Milk Fever: Prevention Strategies with Special Emphasis on Nutritional Management

There are a few diseases/disorders in dairy cattle and buffaloes which occur for improper feeding and/ or nutritional management. Milk fever is one of such disorders which occurs due to faulty feeding practices during the pregnancy period and immediately after calving of dairy animals.

Milk fever is a disease of high producing dairy animals occurring within one or two days after calving. It is because of low calcium supply through feeds and hence the animal is unable to meet the demand of the body’s requirement for heavy drainage of calcium through milk. On an average, there is drainage of about 23 g of calcium for every 10 litres of colostrum produced just after calving. If this amount is added to the daily requirement during this period the need is about 10 times higher than the supply of calcium through feed. When feed-stuffs provided to the cows are unable to meet this requirement of needed calcium, milk fever develops. Milk fever develops when serum calcium drops below 6.5 mg/dl of blood from normal 8-10 mg/ dl of blood.

Milk fever can also be called the ‘gateway disease’ as it increases the risk of other diseases manifold such as mastitis, ketosis, retained placenta, displaced abomasum and uterine prolapsed.

Common observable symptoms in milk fever

1. Depression and unwillingness to move and eat.
2. The body temperature goes below normal and the extremities becomes cold.
3. The muzzle and nose become dry.
4. The eyes become dull and expressionless and the membrane covering the eye turn reddened.
5. The animal lies with its head turned to one side for which the neck assumes an S shape.
6. The pulse and breathing become accelerated and very often breathing becomes laboured and accompanied by groaning.
7. There may be bloating i.e. accumulation of excessive gases in the rumen as the gut becomes paralysed.
8. The animal goes to coma and death may occur within a few hours.

Nutritional strategies to prevent milk fever

Occurrence of Milk fever has direct relationship with the feeding strategies followed during the pregnancy and immediately after calving. Thus, it is possible to prevent milk fever by adopting appropriate feeding strategies during the above mentioned periods. The following feeding strategies are suggested to prevent milk fever occurrence in high milk producing dairy cows.

Restriction of calcium in the prepartum (before calving) period

Calcium is an essential mineral required for a number of functions to sustain life of animals. As a preventive measure of milk fever, calcium should never be supplemented before calving. Dietary calcium level should also be low (intake should be around 20 g/day). Vitamin D helps in absorption of calcium from the digestive tract and significantly helps to prevent milk fever when given a week or so before calving. However, as the commonly fed forages and concentrates provide significant quantities of calcium, manipulation of ration to low calcium level is sometimes difficult practically to ensure low calcium intake. In such situation supplementation of zeolite and vegetable oils can be done as both are known to reduce the absorption of calcium sufficiently.

Magnesium supplementation

Magnesium is another important body element and 70% of body magnesium is found in bones. Magnesium is responsible for membrane stability and thus related with cardiac and skeletal muscle functions and nervous tissue function. It is also related with several enzymes required for body metabolism and most importantly plays very important role in calcium metabolism. Magnesium is essential for maintaining blood calcium level in animals thus indirectly responsible for occurrence of milk fever. Magnesium supplementation at the rate of 15 to 20 g/day along with a source of easily digestible carbohydrate helps in preventing milk fever in dairy animals. During pregnancy magnesium should be supplemented at the rate of 0.4% of dry matter of ration.

Supplementation of calcium to susceptible animal after calving

It is not advisable to use this method as a first line of prevention. Supplementation should be done depending on the quality of ration provided and level of calcium in it, as there are chances of negative effects for breaking of calcium homeostatic pathways in the body.

Manipulating the DCAD of ration

The DCAD i.e. dietary cation-anion difference of ration is directly related with incidence of milk fever. The DCAD of ration can easily be calculated if percentages of concentrations of sodium, potassium, chlorine and sulphur ions of the ration are known [DCAD = (Na + K) – (Cl + S)]. Cattle fed ration with a high DCAD tends to cause milk fever, whereas negative DCAD tends to prevent milk fever. Reduction of DCAD rather than calcium content of ration during prepartum (before calving) is considered as the method of choice for preventing milk fever. It is because feeding more concentrates or cereal silages to dry cows to lower calcium intake may be expensive and may predispose cows to other complications like fatty liver syndrome, ketosis, abomasal displacement for high energy density. The DCAD can be reduced by addition of anionic salts (i.e. salts of chloride, sulphur or phosphorus) to the ration of pre-calving cows. Usually typical ration of dairy cows has DCAD ranging from +100 to +200 meq/ kg dry matter (meq= milliequivalent i.e. one meq is equal to 1/1000th of equivalent weight). Addition of anionic salts (minerals high in Cl and S relative to Na and K) or mineral acids to the ration lowers DCAD and reduces the incidence of milk fever. Addition of three equivalents of anions to 12 kg ration dry matter lowers DCAD by 250 meq/kg.

Other feeding suggestions

1. Just after calving, cow should not be milked completely for about 2-3 days. However, to avoid associated complication like mastitis, the calf should be allowed to suck milk for about 36 hours during this period.
2. Forages rich in calcium should not be fed before calving particularly during the last trimester of pregnancy period.
3. The following formulation can be suggested as a lick on feed: 1 cup molasses + 4 tablespoons linseed oil or meal + 2 tablespoons salt + 2 tablespoons causmag or dolomite.
4. It is important to restrict potassium (K) intake for dry cows to prevent milk fever.

How to treat milk fever

It is always advisable to call a Veterinarian when the animal is sick. Treatment by farmers based on the observable symptoms are not at all advisable. Remarkable success can always be expected if treatment is carried out properly. The following treatment strategies can be followed.

• Intravenous injection of calcium borogluconate (20% solution) or other calcium salts. Special care is required while injecting calcium borogluconate so that it is not made under the skin or the solution does not enter the tissues surrounding the vein since this causes irritation which may result restraining of the animal difficult.
• No commercial oral preparation is available. But, for suffering cows which are still on their feet or have only just sat down and can still hold their heads up, an oral preparation can be suggested. The recipes of that oral preparation are as follows:
• Dissolve calcium chloride (around 150g, but not more than 200 g) in 200 ml of warm cider vinegar.
• After properly dissolving the calcium chloride, add around 150 ml of fish or vegetable oil.
• Then 50 g of causmag or dolomite should be added and the volume of the solution should be made up to 500-600 ml with molasses.
• The solution should be shaken thoroughly before feeding to the animal so that the vegetable oil is suspended well. Vegetable oil helps to protect intestinal mucosa from irritation due to calcium chloride.
• It is advisable not to give more than three treatments with this preparation as calcium chloride may cause stomach ulcers. If at all required calcium chloride should be replaced with lime flour.

Conclusion

The milk fever is not only economically important, but also it causes loss of animals as it occurs at the most productive period of a lactating cow. Economic loss due to milk fever happens because of reduction in quantity of milk as well as expenditure on treatment of disease-affected animal. As milk fever is a metabolic disease directly related with feeding management, adopting appropriate feeding strategy during the pregnancy period and immediately after calving can prevent the occurrence of milk fever. Feeding of proper balanced ration considering the factors predisposing milk fever will help the farmers to avoid this menace successfully.

Source: Farm Magazine of Central Agricultural University