1. Feed Additives and Growth Promotants

2. Feed Additives
Compounds that are added to the diet – other than to supply nutrients to the animal
Example: Antibiotics…no “nutrient requirement” for antibiotics
Urea is not considered feed additive – provides a source of dietary protein (in the form of nitrogen)
Additives used to enhance production efficiency and improve health

3. Feed Additives Feed additives used in small quantities
eg Melengesterol Acetate (MGA)
Toxicity and end-product residue….mixing, delivery and consumption critical
Most feed additives are regulated for these reasons
No one…not even a vet…can authorize use off label
Feed industry developed premixes for effective and safe use

4. “ It is essential to abide by recommended feeding levels with any feed additive”

5. Regulation of Additives
US- Federal Food and Drug Administration (FDA)
Canada- Food Production and Inspection Branch of Agriculture Canada

6. Feed label requirements
“medicated” must appear under the name of the feed
Purpose of the drug
Name and amounts of all active drugs
Required withdrawal period
Cautions against misuse
Directions for the use of the feed

7. Mixing and residue avoidance
Important for safe use
May result in higher production costs
Undesirable side effects

8. Financial loss includes
Carcasses may be condemned
Additional regulations or restrictions
Animals are held until they are free of the illegal substance

9. Mixing recommendations
Know the labeled uses, mixing instructions, and withdrawal times
Clean the mixer before use
Premix the drugs in a large enough quantity
Follow the manufacturer’s instructions
Establish order of mixing

10. Keeping Records
Date the batch was mixed
Mixing order and the amount of medication
Mixing time for the batch
Location where the feed is stored
Number, age, and weight of the animal fed
Medication that was used, the amount, and the concentration
Date of cleaning equipment

11. Health concerns Resistant strain of microorganisms
Ban would raise costs of animal product of the consumer
Increase the death loss among animals being raised
Possible carcinogenic effects

12. Effects of Feed Additives
Primary Effects:
Improve feed efficiency
Promote faster gains
Improve animal health
Increase production of animal products
Secondary Effects:
Reduce acidosis, coccidiosis, bloat, liver abscesses, suppress estrus and control foot rot.

13. Kinds of feed additives and Hormones
Antimocrobial Drugs
Hormones and Hormonelike Compounds
Anthelmintics
Other Feed Additives

14. Antimocrobial Drugs Antibiotics Chemoantibacteral
Produced by living microorganisms
Chlortetracycline, neomycin, oxytetracycline. Penicillin. Streptomycin, tylosin
Chemoantibacteral
Made from chemicals
Carbadox, furazolidone, nitrofurazone, sulfamethazine

15. Antibiotics Classified as antibacterial agents
Limit growth of certain bacteria
Bacteria can cause clinical sickness or subclinical reductions in health (morbidity) that reduces performance
Generally approved for low-level use
Animal response to antibiotics depends on feeding conditions at the time they are used
Difficult to quantify actual response that can be expected

16. Antibiotics
Many antibiotics are normally produced in organisms found naturally in the soil & other places
People exposed for centuries
Generally, used correctly results in healthier animals
No risk to people or livestock?

17. Antibiotics
The primary reason to feed antibiotics to ruminants is to control liver abscesses, foot rot & secondary infections/diseases as a result of shipping stress
Control of liver abscesses is the primary reason to continuously feed antibiotics
Cattle on high grain diets:
 episodes of acidosis =  liver damage and infection

18. Chlortetracycline
Aureomycin, Aureo S700
Numerous recommendations based on production level of animal
Receiving calf AS700 – 350mg of each
48 hour withdrawal time
Aureomycin – 5 days only
AS700 – 28 days

19. Oxytetracyline
Terramycin
75 mg/hd/d =  liver abscesses (cattle)
g/hd/d =  shipping fever complex (cattle)
Feed days before & after arrival
7 day withdrawal time
Tylosin
Tylan
g/t or mg/hd/d (cattle)
Cleared for use with Rumensin and/or MGA

20. Hormones and Hormonelike Compounds
Naturally produced in the animal’s body
Regulate many body functions, such as growth, metabolism, and reproduction
Increase the rate of protein synthesis and muscle development
Improve feed efficiency and increase the rate of growth

21. Hormone Implants Contain active ingredients that are hormone like
Side effects include:
Buller steers, high tailheads, and udder development
Kinds of implants:
Ralgro. Synnovex. Imlus-S. compodose. Ravalor-S

22. Implanting Procedure Restrain thee animal
Don’t use an instrument with a dull needle
Clean needle and implantation site
Implant on the back surface of the ear
Point instrument toward the head
Withdraw the needle slightly before starting the implant.

23. Anthelmintics Dewormers
Compounds used to control various species of worm infested in animals
Hygromycin, loxon, phenothiazine, piperzine, thiabendazole, and tramisol.

