Replacement heifers that are identified early in life should not be implanted. There is no advantage in dystocia or age at puberty; therefore, there is little benefit to implanting replacement heifers. Heifers that are destined for finishing should be implanted to take advantage of the added weight gain. Heifers that are not yet identified as replacements can be implanted once if label directions are carefully followed. Implanting according to the manufacturer’s recommendations should have very minimal effects on reproduction, and will allow the producer to take advantage of added weight gains in the heifers sold at weaning time. Using an approved product and administering it according to label directions is extremely important when using implants in potential replacement heifers.
Injectable steroids are injected into muscle tissue, not into the veins. They are slowly released from the muscles into the rest of the body, and may be detectable for months after last use. Injectable steroids can be oil-based or water-based. Injectable anabolic steroids which are oil-based have longer half-life than water-based steroids. Both steroid types have much longer half-lives than oral anabolic steroids. And this is proving to be a drawback for injectables as they have high probability of being detected in drug screening since their clearance times tend to be longer than orals. Athletes resolve this problem by using injectable testosterone early in the cycle then switch to orals when approaching the end of the cycle and drug testing is imminent.
Some bodybuilders and athletes use trenbolone esters for their muscle-building and otherwise performance-enhancing effects.  Such use is illegal in the United States and many other countries. The DEA classifies trenbolone and its esters as Schedule III controlled substances under the Controlled Substances Act .  Trenbolone is classified as a Schedule 4 drug in Canada  and a class C drug with no penalty for personal use or possession in the United Kingdom .  Use or possession of steroids without a prescription is a crime in Australia .  The infamous "duchess" cocktail administered to Russian athletes at the Sochi Winter Olympics consisted of oxandrolone , a metenolone ester, and a trenbolone ester.