Evaluating Feed Efficiency As A Measure Of Sustainability
May 31, 2018
It is tempting to use feed efficiency as the answer for all questions on-farm sustainability as it represents over 50% of operating expenses of the farm. However, it is important to be ware that these measures will not provide a valid comparison of sustainability across the farm as there are many ways feed efficiency can be calculated. What works best for one farm might not be suitable for another farm.
Calculating feed efficiency for your farm
With that being said, it is still important to calculate feed efficiency to further sustainability goals for individual farms. Various on-farm measures of efficiency are shown below. However, there are advantages and disadvantages for each measurement. It is important to remember that none of these 5 feed efficiency measures by themselves equal sustainability:
1. Physical feed efficiency - amount of milk produced per unit of dry matter intake.
This is usually easy to calculate but it does not take into account for nutrient density, feed cost or cow growth.
Increasing dietary fat such as rumen bypass fats can help increase physical physical feed efficiency.
Physical feed efficiency as a bench mark for sustainable milk production is not ideal. It is encourage to evaluate other economic and efficiency measures concurrently.
2. Efficiency of nutrient usage
Normally used by geneticists rather than nutritionists as it can be used to compare how efficiently specific nutrients are used by individual cows or breeds.
One measure in this category is the gross energy conversion efficiency which is calculated as milk energy output divided by energy intake.
However, this measure ignores the mobilisation of the body reserves which is usually higher in early lactation.
3. Economic feed efficiency
Measures incorporate feed costs and help to bring economic profitability of a farm into the sustainability equation.
Several calculations that fall into the economic feed efficiency.
The most common calculation is milk income over feed cost. This calculation is beneficial for short-term feeding and management decisions but it is not encouraged to use and make long term decisions as the prices of milk and feed fluctuates widely.
Another calculation would be the ration cost efficiency - value of milk produced divided by the dry matter consumed. This method is limited as it does not take bodyweight changes, heifer growth and forage losses into account.
Another measure would be the feed cost per hundredweight - accumulated feed cost divided by the amount of milk shipped. This would take variables such as feed price and dry period length but does not consider heifer enterprise and milk composition.
4. Lifetime efficiency
A measure of lifetime feed energy intake that is converted into milk or being used for reproduction and growth.
One of the advantages of this metric is it takes into account the benefits of earlier calf and heifer growth as well as cow longevity but on the other hand, it is difficult for farmers to calculate due to lack of data available.
5. Total dairy enterprise efficiency
This measure accounts for all nutrient gains and losses in the dairy enterprise such as losses in dairy enterprise which includes losses related to crops, manure and feeding management.
In order to get an accurate measure, it requires integrating accurate farm data, including actual dry matter and nutrient intakes with advance nutrition models and whole-farm dairy models.
It is very challenging to get an accurate measure due to the reasons above but it may be one of the most effective way of maximising dairy feed efficiency.
Feed efficiency plays a big role on the overall efficiency and dairy enterprise sustainability. Each of the measures described above has advantages and disadvantages. Hence, it is recommended to examine the measures simultaneously rather than in isolation.
Feed efficiency goals should also be a moving target rather than a fixed goal depending on the current conditions of each dairy enterprise. Some reasonable dairy efficiency targets to consider:
Feed delivery and intake
Nutrient requirement estimations for different groups of animal