquid food produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals (including breastfed human infants) before they are able to digestion, digest solid food. Immune factors and immune ...

production exceeds the body's ability to mobilize calcium. "

Fever Fever, also referred to as pyrexia, is defined as having a body temperature, temperature above the human body temperature, normal range due to an increase in the body's temperature Human body temperature#Fever, set point. There is not a single ...

" is a misnomer, as

body temperature Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature ...

during the disease is generally not elevated. Milk fever is more commonly seen in older animals (which have reduced ability to mobilize calcium from bone) and in certain breeds (such as

Channel Island The Channel Islands ( nrf, Îles d'la Manche; french: îles Anglo-Normandes or ''îles de la Manche'') are an archipelago in the English Channel, off the French coast of Normandy. They include two Crown Dependencies: the Bailiwick of Jersey, ...

breeds).

Clinical signs

The clinical signs of milk fever can be divided into three distinct stages:

Stage 1

Cows are mobile but show signs of

hypersensitivity Hypersensitivity (also called hypersensitivity reaction or intolerance) refers to undesirable reactions produced by the normal immune system, including allergies and autoimmunity. They are usually referred to as an over-reaction of the immune s ...

and excitability such as restlessness, tremors, ear twitching, head bobbing, and mild

ataxia Ataxia is a neurological sign consisting of lack of voluntary coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements. Ataxia is a clinical manifestation indicating dysfunction of ...

. If not treated, symptoms usually progress to stage 2.

Stage 2

Cows can no longer stand and present in sternal

recumbency Lyingalso called recumbency, prostration, or decubitus in medicine ()is a type of human position in which the body is more or less horizontal and supported along its length by the surface underneath. Lying is the most common position while bein ...

Tachycardia Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal (su ...

, weakened heart contraction and peripheral pulses. Cows appear dull, have dry muzzles, cold extremities and a lower than normal body temperature. Smooth muscle

paralysis Paralysis (also known as plegia) is a loss of motor function in one or more muscles. Paralysis can also be accompanied by a loss of feeling (sensory loss) in the affected area if there is sensory damage. In the United States, roughly 1 in 50 ...

can cause bloat, and the inability to urinate or defecate. Cows often tuck their heads into their flanks. Touma velêyes eståde3

Stage 3

Lateral recumbency, muscle flaccidity, unresponsiveness to stimuli, and loss of consciousness progressing to

coma A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to respond normally to painful stimuli, light, or sound, lacks a normal wake-sleep cycle and does not initiate voluntary actions. Coma patients exhi ...

. Heart rate can approach 120 bpm, with peripheral pulses becoming undetectable. If untreated, progression will continue to death.

Cause

During the dry period (late gestation, non-lactating), dairy cattle have relatively low calcium requirements, with a need to replace approximately 30 g of calcium per day due to utilization for fetal growth and fecal and urinary losses. At parturition, the requirement for calcium is greatly increased due to initiation of lactation, when

mammary A mammary gland is an exocrine gland in humans and other mammals that produces milk to feed young offspring. Mammals get their name from the Latin word ''mamma'', "breast". The mammary glands are arranged in organs such as the breasts in prima ...

drainage of calcium may exceed 50g per day. Due to this large increase in demand for calcium, most cows will experience some degree of hypocalcemia for a short period following

as the metabolism adjusts to the increased demand. When the mammary drain of plasma calcium causes hypocalcemia severe enough to compromise

neuromuscular A neuromuscular junction (or myoneural junction) is a chemical synapse between a motor neuron and a muscle fiber. It allows the motor neuron to transmit a signal to the muscle fiber, causing muscle contraction. Muscles require innervation t ...

function, the cow is considered to have clinical milk fever.

Mechanism

In normal calcium regulation, a decrease in plasma calcium levels causes the

parathyroid gland Parathyroid glands are small endocrine glands in the neck of humans and other tetrapods. Humans usually have four parathyroid glands, located on the back of the thyroid gland in variable locations. The parathyroid gland produces and secretes pa ...

s to secrete

parathyroid hormone Parathyroid hormone (PTH), also called parathormone or parathyrin, is a peptide hormone secreted by the parathyroid glands that regulates the serum calcium concentration through its effects on bone, kidney, and intestine. PTH influences bone re ...

(PTH), which regulates the activation of Vitamin D₃ in the

kidney The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; blood ...

. These two compounds act to increase blood calcium levels by increasing absorption of dietary calcium from the

intestine The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans ...

