Reference histology of veal calf genital and endocrine tissues - An update for screening on hormonal growth promoters

An animal experiment has been performed with 42 veal calves, 21 males and 21 females, which were fed and housed according to European regulations for veal calves. The animals were kept in six groups of seven animals and fed milk replacer supplemented with three different levels of lactulose (0%, 1% and 3%) and some roughage. At the start of the experiment the animals were 1-3 weeks of age and they were slaughtered at 26 weeks. From male animals prostate, bulbo-urethal gland and testes were sampled, from female animals Bartholin's gland, uterus, cervix and ovaries were sampled. From all animals thyroid, thymus, adrenals, liver and kidneys were sampled. Histological investigation of the prostates and bulbourethral glands showed normal histology. This means that dilated tubules, strong secretion, increased mucinous glandular tissue and severe hyperplasia and squamous metaplasia, as is regularly observed in practice in the Netherlands, were not present in these animals. None of these prostates would be judged as positive in the screening for hormones as is performed by the Dutch Food and Consumer Product Safety Authority (VWA). The female calves also showed normal histology of Bartholin's gland except for three animals that appeared to be in oestrus and showed some metaplasie of the ducts but with a normal gland to duct ratio. These animals would be judged as suspect. The liver and kidney showed minor alterations due to slight infections during the experimental period. This experiment showed that it is possible to raise veal calves according to the practice without getting positive histology in the prostate or Bartholin's gland.