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

Milk Fever Disease, often referred to as parturient paresis, frequently occurs in dairy cows just before or after giving birth. This disease tends to affect mature dairy cows that produce high milk yields, and sometimes it can also occur in heifers giving birth for the first time or in beef cattle.

In cases of milk fever, the sudden loss of calcium from the body can cause cows to collapse during childbirth. Animals experiencing milk fever require more calcium minerals and draw them from their body tissues to produce milk. The calcium taken from these body tissues is needed more than the amount that can be obtained from bones or from the feed in their digestive tract. In normal times, bones act as storage sites for excess calcium in the body, and the cow's body can take a small amount of calcium from these storage sites when there's a deficiency. However, in cows that suddenly produce a large amount of milk, the calcium stored in the bones becomes insufficient. This severe calcium deficiency has fatal effects on the body because calcium is needed for muscle and nerve function.

In livestock, the level of calcium in the blood is controlled by various factors. These factors include the reciprocal relationship between the calcium and phosphorus content 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 metabolic processes of animals. The calcium level in the blood drops dramatically when a cow enters the lactation phase. Under normal conditions, lost calcium is usually replenished by the body within a few hours. The parathyroid glands send signals through specific hormones (assisted by vitamin D) to release stored calcium from the bones. However, if the parathyroid glands are not active, these signals will not be sent, and the stored calcium cannot be moved into the bloodstream to counter the deficiency.

The activity of the parathyroid glands is influenced by the rate of calcium intake from the feed. Cows that consume high-calcium feed, such as alfalfa or other legumes, during the dry period before giving birth are more susceptible to milk fever because their bodies have direct access to calcium minerals. The body responds by perceiving an excess of calcium. The absorption of calcium from the intestines is sufficient to maintain normal blood calcium levels when cows are in the dry period. The exchange of calcium between the bones and blood becomes very limited, and the parathyroid glands become less active.

For the proper functioning of the parathyroid gland, the intake of calcium and phosphorus in the feed must be in the correct ratio. Dry cows that consume good-quality grass feed with balanced calcium and phosphorus levels will have a normal calcium and phosphorus ratio in their bodies. This condition reduces the susceptibility to milk fever when cows start producing milk after giving birth.

Age also has a significant influence on a cow's susceptibility to milk fever. Younger animals can mobilize calcium reserves from their bones more quickly. As cows age, calcium becomes more tightly bound to the bones, making it harder to release when needed. With increasing age, a cow's ability to absorb calcium from the intestines also decreases compared to younger animals. Most mature cows tend to produce more milk, reaching peak production around the third and fourth calving. This also becomes another predisposing factor for milk fever cases. Therefore, mature cows that produce a lot of milk have the highest risk of calcium deficiency compared to cows giving birth for the first time.

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