Cattle feed additives are substances added to beef cattle rations in small amounts to change rumen fermentation, reduce liver abscesses, control coccidiosis or supply trace elements, and the US and EU allow very different sets of them. The US sets an approved level per drug and cattle class under 21 CFR 558, from monensin at 5 to 40 g/ton in feedlot rations to melengestrol acetate at 0.25 to 0.5 mg/head/day for heifers.
US ionophores such as monensin and lasalocid are Category I drugs fed without a veterinary order, while tylosin, virginiamycin and chlortetracycline need a Veterinary Feed Directive. These cattle additives come from several of the types of feed additives the EU and US recognise, yet the EU authorises no ionophore, antibiotic, hormone or beta-agonist for cattle. EU beef rations carry live yeast, feed-grade urea, ammonium chloride and trace elements within legal limits, and in the EU 3-NOP is authorised only for dairy cows and cows for reproduction.
Every value on this page is compiled from the EU authorising acts, the EU Register of Feed Additives, the eCFR, FDA documents and named peer-reviewed studies, checked on 3 November 2026; see the methodology.
What Do Feed Additives Do in Beef Cattle Production?#
Feed additives in beef cattle production raise feed efficiency and gain, protect the rumen and liver on high-grain diets, control coccidiosis in calves and close trace-element gaps on pasture. EU law defines them as substances intentionally added to feed or water to perform a listed function (Article 2(2)(a) of Regulation (EC) No 1831/2003) and sorts them into five categories: technological, sensory, nutritional, zootechnical, and coccidiostats and histomonostats. Monensin improved feed efficiency by 6.4 % in a 2012 meta-analysis of beef cattle trials, but only by 2.5 to 3.5 % in the last two decades.
Feedlot, pasture and calf-rearing systems#
Beef cattle pass through three feeding systems that use different additives: milk replacer and starter for calves, forage with supplements or free-choice minerals for stocker and pasture cattle, and high-grain finishing rations in the feedlot. Feedlot rations carry the most additives, and liver abscesses, the target of the VFD antibiotics, affect 10 to 20 % of feedlot cattle (Amachawadi and Nagaraja, Journal of Animal Science, 2016). Pasture cattle can receive drugs through blocks or loose minerals, which is legal in the US only when the drug is approved for free-choice use (21 CFR 510.455). Monensin, for example, is approved in a protein-mineral block at 400 mg/lb, delivering 80 to 200 mg/head/day with one block per five head.
Calves receive coccidiostats in milk replacer, starter or feed. Decoquinate is labelled for cattle including veal calves, while monensin, lasalocid and amprolium carry a "not for veal calves" condition because no withdrawal period is established for pre-ruminating calves. For older cattle, monensin has no withdrawal period and a cattle liver tolerance of 0.10 ppm (21 CFR 556.420), and beef cows receive it at 50 to 200 mg/head/day in at least 1 lb of feed (21 CFR 558.355).
Why EU and US cattle programmes differ#
The EU authorises no ionophore, antibiotic, hormone or beta-agonist as a feed additive for cattle, while the US approves all four classes as medicated feeds under 21 CFR 558. Regulation (EC) No 1831/2003 bars antibiotics other than coccidiostats and histomonostats from authorisation (Article 5(4)), and Council Directive 96/22/EC prohibits beta-agonists and substances with hormonal action for growth promotion in farm animals.
Monensin and lasalocid are ionophore coccidiostats in both markets, but for different animals. In the US both are Category I cattle drugs with feedlot, pasture and coccidiosis claims; in the EU they exist only as ionophore coccidiostats for poultry, as monensin sodium 51701 for chickens and turkeys (Implementing Regulation (EU) 2026/532) and lasalocid 51763 for chickens for fattening (Implementing Regulation (EU) 2023/1172). The missing cattle entry is not an EU ban on ionophores, since both remain authorised coccidiostats.
A US cattle programme therefore does not transfer to EU feed, and the EU tools carry legal minimum or maximum contents instead of US approved levels. 3-NOP shows the reverse gap: the EU authorises it as 4c1 for dairy cows and cows for reproduction, while in the US it is an unapproved animal drug under FDA enforcement discretion for lactating dairy cows (CVM letter of 24 May 2024), not an FDA approval. Neither market covers beef cattle.
