Manure: How Much Nutrients Excreted by Beef Cattle?
Agroscope
Farms operate with a balanced nutrient cycle. Agroscope has adjusted beef-cattle reference values to the latest advances in animal production. The said values can be used for fertilisation planning and are to be used for the assessment of the farm- based nutrient cycle.
Since 1998, all Swiss farms have been legally required to have a balanced nutrient cycle. The method used to calculate the balance for nitrogen and phosphorus requires reference values for nutrient excretions for each livestock category. Since 1999 there have been major advances in beef-cattle production (genetics, feeding and housing) requiring an updating of the reference values.
100 Scenarios Calculated for Beef Cattle
As for most other animal categories, nutrient excretions were calculated by subtracting nutrient retention via body growth from nutrient intake via the diet. For this, 100 scenarios were calculated in order to quantify the impacts of different growth rates, final weights and diet types.
The updated reference values apply for a defined gain of 1400 g per day and a final weight of 530 kg. Thanks to the large number of calculated scenarios, these can be flexibly adapted to modified animal performances (growth rate, final weight) and diet type.
Conclusions
- The reference values for nutrient excretions in beef cattle were revised for the first time since 1999.
- The higher the daily gain and the lower the final weight, the shorter the duration of stay in the pen and the lower the nutrient excretions per animal.
- Despite this, compared to 1999, the shorter duration of stay due to an increased daily gain resulted in a higher turnover per place, thus increasing the nutrient excretions per place and year, especially for nitrogen.
- The higher the proportion of herbage in the diet, the higher the nitrogen, potassium and zinc excretions.
- The excretion of environmentally relevant minerals (phosphorus, copper and zinc) can be limited by supplementing the diet with no more than the recommended amount of minerals.
Bibliographical reference
Manure: How Much Nutrients Excreted by Beef Cattle?
