BSAS: Copper Deficiency Issue Scrutinised at Harper Adams22 April 2013
UK - Researchers at the forefront of dairy science and nutrition are focusing on copper (Cu) availability and how dietary components can affect status indicators.
Researchers at the forefront of dairy science and nutrition are focusing on copper (Cu) availability and how dietary components can affect status indicators.
New insights into basal forages and the effect of Cu antagonists sulphur and molybdenum were presented at the British Society of Animal Science Annual Conference at Nottingham University this week.
Two teams of specialists from Harper Adams University discussed recent investigations into Copper and the effects of sulphur (S) and molybdenum (Mo) on feed intake, performance and copper utilisation.
Widely considered the most important trace element in dairy cow health and performance, Copper deficiency is often related to the presence of S and Mo.
The two elements are thought to restrict Copper absorption as they form thiomolybdates and bind to available Cu.
Thiomlybdates in turn bind with the copper forming complexes which are insoluble in the rumen. This is what is thought to lead to copper deficiency.
The two studies, led by Professor Liam Sinclair and Dr Donna Johnson, both took 56 Holstein-Friesian dairy cows around 35 days into lactation. The animals were randomly allocated to four different dietary treatments.
The feed was varied to a concentrate to maize or grass silage basis. This basal forage was then supplemented with different quantities of S and Mo Concentrations.
The conclusions of Professor Sinclair’s report was that
- A higher level of maize inclusion increased DM intake and milk protein yield
- The addition of S and Mo reduced feed intake and milk yield in cows fed the grass silage (not maize)
- S and Mo also reduced liver Cu status by a greater extent in cows fed grass compared to maize silage (not reflected in plasma Cu or ceruloplasmin: Cu ratio
The conclusions of Dr Johnson’s report was that
- The form of dietary Cu had no effect on far adjusted milk yield
- S and Mo reduced Dry Matter intake in cows fed the inorganic but not organic Cu
- S and Mo also reduced liver Cu levels by approximately 0.9 mg/kg Dry Matter/day
- There was no effect of dietary treatment on liver copper chaperone or transporter mRNA levels, except ATP7B which tended to be increased in cows when fed the organic, but not inorganic Cu with added S and Mo.