Cattle Feed Additive Programme by Production Phase#
The programme table below lists cattle feed additives by phase, with the US approved level and section next to the EU status of the same substance.
| # | Phase | Additive | Function or claim | US level, section, category | EU status |
|---|---|---|---|---|---|
| 1 | Calf feed additives | Decoquinate | coccidiosis prevention (US claim) | 0.5 mg/kg BW/day (22.7 mg/100 lb) for at least 28 days, including veal calves (21 CFR 558.195); Category I | 51756i, 51756ii chickens for fattening only (Impl. Reg. (EU) 2021/2094, to 2031-12-20); no cattle entry |
| 2 | Calves | Amprolium | coccidiosis prevention (US claim) | 5 mg/kg BW/day for 21 days (21 CFR 558.55); Category II | 51777 chickens for fattening and chickens reared for laying only (Impl. Reg. (EU) 2021/2047, to 2031-12-14); no cattle entry |
| 3 | Calves and cattle for fattening | Live yeast probiotics | zootechnical additive (4b gut flora stabilisers; 4a1704 in 4a, 4d24 in 4d) | food without claims (FDA CPG Sec. 689.100) | calves for rearing: 4b1702 S.I. Lesaffre min 1.5 × 10^9 CFU/kg (Impl. Reg. (EU) 2021/367, to 2031-03-22); calves: 4b1711 Danstar Ferment AG represented by Lallemand SAS min 1 × 10^9 CFU/kg (2020/1374, to 2030-10-22); cattle for fattening: 4b1702 min 4 × 10^9 CFU/kg (2025/364, to 2035-03-16), 4b1710 Prosol S.p.A. min 4 × 10^9 CFU/kg (2025/314, to 2035-03-10), 4b1711 min 5 × 10^8 CFU/kg (2023/1170, to 2033-07-06); ruminants for fattening except sheep: 4a1704 All-Technology (Ireland) Ltd min 1 × 10^8 CFU/kg (2026/168, to 2036-02-16); ruminants other than dairy cows and minor dairy ruminants: 4d24 Mazzoleni S.p.A. min 4 × 10^9 CFU/kg (2025/169, to 2035-02-20); all per kg complete feed (12 % moisture), EU legal minimum |
| 4 | Pasture and stocker cattle feed additives | Monensin | feed efficiency (feedlot), coccidiosis, pasture and beef-cow uses | feedlot 5 to 40 g/ton (50 to 480 mg/head/day); pasture 50 to 200 mg/head/day; calves (not veal) 10 to 200 g/ton (21 CFR 558.355); Category I, not VFD | no cattle entry; coccidiostat 51701 for chickens and turkeys (Impl. Reg. (EU) 2026/532, to 2036-04-01) |
| 5 | Pasture and stocker | Bambermycin | gain and feed efficiency | feedlot 1 to 4 g/ton (10 to 20 mg/head/day); pasture 10 to 40 mg/head/day hand-fed; approved free-choice mineral formula (21 CFR 558.95); Category I, over the counter | flavophospholipol removed from the EU Register on 2006-01-01 (Reg. (EC) No 1831/2003 Art. 11(2)) |
| 6 | Pasture and stocker | Poloxalene | legume and wheat pasture bloat | 1 g/100 lb BW/day, 2 g under severe conditions (21 CFR 558.464); Category I | no EU feed additive authorisation found |
| 7 | Pasture and stocker | Selenium in animal feed | trace element | complete feed for cattle max 0.3 ppm; beef cattle limit-fed 3 mg/head/day; free-choice salt-mineral up to 120 ppm (21 CFR 573.920) | 3b: total max 0.50 mg/kg complete feed (12 % moisture), organic Se supplementation max 0.20 mg/kg (Impl. Regs. (EU) 2019/49, 2019/804); sodium selenate 3b803 ruminants only (Impl. Reg. (EU) 2020/377, to 2030-03-26) |
| 8 | Pasture and stocker | Cobalt in animal feed | trace element | GRAS (21 CFR 582.80) | total max 1 mg Co/kg complete feed (12 % moisture), ruminants with a functional rumen; supplementation recommended at most 0.3 mg/kg; provisional authorisation (Impl. Reg. (EU) 2023/1455), ending in 2028 at the latest |
| 9 | Pasture and stocker | Copper in animal feed | trace element | GRAS (21 CFR 582.80); no federal numeric maximum | bovines before the start of rumination 15, other bovines 30 mg Cu/kg complete feed (12 % moisture) (Impl. Reg. (EU) 2018/1039; 3b401 to 3b405 to 2028-08-13) |
| 10 | Feedlot feed additives | Lasalocid | feed efficiency and gain; coccidiosis | feedlot 10 to 30 g/ton (100 to 360 mg/head/day); pasture 60 to 300 mg/head/day (21 CFR 558.311, sponsor Zoetis Inc.); Category I, not VFD | 51763 chickens for fattening only (Impl. Reg. (EU) 2023/1172, to 2033-07-06); no cattle entry |
