Research Articles/Papers-PG/PhD Abstracts

MILK FEVER / HYPOCALCAEMIA IN DAIRY CATTLE

August 20, 2019

717

MILK FEVER / HYPOCALCAEMIA

Nandani Kumari(Assistant Professor Cum Junior Scientist, Deptt. of Animal Breeding and Genetics, R.V.C., B.A..U

Synonym- Milk Fever, Post Parturient hypocalcaemia or parturient paresis.

It is a metabolic disease associated with low serum calcium level found in dairy cattle, buffalo, sheep, goat and even dogs generally during periparturient period.

Etiology- Low serum calcium level is the main cause of Milk fever or Hypocalcaemia other reasons include low serum phosphorus level, High serum potassium level , imbalanced or improper feeding before parturition, Draining the cattle off milk in periparturient period also without proper Dry period, Feeding calcium rich during dry period, Aged cattle, High yielder, Parturition stress in Cattle.

Generally on an average about 23 gms of calcium is drained for every 10 litres of colustrum produced just after calving. If this amount is added to dairy requirement during this period, the need is about ten times higher than the supply of calcium through feed. Milk fever develops when serum calcium level drops below 6.5 mg/dl of blood from normal of 8-10 mg/dl of blood.

Symptoms– Agitation/ excitement, tremor in muscles of head and limb, goes to sitting position, dry muzzle, staring eyes, cold legs, ears , constipation and drowsiness, weaker and faster heartbeat, normal body temperature, especially in cold wet windy weather.

Additional signs might be observed due to complicating factors like Bloat, Pneumonia. Generally the clinical signs can be divided into three stages with hypersensitivity , tremor , excitability, ataxia being witnessed in first stage , sternal recumbancy being seen in second stage and lateral recumbancy being seen in third stage.

Mechanism of Disease Occurance– Decrease in plasma calcium levels causes parathyroid glands to secrete parathyroid hormone(PTH), which regulates the activation of vitamin D3 in Kidney . They act to increase blood calcium levels by increasing the absorption of dietary calcium from intestine, increasing the renal tubular reabsorption of calcium in Kidney. It has been found that tissue is less responsive to parathyroid hormone prepartum compared to post partum. It is believed that hypocalcemia causing milk fever is due to lower level of responsiveness of cow’s tissue to circulating parathyroid hormone. The factor coupled with increased drainage of calcium through milk and or improper calcium supplementation causes decreased plasma calcium causes hyperexcitability of nerves and weakened muscle contraction which results in both tetany and paresis( https://en.w.wikipedia.org/wiki/milkfever )

Treatment-

Calcium magnesium borogluconate administration ( partly by I/V partly S/C)
Organic Phosphorus like Tonophosphan – 15 ml I/M daily for four days
B-Complex-Orally / I/M
Chlorpheneramine maleate/ Avil – 10 Ml -I/M

Note- Along with medicine it is very important to make the animal stand up as it might be a gateway of several other diseases and secondary complications if recumbent for a long period.

Few important querries regarding Milk fever which came to my mind while studying milk fever or I encountered during discussion with farmers or veterinarians are as follows-

Q.1. Is it dependent on age and How?

Ans.- Heifers are generally well managed w.r.t. vitamins and feed supplementation for their calving. Further with increased number of parity/calving ( 4-5^th onwards), the drainage of calcium from serum is more and Hence the risk is increased. According to Garis and Lean, age increases the risk of milk fever by approximately 9% per lactation.

Q.2. What is DCAD and discuss its role in prevention of Milk Fever.

DCAD/ Dietary cation / anion difference is based on the fact that Cations have a positive charge like sodium (Na), potassium (K), calcium (Ca), and magnesium (Mg). Cations in the diet promote a more alkaline (higher blood pH) metabolic state which has been associated with an increased incidence of milk fever. Anions have a negative charge such as chloride (Cl), sulfur (S) and phosphorus (P). Anions promote a more acidic metabolic state (lower blood pH) that is associated with a reduced incidence of milk fever. A cow adjusts to a lower blood pH by buffering the acidic condition. A cow adjusts to a lower blood PH by buffering the acidic condition [Dietary Cation-Anion Difference (DCAD).html.]. Feeding potassium rich forage increases the level of cations leading to increased risk of milk fever.

3.Does dietary phosphorus influence the occurance of Milk fever? How?

Yes, as has been proved by researchers, the relative amount of dietary calcium. Phosphorus influences markedly the size and presumably the activity parathyroids ( Boda and Cole, 1953). His research further showed that a low calcium high phosphorus diet ( calcium- phosphorus ratio of 1.3.3) fed during the last month of the dry period effectively prevents milk fever . The appears to be a direct correlation between Calcium-phosphorus ratio of prepartum diet and the incidence of milk fever. Thus 30%of the animals receiving a dietary calcium-phosphorus ratio of 6:1, 15% of the cows fed a dietary calcium-phosphorus ratio of 1:1, and none of those fed a 1:3.3 dietary calcium-phosphorus ratio exhibited clinical symptoms of milk fever.

Q.4. Is there any effect of serum magnesium /potassium level on milk fever.

According to Meynard and Thompson(2007), the result from 86 animals that were part of 529 post parturient recumbent Holstein Friesan cows treated by the practice confirmed that both pretreatment Ca and P are important risk factors to ADC outcome( Alert Downers Cow outcome), but Mg , K, and age were not. While according to many other relevant literatures, potassium, Phosphorus, Magnesium are all very important via DCADin the body . So uncertainty still persists and as a preventive measure , the forage rich in potassium is avoided in periparturient or lactating cattle and Magnesium and phosphorus is also administered along with calcium in the treatment of milk fever.

REFERENCE-

Andrew J. Allen. Parturient paresis in cows .www.msdvetmanual.com/.metabolic-disorders –of-calcium-metabolism/parturient –paresis in cows.
Boda J.M., Coli.H.H.( 1954). The influence of dietary calcium and phosphorus on the incidence of Milk fever in Dairy Cattle. 4(37). Pp.360-372.

3.Menard, L. and Thompson A. (2007). Milk fever and alert downer cows: Does hypophosphatemia affect the treatment response? . Can Vet J. 45(5): 487-491.