Synthetic Steroidal and Nonsteroidal Estrogen Hormone Growth Promotants in Cattle
Synthetic Steroidal and Nonsteroidal Estrogen Hormone Growth Promotants in Cattle
Hormone | Dose | Duration of Effect (days) | Growth Response | Potential Adverse Effects |
|---|---|---|---|---|
TBA | 200 mg (heifers, cull cows) | 60–90 | 5%–12% | |
TBA + EB | 200 mg TBA + 28 mg EB (steers, heifers) | 90–120 | 10%–20% | Transient increase in sexual behavior |
100 mg TBA + 14 mg EB (steers, heifers) | 90–120 | 10%–20% | Transient increase in sexual behavior | |
150 mg TBA + 21 mg EB (coated implant, steers and heifers grazing pasture) | 200 | |||
200 mg TBA + 28 mg EB (coated implant, steers and heifers) | 200 | |||
TBA + E | 200 mg TBA + 20 mg E (steers, heifers) | 90–120 | ||
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) | 90–120 | |||
140 mg TBA + 14 mg E (heifers) | 90–120 | |||
80 mg TBA + 16 mg E (steers) | 90–120 | |||
80 mg TBA + 8 mg E (heifers) | 90–120 | |||
40 mg TBA + 8 mg E (steers and heifers grazing pasture) | 90–120 | |||
Zeranol | 36 mg zeranol | 90–120 | 10%–15% | |
12 mg zeranol | 90–120 | 10%–15% | ||
Melengestrol acetate | 0.25–0.50 mg/day | As long as it is fed | 3%–10% | Increased mammary development after long-term administration |
E = Estradiol 17-beta. EB = Estradiol benzoate. TBA = Trenbolone acetate. Note: All administered as pellet implants except melengestrol acetate, which is administered in feed. |