| 11 | Feedlot finishing | Laidlomycin propionate in cattle feed | gain and feed efficiency | 5 g/ton (30 to 75 mg/head/day) or 5 to 10 g/ton (30 to 150 mg/head/day) (21 CFR 558.305); Category I, not VFD | no EU Register entry (read 2026-11-03) |
| 12 | Feedlot finishing | Tylosin in animal feed | reduction of liver abscesses | 8 to 10 g/ton (60 to 90 mg/head/day) (21 CFR 558.625); Category I, VFD | deleted as feed additive (Council Reg. (EC) No 2821/98, from 1999-01-01); veterinary medicinal product in medicated feed only (Reg. (EU) 2019/4) |
| 13 | Feedlot finishing | Virginiamycin | reduction of liver abscesses | 13.5 to 16.0 g/ton (85 to 240 mg/head/day) (21 CFR 558.635); Category I, VFD | deleted as feed additive (Council Reg. (EC) No 2821/98, from 1999-01-01) |
| 14 | Feedlot finishing | Chlortetracycline | liver condemnation (cattle over 400 lb); anaplasmosis control claim (beef cattle over 700 lb) | 70 mg/head/day; 0.5 mg/lb BW/day (21 CFR 558.128); Category I, VFD | not a feed additive; veterinary medicinal product in medicated feed (Reg. (EU) 2019/4) |
| 15 | Feedlot finishing | Oxytetracycline | reduction of liver abscesses (growing cattle over 400 lb) | 75 mg/head/day (21 CFR 558.450); Category I, VFD | cross-contamination max 100 µg/kg in non-target feed (Delegated Reg. (EU) 2024/1229) |
| 16 | Feedlot finishing | Bacitracin (bacitracin methylene disalicylate) | liver condemnations | 70 mg/head/day, or 250 mg/head/day 5 days on and 25 days off (21 CFR 558.76); over the counter | bacitracin zinc deleted (Council Reg. (EC) No 2821/98, from 1999-01-01) |
| 17 | Feedlot finishing | Ractopamine | gain, feed efficiency, leanness | 8.2 to 24.6 g/ton (70 to 430 mg/head/day), last 28 to 42 days (21 CFR 558.500); Category I, over the counter | prohibited (Council Directive 96/22/EC Art. 2 and 3(a)) |
| 18 | Feedlot finishing | Lubabegron and zilpaterol (beta-agonists in livestock) | lubabegron: reduction of ammonia gas emissions per lb live weight and hot carcass weight | lubabegron 13 to 90 mg/head/day, last 14 to 91 days (21 CFR 558.330), Category I; zilpaterol Category II (21 CFR 558.4) | prohibited (Council Directive 96/22/EC) |
| 19 | Feedlot heifers | Melengestrol acetate (MGA) | gain, feed efficiency, estrus suppression | heifers fed in confinement for slaughter 0.25 to 0.5 mg/head/day (21 CFR 558.342); Category I, not VFD | prohibited (Council Directive 96/22/EC) |
| 20 | Feedlot finishing | Feed-grade urea | non-protein nitrogen | no 21 CFR 573, 582 or 584 section; state feed law with NPN warning above 8.75 % equivalent crude protein from NPN or above one third of total crude protein (for example 3 CCR 2707, California) | 3d1 ruminants with a functional rumen, max 8 800 mg/kg complete feed (12 % moisture), max 30 % of dietary N from urea-N (Impl. Reg. (EU) 2023/1708, to 2033-09-28) |
| 21 | Feedlot finishing | Ammonium chloride | reduction of urinary pH | no 21 CFR 573, 582 or 584 section | 4d8 BASF SE, ruminants max 5 000 mg/kg complete feed (12 % moisture) for feeding over 3 months or 10 000 mg/kg for up to 3 months (Impl. Reg. (EU) 2024/1786, to 2034-07-18) |
| 22 | Breeding and dairy cows | 3-NOP (Bovaer) | reduction of enteric methane | lactating dairy cows only, 60 to 80 mg/kg DM, unapproved animal drug under enforcement discretion (CVM letter G-150438, 2024-05-24) | 4c1 dairy cows and cows for reproduction, 53 to 80 mg/kg complete feed (12 % moisture) (Impl. Reg. (EU) 2022/565, to 2032-04-28); not beef cattle |
US levels are approved levels under the section named. EU microorganism values are legal minimum contents, not recommended doses, and no maximum content is set for them; trace element, urea and ammonium chloride values are legal maxima.
