Evaluating adrenal activity in African wild dogs (Lycaon pictus) by fecal corticosteroid analysis.

A noninvasive corticosteroid hormone monitoring technique was validated for use in African wild dogs (Lycaon pictus). The double-antibody 125I radioimmunoassay for corticosterone was validated by demonstrating parallelism between serial dilutions of wild dog fecal extracts and the standard curve, recovery of corticosterone added to fecal extracts, and the time course of fecal corticoid excretion after an exogenous adrenocorticotropic hormone (ACTH) challenge. All feces were collected from three female and two male African wild dogs for 72 hr before and 144 hr after i.m. injection of long-acting ACTH (Acthar Gel, 400 IU). Fecal corticosterone immunoreactivity increased 10-30-fold within 24 hr of ACTH administration in all individuals, with peak concentrations from 1,200-8,000 ng/g. High-pressure liquid chromatography analysis revealed that >90% of all corticosterone immunoreactivity was associated with a single peak that exhibited intermediate polarity relative to cortisol and corticosterone reference tracers. Fecal corticosterone immunoreactivity appears to reflect adrenal activity in the African wild dog and, therefore, may be useful for evaluating stress. From a conservation perspective, these techniques can complement in situ and ex situ research studies designed to evaluate how environmental conditions and management strategies affect overall animal health.

Spontaneous lactation is an adaptive result of pseudopregnancy.

Lactation is almost exclusively associated with pregnancy and giving birth. Although lactation can be induced without a preceding pregnancy in some species, this requires exogenous hormones, artificially intense or extended suckling or both. Spontaneous lactation, lactation by females that have neither been pregnant nor experimentally manipulated, is extremely unusual among eutherians. Among nondomesticated animals, spontaneous lactation has been observed repeatedly only in the dwarf mongoose Helogale parvula. We report here spontaneous lactation by free-living dwarf mongooses using data on urinary oestrogen conjugate concentrations (n = 560, 65 females) and body weight (n = 3,096, 25 females) from a population in Serengeti National Park, Tanzania. We use demographic data from this population to demonstrate that spontaneous lactation, and thus the endocrine phenomena that induce it, increase the evolutionary fitness of lactating females.

Early experience.

Because regulatory mechanisms are not fully developed in neonates, they are particularly susceptible to environmental influences on behavior. Events early in life have the potential for multiplicative effects. Perinatal stress appears to alter the function of the HHA axis in an adaptive manner. Optimal levels of stress might therefore be used in the rearing of domestic animals. Further research, including an assessment of animals' welfare, is needed. The early social environment is of critical importance in behavioral ontogeny. Social conditions other than those with which a species has evolved, such as isolation, rearing without conspecifics, or rearing in single-sex groups, can alter later behavior. Effects on agonistic and sexual behavior, in particular, have been well researched. The types of learning involved in primary socialization are not directly known for most farm species, although other features of socialization are well documented. Nutrition plays an obvious role in physical development. Less obviously, it appears that a low plane of nutrition or protein deficiency can permanently impair learning ability through a decrease in the number of brain neurons.