Cattle growth implant

Matrix devices Parenteral Compudose cattle growth implant... 

Estradiol - releasing polymer matrix Figure 4.9 Structure of Compudose cattle growth implant... 

Farmed animals tend to be subjected to compounds that can be classified more easily as drugs. In some cases, animals may encounter compounds in nature that have considerable limitations in inclusion in the diets of farmed animals. An example is the inclusion of zearalenone (Figure 1) and its derivatives in animal diets these have anabolic and oestrogenic properties " and are permitted to be used in some areas of the world but are prohibited from use in others, such as European Union countries. Thus this compound and its reduced isomers (zearalenols, zeranols) improve growth rates in animals but can cause reproductive problems, especially in pigs. Ralgro, which is a commercially prepared derivative of zearalenone, is used as an ear implant in beef cattle as a growth promoter in... 

Diethylstilbestrol, mentioned in Chapters 5 and 9 as a synthetic estrogen that is also a human carcinogen, was used in the United States from the 1950s until 1979 as a growth promoter in sheep and cattle. Small amounts of this drug, added to animal feed or implanted in the flesh of animals ears, increase feed efficiency, and it was very widely used for this purpose. 

Progesterone is used primarily as a growth promotant in cattle in combination with estradiol or its esters. Administration is carried out by subcutaneous implant in the ear, which is subsequently discarded at slaughter. When administered exogenously, progesterone enters the same metabolic pathways and is indistinguishable from the endogenously produced compound. 

Other hormones are used for increasing the milk production and efficiency of lactating dairy cows. In the United States an estimated 63% of all cattle and about 90% of feedlot animals are implanted witli growth hormones. Beef and sheep may be also implanted but not swine. When implants are used in young... 

Growth Performance Response. The consistent net effect of anabolic steroid implant use in growing ruminants appears to be increased rate of protein and live weight gain, and increased live weight at which carcass or empty body fat concentration equals that in nonimplanted cattle thus increasing their potential mature size. Increased feed intake is frequently observed. 

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