THOMSON & JOSEPH LTD. The Mineral Specialists GRASS SILAGE EARLY SEASON MINERAL PROFILE

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1 THOMSON & JOSEPH LTD The Mineral Specialists GRASS SILAGE - EARLY SEASON MINERAL PROFILE CALCIUM INCREASES AT EXPENSE OF PHOSPHORUS PHOSPHORUS DOWN BY 14% POTASSIUM MAINTAINS HIGH VALUE CAB FALLS BY 11% DUE TO HIGHER CHLORIDE CAB REMAINS CLOSE TO +400meq/kg IRON AND ALUMINIUM REDUCED DUE TO LOWER SOIL CONTAMINATION MOLYBDENUM DOWN BY 9% RELATIVE AVAILABLE COPPER STATUS INCREASED BY 12% M ean mineral data from the new crop grass silage samples analysed during June August, has confirmed some interesting differences compared to 2008 and These differences can be largely attributed to the weather patterns experienced during winter and spring. The winter was the coldest since 1978/79 with the average temperature 2.0 C below the mean for Across the country rainfall was 77% of the long term average. This dry trend continued into the spring especially for England and Wales, where during April less than 50% of average rainfall was recorded. As a result, April was the driest since Not surprisingly, April was an extremely sunny month with an average temperature 1.0 C above the long term average of The mineral trends reported here are largely the result of these deviations from the long term norm. PHOSPHORUS LOWEST VALUE FOR 20 YEARS A previous bulletin (July Lower Grass Phosphorus Levels in ) reported a drop of 17% in the mean PHOSPHORUS levels of this season s grass crop. Consequently, it is no surprise that the PHOSPHORUS content of grass silage is also reduced by a similar amount. This year s PHOSPHORUS level is the lowest reported mean value since T&J introduced a forage mineral service in PHOSPHORUS reduced by 14%, from 0.29% in 2009 to 0.25% in. The grass growing season was delayed by about a month due to the coldest winter for 30 years. September % P % Of all the elements PHOSPHORUS is most affected by soil temperature. Low soil temperatures which only recovered during the second half of April, resulted in a reduced uptake of PHOSPHORUS. Grass is generally a good source of CALCIUM and PHOSPHORUS. The reported increase in CALCIUM of 10% is almost certainly related to the decrease in PHOSPHORUS, as these elements are inversely related. As CALCIUM rises PHOSPHORUS declines and vice-versa. PHOSPHORUS decline will increase the risk of DOWNER COW SYNDROME, particularly as cows attain peak milk production and immediately thereafter. PHOSPHORUS is essential for energy utilisation in support of milk production and fertility. The reported decline in mean PHOSPHORUS equates to a reduced dietary intake of 3-5g P/cow/day. To counter this drop in PHOSPHORUS intake supplementary mineral PHOSPHORUS levels will need to be increased by 2-3%. As WHOLE CROP and MAIZE SILAGE are later maturing crops the effects of the late spring should be less apparent in terms of a reduced PHOSPHORUS status, however, this will be checked and reported at the appropriate time. POTASSIUM MAINTAINS HIGH VALUE POTASSIUM mean is close to the 2008 and 2009 values and remains high both in terms of the grass and cow s requirement. It is 4% higher than in 2007 and 7% higher than in Remaining electrolyte minerals of SODIUM and SULPHUR also remain unchanged on 2009 values. The exception is CHLORIDE which is reported at 16% higher POTASSIUM ACTION PLAN % K than last year. No explanation can be given for this increase, although past reports have shown CHLORIDE mean values to be volatile. There is more POTASSIUM in grass than NITROGEN and a readily available supply from soil reserves is essential to maintain acceptable yields of grass. At reported POTASSIUM levels grass silage will remove around 350kg/ha of POTASH (K 2 O) from the soil, of which about 60% is supplied from slurry. The 40% POTASH deficit has to come from fertiliser inputs or soil reserves. It is surprising, given the POTASH fertiliser holidays being practised on many dairy farms, that forage levels have not started to significantly decline as soil reserves are exhausted. However, the answer may lie in a recent NRM survey of soil POTASH levels which showed on average that around 60% of UK soils were replete or excessive for POTASH. Continuing high forage POTASSIUM represents a risk factor for HYPOCALCAEMIA and HYPOMAGNESEMIA which is also influenced by a high CATION-ANION BALANCE largely driven by POTASSIUM AND CHLORIDE. To limit grass POTASSIUM levels: Monitor soil POTASH levels every 3 years Analyse slurry for fertiliser nutrients Develop a plan to ensure grass POTASH needs are met and not exceeded. Page 1

