Premier Beef Feed Additives

Feed Additives For Grazing Beef Cattle

University of Missouri

On-Farm Feed Processing

The importance of producing quality feeds is obvious. The current Good Manufacturing Practices (cGMP) guidelines are devised to assure that feeds are produced to the intended specifications, including the utilization of feed additives. These guidelines address facilities and equipment, product quality assurance, labeling, and record keeping. Some observations you should make on a farm visit or questions to ask your clients include:

Are the feed production facilities and equipment clean and in good repair?

Can medicated feeds be produced accurately? Do you do laboratory analysis to determine accuracy?

Is equipment calibrated at reasonable intervals?

Is the equipment checked for wear at reasonable intervals?

Are other farm chemicals stored away from the feed area?

Are all feed additives labeled?

Are feed formulations kept for one year after mixing?

Purchased Feed

When purchasing feed (Type C), producers should still follow some guidelines to assure that the feed they obtain is being used as intended. Information that producers should have include:

Feed labels for any bag or bulk feed

Scale tickets upon feed delivery

Assurance from the supplier that weighing, labeling, and other quality control is correct

Feed Additives

The Food and Drug Administration (FDA) control feed additives with strict rules for their use. Feed additives cannot be used extra-label. They must be used at the dosage, for the class of cattle, and only with the approved combinations specified on the label. Some feed additives can only be used with a feed mill license.

There are a number of feed additives that are used routinely in grazing cattle diets. These include the ionophores monensin and lasalocid, several non-ionophore antibiotics (bambermycins, bacitracin zinc, and chlortetracycline), coccidial preventative (decoquinate), bloat preventative (proloxalene), and estrus suppression (melengestrol acetate). Other feed additives that are approved for use in confined cattle intended for slaughter do not have a clearance for use in grazing cattle (laidlomycin, virginiamycin, and oxytetracycline). Tylocin, though approved, is seldom used with grazing cattle.

None of the feed additives approved for use in cattle are prescription products. As such, a prescription cannot be written for extra-label use. One swine feed grade antibiotic, tilmicosin, is a prescription product, but it cannot be used extra-label even with a client-veterinary-patient relationship.

Ionophores

Ionophores are polyether compounds included in diets of growing and finishing cattle to improve feed efficiency and animal health. The mechanisms of action are initiated by channeling ions through cell membranes and they have a marked effect on microbial cells in particular.[i] There is a shift in volatile fatty acids produced in the rumen toward more propionate with corresponding reductions in acetate and butyrate.[ii] There is also a reduction in peptidolysis due to the inhibitory effects of ionophores on certain proteolytic bacteria. The result of this is an increased post-ruminal flow of dietary amino acids.

Increase in propionate production for high-roughage diets = 49%

Increase in propionate production for high-concentrate diets = 76%

Metabolizable and net energy values of feeds should increase when ionophores are consumed. It is recommended that when balancing a ration, the NE_mprovided by the diet be increased by 12% if ionophores are included. Ionophore use in conjunction with high roughage diets (pasture, hay or silage) results in the same consumption but increased rate of gain because of improved efficiency of feed utilization. Ionophore use in conjunction with high-energy feedlot-type diets results in decreased feed consumption but similar rate of gain - once again due to improved efficiency of feed utilization.

Now cleared for use in replacement heifers, inclusion of ionophores in heifer diets has been shown to increase the number of heifers that had reached puberty by the start of the breeding season, decrease the age at puberty, decrease the weight at puberty, increase the corpora luteal weight, and increase the amount of progesterone produced. The decrease in age at puberty was independent of improved average daily gain and increased body weight. Moseley et al. (1982) speculate that changes in ruminal fermentation patterns to favor proprionic acid production produce an endocrine response which influences the mechanisms regulating puberty.[iii]

In one trial, monensin added to the mineral mix of cattle grazing native grass improved gain by 7.7% (0.19 lb/head/day; P<0.05) and the steers consumed 32% less mineral (3.4 oz vs. 5.0 oz./head/day; P<0.03) compared to controls.[iv] In numerous trials utilizing both heifers and steers and grazing various forage types (native grass, Bermuda grass, fescue, crop residue, winter wheat) fed a small amount of supplement (1-2 lbs. daily) with or without ionophores, average daily gain was improved 8-45% (0.12-0.22 lbs./day) with ionophores.[v]^{,[vi],[vii],[viii],[ix],[x]}

In addition to their effects on gain and efficiency, ionophore supplementation is effective for the prevention of acute bovine pulmonary emphysema and edema (ABPEE) and bloat when cattle graze lush pasture.[xi] If the ionophore is hand-fed (rather than fed free-choice), it will help prevent and control coccidiosis. Ionophores also impact mineral utilization. In general, ionophores enhance absorption of nitrogen, magnesium, phosphorus, zinc, and selenium with inconsistent effects on calcium, potassium and sodium.[xii]

Non-ionophore antibiotics (ionophore-like)

