ISSUE FOCUS FEED & ADDITIVE MAGAZINE March 2022 33 RISK OF SECONDARY DEFICIENCY Secondary deficiency happens when even at proper level of Cu supplementation, the presence of other dietary factors interferes with mineral absorption and metabolism. This phenomenon is the main cause of Cu deficiency in ruminants. Sulfur (S), molybdenum (Mo) and iron (Fe) are the most important dietary factors to negatively impact Cu absorption. The signs of Cu deficiency vary from mild symptoms such as loss of coat condition and poor growth, to more severe symptoms like infertility and diarrhea. As forage and diet compositions are seasonal and variable from farm to farm, secondary deficiencies are difficult to predict. Therefore, Cu in ruminant diets is usually supplemented well above nutritional requirements, to guarantee Cu absorption regardless of the presence of antagonists. OVERSUPPLY IN DAIRY CATTLE While in the past Cu deficiencies used to occur in grazing ruminants, researchers have observed in a Figure 1 - Cu requirements and maximum Cu dietary level authorized in the EU for ruminants (mg/kg complete feed) 1 Regulation (EU) 2018/1039 Requirements Maximum Cu dietary levels authorized1 10 30 NRC, USA (2000, 2021, 2007) GfE, DE (1995, 2001, 2003) CVB, NL (2005) Agroscope, CH (2006, 2009) INRA, FR (2018) Bovines before the start of rumination 10 - 10 6 - 15 Beef 10 8-10 11-13 10 Dairy 9-18 10 7-17 10-15 Ovines 4-8 - 6-7 5 10 15 Caprines 15-25 10-15 8 8 15-25 35 Other bovines Small ruminants High Concentration Flowability Safety standards Stability Bioavailability Animal performance POTENTIATED ZINC POTENTIATED ZINC MONOVALENT COPPER HIGHLY PURIFIED MANGANESE an international and independent supplier of precision minerals , www.animine.eu
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