INTRODUCTION

Historically, the breeding of giant pandas in ex situ programmes has been difficult due to behavioural incompatibility and interanimal aggression. Because some individuals fail to mate naturally, the potential loss of valuable genes is a major concern to effective genetic management (see Chapter 21). Consistently successful artificial insemination (AI) would allow incorporating genetically valuable males with behavioural or physical anomalies into the gene pool. This strategy becomes even more powerful when used in the context of a genome resource bank (GRB), an organised repository of cryopreserved biomaterials (tissue, blood, DNA and sperm) (see Chapter 7). The use of sperm cryopreservation and AI allows the movement of genes among zoos and breeding centres without needing to transfer animals, which is both stressful and costly.

‘Assisted breeding’ refers to the tools and techniques associated with helping a pair of animals propagate, from AI to embryo transfer to cloning, among others (Howard, 1999; Pukazhenthi & Wildt, 2004). With the exception of AI, there is not much need for most other assisted-breeding techniques for the giant panda. As will be demonstrated here, AI is quite adequate for dealing with most cases of infertility or with helping to maintain adequate gene diversity in the captive population. In fact, the major breeding facilities, especially the China Conservation and Research Centre for the Giant Panda (hereafter referred to as the Wolong Breeding Centre) and the Chengdu Research Base of Giant Panda Breeding, routinely use AI to increase pregnancy success.

INTRODUCTION

Among eutherians, ursids have a significant disparity between maternal weight and neonatal weight (Leitch et al., 1959). The giant panda also produces a smaller litter mass relative to maternal body mass than, for example, the American black bear (Oftedal & Gittleman, 1989; Ramsay & Dunbrack, 1996; Zhu et al., 2001). The giant panda neonate is particularly altricial (i.e. highly dependent on parental care), requiring 24-hour care during the first weeks of life. This chapter deals with the issues and intricacies associated with the newborn giant panda cub, including hand-rearing and medical management.

NEONATAL CARE AND HAND-REARING: METHODS, RESULTS AND RECOMMENDATIONS

Indications for hand-rearing

Although maternal care is always preferred for the giant panda cub, there are situations when human care-giving is mandatory. The most obvious is maternal abandonment, which usually becomes apparent within the first five to ten minutes of birth. A female that abandons her cub will typically leave it on the ground and move away, showing little or no interest. Intervention is also required when the dam holds the cub improperly (malpositioning). Such a cub can neither nurse nor rest, often moves about excessively (in an attempt to achieve proper positioning on its own) and then can fall to the ground. A third complication is the common production of two or more cubs (mean litter size is 1.7; range 1–3) (Schaller et al., 1985).

INTRODUCTION

Among mammals, the giant panda is reproductively unique. The female is a seasonal, monoestrual breeder, experiencing a single- two to three-day period of sexual receptivity once per year, presumably triggered by increasing day length. In the wild, male giant pandas compete with conspecifics for access to oestrous females (Schaller et al., 1985). Giant pandas produce copious sperm numbers (see Chapter 7), presumably as ‘insurance’ to ensure conception and the perpetuation of the male's genes if given the opportunity to mate during a female's brief window of fertility. Although the extraordinarily short oestrus is a fascinating biological trait, it does not appear to limit reproductive success in captivity given that a sexually compatible male is available and breeding occurs. It does, however, present challenges for captive management for cub production.

The wild-born giant panda cub stays with its mother for 1.5 to 2.5 years (Schaller et al., 1985). This almost always is not the case in Chinese zoos and breeding centres, because of the practice of promoting annual cub production by early weaning, usually before six months of age (see Chapter 14). The consequences of this short-term gain on long-term development remain a question, and studies are continuing on the impact of disrupted early rearing on adverse behaviours, including inappropriate aggression, inadequate sexual behaviour and/or incompetent maternal behaviour (see Chapter 14). These anomalies are rather common in the ex situ giant panda world. Many males tend to show aggressive rather than affiliative behaviours, even to females demonstrating strong oestrus.

INTRODUCTION

As for many highly specialised carnivores, breeding giant pandas in captivity has had sporadic gains and setbacks over its 40-year history (see Chapters 1 and 19). Although many husbandry issues have been addressed successfully, we are still learning about behaviour and its relevance to ex situ management. This chapter updates the state of captive breeding at the China Conservation and Research Centre for the Giant Panda in the Wolong Nature Reserve (hereafter referred to as the Wolong Centre). We also provide details of our scientifically guided husbandry and management strategies that are contributing to a rapidly growing database of scholarly knowledge as well as to recent improvements in reproductive success.

Even with our limited knowledge about giant pandas in nature, it appears that, in the presence of plentiful natural resources and the absence of human disturbance, giant pandas mate, become pregnant and rear offspring without problem. Thus, reproduction is not a limiting factor to wild population viability (Lu et al., 2000). Because this is not the case for the ex situ population, we can surmise that reproductive problems are rooted in the captive environment – a place that fails to fully meet the needs of at least some individuals. In principle, and with a proper understanding of species-salient factors, it should be possible to create captive environments that result in, or even surpass, reproductive rates occurring in the wild. Targets for improvement include health, nutrition, husbandry and behavioural management, this chapter concentrating on the latter two factors.

