(By: First Veterinary Medical Functional Officer: drh. Yayuk Kholifah)

Milk Fever Disease, also commonly known as parturient paresis, often occurs in dairy cows just before or after giving birth. This disease tends to affect adult lactating cows that produce high amounts of milk, and sometimes it can also occur in first-time calving heifers or beef cattle.

In cases of milk fever, the sudden loss of body calcium can cause cows to collapse during childbirth. Animals experiencing milk fever require more calcium minerals and extract them from the body tissues to produce milk. The calcium taken from the body tissues is needed more than the amount of calcium that can be obtained from the bones or from the feed in the digestive tract. Under normal circumstances, bones act as storage places for excess calcium in the body, and the cow's body can draw a small amount of calcium from the bone storage when deficient. However, in cows that suddenly produce a large amount of milk, the calcium stored in the bones becomes insufficient. This serious calcium deficiency has fatal effects on the body since calcium is necessary for muscle and nerve functions.

In the animal's body, the level of blood calcium is controlled by many factors. These factors include the reciprocal relationship between calcium and phosphorus in the feed, the amount of phosphorus in the bloodstream, the level of vitamin D in the body, and the proper functioning of the parathyroid and thyroid glands, which play important roles in the animal's metabolic processes. The blood calcium level will drop dramatically when a cow enters the lactation period. In normal conditions, lost calcium is usually replaced by the body within a few hours. The parathyroid glands send signals through specific hormones (assisted by vitamin D) to release the calcium stored in the bones. However, if the parathyroid glands are inactive, these signals will not be sent, and the stored calcium cannot be transferred into the bloodstream to address the deficiency.

The activity of the parathyroid glands is influenced by the rate of calcium intake from the diet. Cows consuming high-calcium feed like alfalfa or other legumes during the dry period before calving are more susceptible to milk fever because their bodies have direct access to calcium minerals. The body responds by considering itself to be in a state of calcium excess. Calcium absorption from the intestines has been sufficient to maintain blood calcium levels during the dry period. The exchange of calcium between bones and blood becomes minimal, and the parathyroid glands become less active.

For the parathyroid glands to function normally, the intake of calcium and phosphorus in the diet must be in the proper ratio. Dry cows that consume a well-balanced grass diet with appropriate levels of calcium and phosphorus will have a normal calcium-to-phosphorus ratio in their bodies, reducing their susceptibility to milk fever when they start producing milk after calving.

Age also has a significant influence on a cow's susceptibility to milk fever. Younger animals can mobilize calcium reserves from their bones faster. As cows age, calcium becomes more tightly bound to the bones, making it more difficult to be released when needed. As cows age, their ability to absorb calcium from the intestines decreases compared to younger animals. Most mature cows tend to produce more milk, reaching peak production during their third and fourth calvings, which is also a predisposing factor for milk fever. Therefore, mature cows producing a lot of milk have the highest risk of calcium level drops compared to cows giving birth for the first time.

Keyword: Artificial Insemination, Cattle, AI, Livestock Farming, Livestock, Milk Fever