Nitrogen and phosphorus excretion on mountain farms of different dairy systems

Schiavon, Stefano; Sturaro, Enrico; Tagliapietra, Franco; Ramanzin, Maurizio; Bittante, Giovanni

doi:10.1016/j.agsy.2018.10.006

Cited by 13 publications

(2 citation statements)

References 40 publications

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“…Nutrients ( Ex , g cow −1 day −1 ) excreted by the lactating herd on each farm at each interview were assigned to management units (paddocks, the dairy shed, yards, laneways, feed pads, and holding areas) to give the load (kg) of N, P, K, S, Ca and Mg deposited by the herd on each day (Equation (1)); this resulted in a total of 1464 records ( Supplementary Table S1 ). Unlike the study of Schiavon et al [ 24 ], ammonia volatilisation was not accounted for in this study due to the variation in diets, regional and seasonal climatic conditions which would variously influence losses [ 25 ].

where Load Unit is the amount of a nutrient deposited in one of the management units by the lactating herd on the day of the interview, Ex (g cow −1 day −1 ) is the amount of a nutrient excreted by each cow on the day of the interview, Time pc is the percent of the day spent in each management unit, and Herd Lact is the number of cows in the lactating herd on the interview day.…”

Section: Methodsmentioning

confidence: 99%

Estimating Excreted Nutrients to Improve Nutrient Management for Grazing System Dairy Farms

Aarons

Gourley

Powell

2023

Animals

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Improving nutrient management in grazing system dairy farms requires determining nutrient flows through animals, the placement of cows within farms and potential for collection, and the re-use and loss of nutrients. We applied a model incorporating data collected at a range of temporal and spatial scales to quantify nutrient excretion in all locations that lactating herds visited on five days over a year on 43 conventional and organic grazing system dairy farms. The calculated nutrient loads excreted by cows in different places were highly skewed; while N, P and K deposited loads were consistent across the year, S, Ca and Mg loads varied between sampling times and seasons. The greatest mean and range in nutrient loads were deposited in paddocks, with the smallest amounts deposited in dairy sheds. All excreted nutrient loads increased with farm and herd sizes and milk production. Mean daily loads of 112, 15, 85, 11, 22 and 13 kg of N, P, K, S, Ca and Mg were deposited by the herds which, when standardised to a 305-day lactation, amounted to 24, 4, 20, 3, 5 and 3 t excreted annually, respectively. In addition to routine manure collection in dairy sheds, ensuring collection and recycling of nutrients excreted on feed pads and holding areas would decrease potential nutrient losses by 29% on average. Non-collected, recycled nutrients were disproportionately returned to paddocks in which cows spent time overnight, and except for S and Ca, nutrient loading rates were greater than rates applied as fertilisers. These data demonstrate the extent of excreted nutrients in grazing dairy systems and indicate the need to account for these nutrients in nutrient management plans for Australian dairy farms. We propose incorporating excretion data in current budgeting tools using data currently collected on most Australian grazing system dairy farms.

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Section: Methodsmentioning

confidence: 99%

Estimating Excreted Nutrients to Improve Nutrient Management for Grazing System Dairy Farms

Aarons

Gourley

Powell

2023

Animals

View full text Add to dashboard Cite

show abstract

“…Daily intake of P and its flux passing through six compartments (rumen, small intestine, large intestine, plasma, bone, and soft tissues) were described by the model. The primary model input was P intake which is readily determined from dietary P concentrations and dry matter (DM) intake; thus, DM intake and concentrations of dietary P are essential observations for predicting excretion of P (SCHIAVON et al, 2019).…”

Section: Discussionmentioning

confidence: 99%