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Combinations of growth promoters in veal calves: consequences for screening and confirmation methods
- Source :
- Zentralblatt fur Veterinarmedizin. Reihe A. 45(6-7)
- Publication Year :
- 1998
-
Abstract
- This study investigates the influence of low dosages of beta-agonists combined with other growth promoters on screening and confirmation methods in male veal calves. Five groups of four calves were treated for 6 weeks with combinations of low dosages of beta-agonists (beta AG, clenbuterol, mabuterol and mapenterol, 0.4 microgram/kg each twice daily) in combination with 17 beta-estradiol (E2, 5 mg per animal per 14 days), methylthiouracil (MTU, 2.857 mg/kg bw twice daily) and dexamethasone (DEX, 4 mg per animal per 10 days during the last 20 days of treatment). Another group of four untreated animals served as controls. The weight and size of the thymus was reduced in the DEX group, the MTU group showed enlarged thyroids. Histologically the prostates showed vacuolar degeneration in the beta AG animals and metaplasia in the E2 group. Some vacuolization was also observed in the controls. The testis showed impaired development in all treatment groups, E2 leading to the most severe changes. DEX led to cortical atrophy of the thymus. MTU induced hyperplastic changes in the thyroid. These results indicate that comedication does not markedly affect the histological changes induced in the hormonal target tissues. For screening purposes histology of the prostate can be used as a marker for oestrogens, whereas the weight of the thymus and thyroid can be used as an indication for the use of corticosteroids and thyreostatics, respectively. Vacuolization in the prostate appeared no reliable indication for beta-agonists. Samples of urine, faeces, liver and eye (retina/choroid) were analysed for beta-agonists. E2 significantly increased the levels of all beta-agonists in the liver and faeces, whereas DEX significantly reduced these levels. These observations show that additional medication with different groups of growth promoters can markedly alter the excretion of beta-agonists and thus influence (regulatory) control.
- Subjects :
- Male
medicine.medical_specialty
Meat
Growth
Thymus Gland
Biology
Methylthiouracil
Dexamethasone
Pathology and Forensic Medicine
Excretion
Internal medicine
medicine
Animals
Clenbuterol
2-Hydroxyphenethylamine
Metaplasia
Aniline Compounds
General Veterinary
Estradiol
Thyroid
Body Weight
Prostate
Histology
Organ Size
Adrenergic beta-Agonists
Endocrinology
medicine.anatomical_structure
Vacuolization
Body Constitution
Cattle
Hormone
medicine.drug
Subjects
Details
- ISSN :
- 05147158
- Volume :
- 45
- Issue :
- 6-7
- Database :
- OpenAIRE
- Journal :
- Zentralblatt fur Veterinarmedizin. Reihe A
- Accession number :
- edsair.doi.dedup.....7c43613b6a9ae591779b98c00fe109c5