Routine Prevention of Mineral Deficiencies in Beef Herds

Phil Rogers <>,
Teagasc [Irish Agriculture & Food Development Authority] Homepage

Nov 16, 2000

Introduction | Diagnosis | Routine cattle supplements | Top-class mineral formulations
 Types of minerals for cattle | Dry-cow mineral | Post-calving mineral | Tetany-control mineral
Drystock/calf mineral | Fixed-rate or free-access? | Free-access minerals
Best mineral programmes for beef herds | Beef cows (precalving inside, precalving outside, postcalving inside, postcalving outside) | Calves (indoors, outdoors) | Weanlings, growers, finishers (indoors, outdoors) | Mineral supplements developed with Grange | Web references |

INTRODUCTION: Most Irish forages have multiple mineral imbalances, especially combinations of low magnesium (Mg), sodium (Na), copper (Cu), selenium (Se), iodine (I), together with high nitrogen (N), potassium (K), sulphur (S) and molybdenum (Mo). Thus, most unsupplemented Irish cattle have multiple imbalances, especially of Mg, Co, Cu, I and Se. Mineral deficient herds are at risk of grass tetany, milk fever, calving problems, retained placenta, infertility, perinatal and postnatal calf losses, lower herd immunity (scours, pneumonia, joint-ill, mastitis, metritis, bacterial, viral and protozoal infections and parasitism) and lower milk yield and growth.

DIAGNOSIS of mineral imbalances in cattle uses analysis of blood and/or liver samples from the problem group(s), sometimes with analysis of feed and soil samples from the farm. Recent research in beef animals, however, showed low status of liver Cu in 25% and of blood Se in 14% and I in 71% of cull beef cows and finished cattle at slaughter. Co deficiency occurs in some herds.

CATTLE NEED ROUTINE SUPPLEMENTS: All cows, replacements, calves, weanlings and finishers need routine supplements. Except for tetany-control, and in herds with atypical problems, most cows need minerals for 5 months only (1 month precalving and 4 months postcalving). Weanlings and finishers need routine supplements in winter and suckling calves <4 months of age may need veterinary supplements (bullets, boluses etc) in herds with Mg or trace element deficiency.

Table 1. Top-class formulations for mineral mixes for COWS AND OTHER CATTLE on grass silage or herbage as the main forage.


Cows pre-calving

Cows post-calving

Cows in tetany time


Allowance of mineral mix (g/head/day)




2g/10kgLW (2)

g/100 g mix





mg/kg mix





iu/kg mix
Vit A
Vit D3
Vit E(6)





(1) Never feed cattle minerals to sheep, and vice-versa. Cattle minerals may cause copper toxicity in sheep. Never feed cow minerals to calves, as scouring and urinary stones and copper toxicity may follow.
(2) If recommended daily allowances are above or below those shown, adjust the trace-element and vitamin levels down or up, accordingly. One would normally feed 150-180 g minerals in home-mixed lactation diets. Special minerals are needed if silages based on whole-crop maize or fodderbeet are fed.
(3) To prevent urinary stones in drystock, feed low levels (0-3%) of Mg in mineral mixes.
(4) Some authorities double these amounts of Mn for breeding females, especially in groups with severe infertility and suspected Mn deficiency
(5) The maximum Se supplement was reduced to 5 mg Se/cow/d, as from January 1 1996. Do not feed high Se minerals to cattle within 5 miles of a known Se-toxic farm unless blood test indicates no risk of Se toxicity.
(6) The higher Vit E levels are 4-6 times higher than usual (underlined values are more usual). Research in USA and elsewhere shows that high levels of Vit E improve immunity and reduce mastitis incidence.


TYPES OF MINERAL SUPPLEMENTS FOR CATTLE: Beef cattle need at least four mineral mix formulas: 1) Dry-Cow Mineral, 2) Post-calving Mineral, 3) Tetany-Control Mineral, and 4) Drystock Mineral. These are not interchangeable. Also, special feeds (e.g. maize or fodder beet silage, high-pulp diets) require Special Balancers. One may include the appropriate supplement in the concentrate, or dust it on the forage, indoors, or at pasture. Depending on competition for forage space, one should subdivide the day's allowance into 2-4 parts, dusted onto forage 2-4 times/d. Attempts to dust self-feed faces may fail unless great care is taken to dust the whole face and to allow for wastage (mineral falling to the ground during dusting). Beef farmers need some veterinary supplements (especially boluses, bullets and water medications) for suckling calves, in addition to high-specification mineral mixes for older cattle. Do not feed cow minerals to drystock (weanlings, stores or finishers), especially to young males. Do not feed cattle minerals to sheep.