INTRODUCTION

While many recent advances have been made in the breeding of giant pandas ex situ, historically this species has never reproduced well in captivity. Sexual incompatibility, health problems, low fecundity and a juvenile mortality rate in excess of 70% have contributed to low reproductive success (O'Brien & Knight, 1987; O'Brien et al., 1994; Peng et al., 2001a, b). Wild- and captive-born giant pandas, particularly those captured at a young age, traditionally had difficulty producing offspring in captivity upon becoming adults (Lu & Kemf, 2001). As a result, the ex-situ giant panda population has not been self-sustaining and, until recently, its growth has relied on introducing animals captured from nature. In some cases, this included individuals that appeared ill (rescues) or cubs that were believed to be neglected or abandoned by their mothers. Later field studies, however, revealed that females often leave cubs alone for four to eight hours while foraging, and in one documented case for 52 hours (Lu et al., 1994). Recently, China has placed a general moratorium on capturing wild giant pandas for captive breeding (Lu & Kemf, 2001), a move that forces the breeding community to develop a self-sustaining population.

The goal, however, is not only ensuring demographic self-sustainability but also the maintenance of genetic diversity. The deleterious effects of inbreeding are well recognised (O'Brien, 1994a; Frankham, 1995; Hedrick & Kalinowski, 2001; Frankham et al., 2002).

INTRODUCTION

There is surprisingly little published information about giant panda biology, especially in the life sciences. This poor quantity (and quality) of data has been due primarily to too few individual animals available for study and a traditional hands-off policy towards hands-on research in such a rare and high-profile species. However, recent changes (see Chapter 2) have created important, new opportunities for giant panda investigations. People responsible for ensuring that the species survives now realise that giant pandas living in zoos and breeding centres are a valuable research resource (see Chapter 1). It also has been recognised that this population must be intensively managed if it is truly to support giant pandas that are surviving precariously in nature. The intended result will be an ever-increasing amount of new, scholarly information and sufficient panda numbers to continue educating the public, helping to raise conservation funding, serving as a hedge against extinction, and even as a source of animals for potential reintroductions. However, these laudable goals can only be achieved by first understanding and then rigorously managing the captive population so that it becomes demographically and genetically stable. This, in fact, has become the mantra of Chinese managers of the ex situ population: ‘to develop a self-sustaining, captive population of giant pandas that will assist supporting a long-term, viable population in the wild’ (see Chapter 2).

INTRODUCTION

Nutrition involves a series of processes whereby an animal uses items in its external environment to support internal metabolism (Robbins, 1993). The nutrition and consequent nutritional status of an animal are basic to all aspects of health, including growth, reproduction and disease resistance. Thus, appropriate nutrition and feeding are essential to a comprehensive animal management and preventative medicine programme.

The giant panda's obligate dependence upon bamboo as a primary energy and nutrient source has been well described (Sheldon, 1937; Schaller et al., 1985). Many aspects of panda biology are directly related to its adaptations for utilisation of this highly fibrous, low energy density food, thus demonstrating the inseparable influence of nutrition on behaviour, reproduction and other physiological functions. There may be few other species that more effectively illustrate how an understanding of nutritional adaptations helps us interpret the species ecology.

This chapter describes insights into the nutritional adaptations of the giant panda while identifying priority research that will fill gaps in our understanding of these unique abilities. Historical and current strategies on feeding giant pandas in captivity are presented along with recommendations for improving nutrition and dietary husbandry to promote health and feeding behaviours.

ANATOMY, PHYSIOLOGY, GUIDELINES AND ASSESSMENT

Feeding ecology and anatomical adaptations to a herbivorous diet

More than 99% of the food consumed by the free-ranging giant panda consists of bamboo (Schaller et al., 1985). Yet the giant panda is unique in that it has the relatively simple gastrointestinal tract of a carnivore.

INTRODUCTION

The Giant Panda Biomedical Survey sought to establish a baseline of scientific information on giant pandas living in Chinese zoos and breeding centres as a first step towards establishing a self-sustaining captive population (Zheng et al., 1997; see also Chapter 2). To produce the most information that would allow an understanding of the health and reproductive status of the extant population, we chose an interdisciplinary approach to examine as many health and reproductive traits as possible. What was crucial was the trusting relationship that developed early in the process between the Chinese and American teams which led to a thorough understanding of giant panda biology – information that not only was fascinating from a scholarly perspective but also valuable to improving ex situ management.

This chapter provides detailed methods and medical findings following the assessment of more than 60% of the living Chinese population of giant pandas (as existed in 1996 when the need for a Biomedical Survey was recognised). The results in this chapter address issues ranging from disease conditions to reproductive compromise, all of which ultimately allowed classifying each animal as to its usefulness in achieving the goal of population self-sustainability. The practices and reference values described here will also be useful to those who are interested in closely studying and managing giant pandas in the future.