Arthrosis is on the rise among cattle, but farmers can fight it with
correct phosphorus supplementation. Annelie Coleman reports.
The recent prevalence of arthrosis, which causes cartilage degeneration among cattle, is putting a new focus on mineral supplements, interaction between minerals and the use of macro and micro minerals.
Phosphorus is a major macro mineral described in the specifications for Arthrocur, a mineral premixture lick developed to prevent the disease. So says Dr Hannes Viljoen, animal nutritionist and MD of Animal Nutrition and Health (ANH).
University of Pretoria research in the North West and the Northern Cape, headed by Prof Leon Prozesky, has found arthrosis is mainly caused by a mineral imbalance and vitamin shortage. Arthrocur was developed for the research trials, and a number of manufacturers have committed to supplying it in their licks.
Phosphorus in animal nutrition
“Eighty percent of the body’s phosphorus is found in the skeleton, but it’s present in all body cells,” explains Dr Viljoen.
“It plays an important role in metabolic processes such as developing and maintaining bones, energy and protein metabolism, enzyme systems, fertility and milk production. The symptoms of a deficiency usually begin with depressed appetite, resulting in poor growth and feed efficiency.
Other symptoms are decreased fertility and pica, or chewing foreign material. In serious cases, the animals will have swollen and stiff joints and even brittle bones.”
Dr Viljoen says a large number of phosphorus products are commercially available. “The main products are mono-ammonium phosphate (MAP), monocalcium and monodicalcium phosphate (MCP and MDCP), and dicalcium phosphate (DCP). Phosphoric acid is also used in manufacturing certain licks.
“Bone meal was used in the past, but it’s now prohibited as a feed for ruminants.”
Bio-availability of phosphorus
“Fractions of the minerals are lost in the normal digestive and metabolic processes,” Dr Viljoen explains. “The fraction the animal can absorb and use is called the bio-available fraction.
“It’s quite difficult to determine the amount of bio-available phosphorus in ruminants, because it’s actively recirculated through the animals’ saliva, and bone phosphorus is very mobile.”
The utilisation of inorganic feed phosphate supplements has been studied worldwide. The results show distinct differences in how animals utilise different phosphorus sources
The bio-availability of phosphorus in forage can differ by 50% to 95%, depending on the type of forage and its maturity. Variations also occur in concentrates. Also, factors such as heat treatment can lower the bio-available phosphorus content considerably.
French researchers found bone meal has only 50% to 60% bio-available phosphorus for ruminants.
“MCP products commercially available in South Africa were found to contain 10% to 65% MCP,” said Dr Viljoen. “Farmers have to be familiar with the products they use, and adapt intake to supply enough bio-available phosphorus for the best nutrition and health.
“To address differences in product compositions, guidelines have been developed for preventing arthrosis”
Contact Dr Hannes Viljoen at [email protected] 082 806 3488
