Phosphorus project to help dairy farmers determine feed budget

phosphorus-project-helps-determine-budget.jpgThanks to an ongoing research project, Manitoba dairy farmers will soon have more information when developing best management practices to optimize the use of phosphorus in the diet of their cows. The project, lead by Dr. Kees Plaizier, professor at the University of Manitoba, is supported by funding through Growing Forward 2's Growing Innovation program.

The first phase of the project surveyed 30 cows on 10 selected farms once a month from October 2010 to October 2011. It found that Manitoba's dairy cows, on average, are consuming more phosphorus than required, but this has not resulted in a build-up of soil phosphorus levels above the regulatory threshold limits.

Plaizier's findings indicate that, on average, only 35 per cent of phosphorus fed to a cow ends up in the milk, the rest is excreted. However, there is considerable variation between each individual cow and between farms. There is room for improvement, especially in farms where soil test phosphorus levels have been climbing over time. He says if farmers fed each individual cow the amount of phosphorus they are required to have, the farmer will save money and reduce inefficiencies.

"Phosphorus is an essential nutrient," says Plaizier. "It is required for the normal functioning of a cow, yet there is a balance. If a cow is provided with more phosphorus than she needs the excess phosphorus will end up in the manure."

Individual diets for each cow a possibility

If each dairy cow on a farm was being fed closer to its required amount, there can be whole farm feed cost savings. Plus the phosphorus content in manure would be lower, which can mean lower manure management costs, says Plaizier. He and his team hope to use technology, such as precision feeding, to fine-tune a phosphorus supply to suit the individual requirements of each cow.

"The issue comes when you're feeding the cow too much phosphorus, and it's not deliberate, and that nutrient is not being used. We're confident that Dr. Plaizier's study will help manage and effectively use the nutrient to the advantage of our farmers," says Dr. Rob Berry, dairy specialist with Manitoba Agriculture, Food and Rural Development (MAFRD).

Phosphorus recycled naturally on farms

According to John Carney, executive director of the Manitoba Livestock Manure Management Initiative, excess phosphorus is not a terrible thing for crops, as many crops that are typically grown on dairy farm fields require a lot of phosphorus to grow.

"It can be one of the best systems - the animal recycles their phosphorus to a plant, which helps it grow, and eventually can be fed back to the animal," Carney says.

The second phase of Plaizier's study began November 2014 and will survey 30 cows on each of the 15 selected farms once a month until November 2015.