@article{MAKHILLJAVA200543366,
    title = {Effects of Dietary Supplementation on Phosphorus Metabolism in Sheep},
    journal = {Journal of Animal and Veterinary Advances},
    volume = {4},
    number = {3},
    pages = {349-355},
    year = {2005},
    issn = {1680-5593},
    doi = {javaa.2005.349.355},
    url = {https://makhillpublications.co/view-article.php?issn=1680-5593&doi=javaa.2005.349.355},
    author = {Dorinha M.S.S. Vitti,Ermias Kebreab,Jo?o B. Lopes,Adibe L.Abdalla and},
    keywords = {},
    abstract = {Phosphorus (P) metabolism in sheep was studied using 98 Suffolk sheep, which were given various levels of P supplementation in their diet and administered a single dose of isotopic 32P in their blood. About 62% of P intake was excreted in faeces. Endogenous loss in faeces ranged from 8.6 to 84.0 mg P/kg body weight (BW) daily and was linearly related to P intake. Minimum endogenous faecal P loss was estimated at 8.63 mg/kg BW/day. Dietary P absorption was positively and linearly related to P intake at all intake levels, but the efficiency of absorption decreased at higher intakes. This suggests that P absorption involves not only a passive mechanism but also an active process, possibly due to homeostatic control. Taking an average 63% absorption efficiency, requirement of dietary P for maintenance was calculated to be 28.3 mg/kg BW/day. For a 35-kg sheep, this is equivalent to 0.99 g P/day to replace endogenous P losses fed at maintenance. Non linear relationships of salivary P with absorbed, endogenous feacal P and dry matter intake were established, suggesting that regulation of P secretion in saliva could be by active and passive mechanisms. Urinary loss of P was low, even at high levels of P intake. The paper demonstrates the relevance of understanding P metabolism and the need to estimate P requirements for ruminants accurately, in order to optimise production but avoid excessive P outputs to the environment.}
    }