In a project that might some day provide significant advances in medical research, ISU researchers are using mathematical models to help better understand milk fever in dairy cows.

Mustafa Kammash, associate professor in electrical and computer engineering, used control theories to interpret the biological interactions involved with the common bovine disorder.

“Researchers have not looked at the problem from [a mathematical] perspective,” Kammash said. “This is a new tool for study of the disorder. This marriage of engineering and biology can be very fruitful.”

Kammash said milk fever is an imbalance of calcium concentrations in the plasma within a cow’s bloodstream. During calving, physical stresses as well as natural lactation cause the levels of calcium to drop drastically. Normally, a cow’s body reacts to correct the problem.

However, cows suffering from milk fever are not able restore the calcium to the correct level. If untreated, the calcium levels can drop to levels fatal to the animal, he said.

Kammash said the math behind control theory explains the interaction of systems based on feedback. Similar to the way the common thermostat maintains a temperature by constantly monitoring the ambient temperature in the room, the endocrine system of a cow monitors the calcium levels in the bloodstream.

When temperature in the room drops, the heat turns on, and when the calcium levels drop, the cow’s glands produce hormones to correct it.

After analyzing the calcium concentration and hormone levels in healthy cows during calving, Kammash produced a model that described the relationship between the hormones and the calcium levels.

“Our model does explain the observed phenomenon,” he said.

Hana El-Samad, graduate student in electrical and computer engineering, joined Kammash in his research and wrote her thesis about the research. El-Samad, who is now pursuing her doctorate, believes the research proves that control theory, commonly associated with industry, is applicable to the life sciences.

“Part of the research was to prove that control theory could be applied to these [biology and physiology] fields,” El-Samad said.

Research into causes of milk fever has been going on for many years, and only recently was the existence of a second hormone within the interaction verified. The existence of that second hormone was proven through mathematics in only a month, El-Samad said.

“This bringing together of engineering and biology to have a new and effective way of understanding a disorder … gives a fresh view on the subject and better describes the situation,” Kammash said.

In the future, Kammash wants to apply these models using control theory to other biological systems. Kammash said he would like to look at the human endocrinology systems using control theory and attempt to give the systems a more solid mathematical basis.

El-Samad and Kammash worked on the project with Jesse Goff, a research scientist at the National Animal Disease Center in Ames. Goff was unavailable for comment.