Merck Manual

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Natural Steroid Hormones for Consideration as Growth Promoters

Natural Steroid Hormones for Consideration as Growth Promoters

Hormone

Forma

Dosage

Duration of Effect (days)

Growth Response

Potential Adverse Effects

Estradiol

1 - Pellet

20 mg EBb + 200 mg P4c (steers)

100–120

10%–15%

Transient increase in sexual behavior

Estradiol

2 - Pellet

20 mg EB + 200 mg testosterone propionate (heifers, cull cows)

100–120

5%–15%

Udder development

Estradiol

3 - Pellet

10 mg EB + 100 mg P4 (veal calves)

100–120

0–8%

Estradiol

4 - Silastic rubber

45 mg estradiol (steers)

365

10%–15%

Transient increase in sexual behavior

Estradiol

5 - Silastic rubber

24 mg estradiol (steers)

200

10%–15%

Transient increase in sexual behavior

Estradiol

6 - Polylactic acid

28 mg estradiol (steers)

365

10%–15%

Transient increase in sexual behavior

Progesterone

See 1 and 3 above

Testosterone

See 2 above

a Implants must be placed SC between the ear cartilage and skin to comply with label instructions so that consumption of residues may be avoided.

b Estradiol benzoate

c Progesterone