2 250 Target slurry at low POTASH index soils. Where grass POTASSIUM is high (>2.5%) apply SALT to pastures in spring (50-100kg/ha) to correct wide forage K:Na ratios due to imbalanced soil levels. Improve soil fertility through aeration and mineral balance correction to ensure more POTASH is stored in Organic Matter and Soil Biology to avoid excessive uptakes from the soil solution. For livestock, balance high K forage levels with MAGNESIUM and SALT supplementation, as appropriate. Ensure stock have access to free choice SALT to depress POTASSIUM and support MAGNESIUM absorption. Only exception to SALT supplementation is Transition cows, where it should be avoided. CATION-ANION BALANCE (CAB) DECLINES BUT REMAINS HIGH 450 CAB decline due to higher CHLORIDE level. CAB reduced to level but remains high at +393 meq/kg High CAB will increase alkalinity in cow s fluids (blood, urine) which will depress CALCIUM utilisation at calving, which will increase risk factors for: Retained cleansings Metritis Poor milk initiation Displaced abomasums Reduced dry matter intake Ketosis CAB ACTION POINTS Attention to limiting POTASSIUM levels in grass has already been highlighted. Analyse forages for electrolyte minerals (K +, Na +, Cl -, S - ) and calculate CAB value. Adjust forage ratios in Transition diet to ensure DCAB is within 0 to +100meq/kg and POTASSIUM is <1.5%. If forage ratio adjustment cannot meet the above targets use anionic salts (MAGNESIUM CHLORIDE/SULPHATE, CALCIUM CHLORIDE/SULPHATE to achieve dietary targets. For Partial Anionic diets, target macro-mineral levels in Transition diet as follows: CALCIUM g/d, PHOSPHORUS g/d, MAGNESIUM g/d, SODIUM10-20 g/d. Boost CALCIUM and PHOSPHORUS supply at calving with CALCI-P +, an orally dosed liquid supplement containing MAAC CALCIUM chelate and based on Propylene Glycol. LESS SOIL CONTAMINATION REDUCES IRON CAB meq/kg Because of the generally drier weather in April into May, soil contamination levels, as measured by the TITANIUM concentration, dropped by 7%. An equivalent decline of 8% for IRON was reported, relative to the 2009 mean The mean IRON level of 307 mg/kg is slightly below the 5 year average of 333mg/ kg and is similar to the 2008 mean level. In recent years IRON levels have stabilised with any fluctuations related to weather conditions at harvesting. But it must be recognised that IRON levels have doubled over the past 20 years. The reasons for the continuing high IRON level are well known and include: Increased use of large, heavy machinery for harvesting grass, picking up soil. Compacted anaerobic soil increases IRON solubility encouraging increased uptake by grass. Less rolling of silage fields prior to cutting. High applications of anaerobic slurry which depletes soils of oxygen. IRON in soil is primarily in a chemically oxidised state, but becomes reduced in the anaerobic conditions of the silage pit. This chemical change increases the reactivity of IRON, which in turn raises the dietary requirement for anti-oxidants including VITAMIN E, SELENIUM and COPPER. Continuing high IRON level exerts a strong competitor pressure on the absorption of other trace elements including ZINC, MANGANESE and COPPER. At X3 higher than the cow s requirement for IRON, the excessive levels in grass silage are a significant challenge to cow health and productivity. IRON ACTION POINTS Most important point is to take action to minimise soil contamination when cutting grass. Make contractors aware that by keeping the cutter bar too low there are risks to cow health. Discuss with farmers the rolling of silage fields prior to cutting. Use BioAg s Digest-it slurry digesting bug to aerobically compost slurry to ensure it is not toxic to soils by depleting them of oxygen, which can reduce soil fertility and create the anaerobic conditions which stimulate IRON uptake. Aerate soils and reduce compaction as part of a soil improvement programme, the main aim of which is to ensure oxygen penetration to root zones. Analyse grass silage each season to determine IRON levels and their potential threat to cow health. Use mineral analysis data to develop a customised balanced mineral supplement which is capable of minimising IRON competitive absorption pressures. MOLYBDENUM FALLS AND RELATIVE AVAILABLE COPPER INCREASES MOLYBDENUM has fallen 9% in due to dry weather during the key growing months of April and May. It is similar to the 2007 mean level. Relative Available Copper Status has increased, as a result of the drop in MOLYBDEUM, from 50 to 56% of the expected norm. Page 2 September Fe mg/kg