Bambermycins is a relatively new antibiotic that is classified as a non-ionphore antibiotic. However, it has some ruminal effects similar to those of ionophores and is expected to exert similar effects on animal performance. Published research evaluating the effects of bambermycins on the performance of grazing cattle is very limited. One trial compared bambermycins, monensin, and lasalocid, each in a 2-pound soybean meal-milo supplement, for their effects on gains of stocker cattle grazing native short grass range. The antibiotics performed similarly and increased daily gain by 0.3 lbs.[xiii]

Non-ionophore antibiotics

Both oxytetracycline and chlortetracycline are approved for improved feed efficiency, increased rate of gain, and reduction of liver abscess in growing cattle. In addition, chlortetracycline is approved for control of anaplasmosis. Published research that quantifies the improvement in feed efficiency and increased gain in grazing animals is lacking. It is assumed that improvement of average daily gain is similar to that found with ionophore antibiotics (i.e. 15%, range = 8-45%).

Steroid hormone

Melengestrol acetate (MGA) is a synthetic progestogen and is fed to heifers to suppress estrus and increase rate of gain. It is approved for use in grazing heifers that are intended for reproduction but should not be fed in excess of 24 days. Reduced conception rates can be expected if heifers are bred within 1 to 12 days after withdrawal of MGA.

Anti-parasitic

Intestinal protozoal organisms (Eimeria sp.) often cause clinical and subclinical disease (coccidiosis) in young, stressed cattle. Feed additives to control coccidiosis should be added to the ration of growing cattle (usually at weaning). Decoquinate is approved at a rate of 22.7 mg/100 lbs of body weight, which is added to the ration for at least 28 days during periods when coccidiosis is likely to be a hazard. Amprolium can be used to treat clinical cases of coccidiosis by adding it to the feed or water at the rate of 10 mg/kg for 5 days followed by 5 mg/kg for 16 more days. If amprolium is used as a preventative, rather than as a treatment, include it at the rate of 5 mg/kg in either the feed or water for 21 days.

Bloat prevention

Poloxalene can be included in a grain supplement or mineral mix to aid in the prevention of legume and wheat pasture bloat in calves grazing those lush forages.

Trade Issues

The European agriculture ministers recently banned the use of four feed antibiotics. The ban for European farmers will take effect June 30, 1999. It is expected that imports will also be expected to meet these new requirements. The four antibiotics involved are: bacitracin zinc, spiramycin, virginiamycin and tylosin phosphate. All the articles that I have read have been confusing in that the authors and those they interview keep switching their remarks between issues of resistance and residues, making the reason for the ban unclear.

Increased Rate of Gain - Pasture cattle (slaughter, stocker, feeder, and dairy and beef replacement heifers)

(or after the 5^th day - feed at the rate of 400 mg/head every other day in > 2 lbs. feed)

Prevention and Control of Coccidiosis - cattle in confinement and semi-confinement

10-30 grams monensin per ton of feed 100 to 360 mg. monensin/head/day (depending on body weight)

25-400 grams monensin per ton of feed 50 to 200 mg. monensin/head/day in >1 lbs. feed

As a free-choice mineral Type C feed: Must be manufactured under a feed mill license

Feed companies, after filing a FDA 1900 form, may include Rumensin in free-choice mineral mixes for increased rate of gain in pasture cattle, including replacement heifers.

This approval allows for use of 80 grams per lb monensin Type A articles to make a monensin Type C medicated free-choice mineral mix containing 1,620 grams per ton of monensin. Feed companies will have some flexibility of contents to use in the vitamin/trace mineral package as long as ingredients are comparable to those used for other free-choice feeds.

Increased Rate of Gain - Pasture cattle (slaughter, stocker, feeder cattle, and dairy and beef replacement heifers)

Warning: Do not allow horses or other equine species access to formulations containing monensin. Do not feed to cattle in the undiluted form. Do not feed to lactating dairy cows.

Improved Feed Efficiency and Increased Rate of Gain - Cattle in confinement for slaughter

Increased Rate of Gain - Pasture cattle (slaughter, stocker, feeder cattle, and dairy and beef replacement heifers)

1 mg lasalocid/2.2 pounds body weight/day (maximum of 360 mg. lasolocid/head/day, i.e. up to 800 lbs.)

As a free-choice mineral Type C feed: Must be manufactured under a feed mill license

Feed companies will have some flexibility with regards to the vitamin/trace mineral package as long as ingredients are comparable to those used for other free-choice feeds.

Increased Rate of Gain - Pasture cattle (slaughter, stocker, feeder cattle, and dairy and beef replacement heifers)

Warning: Do not allow horses or other equine species access to Type A articles or Type B feeds containing lasalocid. Do not feed to cattle in the undiluted form. Do not feed to lactating dairy cows.

Improved Feed Efficiency and Increased Rate of Gain - Cattle in confinement for slaughter

Increased Rate of Gain - Pasture cattle (slaughter, stocker, feeder, and dairy and beef replacement heifers)

35-70 mg/head/day bacitracin zinc in at least 1 pound and not more than 10 pounds of supplemental feed

Improved Feed Efficiency and Increased Rate of Gain - Cattle in confinement for slaughter

Warning: Do not allow horses or other equine species access to feeds containing laidlomycin.