DRY-COW MINERAL FOR GRASS OR SILAGE BASED-DIETS: Table 1 shows the top-specifications for bovine minerals. The usual feeding rate is 100 g of mineral mix/head/d for 4-6 weeks pre-calving to prevent milk fever and hypocalcaemia-related problems (hypotonia, prolapse or delayed involution of the uterus, metritis, delayed onset of heat, mastitis, left displacement of abomasum etc). In an outbreak of periparturient problems (excluding hypocalcaemia) in cows (slow calving, retained placenta) or calves (stillbirth, weak calves, low postnatal immunity etc), good results often follow within 1 week after access to the mineral.

POST-CALVING MINERAL: Table 1 shows the top-specifications for bovine minerals. The usual feeding rate is 100-150 g of mineral mix/cow/d, fed indoors to cows from calving until turnout to pasture.

TETANY-CONTROL MINERAL: Table 1 shows the top-specifications for bovine minerals.  Calved beef cows at grass on intensive farms, or on farms with a history of grass tetany, routinely need 130-160 g/cow/d, fed from turnout until the end of May or early June. Some herds may need Mg supplements for longer. Beef cows also need a high-Mg supplement for about 1 week after weaning in the autumn, or from calving to housing if they calve at pasture in autumn. Feed it in a fixed amount (0.5 or 1.0 kg) of commercial ration, or in 0.5 or 1.0 kg of home-mixed molassed carrier feed.

DRYSTOCK/CALF MINERAL: Table 1 shows the top-specifications for bovine minerals.  The usual feeding rate of drystock/calf mineral is 20 g/100 kg liveweight/d. Indoors, one can dust the mineral on forage, or include it the concentrates. At pasture, one can trough-feed it in molassed carrier feed (200-300 g for weanlings or 400-600 g for yearlings).

FIXED-RATE OR FREE-ACCESS MINERAL FEEDING FOR CATTLE: Fixed-rate feeding of well balanced formulas (in feed, on feed, or in water) is the cheapest and best way to supplement. If possible, dust the mineral on forage, or put it in a daily allowance of concentrate, or in a small but fixed amount of special palatable carrier. Indoors, one can dust the daily allowance over the forage, or include it in the daily allowance of concentrate. At grass, one can put it in a small but fixed amount of carrier. Include molasses (at 6% total weight) to make it palatable. One can mix the full daily allowance of mineral mix with 3-4 times its weight of carrier. Minimum amounts of home-mixed carrier (rolled barley + minerals + molasses) needed per day are: cows and adults 450 g, yearlings 350 g, weanlings 250 g. It is essential to allow enough trough-space.

FREE-ACCESS SUPPLEMENTATION: Free-access (ad-lib) systems include home-made mixes (such as 50/50 molasses/mineral mix) and commercial mineral blocks, buckets, licks, ball-feeders and loose minerals in troughs. Unfortunately, on ad lib systems intake between animals varies widely. Blood tests confirm that ad lib systems fail to protect 30-60% of animals in the group. There is no role for free-access minerals in animals fed indoors or in yards. It is easy and preferable to provide fixed-rate feeding of minerals in that case. Fixed-rate feeding of minerals to grazing suckler cows or drystock may not be possible at grass in marginal areas. There, free-access minerals, or veterinary supplements may be required to correct deficiencies.

The best mineral supplementation programmes for beef herds are:.

Precalving, in on winter diets Dust Dry Cow Mins on silage or damped forage for the last 4+ weeks (Table 1).
Precalving, out at pasture Feed Dry Cow Mins (Table 1) for the last 4+ weeks (i) on silage or damped forage fed at pasture, or (ii) in 0.5 or 1.0 kg molassed carrier feed in troughs. (iii) Otherwise consider water medication with soluble Mins (not as reliable in dry cows as in calved cows). On wet or cold days, dry cows may drink very little. (iv) Use free choice mins (Dry Cow blocks, etc) as a last resort.
Postcalving, in on winter diets Feed Post-Calving Mins (Table 1) from calving to turnout, (i) dusted on silage or damped forage, or (ii) in a small daily allowance of concentrate
Postcalving, out at pasture Feed Tetany-Control Min (Table 1) for up to 4 months postpartum, or longer if needed. Also feed it for a few days before and after weaning. (i) Dust the Min on silage / damped forage at grass, or (ii) feed 30-40 g Mg + trace elements in 0.5 or 1.0 kg of special Beef Cow Summer Nut, or 0.5 or 1.0 kg of DIY molassed carrier feed. (iii) Water medication with Mg and trace elements. (iv) Consider pasture dusting with Calmag if trace-elements not a problem at grass. (v) Vet products: Though more expensive than mineral mixes, some products (Deposel, Ionox, Cosecure, CuO boluses, Vitamin B12 injection) are effective if used at adequate dose rates. Others are irritant: avoid Cu injection if possible, and especially close to breeding. (vi) Use free choice mins (Tetany Control blocks, molasses : magnesite 50/50 mix, etc) or Mg bullets only as a last resort. New Mg bullets (Optimag, releasing 3 g Mg each/d) give 3 times more Mg than older bullets. However, Mg bullets are unreliable for tetany prevention unless at least 2 Optimags are dosed/cow every 4-5 weeks
Indoors (i) Suckies pose a special problem because milk is a poor source of Mg and trace elements. As weaning may be delayed for 6-9 months, deficiency of Cu, Se and I may arise in unsupplemented calves. Unless they are valuable pedigree stock, few suckies get creep feed that could be used to carry minerals. Vet Mins (boluses, bullets, injections (but avoid Cu and I injection), and drenches) may be the only practical ways to supplement their mineral status. If calf tetany occurs consider 2-4 of the old Mg bullets, or 1 Optimag (if it does not choke the calf).

