INTRODUCTION
Fallow deer are distributed widely in England and are the species most com¬
monly found in English deer parks. The fallow deer is a seasonally breeding
animal, mating occurring in October and the early part of November. The
antlers are cast in April and May and the new ones start growing almost
immediately, being fully grown and cleaned of 'velvet' by mid-September
(de Nahlik, 1959).
From observations on the reproductive cycle of female fallow deer, it would
appear that the period of mating is more extended than is generally realized
(Armstrong, Chaplin, Chapman & Smith, 1969). Therefore it becomes of
interest to determine when and for how long the male fallow deer remain in
breeding condition. This paper describes observations on the testes and
epididymides of immature and adult fallow deer killed throughout the year.
1
2 D. I. Chapman and Norma G. Chapman
MATERIAL AND METHODS
The testes and epididymides of thirty-seven fallow deer were available for exam¬
ination and included thirteen fawns, five yearlings and nineteen adults. The
specimens were obtained either from Richmond Park in Surrey or from wild
deer killed in Essex, apart from deer No. 14 which came from Hampshire. The
details of locality, date killed, age and weight are given in Table 1. The majority
of fallow deer in Richmond Park and many of those in Essex were born inJune
and the ages of the fawns and the yearlings have been calculated from 1st June.
The estimated age of the fawns and yearlings is supported by the fact that deer
of known age (having been marked within a few days of birth) have similar
antler and tooth development. The ages of the adult deer are unknown.
None of the fawns estimated to be 6 to 7 months of age had antlers. Fawn
No. 11 had antler pedicels and fawn No. 13 had antlers in 'velvet' and these
consisted of single spikes 13 cm in length. The antlers of the yearlings (Nos.
14 to 18) were small knobs in hard horn. Deer Nos. 27 to 29 had antlers which
were in 'velvet' while all the other deer were in hard horn.
The specimens were fixed firstly in 4% aqueous formaldehyde solution and
then in Bouin's solution. The testes and epididymides were separated after
fixation and weighed on a balance accurate to 0-1 g. Sections (10 μ) of the testes
and the tail of the epididymides were cut and stained with haematoxylin and
eosin and the mean diameters of the seminiferous