BIOLOGY AND BEHAVIOR

A major difference between chital deer and fallow deer is the temperate origins of the latter, whereas chital deer originate in India, Nepal, Bhutan, and Sri Lanka.⁶ As a tropical species it was believed that their major attribute would be their ability to breed all year round, with the potential for chital hinds to produce three offspring in 27 months. This is in contrast to fallow deer that produce only one offspring annually, with strict reproductive seasonality imposed by photoperiodic variation. However, it soon became apparent that chital deer on farms in southern Australia were not realizing this high reproductive potential, partly because of the high perinatal mortality rate. Many calves born in the winter months died within a day or so of birth, especially in very inclement weather. In addition, there were often major problems when attempts were made to handle groups of chital deer on farms, given that such groups almost invariably contained all age classes, including antlered stags. With the timorous nature of the species and their often panic-stricken reaction to being closely approached, there were frequent losses from trauma and postcapture myopathy.

During the studies on chital deer at Camden it became apparent that chital deer were quite readily yarded and handled after a suitable “training and taming” process, especially once the deer were segregated into appropriate gender and age groups for management purposes.⁷ Studies on the physiologic responses of chital deer to regular handling confirmed that this taming process did occur.⁸ To reduce the risks of traumatic injuries during yarding, antler growth is always prevented by velvet antler removal or surgical polling. Well-trained chital deer can in fact be yarded and handled as readily as can fallow deer, through identical facilities.²

REPRODUCTION

It had been noted that chital hinds were capable of producing calves in every month of the year in India, Nepal, Hawaii, and Texas as well as in Australia.^6,9–11 However, when data were collected at Camden over several years it was found that there was a preponderance of calves born in the second half of the year.³ This fitted well with observations made on the antler cycles of chital stags, with a high level of synchrony in their cycles being noted. Most stags cast their antlers in late winter and early spring, between August and October, with the subsequent development of hard antlers and other secondary sexual characteristics and a period of rutting behavior in January to June. This fitted with observations that showed that chital hinds cycle all year round if unmated, with an estrous cycle length of 19.3 ± 1.3 days and a gestation period of 234.5 ± 3.0 days. Moreover, chital hinds were known to conceive quite quickly after parturition, and it was revealed that the interval from calving to conception ranged from 18 to 118 days, with an average of 48.1 ± 27.8 days.¹² Subsequent work showed that the first detected estrus occurred at a mean time of 26.9 ± 3.0 days after parturition. Furthermore, hinds in contact with a stag in this study had a significantly shorter interval from parturition to first ovulation compared to hinds not in contact with a stag (93% compared to 43%, respectively).¹³