Partitioning of nutrient and trace elements in feed between body retention, faeces and urine by growing dairy-breed steers

Abstract

The partitioning of nutrients and trace elements from feeds, drinking water and mineral supplements on growth, faeces and urine of growing cattle was studied with eight steers in a balanced Latin square design with two replicates, each comprising four treatments (diet compositions), four periods and four animals. The treatments were four rations with a silage proportion of 15, 30, 60 and 100% of the dry matter. Records were taken of the individual intake of silage, concentrates, mineral supplements and water, and excretions by collecting all urine and faeces. All feeds, urine, faeces and water were analysed for their content of Al, Ca, Cd, Cl, Co, Cu, Fe, K, Mg, Mn, Mo, N, Na, Ni, P, S, Se, and Zn. Elements that were mainly excreted in faeces (Ca, Cd, Cu, Fe, P, and Zn) tended to have a constant uptake in amount. As there is a fairly good correlation between DM consumption and faeces production, it is possible to estimate the amount of these elements excreted at farm level by analysing a faeces sample. Elements that are excreted in significant amounts in both faeces and urine (Cl, K, Mg, Mo, N, Na, S, and Se) tended to have a constant uptake over treatments as a fraction of the feed content. It is more difficult to estimate the amounts of these elements at farm level because it is more difficult to predict urine production than faeces production.

Keywords:

• cattle
• environment
• excretion
• feed intake
• mineral elements
• net uptake
• nutrient balance
• water intake

Acknowledgments

The study was kindly financed by the Foundation for Strategic Environmental Research (MISTRA) as a part of the Food 21 project, and by the Swedish Board of Agriculture.

Notes

Gustafson, G. M. and Olsson, I. (Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences. Box 7047, SLU, SE-750 07 Uppsala, Sweden; Kungsängen Research Centre, SLU, SE-753 23 Uppsala, Sweden). Partitioning of nutrient and trace elements in feed between body retention, faeces and urine by growing dairy-breed steers.

Additional information

Notes on contributors

Gunnela M Gustafson

Gustafson, G. M. and Olsson, I. (Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences. Box 7047, SLU, SE-750 07 Uppsala, Sweden; Kungsängen Research Centre, SLU, SE-753 23 Uppsala, Sweden). Partitioning of nutrient and trace elements in feed between body retention, faeces and urine by growing dairy-breed steers.