Calf programmes centre on coccidiosis control and live yeast. Amprolium is a Category II drug, so a feed mill needs a medicated feed mill licence to use its Type A article, while decoquinate is fed for at least 28 days. Neither coccidiostat has an EU cattle entry; the EU calf tools are live yeasts, 4b1702 for calves for rearing at a legal minimum of 1.5 × 10^9 CFU/kg and 4b1711 for calves at 1 × 10^9 CFU/kg complete feed.
Pasture and stocker programmes combine an ionophore or bambermycins with bloat control and trace elements. Monensin on pasture runs at 50 to 200 mg/head/day and lasalocid at 60 to 300 mg/head/day, and bambermycins holds an approved free-choice mineral formula. Poloxalene, the US bloat-control drug for legume and wheat pasture, starts 2 to 3 days before exposure. Selenium for cattle is capped at 0.3 ppm in US complete feed, while the EU sets total maxima for selenium, copper and cobalt.
Feedlot finishing programmes stack drugs: US rations can pair an ionophore with a VFD antibiotic against liver abscesses and add melengestrol acetate for heifers. Each drug pair must be a listed combination, so laidlomycin may be combined with chlortetracycline (21 CFR 558.128) but has no approved combination with ractopamine. Beta-agonists close the finishing period, ractopamine for the last 28 to 42 days and lubabegron for the last 14 to 91 days. EU feedlot rations carry live yeast, feed-grade urea up to 8 800 mg/kg complete feed and ammonium chloride under 4d8.
Which Additives Address Which Cattle Production Problem?#
Each cattle production problem has its own additive set: ionophores for feed efficiency, VFD antibiotics for liver abscesses, coccidiostats for calves, poloxalene or monensin for pasture bloat and trace elements for mineral gaps. The table pairs each problem with the US additive classes, the EU tool and the page on the problem or class.
| # | Problem | US additive classes | EU tool | Page |
|---|---|---|---|---|
| 1 | feed efficiency and gain | ionophores, bambermycins, beta-agonists | live yeast (cattle for fattening) | Feed conversion ratio |
| 2 | ruminal acidosis | ionophores, live yeast | live yeast | Ruminal acidosis prevention |
| 3 | rumen buffering | sodium bicarbonate | EU feed material, not a feed additive | Rumen buffers |
| 4 | non-protein nitrogen and rumen modification | urea (state feed law) | urea 3d1 | Rumen modifiers for cattle |
| 5 | liver abscesses | tylosin, virginiamycin, chlortetracycline, oxytetracycline, bacitracin methylene disalicylate | none | feedlot rows of the programme table |
| 6 | coccidiosis in calves | decoquinate, amprolium, lasalocid, monensin | none for cattle | Coccidiosis control |
| 7 | pasture bloat | poloxalene, monensin | none found | pasture rows of the programme table |
| 8 | enteric methane | 3-NOP, lactating dairy cows only, enforcement discretion | 3-NOP 4c1 (dairy cows, cows for reproduction) | Methane-reducing feed additives for cattle |
| 9 | mycotoxins | no US mycotoxin claim | bentonite 1m558 (printed expiry 2023-11-19; the EU Register records a renewal application and still lists the entry pending the Commission decision (Article 14 of Regulation (EC) No 1831/2003)); 1m03i in maize-based silage | Mycotoxin binders |
| 10 | trace-element supply | selenium, cobalt, copper | 3b total maxima | Trace minerals in animal feed |
| 11 | E. coli O157 shedding | direct-fed microbials (food without claims) | none for this purpose | Direct-fed microbials |
Sodium bicarbonate and the other rumen buffers are EU feed materials (Regulation (EU) No 68/2013 as amended by Regulation (EU) 2022/1104), not feed additives, so they carry no identification number. For cattle compound feed the only 1m entry is bentonite 1m558 for aflatoxin B1, at a maximum of 20 000 mg/kg complete feed (Regulation (EU) No 1060/2013), and fumonisin esterase 1m03i covers maize-based silage for all species. A binder never lifts a limit: compound feed for dairy cattle and calves may contain at most 0.005 mg/kg aflatoxin B1 (Directive 2002/32/EC).