, increasing renal tubular reabsorption of calcium in the kidney, and increasing resorption of calcium from bones. It has been found that tissue is less responsive to

prepartum, compared to postpartum. It is believed that hypocalcemia causing milk fever is due to a lower level of responsiveness of the cow's tissues to circulating parathyroid hormone. The resultant decreased plasma calcium causes hyperexcitability of the

nervous system In biology, the nervous system is the highly complex part of an animal that coordinates its actions and sensory information by transmitting signals to and from different parts of its body. The nervous system detects environmental changes th ...

and weakened muscle contractions, which result in both tetany and

paresis In medicine, paresis () is a condition typified by a weakness of voluntary movement, or by partial loss of voluntary movement or by impaired movement. When used without qualifiers, it usually refers to the limbs, but it can also be used to desc ...

Prevention

Diet

Proper dietary management will prevent most cases of milk fever. This generally involves close attention to mineral and

fiber Fiber or fibre (from la, fibra, links=no) is a natural or artificial substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate ...

levels in the diet prior to calving, as well as improving cow comfort to eliminate other problems that may interfere with appetite (and so trigger hypocalcemia). General advice is to restrict calcium intake before calving, as this leads to the parathyroid gland stimulating the release of calcium from bones.

Calcium Salts

A synthetic analogue of

25-hydroxycholecalciferol Calcifediol, also known as calcidiol, 25-hydroxycholecalciferol, or 25-hydroxyvitamin D3 (abbreviated 25(OH)D3), is a form of vitamin D produced in the liver by hydroxylation of vitamin D3 (cholecalciferol) by the enzyme vitamin D 25-hydroxylas ...

can be given by injection in the days leading up to calving, although the timing of this

prophylaxis Preventive healthcare, or prophylaxis, consists of measures taken for the purposes of disease prevention.Hugh R. Leavell and E. Gurney Clark as "the science and art of preventing disease, prolonging life, and promoting physical and mental hea ...

makes it difficult to use. Oral administration of a dose of a

calcium salt Although most compounds are referred to by their IUPAC systematic names (following IUPAC nomenclature), traditional names have also been kept where they are in wide use or of significant historical interests. A Ac * Actinium(III) chlorid ...

in a gel has been advised by some veterinarians. An orally administered bolus containing a much higher concentration of calcium than the injectable solutions can also be given so long as the cow is standing or sitting up. If the cow is lying 'flat out' then immediate intravenous therapy is required to avoid death.

Treatment

Treatment generally involves calcium injection by intravenous, intramuscular or subcutaneous routes. Before calcium injection was employed, treatment comprised inflation of the udder using a pneumatic pump. Inflation of the udder worked because the increased pressure created in the udder pushed the calcium in the udder back into the bloodstream of the cow. Intravenous calcium, though indicated in many cases, is potentially fatal through "heart blockade", or transient high calcium levels stopping the heart, so should be administered with care. Cows are to be fed

jaggery Jaggery is a traditional non-centrifugal cane sugar consumed in the Indian Subcontinent, Southeast Asia, and Africa. It is a concentrated product of cane juice and often date or palm sap without separation of the molasses and crystals, and can ...

along with the lime water mixture. In unclear cases of

downer cow A downer is an animal, usually livestock, that cannot stand on its own and therefore is to be killed. A downed animal, one that is unable to stand, is not necessarily a downer. Causes The animal's inability to stand may be caused by illness or ...

s, intravenous calcium injection can lead to

diagnosis Diagnosis is the identification of the nature and cause of a certain phenomenon. Diagnosis is used in many different disciplines, with variations in the use of logic, analytics, and experience, to determine " cause and effect". In systems engin ...

. The typical reaction will be a generalized

tremor A tremor is an involuntary, somewhat rhythmic, muscle contraction and relaxation involving oscillations or twitching movements of one or more body parts. It is the most common of all involuntary movements and can affect the hands, arms, eyes, fa ...

of the

skeletal muscle Skeletal muscles (commonly referred to as muscles) are organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other types of muscl ...

s, and sometimes

cardiac arrhythmia Arrhythmias, also known as cardiac arrhythmias, heart arrhythmias, or dysrhythmias, are irregularities in the heartbeat, including when it is too fast or too slow. A resting heart rate that is too fast – above 100 beats per minute in adults ...

Defecation Defecation (or defaecation) follows digestion, and is a necessary process by which organisms eliminate a solid, semisolid, or liquid waste material known as feces from the digestive tract via the anus. The act has a variety of names ranging f ...

urination Urination, also known as micturition, is the release of urine from the urinary bladder through the urethra to the outside of the body. It is the urinary system's form of excretion. It is also known medically as micturition, voiding, uresis, ...

and

eructation Burping (also called belching and eructation) is the release of gas from the upper digestive tract (esophagus and stomach) of animals through the mouth. It is usually audible. In humans, burping can be caused by normal eating processes, or as ...

are frequent during the treatment, due to pharmacological effect of calcium on the

smooth muscle Smooth muscle is an involuntary non-striated muscle, so-called because it has no sarcomeres and therefore no striations (''bands'' or ''stripes''). It is divided into two subgroups, single-unit and multiunit smooth muscle. Within single-unit mus ...

