Proposed New Code of Practice for Copper Supplementation of Ruminant Livestock April 2011 Bulletin Richard Keel

Transcription

1 11 April 2011 Proposed New Code of Practice for Copper Supplementation of Ruminant Livestock April 2011 Bulletin Richard Keel 11

2 Proposed New Code of Practice for Copper Supplementation of Ruminant Livestock Recent discussions with the VLA (Veterinary Laboratories Agency) from across the industry, has highlighted a potential need to review copper levels in some ruminant diets. Copper is a critical trace element, and has many essential roles within the ruminant. Dietary sources of molybdenum, iron and sulphur have an impact on the copper requirement and potential absorption. Copper is an essential trace element for ruminant livestock and its deficiency historically has been more commonly diagnosed than other trace elements across specific areas of the UK. The rise in the number of toxicity cases in recent years has prompted an industry led working group to investigate the causes of copper toxicity in cattle and to propose the following new code of practice for its supplementation in cattle which was presented at the SFT Ruminant Conference last week in Coventry. 10 Point Proposed Code of Practice For Copper Supplementation This code of practice is a proposal for farmers, vets & nutritional advisors/suppliers of mineral supplements to farm to consider - 1. Copper status of cattle should be regularly assessed, particularly before supplementation is considered. 2. Supplementation should be carefully considered by nutritional advisers and vets before providing advice on input levels. 3. Copper inputs from all applicable sources (e.g. grass, forages, compounds, straights, mineral powders, mineral blocks, mineral buckets, boluses, injections and water supply) should be fully investigated and calculated to ensure that, in total, there is no excess. 4. Copper concentration in the total diet should usually be formulated to 20 mg/kg DM. 5. If there is any doubt about the dietary copper input, feeds (including pasture and forage) should be analysed for copper content. 6. To help avoid confusion, feed analysis reports should not report estimated copper availability levels. The concentrations of copper antagonists should be measured and individually reported. 7. If all interested parties agree that it is necessary to exceed 20 mg/kg DM of copper in the total diet (but not exceed the statutory limit), supplementation levels should be fully considered and the course of action agreed. 8. A full risk assessment should be carried out before a prescription is written for copper supplementation in excess of 40 mg/kg DM. 9. Supplementation action plans should be regularly reviewed to assess effectiveness and outcome of copper status. 10. Records of changes to copper supplementation and protocols should be kept and added to herd health plans. N.B. The Maximum Permitted Level (MPL) of copper in cattle feed is set out in EU Regulation 1334/2003 at 35 mg/kg at 88% dry matter (DM), which equates to 40 mg/kg DM. Supplementation at levels greater than this can only be undertaken after a full risk assessment and by written prescription by the veterinary surgeon responsible for the animals.

3 Comments - On Farm Practical Implications To Be Considered 1. No assumptions should be taken in future with regards to historical copper antagonisms with farmers. 2. Setting a proposed target level of 20mg/kg DM will potentially have a significant impact on feed compound levels. In some cases, copper levels will need to be reviewed downwards based on feed rates of mineralised compound feeds, etc. 3. When advising on farm, copper levels in compound feed and more importantly feed rates, should be precisely ascertained with the farmer customer/prospect. 4. Copper Availability values on forage mineral reports should probably be withdrawn until more precise equations are determined with regards to the absorption of copper within the ruminant based on modern UK forages. 5. Total copper supply from forages, feed ingredients, compounds, blends, minerals, (and boluses) should be considered and calculated accurately. 6. Between 2005 and 2010, the VLA confirmed a diagnosis of 143 incidents of copper toxicity in cattle. 114 cases were lactating dairy cows. It has been asked, how many cases were not reported? Forage Mineral Averages (mg/kg DM) Forage Type Cu Mo S Fe Grass Silage Maize Silage Whole Crop (Source Thompson & Joseph) Published Copper Requirements ARC 1980 NRC 2001 INRA 1989 Cattle 12mg/kg DMI Growing Heifers 9 10mg/kg DMI, Dairy Cows 11mg/kg DMI Ruminants 10mg/kg DMI A higher focus on the diet fed; especially when the forage mix/compound feed rate is altered, copper should be a critical part of the mineral supplement review. Accurate information from the farmer needs to be supplied to enable advisors on farm to undertake an accurate review of the mineral supplementation program. For example, specific compound feeding rates in relation to dry matter intake of the herd. Background levels from forages fed, and other sources of ingredients containing copper fed in the diet should be considered. As a typical level, 100mg background copper form forages, needs to be taken into the overall calculation. In specific areas of the UK, levels of copper antagonists are sufficiently high to require levels to copper supplementation significantly greater than 20mg/kg DM proposed. For example, in the south west, we regularly receive mineral forage reports back from laboratories with levels of molybdenum in excess of 10mg/kg DM and higher! With regard to the source of copper used in supplements, (organic &/or inorganic), it is still unclear which sources have what effect inside the body of the animal. Further research work should be undertaken by the industry and research institutes.

4 Typical Copper Intake Calculator This simple calculator is available for customers of Feed Supplements for those who wish to use on farm. A typical farm example is enclosed below. COPPER INTAKE Fresh DM % RATION Intake DMI analysis mg/kg Ration conc INGREDIENT Kg kg mg Cu DM intake Cu mg/kg DM Silage av 3 yr 25 26% Grass 0 19% Straw 0 85% Maize sil 15 24% Brewers Grains 7 25% Trafford Gold 0 44% Barley 2 84% Wheat 2 84% Soya ext 0 88% Hipro soya % Soya Hulls 0 88% Dist grains 0 88% Gluten 0 88% Maize res 0 88% Rape ext % DMP 0 87% premix 0 87% Parlour cake, 6 87% Mineral % Cosecure= 1 dose TOTALS COPPER Total required Requirement mg mg/kg DM Copper Levels Supplied By Minerals Based on 100%DM Mineral Feeding Rate/Hd/Day 100g 125g 150g 175g 200g Inclusion Copper in Mineral mg/kg 1, , , , , , ,

5 Summary All farms should look to implement a Good Practice copper supplementation procedure to demonstrate a need for supplementation and the precise level. Simple user friendly mineral formulation models such as Minerva which is free and easy to use, from Feed Supplements will help farm customers remain safe when supplementing lactating cows. Please contact myself if you require a demonstration of Minerva. The oversupply of copper to the liver causes the breakdown of red blood cells. Certain breeds of livestock appear more susceptible to the accumulation of copper in the liver than others. For example, Jerseys are known to be less tolerant to copper than Holstein breeds (Weiss et al 2008). Quite often, the total copper supply from all sources fed on farm is not being checked on a regular basis and may exceed permitted levels in some specific circumstances. Finally, if in doubt, feel free to call me. Richard Keel Business Manager Feed Supplements Mineral Division Car richard.keel@molevalleyfarmers.com