Ögren, Gunilla
(2013).
Phosphorus to horses and cows.
Uppsala :
Sveriges lantbruksuniv.
, Rapport / Sveriges lantbruksuniversitet, Institutionen för husdjurens utfodring och vård, 0347-9838
; 283
ISBN 978-91-576-9116-3
[Licentiate thesis]
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PDF
479kB |
Abstract
It is important from a nutritional perspective to meet the phosphorus (P) requirements of animals. From an environmental perspective however, it is important not to feed more P than necessary, because excessive P will mainly be excreted with feces, and the soluble P fraction is vulnerable to runoff losses and may contribute to eutrophication. The recommended dietary P levels to dairy cows have successively decreased over the years but recently, an increase in the requirements to growing horses was suggested because fecal endogenous P losses might be higher than previously estimated. The main aim of this thesis was to assess fecal P losses in growing horses, and in brood mares and dairy cows kept on pasture in Sweden.
In paper I, P balance and fecal P losses in growing horses in training fed a forage-only diet ad lib with (HP) or without (LP) P supplementation was studied. In addition, the proportion of the extractable (in dilute HCl solution) inorganic P fraction (Pi) of total P (TP) in feces was assessed. Fourteen Standardbred horses (aged 20 months) were used in a cross-over experiment. Feed intake was measured and spot samples of urine and feces were collected. Acid insoluble ash was used as indigestible marker to assess daily fecal output. Estimated P retention was low (<1.7 g/day) and only that for diet HP was significantly higher than 0 g/d. The fecal endogenous P losses were estimated to be less than 10 mg/kg body weight, which do not support the suggested increase in P requirements. The proportion of Pi of TP was > 85% and Pi increased linearly with P intake.
In paper II, TP and Pi in feces from lactating and non-lactating dairy cows (n=167) and brood mares (n=74) kept on pasture was investigated and also the use of P supplements. Samples of feces, forages and pastures biomass were collected. The proportion of Pi of TP was greater for lactating horses than lactating cows (63±4 vs 49±5 %). Supplementation of lactating animals with P generally matched their estimated requirements and was therefore justified, while supplementation of non-lactating animals could not be justified.
In conclusion, an increase in P requirement to growing horses seems not to be justified, and the high proportion of Pi in feces from horses indicates that P overfeeding of horses might be potentially more harmful to the environment than P overfeeding of dairy cows.
Authors/Creators: | Ögren, Gunilla | ||||||
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Title: | Phosphorus to horses and cows | ||||||
Series Name/Journal: | Rapport / Sveriges lantbruksuniversitet, Institutionen för husdjurens utfodring och vård | ||||||
Year of publishing : | 2013 | ||||||
Number: | 283 | ||||||
Number of Pages: | 43 | ||||||
Papers/manuscripts: |
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Place of Publication: | Uppsala | ||||||
Publisher: | Institutionen för husdjurens utfodring och vård, Sveriges lantbruksuniversitet | ||||||
Associated Programs and Other Stakeholders: | SLU - Research Areas for the Future > Future Animal Health and Welfare (until Jan 2017) | ||||||
ISBN for printed version: | 978-91-576-9116-3 | ||||||
ISSN: | 0347-9838 | ||||||
Language: | English | ||||||
Publication Type: | Licentiate thesis | ||||||
Full Text Status: | Public | ||||||
Agris subject categories.: | L Animal production > L02 Animal feeding L Animal production > L51 Animal physiology - Nutrition Q Food science > Q55 Feed additives | ||||||
Subjects: | (A) Swedish standard research categories 2011 > 4 Agricultural Sciences > 402 Animal and Dairy Science > Animal and Dairy Science. | ||||||
Agrovoc terms: | horses, dairy cows, animal nutrition, phosphorus, supplements, faeces, pasture feeding, unrestricted feeding, environmental impact | ||||||
Keywords: | fosfor, träckprov, nutrition, hästar, kor | ||||||
URN:NBN: | urn:nbn:se:slu:epsilon-e-1440 | ||||||
Permanent URL: | http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-1440 | ||||||
ID Code: | 10394 | ||||||
Faculty: | VH - Faculty of Veterinary Medicine and Animal Science | ||||||
Department: | (VH) > Dept. of Animal Nutrition and Management | ||||||
External funders: | Stiftelsen Lantbruksforskning | ||||||
Deposited By: | Gunilla K Ögren | ||||||
Deposited On: | 08 May 2013 06:03 | ||||||
Metadata Last Modified: | 15 Apr 2015 22:10 |
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