One gland, two lobes: organogenesis of the "Harderian" and "nictitans" glands of the Chinese muntjac (Muntiacus reevesi) and fallow deer (Dama dama).

The nictitans and Harderian glands are enigmatic glands situated in the anterior aspect of the orbit. Traditionally, the nictitans and Harderian glands of mammals have been considered to be two fundamentally distinct glands. However, a consistent, unambiguous distinction between these two glands has remained elusive due to conflicting anatomical and histochemical definitions. The Harderian gland was originally described, and first distinguished from the nictitans gland, in adult deer. We examined the organogenesis and histochemistry of the anterior orbital glandular mass in two species of deer (Muntiacus reevesi and Dama dama) to determine whether it comprises two distinct glands or one bilobed gland. The anterior orbital regions of 30 fetal specimens of both species, along with some adult material, were examined histologically. Four stages of glandular organogenesis were observed. Most notably, both glandular portions developed from the same inception point, but the deep lobe developed faster than the superficial lobe. The common inception point and the relationship of the collecting ducts clearly shows that this is a single glandular mass that differentiates into two lobes rather than two distinct glands. Moreover, although the histochemical profiles of the two lobes differ slightly, both lobes produce lipids, which is further indication that these are not profoundly different glands but part of a single, heterogeneously developed gland. Thus, it is proposed that the terms nictitans and Harderian glands, as separate entities, be discontinued and that the entire gland be referred to as the anterior orbital gland (glandula orbitalis anterior), with superficial and deep lobes (pars superficialis and pars profundus, respectively).

Evidence that the seasonal antler cycle of adult Reeves' muntjac (Muntiacus reevesi) is not associated with reproductive quiescence.

Data were obtained from post-mortem investigations of 190 culled and road-killed muntjac bucks between 1967 and 1989. Although adult bucks (i.e. those having undergone at least one antler cycle) have a synchronous annual antler cycle, unlike temperate-zone cervids there was little seasonal variation in testis size or activity, or in the size and activity of the epididymidis or accessory reproductive glands. Spermatogenesis was not abated when the antlers were in velvet and year-round fertility was achieved without additional sperm storage. There was little seasonal change in plasma testosterone concentrations in samples obtained from captive and free-living bucks although castration caused antler casting and prevented mineralization. Hence the data are equivocal as to the role of steroids in driving the antler cycle; experimental work on this species would be valuable in examining the mechanisms which regulate the antler cycle.

Deformities of the metacarpus and metatarsus in fallow deer (Dama dama L.).

Radiographic examination of the metacarpus and metatarsus from 333 fallow deer revealed a high incidence of animals with an angular deviation of at least one epiphysis. The incidence in males (59 per cent) was significantly higher than that in females (21 per cent). The cloven hoof is bent laterally and a deviation of up to 23 degrees was recorded. A deer with one deformed foot is equally likely to have 2, 3 or 4 deformed feet and no bone is more susceptible than others. Fusion of the epiphyses commenced at about 16 months and was complete by about 32 months, and the angular deformity occurred before this age. The incidence increases with increasing age in deer whose epiphyses have not yet fused. Other radiographic changes noted were growth plate deformities in young deer of 8 to 12 months of age and bowing of the shaft of the cannon bone in some older animals. It is suggested that the following sequence of events could involve all 3 defects and provide an explanation for the gross angular deviation of the foot seen in some deer. First, a defect in the process of calcification as a result of a nutritional deficiency causes hypertrophy of the cartilage of the growth plate, with local epiphyseal damage. Second, a compression or a breakdown of the cartilage of the cannon bone, particularly if on one side only, causes angular deviation of the epiphysis. Subsequent ossification leads to fusion of the diaphysis with the epiphysis at an abnormal angle. Third, the defect in calcification of the diaphysis leads to a weakness in the bone which, if stressed, becomes deformed and, after subsequent ossification, is seen as a bowing of the cannon bone.

Some haematological data for fallow deer (Dama dama) in England.

The concentrations of haemoglobin, erythrocytes and leucocytes and the packed cell volume, plasma viscosity and some red cell indices were measured in the blood of 42 fallow deer and analysed with respect to age, season and sex. The mean haemoglobin concentration was greater in females than in males. In all the deer the number of leucocytes was considerably smaller than in the usual domestic mammals, namely, cats, cattle, dogs, goats, horses, pigs and sheep. Plasma viscosity was statistically greater in male deer more than two years old than in female deer of similar ages.

Some serum constituents of fallow deer (Dama dama).

The concentrations of calcium, inorganic phosphorus, proteins and total bilirubin and the activities of some enzymes in the sera of 54 fallow deer are presented. Electrophoresis of the serum proteins indicate that fallow deer have a single alpha-globulin whereas red deer have two.

Serum constituents of red deer (Cervus elaphus).

The concentrations of proteins, total bilirubin, calcium and inorganic phosphate and the activities of some enzymes were measured in the sera from 49 red deer. The results were analysed with respect to age, season and sex.

Morphology of the male accessory organs of reproduction of immature fallow deer (Dama dama L.) with particular reference to puberty and antler development.

The accessory organs of reproduction of male fallow deer are fully active for the first time during the animal's second rut, at 16 months of age. Antler pedicles develop at about 9 months, at the same time as the seminiferous tubules show a marked increase in diameter. The accessory organs show an increase in size at approximately 14 months of age when the deer weigh about 45 kg and maturation of the first pair of antlers is occurring. Puberty commences at about 9 months, pauses during the period of active antler growth and recommences at about 14 months, culminating with the appearance of spermatozoa at 16 months of age. Androgenesis precedes spermatogenesis.

Yersiniosis in a free-living fallow deer.

A case of yersiniosis in a free-living fallow deer is described. Pathological examination revealed an emaciated carcase with numerous abscesses of various sizes throughout the abdominal and thoracic cavities. Staining of material from the abscesses showed a small Gram-negative coccobacillus which was identified as Yersinia pseudotuberculosis type 1A.