Evidence from meta-analyses in beef cattle#
Monensin improved feed efficiency by 6.4 % and daily gain by 2.5 % and cut dry matter intake by 3 % in beef cattle, in the meta-analysis by Duffield, Merrill and Bagg (Journal of Animal Science, 2012). The same abstract limits the feed efficiency gain to 2.5 to 3.5 % in the last two decades, at a mean dose of 28.1 mg/kg dry matter. For lasalocid, the meta-analysis by Golder and Lean (Journal of Animal Science, 2016) found daily gain higher by 40 g/d and hot carcass weight higher by 4.73 kg, and the choice between the two ionophores by species and safety is set out in monensin vs lasalocid. On pasture, Gadberry and colleagues (Translational Animal Science, 2022) reported that monensin raised daily gain by 0.0784 kg/d (about 10 %), with a bloat change of -20 %.
Live yeast raised rumen pH by 0.03, total volatile fatty acids by 2.17 mM and organic matter digestibility by 0.8 % across 157 experiments in ruminants generally, in the meta-analysis by Desnoyers and colleagues (Journal of Dairy Science, 2009). Direct-fed microbials lowered faecal E. coli O157 shedding in cattle to an odds ratio of 0.46 (95 % CI 0.36 to 0.60) in the meta-analysis by Wisener and colleagues (Zoonoses and Public Health, 2015), a result that is not a US label claim.
Ractopamine and zilpaterol increased gain, hot carcass weight, longissimus muscle area and gain-to-feed ratio in the cattle meta-analysis by Lean, Thompson and Dunshea (PLoS One, 2014), and raised Warner-Bratzler shear force by 0.43 and 1.2 standard deviations respectively. For liver abscesses, the network meta-analysis by Young and colleagues (Journal of Veterinary Internal Medicine, 2026) found continuous tylosin superior to no treatment and early withdrawal not equivalent to continuous feeding. In the randomised controlled trial of the same work, the odds ratio for severe (A+) abscesses was 0.75 (95 % CI 0.51 to 1.11), an interval that includes 1.
Cattle-Specific Regulation: EU and US Status Side by Side#
Cattle feed regulation splits on one line: the US approves drugs in feed section by section under 21 CFR 558, while the EU limits cattle feed to authorised additives under Regulation (EC) No 1831/2003 and bans hormones and beta-agonists under Council Directive 96/22/EC. Withdrawal periods and carry-over limits then differ by drug and by species.
EU: what cattle feed may and may not contain#
EU cattle feed may contain live yeast, urea, ammonium chloride, trace elements and, for dairy cows and cows for reproduction, 3-NOP, but no growth-promoting antibiotic, ionophore, hormone or beta-agonist. EU cattle feed lost its antibiotic growth promoters in two steps: tylosin, virginiamycin and bacitracin zinc were deleted by Council Regulation (EC) No 2821/98 from 1 January 1999, and the last EU antibiotic growth promoters, flavophospholipol among them, were deleted from 1 January 2006 (Article 11(2) of Regulation (EC) No 1831/2003). Chlortetracycline and tylosin reach EU cattle only as veterinary medicinal products in medicated feed under Regulation (EU) 2019/4.
