Abstract:
This paper describes absorption, metabolism, excretion and availability of phosphorus in ruminants. Phosphorus is an important constituent of various body parts of animals. Deficiency of phosphorus has been reported at global level leading to disorders of skeletal, muscular and nervous systems, decreased efficiency in terms of reproduction and milk production and intravascular hemolysis. Salivary glands having a higher concentration of P compared with the blood plasma play an important role in P homeostasis. Recycling of P is stimulated by parathyroid hormone. Phosphorus may be absorbed from the small intestine via a vitamin D dependent active transport system and/ or passive absorption system. Livestock forages contain an organic form of P (phytate) which must by hydrolyzed to make P available to be absorbed. Absorption of P depends upon its solubility, pH, concentration of available P, forage source, plasma level of Ca, age of animal and genetics. Major route of excretion of P is faeces. However, when dietry P is in excess, urinary P excretion is increased. Availability of minerals varies from soil to plants. In Pakistan, marginal to severe deficiency of P has been documented in Sahiwal and Okara. Berseem (Trifolium alexandrinum) has been found notoriously low in phosphorus. To improve the P contents in roughages, superjuice prepared from superphosphate appears the cheapest source of P for livestock feeding in Pakistan.
Page(s):
689-693
DOI:
DOI not available
Published:
Journal: International Journal of Agriculture and Biology, Volume: 7, Issue: 4, Year: 2005