Table: Synthetic Steroidal and Nonsteroidal Estrogen Hormone Growth Promotants in Cattle and Sheepa-Merck Veterinary Manual

Synthetic Steroidal and Nonsteroidal Estrogen Hormone Growth Promotants in Cattle and Sheep^a

Hormone^b	Dose^b.c	Duration of Effect (days)	Growth Response	Potential Adverse Effects
TBA	200 mg (heifers)	60–90	5%–12%
TBA + EB	200 mg TBA + 28 mg EB (steers and heifers)	150–200	10%–20%	Transient increase in sexual behavior Udder development Vaginal and rectal prolapse Ventral edema
100 mg TBA + 14 mg EB (steers and heifers)	100–140	10%–20%	Transient increase in sexual behavior Udder development Vaginal and rectal prolapse Ventral edema
150 mg TBA + 21 mg EB (coated implant, steers and heifers grazing pasture)	180–200	10%–20%
200 mg TBA + 28 mg EB (coated implant, steers and heifers)	200
TBA + E	200 mg TBA + 20 mg E (steers and heifers)	80–120
200 mg TBA + 20 mg E (coated implant, heifers)	Initial and delayed release implant that provides hormonal payout for up to 200 days after implantation
200 mg TBA + 20 mg E (coated implant, steers)	Delayed release implant that does not begin hormonal payout until ~70 days after implantation
200 mg TBA + 40 mg E (coated implant, steers)	Initial and delayed release implant that provides hormonal payout for up to 200 days after implantation
120 mg TBA + 24 mg E (steers)	100–140
140 mg TBA + 14 mg E (heifers)	100–140
80 mg TBA + 16 mg E (steers)	100–140
80 mg TBA + 8 mg E (heifers)	100–140
40 mg TBA + 8 mg E (steers and heifers grazing pasture)	100–140
Zeranol	36 mg	70–100	10%–15%
)12 mg	90–120	10%–15%
Melengestrol acetate	0.25–0.50 mg/day (heifers)	For the intended duration	3%–10%	Increased mammary development after long-term administration
^a Individual product labeling should be consulted for specific purposes and dosages in food-producing animals. ^b E, estradiol 17-beta; EB, estradiol benzoate; TBA, trenbolone acetate. ^c All administered as pellet implants except melengestrol acetate, which is administered in feed.

Hormone^b

Dose^b.c

Duration of Effect (days)

Growth Response

Potential Adverse Effects

TBA

200 mg (heifers)

60–90

5%–12%

TBA + EB

200 mg TBA + 28 mg EB (steers and heifers)

150–200

10%–20%

Transient increase in sexual behavior

Udder development

Vaginal and rectal prolapse

Ventral edema

100 mg TBA + 14 mg EB (steers and heifers)

100–140

10%–20%

Transient increase in sexual behavior

Udder development

Vaginal and rectal prolapse

Ventral edema

150 mg TBA + 21 mg EB (coated implant, steers and heifers grazing pasture)

180–200

10%–20%

200 mg TBA + 28 mg EB (coated implant, steers and heifers)

200

TBA + E

200 mg TBA + 20 mg E (steers and heifers)

80–120

200 mg TBA + 20 mg E (coated implant, heifers)

Initial and delayed release implant that provides hormonal payout for up to 200 days after implantation

200 mg TBA + 20 mg E (coated implant, steers)

Delayed release implant that does not begin hormonal payout until ~70 days after implantation

200 mg TBA + 40 mg E (coated implant, steers)

Initial and delayed release implant that provides hormonal payout for up to 200 days after implantation

120 mg TBA + 24 mg E (steers)

100–140

140 mg TBA + 14 mg E (heifers)

100–140

80 mg TBA + 16 mg E (steers)

100–140

80 mg TBA + 8 mg E (heifers)

100–140

40 mg TBA + 8 mg E (steers and heifers grazing pasture)

100–140

Zeranol

36 mg

70–100

10%–15%

)12 mg

90–120

10%–15%

Melengestrol acetate

0.25–0.50 mg/day (heifers)

For the intended duration

3%–10%

Increased mammary development after long-term administration

^a Individual product labeling should be consulted for specific purposes and dosages in food-producing animals.

^b E, estradiol 17-beta; EB, estradiol benzoate; TBA, trenbolone acetate.

^c All administered as pellet implants except melengestrol acetate, which is administered in feed.