Farms operate with a balanced nutrient cycle. Agroscope adjusted the reference values for suckling calves to the latest advances in animal production. The values for feed intake and nutrient excretion are now lower.
Since 1998, a balanced nutrient cycle at farm level has been enshrined in law. The method used to calculate the nitrogen and phosphorus balances requires reference values for nutrient excretions in each livestock category.
In suckler-cow production, reference values were established in 1994 and revised in 2001. The values for suckler cows were updated in 2016, and now it is the calves’ turn. The update includes newly available data on calf feed intake, as well as current market data on calf performance.
Two production systems for suckling calves
The two most important production systems, consisting in the slaughter of the suckling calves at either around five-and-a-half months or ten months of age, were taken into account. For the ten-month-old animals, nine scenarios (3 final weights x 3 ages at slaughter) were investigated in order to determine their influence on feed intake and nutrient excretion.
As with the majority of other animal categories, nutrient excretions were calculated by subtracting nutrient retention via body growth from nutrient intake via the diet.
- With the updated reference values, suckling-calf forage intake was reduced by 33% compared to 2001.
- Compared to 2001, the updated nitrogen and phosphorus excretion of suckling calves was reduced by 29% and 7% respectively.
- The sum of the reference values for calf and cow are relevant for a farm with a suckler-cow herd. The animals’ total forage intake and nitrogen and phosphorus excretion were 6%, 11% and 14% lower, respectively, than in 2001.
- The new reference values for suckling calves and suckler cows therefore relieve some of the pressure in terms of farm nutrient balance compared to 2001.
Manure: Nutrient Excretion by Calves from Suckler Cows