3 COPPER remains under pressure with average Grass Silage supplying only around half of the Available COPPER you would reasonably expect this forage to provide. Mo mg/kg MOLYBDENUM ACTION POINTS Following a soil improvement programme to reduce IRON will also have a depressive effect on the uptake of MOLYBDENUM. MOLYBDENUM, like IRON, becomes more soluble under anaerobic conditions in the soil. Aerating soils will reduce forage MOLYBDENUM levels. Also ensure soil SULPHUR (sulphate) levels are adequate as SULPHUR is a potent binder of MOLYBDENUM in soils, just as it is in the rumen. Analyse grass silage to identify MOLYBDENUM challenge and to develop appropriate dietary intakes of rumen soluble COPPER and SULPHUR to suppress MOLYBDENUM absorption, through the creation of rumen insoluble compounds. COPPER supplementation should be supported by COPPER-16 MAAC, the glycine chelated source of COPPER to provide a rumen protected, bioavailable and well-utilised COPPER source in support of cow health, fertility and production. OTHER TRACE ELEMENTS MANGANESE, COPPER, COBALT and SELENIUM concentrations are similar to 2009 levels. Note MANGANESE remains high and generally in excess of ruminant dietary requirements. ZINC is 10% higher in average grass silage compared to 2009, but remains well below animal requirements. The background to the increase in ZINC is not immediately clear. IODINE mean values fluctuate widely year on year, possibly due to the proportion of forage samples received from coastal areas. The mean value is within the range reported in recent years Relative Available Copper Status % COBALT, IODINE and SELENIUM while essential for livestock appear to have no physiological role in plants. Consequently they are effectively contaminants in silage, hence their low concentrations. Supplementation of these elements is essential for maintaining animal health. SUMMARY Main points in Grass Silage are: PHOSPHORUS reduced by 14%. Consider increasing PHOSPHORUS supplementation by 2-3% in farm minerals. POTASSIUM remains high and a risk to cow health at calving. CAB falls by 11% due to higher CHLORIDE, but remains high at +393 meq/kg. Lower Soil Contamination has reduced IRON levels by 8%. MOLYBDENUM lower by 9% due to dry spring weather. Reduced IRON and MOLYBDENUM increases the Relative COPPER Available Status by 12%, from 50 to 56% Need to review COPPER supplementation against a background of reduced antagonism from IRON and MOLYBDENUM. TRANSLATED INTO RISK FACTORS FOR MINERAL RELATED DISORDERS IN THE FORTHCOMING SEASON: RED ALERT! - PHOSPHORUS DEFICIENCY REDUCED MILK PRODUCTION AND FERTILITY. RED ALERT! - CALCIUM DEFICIENCY AT CALVING HYPOCALCAEMIA. RED ALERT! - COPPER ANTAGONISTIC PRESSURE REDUCED CHECK COPPER SUPPLEMENTATION. RED ALERT! - OXIDATIVE STRESS FROM HIGH IRON HEALTH AND FERTILITY PROBLEMS. To ensure cow health, fertility and production is not compromised by these potential Risk Factors use: T&J Forage Mineral Analysis Service T&J Mineral Check to formulate balanced supplements Novus MAAC chelated minerals Page 3 September

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5 Forage Year % Difference No. of Samples v 2009 Calcium % Phosphorus % Magnesium % No change Potassium % No change Sodium % No change Chloride % Sulphur % No change CAB meq/kg Iron mg/kg Aluminium mg/kg Manganese mg/kg No change Copper mg/kg No change Zinc mg/kg Cobalt mg/kg No change Molybdenum mg/kg Iodine mg/kg Selenium mg/kg No change Relative Available Copper Status % Soil Contamination Titanium mg/kg Data covers the period 1st June to 27th August and relates to 1st Cut silage. Results are expressed on a Dry Matter Basis. THOMSON & JOSEPH LTD Phone: The Mineral Specialists Fax: enquiries@tandj.co.uk Page 5 September

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