MVSc

Captive population of spotted deer (Cervus axis axis) maintained in zoological gardens, Thrissur were utilized to study the breeding behaviour and testosterone level of males. Out of a total of 45 males, four males in the higher order of hierarchy were selected for the study. A total of 436 hours of observation were carried out by focal animal sampling technique using a behaviour score sheet. Faecal samples were collected from these animals and stored at -20 ºC, until it was extracted for measurement for faecal testosterone and cortisol by radioimmunoassay.

Seasonal breeding activity was deduced by reducing the gestation period from the date of birth and monsoon season (35 %) followed by summer season (31%) were selected as the seasons of maximum breeding. Raining season was avoided to eliminate the errors in sample collection and observation of the herd was done in winter and summer.

Four males in the higher order of hierarchy were identified based on their body size, antler size, capacity to take the vantage positions and dominance. Animals were named as alpha I, alpha II, velvet I and velvet II. The dominant male of the group was found to develop the longest antlers among the group. Similarly, the body size was more in the velvet forming stage. The blackness of the face, especially the area around the muzzle increases from non-breeding to the breeding stage. The antler cycle of males includes different stages like pedicle formation, velvet growth, velvet shedding, hardened antler stage (rutting stage) and antler cast state.

Largest harem size was observed in alpha I(26)followed by alpha II(16).The most frequently observed breeding activity was sniffing 70.78% followed by flehmen 8.98%.Maximum score for breeding behavior was obtained for alpha I(13)followed by alpha II (11).But the actual breeding frequency was more in velvet I (6) followed by velvet II ,which is four per day.

The mean testosterone concentration in the pedicel formation stage was 8.55±0.44ng/g of dry weight of faeces (ng/g) and concentration in the velvet stage was about 4.74±0.15ng/g. In the velvet shedding stage, the testosterone concentration was 17.77±0.71ng/g. In the rutting stage of velvet I and velvet II, the concentration was about 19.64±0.86ng/g and 16.08±0.47ng/g respectively and for alpha I and alpha II the level was 19.2±0.97ng/g and 12.8±1.58ng/g. The mean testosterone concentration in the casting stage was 6.37±0.30ng/g.

The mean testosterone concentration in the stags which where in rutting stage during summer exhibited a testosterone level of 17.95±0.65ng/g and in winter rutting males the concentration was 16.19±0.18ng/g.

Individual differences in the basal and peak values of faecal cortisol metabolites were observed. Mean cortisol concentration in the pedicle formation stage was 118.67±3.99ng/g and in velvet stage, it was 337.77±2.78ng/g. In the velvet shedding stage, the mean cortisol concentration decreased to 110.83±8.83ng/g. The mean cortisol concentration in the rutting stage was 121.07±6.88ng/g and in the casting stage the concentration was 114.54±5.57ng/g. There was no correlation between the breeding score and cortisol in any of the stages of sexual cycle. Similarly no correlation was found between the faecal cortisol level and faecal testosterone level.

A positive correlation (ρ=. 878, p<. 01) between the breeding score and faecal testosterone was observed in animals during velvet stage. A similar correlation was also observed during velvet shedding stage and rutting stage. But in the antler casting stage and pedicel formation stage no significant correlation was seen.

The results of the present study suggests that in captive herds of spotted deer, non invasive method can be successfully used to find out the testosterone levels, which can be integrated with breeding behaviour to have a better understanding of the breeding patterns of the group. This knowledge of breeding behavior in relation to testosterone level can be effectively used to adopt some measures to contain the population size.