By Svein Inge Meland
Researchers have developed a new method of detecting a metabolic disease that affects dairy cows after calving. The aim is to determine whether cows are at risk of contracting the disease before they actually become sick.
The idea behind the new method is to combine data from the analysis of a cow's milk with other information about the cow to predict future progression in the animal's health.
"As we become more skilled at detecting this disease at an early stage, there will be benefits for animal health, milk production, profitability and the climate," says Professor Olav Reksen at the Norwegian University of Life Sciences (NMBU).
The project is being coordinated by NMBU, with SINTEF and the Norwegian Institute of Food, Fisheries and Aquaculture Research (Nofima) acting as project partners. The research team has used data taken from milk sample analyses to develop a model that can detect the presence of the metabolic disease subclinical ketosis.
Critical period after calving
After calving, a cow's energy requirements increase by between five- and six-fold. At the same time, she has to produce between 30 and 35 kilos of milk on the day after her calf has been born. This makes it easy for her to become energy-deficient.
"When a cow obtains too few carbohydrates, it resorts to burning its fat reserves in an attempt to get enough glucose," explains Reksen. "Exactly the same thing happens when people fast. Under these conditions, a cow may contract metabolic diseases such as subclinical ketosis, among others," he says.
An invisible disease that creates problems
Clinical ketosis is a metabolic disease that is easy to identify and treat. The problem with subclinical ketosis is that it exhibits no visible symptoms, and is thus difficult to detect.
Subclinical ketosis appears in between 15 and 20% of cows after they have given birth. The condition causes poorer feed uptake, lower levels of milk production, reduced fertility and an increased risk of contracting other metabolic diseases. It is common for cows to be sick for between two and three weeks, but the disease may continue for longer. To date, it has only been possible to detect subclinical ketosis by means of blood tests.
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