Nordqvist, Maria
(2012).
Assessing phosphorus overfeeding in dairy cows.
Uppsala :
Sveriges lantbruksuniv.
, Rapport / Sveriges lantbruksuniversitet, Institutionen för husdjurens utfodring och vård, 0347-9838
; 279
ISBN 978-91-576-9081-4
[Licentiate thesis]
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Abstract
Faecal total phosphorus (TP) from dairy cows consists of a largely insoluble fraction and a soluble P fraction (SP), which mainly represents excess P. The soluble fraction increases proportionately with increased P feeding as excess P is mainly excreted with the faeces in soluble form. Determination of the acid-soluble P fraction in faeces has been suggested as a useful tool to identify excessive P feeding.
The overall aim of this licentiate thesis was to gain a better understanding of how different fractions of faecal samples can be used as tools to map P (over)feeding in dairy cows.
Paper I studied faecal excretion of different P fractions in 42 dairy cows fed a wide range of rations with varying P content ranging from approximately 70% up to 190% of their requirement. Faecal excretion of TP and SP was determined. The slope of the regression indicated that there was a significant relationship between actual measured SP and indirectly calculated regulated P. TP and SP were correlated and it was suggested that they can both serve as markers of P overfeeding
Paper II screened intake and faecal excretion of P on Swedish commercial dairy farms, with special emphasis on comparing farms with organic (N=14) and conventional (N=15) production systems. In each herd, intake of P and other nutrients in feeds was determined for 10 cows in varying stages of lactation. Milk yield and faecal content of P (TP and SP) were also determined for these cows. The results indicated that cows in both management systems consumed more P than they required. However the level of overfeeding was higher for cows in conventional systems. Pooling faecal samples from lactating cows improved the correlation between faecal P concentration and calculated P requirements. SP and TP appeared to be equally good in reflecting P intake relative to predicted requirement. It was shown that slurry samples could be used to evaluate P feeding on herd level.
In conclusion, this thesis showed that P overfeeding is greater in conventional dairy herds than in organic dairy herds and that both SP and TP in faecal samples can be used as markers of P overfeeding in dairy cows.
Authors/Creators: | Nordqvist, Maria | ||||||
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Title: | Assessing phosphorus overfeeding in dairy cows | ||||||
Series Name/Journal: | Rapport / Sveriges lantbruksuniversitet, Institutionen för husdjurens utfodring och vård | ||||||
Year of publishing : | 21 May 2012 | ||||||
Number: | 279 | ||||||
Number of Pages: | 39 | ||||||
Papers/manuscripts: |
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Place of Publication: | Uppsala | ||||||
Publisher: | Dept. of Animal Nutrition and Management, Swedish University of Agricultural Sciences | ||||||
ISBN for printed version: | 978-91-576-9081-4 | ||||||
ISSN: | 0347-9838 | ||||||
Language: | English | ||||||
Publication Type: | Licentiate thesis | ||||||
Full Text Status: | Public | ||||||
Agris subject categories.: | L Animal production > L02 Animal feeding | ||||||
Subjects: | (A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 402 Animal and Dairy Science > Animal and Dairy Science. | ||||||
Agrovoc terms: | dairy cows, phosphorus, animal feeding, overfeeding, sweden | ||||||
Keywords: | dairy cow, phosphorus, faeces | ||||||
URN:NBN: | urn:nbn:se:slu:epsilon-e-531 | ||||||
Permanent URL: | http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-531 | ||||||
ID Code: | 8898 | ||||||
Department: | (VH) > Dept. of Animal Nutrition and Management | ||||||
External funders: | Stiftelsen Lantbruksforskning | ||||||
Deposited By: | Maria Nordqvist | ||||||
Deposited On: | 25 May 2012 12:49 | ||||||
Metadata Last Modified: | 02 Dec 2014 10:51 |
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