Reproduction in the endangered African wild dog: Basic physiology, reproductive suppression and possible benefits of artificial insemination

Abstract

a b s t r a c tThe African wild dog (Lycaon pictus) is an endangered exotic canid with less than 5500 animals remaining in the wild. Despite numerous strategies to conserve this species, numbers of free-living animals are in decline. It is a highly social species with a complex pack structure: separate male and female dominant hierarchies with, typically, participation of subdominant adults in the rearing of the dominant breeding pairs' pups. Basic reproductive knowledge is largely missing in this species, with only limited information available on the profile of reproductive hormones, based on non-invasive endocrine monitoring. The dominant or alpha male and female are reproductively active and the subdominants are generally reproductively suppressed. However, the occasional production of litters by subdominant females and evidence of multiple paternity within litters suggests that fertility of subordinates is not completely inhibited. In this respect, there are still considerable gaps in our knowledge about the mechanisms governing reproduction and reproductive suppression in African wild dogs, particularly the influence of dominance and pack structure on both male and female fertility. Given concerns over the long-term survival of this species, further research in this area is essential to provide valuable information for their captive breeding and conservation. Reproductive information can also be applied to the development of Assisted Reproductive Techniques for this species; the utility of which in African wild dog conservation is also discussed.

Social rank does not affect sperm quality in male African wild dogs (Lycaon pictus)

“…In some social species such as meerkats, elevated cortisol in subordinate animals is a common mechanism for reproductive suppression of the hypothalamic-pituitary-gonadal axis (Creel 2001;Van den Berghe et al 2012). We did not see differences in fGCM concentrations between dominant and subordinate AWDs, which is consistent with previous studies conducted in semi-natural captivity (de Villiers et al 1997), and the wild (Van der Weyde 2013).…”

“…This species, classified as endangered by the IUCN (Woodroffe and Sillero-Zubiri 2012), requires effective management of the captive and free-living population (Frantzen et al 2001). Development of artificial insemination and sperm banking are key elements for the overall conservation management of this species (Van den Berghe et al 2012). Subordinate males are generally directly related to the dominant or alpha male (brothers or juvenile offspring) but share only 50% of their alleles at best; making the preservation of their genetic diversity equally important for sperm banking initiatives.…”

“…However, given that the alpha pair reproduces, it is not clear whether subordinate males are reproductively suppressed by behavioural or physiological mechanisms as seen in other species (Creel 2005;Young et al 2006;Barja et al 2008;Van den Berghe et al 2012).…”

“…However, 'physiological castration' through higher stress levels in subordinate animals may be unlikely in AWDs as it is usually the dominant male and female that show higher glucocorticoid levels without exerting any obvious negative effects on their fertility Van den Berghe et al 2012).…”

Seasonal Changes on Epididymal Histology and Testosterone Receptors in Iraqi Dogs

“…There was a long history of cohabitation between human and dogs but there was little information and many aspects of canine reproductive concerning the effect of breeding season (Gavrilovic et al, 2008;Van den Berghe et al, 2012). Seasonal changes in semen parameters were observed in undomesticated canids and the testosterone production reach peak during breeding season (Strzezek et al, 2015).…”