Virginiamycin (Vmax)

Improved Feed Efficiency - Cattle in confinement for slaughter

Reduction in Incidence of Liver Abscesses - Cattle in confinement for slaughter

Increased Rate of Gain - Cattle in confinement for slaughter

Oxytetracycline (OXTC, Pennox & Terramycin)

Improved Feed Efficiency and Increased Rate of Gain - calves up to 250 lbs.

Improved Feed Efficiency and Increased Rate of Gain - calves 250-400 lbs.

Improved Feed Efficiency, Increased Rate of Gain and Reduction of Liver Abscesses – Growing cattle >400 lbs.

Prevention and Treatment of Early Stages of Shipping Fever

Treatment of Bacterial Enteritis (E. coli) and Bacterial Pneumonia (P. multocida) – Calves, growing cattle, beef cows

Approved combinations

Withdrawal

Chlortetracycline (Aureomycin, CLTC, Pennchlor & ChlorMax)

Improved Feed Efficiency and Increased Rate of Gain - calves up to 250 lbs.

Improved Feed Efficiency, Increased Rate of Gain and Reduction of Liver Abscesses – Growing cattle >400 lbs.

Prevention and Treatment of Early Stages of Shipping Fever

Treatment of Bacterial Enteritis (E. coli) and Bacterial Pneumonia (P. multocida) – Calves, growing cattle, beef cows

Control of Active Infection of Anaplasmosis – Cattle <700 lbs.

Control of Active Infection of Anaplasmosis – Cattle >700 lbs.

Approved combinations

Sulfamethazine – Feed for 28 days – maintenance of weight gains in the presence of BRD

Withdrawal

Tylosin (Tylan)

Reduction in the Incidence of Liver Abscesses -

Approved combinations

Withdrawal

Approved combinations

Withdrawal

No feed mill license needed for Type C feeds (30 day expiration date for Type C feeds)

Improved Feed Efficiency, Increased Rate of Gain, and Suppression of Estrus- Cattle in confinement for slaughter

Suppression of Estrus in Heifers Intended for Reproduction – Replacement heifers

Do not exceed 24 days of feeding in heifers intended for reproduction. Reduced conception rate can be expected if heifers are bred at estrus observed within 1 to 12 days after withdrawal of MGA

Oxytetracycline – increased feed efficiency, improved rate of gain, reduced liver abscesses

[i] Bergen WG, Bates DB: Ionophores: Their effect on production efficiency and mode of action. J. Animal Science 58:1465-1483, 1984.

[ii] Van Maanen RW, Herbein JH, McGilliard AD, Young JW: Effects of monensin on in vivo rumen propionate and blood glucose kinetics in cattle. J. Nutrition 108:1002-1007, 1978.

[iii] Moseley WM, Dunn TG, Kaltenbach CC, Short RE, Staigmiller RB: Relationship of growth and puberty in beef heifers fed monensin. J. Animal Science 55:357-362, 1982.

[iv] Brazle FK, Laudert SB: Effects of feeding Rumensin in a mineral mixture on steers grazing native grass pastures. 1998 Cattlemen’s Day, KSU Report of Progress 804, Manhattan, KS. pp 123-125.

[v] Rouquette FM, Jr., Griffin JL, Randel RD, Carroll LH: Effect of monensin on gain and forage utilization by calves grazing bermudagrass. J. Animal Science 51:521-525, 1980.

[vi] Spears JW, Harvey RW: Performance, ruminal and serum characteristics of steers fed lasalocid on pasture. J. Animal Science 58:460-464, 1984.

[vii] Wagner JF, Brown H, Bradley NW, Dinusson W, Dunn W, Elliston N, Miyat J, Mowrey D, Moreman J, Pendlum LC, Parrott C, Richardson L, Rush I, Woody H: Effect of monensin, estradiol controlloed release implants and supplement on performance in grazing steers. J. Animal Science 58:1062-1067, 1984.

[viii] Potter EL, Muller RD, Wray MI, Carroll LH, Meyer RM: Effect of monensin on the performance of cattle on pasture or fed harvested forages in confinement. J. Animal Science 62:583-592, 1986.

[ix] Anderson MA, Horn GW: Effect of lasalocid on weight gains, ruminal fermentation and forage intake of stocker cattle grazing winter wheat pasture. J. Animal Science 65:865-871, 1987.

[x] Boucque CV, Fiems LO, Cottyn BG, Buysse FX: Long-term supplementation of lasalocid-sodium for beef bulls during grazing and subsequent finishing period. Archiv fur Tierernahrung 38:995-1003, 1988.

[xi] Wikse SE, Craig TM, Hutcheson DP: Nutritional and dietary interrelationships with disease of grazing beef cattle. Vet Clinics N. America – Food An. Pract. 7:143-152, 1991.

[xii] Spears JW: Ionophores and nutrient digestion and absorption in ruminants. J. Nutrition 120:632-638, 1990.

[xiii] Vanzant ES: Comparison of antibiotic feed additives for stocker cattle in West-Central Kansas. 1996 Roundup, KAES Report of Progress 760, Hays, KS pp.6-8.