Dairy cows are ruminants. The rumen is the first stomach. In the rumen there is a symbioses with the rumen bacteria. These bacteria are able to ferment feed particles and so deliver valuable nutrition to the cow. In order to multiply and ferment enough feed, the bacteria need sufficient energy and protein at all times.
The feeding pattern of a healthy cow is 8 to 12 meals a day, so that there is a load of feed available in the rumen every 2 to 3 hours. Different feedtypes have different fermentation characteristics. Some energy sources like sugars are easily degradable and gone after a few hours, while others take more time. Fine tuning a ration also means finetuning these characteristics. Figure 1 shows an overview of where each feed ingredient is digested and which nutrient is used for which milk component.
Nutrients in forage
Forage nutrition values can be influenced by several factors, for example the time of mowing. The amount of protein and sugar are contra related, depending on the grass species. This is due to the amount of sun light, level of fertilizer and outside temperature. During spring, when, on average, days are sunny and nights are cold, the morning is best time to mow in order to obtain a high sugar content. During the growing season, the highest sugar contents are usually found in forage at the end of a sunny day.
The nutritive value of forage comes from digestible organic matter, which consists of structural carbohydrates and non-structural carbohydrates, protein and fats. (Figure 2) When the digestible organic substance breaks down in the rumen and intestine, nutrients are released which can be used to form milk components and body reserves. Milk is a complex product consisting of more than 100 different substances. These substances are dissolved in water or are present in the form of free particles (suspensions, emulsions in water).
Figure 2 Build-up of roughage
Sampling your pits
In most areas roughage is the basis for the ration. So before feeding a particular pit, it is important to analyze the actual nutrition values. Specialized local companies can analyze this and deliver a comprehensive, in-depth report. This report is mainly used by feed experts and nutritionists, so that they can recommend the most effective ration, i.e. the ration that best matches the cows’ needs. This will result in maximum feed efficiency.