Prognosis

The prognosis is generally good, even in advanced cases. However, some cows can relapse the following day, and even a third time the day after. (unpublished data) Without treatment, between 60% and 80% of cows usually die, although death rates as high as 90% have been recorded.

History

It is thought that milk fever has existed for a very long time in dairy cattle. The first reports in veterinary literature can be traced to around 1793.

Early Theories

Early treatments involved

venesection In medicine, venipuncture or venepuncture is the process of obtaining intravenous access for the purpose of venous blood sampling (also called ''phlebotomy'') or intravenous therapy. In healthcare, this procedure is performed by medical labor ...

, but this proved ineffective.

Potassium Iodide

In the late 1800s, Jurgens Schmidt proposed the use of an infused solution of

potassium iodide Potassium iodide is a chemical compound, medication, and dietary supplement. It is a medication used for treating hyperthyroidism, in radiation emergencies, and for protecting the thyroid gland when certain types of radiopharmaceuticals are us ...

for treatment. A follow-up study of this treatment by

Danish Danish may refer to: * Something of, from, or related to the country of Denmark People * A national or citizen of Denmark, also called a "Dane," see Demographics of Denmark * Culture of Denmark * Danish people or Danes, people with a Danish a ...

veterinarians showed that 90% of cows recovered after use of the treatment, compared with only 20-40% survival without. A study in

Iowa Iowa () is a state in the Midwestern region of the United States, bordered by the Mississippi River to the east and the Missouri River and Big Sioux River to the west. It is bordered by six states: Wisconsin to the northeast, Illinois to the ...

showed that 76.5% of cows recovered after use of the treatment. However, the premise of the Schmidt treatment was misleading, as later veterinarians used water alone to the same success rate.

Udder Inflation

In 1901, Anderson and Evers trialled a treatment of udder inflation with air, which reduced mortality rates to just 1%. although with the added complication of

mastitis Mastitis is inflammation of the breast or udder, usually associated with breastfeeding. Symptoms typically include local pain and redness. There is often an associated fever and general soreness. Onset is typically fairly rapid and usually occurs ...

. Although this was an effective treatment (and is still used as a backup today), it was not understood at the time why it worked, and remains the source of some debate. Some scientists believed that udder inflation could cause stimulation that then prevents calcium loss. Other scientists suggested that udder inflation prevented milk secretion, reducing calcium loss overall. This may prevent calcium being taken from the blood plasma.

Later Theories

The true cause of milk fever was first suggested by Prof

John Russell Greig John McDougal Russell Greig CBE FRSE MRCVS (September 1889-1 May 1963) was a Scottish veterinarian who was Director of the Moredun Research Institute from 1930 to 1954. He is noted for the development of several important animal vaccines: Enzo ...

and

Henry Dryerre Prof Henry Dryerre FRSE MRCS LRCP (1881–5 February 1959) was a Scottish veterinarian and animal physiologist. He was Emeritus Professor of Physiology at the Dick Veterinary College in Edinburgh. The Carnegie Trust for the Universities of Sco ...

in March 1925, at the

Moredun Research Institute The Moredun Research Institute is a scientific research institution based at the Pentlands Science Park, in the Bush Estate area of Midlothian, Scotland. It conducts research into diseases of farm livestock and the promotion of animal health and ...

Scotland Scotland (, ) is a country that is part of the United Kingdom. Covering the northern third of the island of Great Britain, mainland Scotland has a border with England to the southeast and is otherwise surrounded by the Atlantic Ocean to the ...

. This idea was later confirmed experimentally by Little and Wright in May 1925. By 1933, Pulles began treatments with

magnesium chloride Magnesium chloride is the family of inorganic compounds with the formula , where x can range from 0 to 12. These salts are colorless or white solids that are highly soluble in water. These compounds and their solutions, both of which occur in natu ...

and

calcium chloride Calcium chloride is an inorganic compound, a salt with the chemical formula . It is a white crystalline solid at room temperature, and it is highly soluble in water. It can be created by neutralising hydrochloric acid with calcium hydroxide. Ca ...

, which is the basis for modern pharmaceutical treatments.

References

External links

Prevention of Milk Fever

University of Kentucky The University of Kentucky (UK, UKY, or U of K) is a Public University, public Land-grant University, land-grant research university in Lexington, Kentucky. Founded in 1865 by John Bryan Bowman as the Agricultural and Mechanical College of Kentu ...

Parturient Paresis in Cows (Milk fever, Hypocalcemia)

The Merck Veterinary Manual The ''Merck Veterinary Manual'' is a reference manual of animal health care. It was first published by Merck & Co., Inc. in 1955. It contains concise, thorough information on the diagnosis and treatment of disease in a wide variety of species. ...

{{Commons category, Hypocalcemia in ruminants Bovine diseases Dairy farming