Live yeast for cattle for fattening is authorised as 4b1702 (S.I. Lesaffre) and 4b1710 (Prosol S.p.A.) at a legal minimum of 4 × 10^9 CFU/kg complete feed and as 4b1711 (Danstar Ferment AG represented by Lallemand SAS) at 5 × 10^8 CFU/kg, while 4a1704 and 4d24 name broader ruminant categories. These holder-bound values are legal minimum contents, not doses. Feed-grade urea 3d1 allows at most 30 % of dietary nitrogen from urea nitrogen (Implementing Regulation (EU) 2023/1708), ammonium chloride 4d8 (BASF SE) reduces urinary pH at up to 5 000 or 10 000 mg/kg depending on feeding length, and 3-NOP 4c1 runs from 53 to 80 mg/kg complete feed (Implementing Regulation (EU) 2022/565).
Trace elements carry EU total maxima per kg complete feed (12 % moisture): copper 15 mg/kg for bovines before the start of rumination and 30 mg/kg for other bovines (Implementing Regulation (EU) 2018/1039), selenium 0.50 mg/kg, and cobalt 1 mg/kg under a provisional authorisation (Implementing Regulation (EU) 2023/1455) that ends in 2028 at the latest. Tylosin, chlortetracycline and oxytetracycline residues in non-target feed are limited to 100 µg/kg (Delegated Regulation (EU) 2024/1229, applicable from 20 May 2025).
US: Category I drugs, VFD drugs and approved combinations#
In the US, monensin, lasalocid, laidlomycin, bambermycins, decoquinate, poloxalene, melengestrol acetate and ractopamine are fed to cattle without a veterinary order, while tylosin, virginiamycin, chlortetracycline and oxytetracycline need a Veterinary Feed Directive. Category I means a mill needs no medicated feed mill licence to make Type B or C feeds from the Type A article, while amprolium and zilpaterol are Category II drugs (21 CFR 558.4). Category and VFD status are separate, so tylosin is a Category I drug and still needs a VFD.
Veterinary Feed Directive drugs in cattle feed are medically important antimicrobials with liver abscess, liver condemnation or anaplasmosis claims, and tylosin and virginiamycin feeds need a Veterinary Feed Directive from a veterinarian. Under 21 CFR 558.6, VFD feed may not be fed after the VFD expires, extralabel use in feed is not permitted and records are kept for 2 years. Chlortetracycline lost its growth claims under FDA Guidance for Industry #213.
Approved combinations are listed in the drug sections: laidlomycin propionate with chlortetracycline only, melengestrol acetate with lasalocid, monensin, oxytetracycline, ractopamine, tylosin and zilpaterol (21 CFR 558.342), and virginiamycin with monensin, lubabegron and ractopamine (21 CFR 558.635). Direct-fed microbials sit outside 21 CFR 558, as food without claims under FDA CPG Sec. 689.100.
Withdrawal periods, tolerances and maximum contents#
Most US cattle feed drugs carry no withdrawal period, but oxytetracycline (5 days for one sponsor), amprolium (24 hours) and chlortetracycline (by sponsor and claim) do, and several are not for veal calves. The table gives each drug's US withdrawal next to its tolerance under 21 CFR 556 or its use condition.
| Drug | US withdrawal (cattle) | Tolerance or use note |
|---|---|---|
| Monensin | none listed | not for veal calves; cattle liver 0.10 ppm (21 CFR 556.420) |
| Lasalocid | none listed | not for veal calves; cattle liver 0.7 ppm (21 CFR 556.347) |
| Laidlomycin propionate | none stated | tolerances in 21 CFR 556.346 |
| Bambermycins | none stated | tolerances not required (21 CFR 556.75) |
| Tylosin | none stated for the liver abscess claim | 0.2 ppm edible tissues (21 CFR 556.746) |
| Virginiamycin | none stated | tolerances not required for cattle |
| Chlortetracycline | varies by sponsor and claim | no withdrawal established in pre-ruminating calves |
| Oxytetracycline | 0 days (sponsor 066104) or 5 days (sponsor 069254) | not approved for female dairy cattle 20 months or older |
| Decoquinate | none listed | not for cows producing milk for food; muscle 1 ppm, other tissues 2 ppm (21 CFR 556.170) |
| Amprolium | 24 hours | not for veal calves; 0.5 ppm tissues, 2.0 ppm fat (21 CFR 556.50) |
| Melengestrol acetate | none stated | cattle fat 25 ppb (21 CFR 556.380) |
| Ractopamine | none stated | tolerances in 21 CFR 556.570 |
| Poloxalene | none | tolerance not required (21 CFR 556.517) |
EU maximum contents for the same rations are the legal maxima in the programme table: urea 3d1, ammonium chloride 4d8, copper, selenium and cobalt.
