Oh where, oh where has the nitrogen gone? Oh where, oh where can it be?
That’s what Sebastian I Arriola Apelo, an assistant professor in the Department of Dairy Science at UW-Madison, is trying to find out.
“The purpose of my research is to minimize nitrogen losses from dairy production systems,” Arriola Apelo said.
But why is lost dietary nitrogen so important?
A dairy cow only uses 25 percent of the dietary nitrogen from her feed for milk production. The rest is excreted to the environment.
“Most of it in dairy production systems is used by farmers as fertilizer for their soil,” Arriola Apelo said. “But there is a big risk of leakage of nitrogen to surface waters and to the environment which could affect the air quality.”
The inefficiency of the nitrogen is also a financial loss to the dairy farmers. The nitrogen that’s excreted is “money that is not capturing product,” Arriola Apelo said.
This lost dietary nitrogen is a problem for both dairy farmers and the environment, and Arriola Apelo is looking for a way to fix the problem.
“Improving that efficiency is the main objective, and we know from other production systems, like monogastrics, pigs and chickens, that it’s possible, post-absorption, to acquire higher efficiencies,” Arriola Apelo said.
Arriola Apelo looks at the interaction between the metabolism of amino acids in the liver and in the mammary gland, and how those amino acids talk to those organs to regulate metabolic processes, mainly milk protein synthesis. He is using a quantitative approach to determine the mathematical function that describes those possible responses.
Arriola Apelo explained there is a “very large, nation-wide established nutrient requirement system” used to formulate rations for dairy cattle. The system tells the farmer how much the cow requires to produce at their target production level. Then, the farmer formulates the ration to meet those requirements.
“How you calculate those requirements — it’s a model that tries to represent the reality, but it’s a simplified version and that’s why it is a model. So, that simplification of the reality today is too much. It’s too much simplified, so the production requirements are too large,” Arriola Apelo said.
While a new version of this system is scheduled to come out next year, Arriola Apelo believes there is still a lot that needs to be improved.
“The newer version is trying to improve that error, but I believe there is still much to do research-wise to understand biology better and continue reducing that error in production,” Arriola Apelo said. “I believe that is going to allow us to reduce the inefficiencies and increase the efficiency of the utilization of the nitrogen.”
While improving feed efficiency and reducing dietary nitrogen loss will help dairy farmers financially, this research is important for other reasons too.
“It’s important because the dairy producers are under government pressure to reduce nitrogen excretion and there’s public and consumer pressure to produce under more environmentally friendly practices,” Arriola Apelo said.
While this research might not immediately seem important to the everyday consumer, Arriola Apelo emphasizes that improving nitrogen efficiency in dairy cattle is important for everyone.
“It’s a win-win situation. If we improve the nitrogen efficiency, the dairy producer will have more land to dedicate to energy sources like corn or for food production for humans,” Arriola Apelo said. “And since less is going to the environment, it’s a win situation for the rest of the society as well. So society wins, the producer wins. We can improve the dairy production systems for the farmer, the consumer and for the environment.”