Practices, such as outdoor yards for cattle exercise, forested feedlots for cattle raising and slurry application to grass fields, have become more common during the last two decades on cattle farms. At the same time, untilled buffer zones have been established between source fields and water courses for the removal of sediment and nutrients from surface runoff. This thesis sums up studies on phosphorus (P) and nitrogen (N) losses to water from forested feedlots and slurry-amended grass fields. Moreover, different ways of mitigating the losses in a boreal climate are discussed. Studies were conducted in 1996 2008 at Jokioinen, Tohmajärvi, Ruukki and Taivalkoski. Water samples representing surface runoff were collected from open ditches and analysed e.g. for total solids (sediment) as well as total P (TP), dissolved reactive P (DRP) and total N (TN) to estimate nutrient losses from forested feedlots with different stocking rates (animal units per hectare, AU ha-1) and from slurry-amended grass. Surface runoff samples were similarly analysed to evaluate the efficacy of 10 m wide buffer zones to decrease and retain nutrient losses from pasture and tilled soil. The soil was sampled for plant-available P and mineral nitrogen (SMN) analyses. Fairly high TP (0.9 1.4 kg ha-1 yr-1) and TN (4 16 kg ha-1 yr-1) losses occurred in ditch water from forested feedlots where cattle had been reared for 1 3 years. These amounts correspond to the annual losses from cropped fields. The plant-available P (up to 20 mg L-1) in surface soil and the amount of SMN (up to 100 400 kg ha-1) in the 60 cm deep soil layer were highest in places where the cattle gathered, such as bedded and feeding areas (called high-input areas). On coarse-textured soils, common in central and western Finland, there is a risk that NO3-N is leached from highinput areas into the ground water. Removal of dung from the bedded and feeding areas resulted in lower nutrient amounts in soil as well as lower P and N losses to water. High losses of TP and DRP (4.4 and 3.6 kg ha-1 yr-1, respectively) also occurred in surface runoff from the grass fields where surface application of slurry (40 t ha-1) in autumn was followed by rainfall. Injection of the slurry into the soil decreased TP and DRP losses by 79 and 86%, respectively. Injection may, however, enhance N leaching into drainage water on coarsetextured soils. The buffer zones along watercourses were less important in the grazed field than in autumn-tilled soil due to the smaller erosion and nutrient losses from grass than from tilled soil. The surface runoff losses of sediment, TP and TN decreased by more than 50, 30 and 50%, respectively, by buffer zones on tilled soil. In spring, the implementation of buffer zones even increased the losses of DRP, but mowing and removing the residue from the buffer zones effectively decreased the DRP losses in surface runoff. Nutrient losses on cattle farms can be mitigated by removing dung from the areas of forested feedlots with high stocking rates (> 5 AU ha-1 yr-1) using injection of slurry instead of broadcasting, and establishing buffer zones between source areas and watercourses.