Carry-over and feeding errors between species#
Cattle feed with monensin must never reach horses: the US label states that ingestion of monensin by horses has been fatal, and the EU caps monensin carry-over at 1.25 mg/kg in feed for equines, sheep, goats and bovines. Horses tolerate far less monensin than cattle: the oral LD50 is 2 to 3 mg/kg body weight in horses against 50 to 80 mg/kg in cattle (Nebbia and colleagues, Journal of Veterinary Pharmacology and Therapeutics, 2001).
Copper is the second cross-species risk. The EU maximum for ovines is 15 mg/kg complete feed, and ovine feed above 10 mg Cu/kg must warn that the copper level may cause poisoning in certain breeds of sheep (Implementing Regulation (EU) 2018/1039). The monensin carry-over maximum, set by Regulation (EU) No 574/2011, sits with the other undesirable substances in feed of Directive 2002/32/EC.
Sourcing Checklist for Cattle Feed Additives#
Source a cattle feed additive in seven checks, from the destination market to the certificate of analysis. The seven checks are listed below in the order a buyer meets them.
- Confirm the destination market, because a drug approved under 21 CFR 558 can have no EU status.
- Match the label species to the act or section, for example "cattle for fattening" in the 4b1702 act.
- Check the Category and VFD status of each drug.
- Check that each drug pair is a listed combination.
- Check the free-choice approval before a drug goes into a block or loose mineral.
- Check trace-element totals against the EU maxima, copper first where sheep share the feed.
- Ask for FAMI-QS or GMP+ certification and a certificate of analysis for each lot.
A quote should name the identification number or 21 CFR section, the label species and the content per kg. For live yeast, ask for the CFU count per gram of product, since the EU legal minimum applies per kg of complete feed.
Cattle Feed Additive Questions#
Three questions about cattle feed additives come up beyond the programme itself: what counts as non-nutritive, what goes into dairy mineral supplements and which medicated feeds are approved. Cattle share rules with the other ruminant programmes among the feed additives by species, and the table names the three related programmes that matter most to cattle formulators.
| Programme | Why it matters for cattle formulators |
|---|---|
| Feed additives for dairy cows | 3-NOP and the dairy uses of live yeast and monensin sit there |
| Sheep and goat feed additives | EU copper maxima of 15 mg/kg (ovines) and 35 mg/kg (caprines) complete feed |
| Horse feed additives | monensin label caution and the 1.25 mg/kg carry-over maximum |
What are non-nutritive feed additives?#
Non-nutritive feed additives are additives that change how cattle use feed rather than supplying nutrients, such as ionophores, live yeast, coccidiostats and 3-NOP; in the EU they fall mainly under the zootechnical category and the coccidiostats and histomonostats category. Monensin is the US example, approved as a Category I drug for feed efficiency, while live yeast and 3-NOP (functional group 4c) are EU zootechnical additives.
What do mineral supplements for dairy cattle contain?#
Mineral supplements for dairy cattle carry trace elements such as copper, selenium, cobalt and zinc within EU maximum contents, plus calcium, phosphorus and magnesium sources that the EU classes as feed materials. The EU total maxima per kg complete feed (12 % moisture) for three of these trace elements are listed below.
- Copper: 15 mg/kg before the start of rumination, 30 mg/kg for other bovines (2018/1039).
- Selenium: 0.50 mg/kg, of which organic selenium supplementation at most 0.20 mg/kg (2019/49, 2019/804).
- Cobalt: 1 mg/kg for ruminants with a functional rumen (2023/1455).
Which medicated feed additives are approved for beef cattle and calves?#
US medicated feeds for beef cattle and calves include monensin, lasalocid, laidlomycin, decoquinate, amprolium, tylosin, chlortetracycline and melengestrol acetate, each under its own 21 CFR 558 section; the EU authorises none of them for cattle.
Each drug reaches the mill as a Type A medicated article that is mixed into Type B and C feeds, and Type A, B and C articles are explained under medicated feed.