(ii) Calves on milk replacer + concentrates: Ensure that the milk replacer and/or the meal allowance supplies enough calf minerals and vitamins.

Out at pasture Vet Mins (boluses, bullets, injections but not Cu!). In calf tetany, use 2-4 old Mg bullets, or 1 Optimag. Consider water medication after 4 months of age. Until then, suckies can not be relied upon to take enough minerals via the drinking water, but after 4 months, water medication can be useful. Older calves may ingest minerals from free-choice systems (blocks, licks etc), but with the same unreliability as for other cattle. Use free choice mins (Drystock blocks, etc) as a last resort.
Indoors on forage + concentrates Feed Drystock Min (Table 1., at 20 g/100 kg LW/d in feed, or dusted on forage. This has few problems for cattle indoors. Consider water medication to supply trace elements.
Out at pasture Consider (i) water medication, (ii) trough feeding of Drystock Min (Table 1) in a palatable carrier (20 kg drystock mineral + 70 kg rolled barley + 10 kg molasses) at fixed rates (100 g carrier/100 kg LW), or (iii) Vet trace elements. Those methods may be impractical or costly on marginal farms. If so, access to free-choice systems (home-made licks of 1:1 molasses:Drystock Min, Min Blocks, Min Buckets, etc) may be the only practical solution at grass. Use free choice Drystock Min only as a last resort.

Grange Research led to the development of many commercial products, including Dry Cow Minerals [sold by most suppliers], Cosil [a Cu-fortified silage additive] and Flowmag, Flowtrace and Magtrace [Mg and trace-element supplements via the water supply - by Preference Products]. They also include Aquadyne and Aquasel [tablets to dose I and Se via the water supply - Mayo Healthcare], Ionox [a slow-release bolus to give I, Se and Co to grazing cattle - Animax / Bayer] and Temol [a trace element fortified silage additive - Premier Molasses]. We advised many other Irish pharmaceutical companies (for example Whelehans, Ancare, Foran Chemicals and Chanelle) on suitable formulations for their Multitrace doses, drenches and water-medication systems for sheep and cattle. Our criticism of older Mg bullets and Alltrace bullets led to development of much better formulations.

Mineral-related topics available on the Grange Interim Web Pages:



Are Mineral Tests in Milk reliable to assess Mineral Status of Cattle? /bldlab.htm
Bovine abortion, perinatal & early postnatal problems perinatb.htm
Bovine fertility & control of herd infertility infertil.htm
Bovine hypocalcaemia & Milk Fever milkfeve.htm
Bovine illthrift / poor performance / weight loss illthbov.htm
Bovine magnesium supplements mgsupbov.htm
Bovine mineral mixes mins_bov.htm
Bovine pica, urine drinking & depraved appetite picaurin.htm
Bovine rough, faded coats poorcoat.htm
Control of mineral imbalances in cattle & sheep: A reference manual for Advisers & Vets 3control.htm
DM, major elements & trace elements in Irish grass, silage & hay 0forage.htm
Iodine supplementation of cattle. End of Project Report: Project No. 4381 i_report.htm
Iodine supplements for cattle, sheep & horses iodsupp.htm
Lamb illthrift illthovi.htm
Poisoning in sheep by copper (Cu): Control cutox.htm
Scour in cattle & sheep scourall.htm
Selenium toxicity in farm animals: treatment and prevention setoxicity.htm
Urinary calculi in lambs & calves calculi.htm