Fat cows wouldn’t be an issue if they weren’t subject to a higher risk of metabolic diseases, particularly ketosis. Maintaining herd condition and holding it at the correct level can be a very fine line. To successfully manage the conditioning of our herds, we first need to understand the processes at play and the nutritional factors that govern and balance it.

Ketosis in dairy cattle is triggered by an energy deficiency in early lactation. When blood glucose levels reach a low point, the body then begins to mobilise body fat as an alternative energy source. The downside to mobilising large amounts of fat is that it risks clogging the liver, which can run the risk of catastrophic liver failure, or what is termed as fatty liver disease. Stored fat is also considered an inefficient means of creating energy, and in some instances mobilising it can use more energy than it creates.

Under the right circumstances converting fat to energy should be a normal, healthy, and efficient process. As mentioned earlier, this process can be extremely beneficial in times of short term food shortage or stress periods. In this way it can be utilised when extra energy is required to plug gaps, such as calving and early lactation.

Science is now showing us that if the body is nutritionally balanced, the process of converting fat to energy can be more efficiently managed without experiencing the negative downsides. In order to prevent fatty liver and maintain general liver health, nutrients play a paramount role. The key nutrients in this process are defined as methyl donors, which are the amino acids; choline, methionine, and betaine. These methylated compounds contain a one-carbon group), which have the ability to play a fundamental role in hundreds of metabolic reactions. A deficiency of any one of these elements can jeopardise the health and the economic performance of the early lactating cow.

Towards late gestation, the requirement for methionine increases in dairy cows due to inadequate DMI, as well as the increased protein demand to support foetal growth and the onset of the next lactation. Milk contains a high amount of methylated compounds (choline and methionine) as components of milk fat micelles or proteins. At the beginning of lactation, a dairy cow has a high demand for these compounds due to high metabolic need. The availability of ready-to-use methyl groups is low in ruminants because of the extensive rumen degradation that takes place at this time, as well as the reduced DMI at the onset of the lactation. This creates a shortage of methylated compounds, particularly in the lead up to calving and in early lactation