Pour on application of growth promoters in veal calves: analytical and histological results†

Abstract

To investigate the possibilities for screening and confirmation methods when the 'pour on' method of application is used for administration of growth promoters, an animal experiment was performed using a cocktail of a combination of growth promoters derived from (illegal) practice. Two cocktails were used, cocktail A consisting of stanozolol and estradiol benzoate and cocktail B consisting of stanozolol, estradiol benzoate and beclomethasone dipropionate. The intended dose per animal was 110 mg stanozolol, 25 mg estradiol and 10 mg beclomethasone. The experiment was performed on 20 male veal calves, 16 treated and 4 vehicle treated controls and 3 female veal calves, 2 treated and 1 vehicle treated control. Half of the animals were shaven prior to the application of the drugs. The cocktails were administered using two types of vehicles: vehicle A; Miglyol 840 with butylated hydroxytoluene and vehicle B; di(ethyleneglycol) monobutylether. During a 28 day treatment period, one group of animals was treated once a week, another group of animals was treated once every two weeks and slaughtered. Preliminary results showed that pour on application of anabolic steroids markedly increased growth performance of veal calves, the animals treated with cocktail A performed better than the animals treated with cocktail B. Macroscopically, the thymus was reduced in weight and size in the B animals. The bulbo-urethral glands were enlarged in all treated animals. Histologically all treated animals showed squamous metaplasia in the prostate, bulbo-urethral gland and Bartholins glands. Moreover, a changed secretion pattern was observed in both the prostate and the bulbo-urethral gland. Severe cortical atrophy was observed in the thymus and to a lesser extent the adrenals of the beclomethasone treated animals. The recently discovered 16 beta-hydroxy-metabolite of stanozolol was detected in urine, in relatively high concentrations. This is the first report of the excretion of this metabolite in urine after pour on administration showing the prospect for detection of dermal treatment. Estradiol levels were remarkably elevated (up to 200 micrograms l-1) exceeding the endogenous levels (< 1 microgram l-1).

Effects of Low‐dose Dexamethasone on Thymus Morphology and Immunological Parameters in Veal Calves

“…Although it has long been recognised that synthetic glucocorticoids have immunosuppressive activities, dexamethasone and other corticosteroids are frequently used as illegal growth promoters in livestock production, because of improved feed intake, increased live weight gain, reduced feed conversion ratio, reduced nitrogen retention and increased water retention and fat content (Istasse et al., 1989). A few studies have shown a significant reduction of the thymic tissue, namely cortical atrophy and fatty infiltration, following the use of therapeutic doses of synthetic corticosteroid (Guarda et al., 1983, 1990; Groot et al., 1998; Schilt et al., 1998). These findings have been correlated with apoptosis of thymocytes (Sun et al., 1992), a finding also related to elevated endogenous corticosterone levels in mice (Gruber et al., 1994; Tarcic et al., 1998).…”

Pathology of the Testicle and Sex Accessory Glands Following the Administration of Boldenone and Boldione as Growth Promoters in Veal Calves

“…In addition, N/N+C ratio was lower in treated groups than in the control group. The evident tendency of the value may suggest that, following the administration of androgens, [15,20]. As testosterone is the primary substrate for the synthesis of estradiol in the male, the aromatization of BOL and ADD could produce sufficient estradiol to induce the urothelial cell swelling.…”

Effects of Phyto-Oestrogens on Veal Calf Prostate Histology

“…Oestrogenic hormones induce characteristic lesions consisting of squamous metaplasia in the glandular tissue of the prostate and bulbourethral glands of male animals and in Bartholin's glands in females (Kroes, 1970;Gropp et al, 1976;Schaudinn and Beck, 1977;Grandmontagne, 1986;Deschamps et al, 1987;Rosmini, 1987;Groot et al, 1989;Girardi et al, 1990;Groot en den Hartog, 1990;Biolatti et al, 1994;Finazzi et al, 1993;Schilt et al, 1998;Groot et al, 2000).…”