24. Other Feed Additives
Balance pH level/buffers
Bloat regulators
Prevent stress
Probiotics
Organic acids
Estrus suppressants
Coccidiostats
Ionophores
Xanthophyll: makes egg yolks yellow
Tranquilizers: calms nerves (cattle, turkeys)
Antioxidants: prevents feed from getting rancid
Pellet Binders: keeps feed in pellet form
Flavoring Agents: makes feed taste better

25. Use of feed additives for livestock

26. Beef Cattle Antiboiotic Hormones 3 to5% improvement in feed efficiency
Rumensin or Bovatec
Improve feed efficiency, rate of gain, affect fermentation
Hormones
Melengestrol acetate for heifers
Suppresses estrus
Increases rate of gain and feed efficiency
No effect to bulls or steers

27. Dairy
Most antibiotics are used for young dairy animals, lactating dairy animals are prohibited from the use
Forage preservatives
Buffers
Propylene glycol
BST

28. Sheep and Goats Few feed additives produces due to the small industry
Feeder lambs respond well to antibiotics

29. Swine
Young swine have the greatest economic return with use of antibiotics
Anthelmintic treatment is profitable is young swine

30. Poultry
Lasalocid sodium and monensin sodium are the most common additives
Improve feed efficiency and growth

31. Ionophores
Ionophores selectively affect certain microorganisms by altering the passage of ions through pores on their outer cell membrane
Originally used as a coccidiostat in poultry industry…later shown to enhance feed efficiency in cattle by altering the microbial fermentation of feed in the rumen

32. Ionophores Results in selection of certain microorganisms in the rumen
Inhibits or depresses certain MCO growth
Alters rumen fermentation
Usually  propionate production
Reduction in protein degradation in the rumen
Propionate tends to enhance energetic efficiency of growth
Reducing protein degradation increases amount of protein that bypasses rumen to lower digestive tract

33. Effects of ionophores:
Improve efficiency of energy metabolism by changing the VFA profile &  energy lost in fermentation
 energy retention
Reduce digestive upsets = reduced stress = improved animal performance

34. Too high of a level of ionophore can reduce cellulolytic bacteria
 fiber digestion
 rumen protein = ruminal protein shortage
Growing cattle: high-roughage diets
Improved daily gain (5 - 15%) & feed efficiency (8 - 12%)
Finishing cattle: high-concentrate diets
Improved feed efficiency (6 - 8%) and subtle improvement in daily gain (1 - 3%)
Prevention or control of bloat and acidosis

35. Common ionophores on the market:
Rumensin (Monensin Sodium)
g/ton
Bovatec (Lasalocid Sodium)
g/ton
1 mg/2.2 lb. of BW = control of coccidiosis
Cattlyst (Laidlomycin Propionate Potassium)
g/ton

36. Use of ionophores in levels higher than approved is not only illegal but can be toxic to cattle
Horses are especially susceptible to ionophore toxicity

37. Coccidiostats
Protozoal organisms – can invade and destroy the intestinal mucosa
Present in most animals at subclinical numbers….generally do not affect performance or health
Numbers increase to a point where production is impaired

38. Coccidiostats
Cause irritation of the digestive tract….scours and bloody stools
Stress (due to shipping), abrupt diet changes, weather changes can all cause episodes of clinical coccidiosis
Interpretation of fecal coccidia is difficult, since a clinical problem can exist with low coccidia counts

39. Coccidiostats
4 additives are approved for prevention and treatment
Amprolium (Corrid)
Decoquinate (Deccox)
Lasalocid (Bovatec)
Monension (Rumensin)

40. Estrus Suppressants Melengesterol Acetate (MGA)
Synthetic hormone similar in structure and activity to progesterone
Steroidal feed additive used to suppress estrus (cyclic sexual activity or heat)
Results in improvements in growth rate and feed efficiency
Breeding females:
Used to synchronize females for breeding

41. Estrus Suppressants Feedlot heifers:
Suppress estrus =  growth performance
+3 - 7% for ADG & FE
 injury,  dark cutters,  energy expended by chasing heifers
mg/hd/d (cattle)
Cleared for use with Rumensin, Bovatec & Tylan
48 hour withdrawal period

42. Estrus Suppressants Response of feedlot heifers to MGA depends on:
The age of the heifer
Number of sources of heifers being fed together
Amount of space per heifer
Implant effects
Adequate mixing

43. Buffers
Added to the diet to aid in resisting pH changes of the rumen when acids are present
Large quantities of organic acids produced in rumen by microbial fermentation
Reduces incidence of acidosis on high grain diets
SALIVA is principle source of rumen-buffering agents
Performance is variable
-2 - 5% improvement in ADG & FE

44. Buffers Sources: Sodium Bicarbonate: 0.75 - 1.5% diet DM
Limestone: 1.0% diet DM
Sodium Bentonite: % diet DM
Magnesium oxide: % diet DM

45. Growth Promotants in Ruminants
Redirection of nutrients from fat deposition to lean tissue deposition.
 Growth hormone secretion
 pituitary response to GHRH =  GH secretion
 steroidal effect on growth of skeletal muscles through  [IGF’s]

46. Growth Promotants in Ruminants
Given to cattle to improve:
Feed Efficiency: % in growing cattle
% in finishing cattle
Daily Gain: +.33 lb./d in growing cattle
% in finishing cattle
4 - 16% improvement in DMI

47.  cost of gain,  % choice carcasses (25%),  % lean
Altered or aggressive pen behavior (bullers)
Estradiol implants reduce NEg requirement by 5%
2 E2 implants = % NEg requirement reduction

48. Selection for growing & finishing cattle
Most implants are effective from 50 to 100 days
Selection for growing & finishing cattle
Most are cleared for use in confinement cattle and some are available for grazing cattle
There are 6 individual component implants & 10 combination implants currently on the market
Implant wars = changing companies and products

49. Estrogens
Estradiol 17 (Compudose)
Estradiol Benzoate (71% E17) - Synovex
Zeranol (produced from the production of mold) Ralgro
Androgens
Testosterone Propionate (Component)
Trenbolone Acetate (TBA) Finaplix

50. Progesterones
Progesterone (Component)
Melengesterol Acetate (MGA)
Combination implants
Estradiol & TBA RevS
Estradiol benzoate & TBA Synovex