Optimization should also be done for different time periods. Short-term optimization is usually just optimizing feeds based on their current costs and perhaps balancing the homegrown feeds with bought feedstuffs. Medium-term frame optimization is about planning how to use pastures, what crops to grow and how the crop rotation is implemented. Long-term optimization is about what type of feed to use (total mixed ratio, liquid / solid / semi-solid feeds) and what kind of machinery and knowledge is needed to produce and distribute the feed for the animals.
There are several different recommendations for cattle, many of which have been referenced to in this blog. However, every cow, heifer and calf is unique, and every cattle has its own specific needs. Feed optimization should consider the prices of the feeds, the professionally analysed qualities of the home-grown feed and the predicted eating capacity of the animals (TDMI, total dry matter intake). These provide data for calculating the estimated milk yield, which is the basis of calculating the nutritional needs of each animal group. For detailed information about the TDMI, please refer to Huhtanen et al. (2008).TDMI index is calculated for silage DM intake (SDMI) and concetrate DM intake (CDMI) separately. TDMI = SDMI + CDMI - 1000, and each TDMI point is approximately 90-100 g DM / d.
|Online SDMI calculator by MTT|
CDMI differs from TDMI and SDMI. It describes how much less silage the animal eats when the amount of concentrate is increased. Generally, the more concentrate is offered, the less silage the animals eat. The replacement ratio is approximately 0.47: for each 1 kg of concentrate added, the cows decrease their consumption of silage by 0,47 kg. Protein in the concentrate impacts consumption to both directions: when the crude protein content of the concentrate incerases over 170 g/kg DM, consumption of feed increases; when the amount of rumen-digestable protein increases, consumption decreases. Cows are hence able to regulate their intake of nutrients by altering their consumption of concentrate and silage (Kuoppala et al 2008).
Several factors affect the eating potential of the cow. The factors can be classified into four main categories:
- Feed-based factors
- Animal-based factors
- Environmental and management factors
|Examples of changes in the body after feeding.|
So why is it important for a cow to eat as much as possible? Dairy cows have been bred to produce spectacular amounts of milk, which far exceeds the needs of the calf. The production of milk requires huge amounts of nutrients, but the cow can only eat a certain amount of feed a day. The nutritients it doesn't receive from feed are absorbed from the animal's own tissues, leading to weight-loss and possible metabolism-related illnesses. Feed optimization can ensure that the cow gets the right amount of right feeds with accetable costs. Increased eating also increases milk yield. Studies have shown that the regression between TDMI and milk yield is 0,9499.
The farmer has several possibilities to increase TDMI and thus increase the milk yield:
- Ensure a high D-value for the silage. 10g / kg DM increase in D-value increases cfeed consumption by 175 g DM/day.
- Ensure successful preservation (fermentation, baling, wilting). Oxygen-free preservation and low pH prevent molding and wrong types of fermentation. When the fermentation acids increase 10 g / kg DM, consumption decreases 128 g DM d.
- Include whole crop silage or forage and cereal silage into the basic grass-based silage. Inclusion of 30-70 % of red clover increases consumption by 1,3 kg and milk yield 1,3 kg / day.
- Include peas, oat or broad beans to the silage.
- Optimize the DM content of the silage. Consumption increases linearly until 42 % of DM, and then begins to decrease.