Assessment of urinary volatile compounds and proteins in the female goat Capra hircus: A pilot study to reveal potential indicators of oestrus

Scent detection dogs as a novel method for oestrus detection in an endangered species, the Tasmanian devil (Sarcophilus harrisii)

Captive breeding is a critical tool for conservation of endangered species. Identifying the correct time to pair males and females can be a major challenge for captive breeding programmes, with current methods often being invasive or slow. Detection dogs may provide a non-invasive way to determine female receptivity, but this has not been explored in captive wildlife. This exploratory study investigated the use of detection dogs as a novel method of oestrus detection in the endangered Tasmanian devil (Sarcophilus harrisii). Faecal samples were collected from 11 captive female devils during the breeding seasons of 2020 and 2021. Three dogs with prior detection experience were trained and subsequently assessed (n = 188 searches per dog), on their ability to discriminate between oestrus and non-oestrus devil faecal samples, in a one sample set-up. When assessed on training samples, dogs were able to correctly discriminate oestrus from non-oestrus with a mean sensitivity of 69.1% and mean specificity of 65.7%. When assessed on novel samples, their sensitivity to oestrus dropped (mean sensitivity of 48.6%). However, they were still able to correctly identify non-oestrus samples (mean specificity of 68.1%). This study is the first to explore detection dogs' ability to identify oestrus in a captive breeding programme for endangered wildlife, providing a promising tool for non-invasive monitoring of reproductive status in wildlife.

Detection of estrous biomarkers in the body exudates of Kangayam cattle (Bos indicus) from interplay of hormones and behavioral expressions

Behavioral expressions and biochemical composition of body exudates are significantly altered in concert with the endocrine status, which are all clear indicators of physiological conditions of animals. In this study, we sought to infer about the reproductive physiological status of Kangayam cattle (Bos indicus) by analyzing behaviors, endocrine pattern, and body exudates and further to discover estrous biomarkers so as to facilitate timely artificial insemination/mating and to aid in aspects of conservation of the species. Therefore, in this study, we followed Kangayam cows through pre-estrous to post-estrous phases to correlate the endocrine dependence of biochemical constituents in urine and cervical mucus and sought to identify estrous biomarkers. Behavioral estrus was confirmed in 10 cows, from which urine samples were collected and subjected to determination of LH, FSH, estrogens, progesterone, proteins, and lipids. Furthermore, urinary fatty acids and proteins were profiled using gas chromatography and SDS-PAGE, respectively. The volatile compounds in the urine and cervical mucus were identified by gas chromatography-mass spectrometry analysis. The data revealed that LH, FSH, and estrogen levels increased significantly in estrous urine compared with nonestrous urine, whereas progesterone status was vice versa (P < 0.05). The lipid content was also significantly higher in estrous urine than in pre- and post-estrous urines (P < 0.05). There were also cyclical variations of volatiles and fatty acid profiles across phases of the estrous cycle. More acidic compounds were present in estrous urine, rendering it more acidic, than in pre- and post-estrous urines. Interestingly, oleic acid, which was present as a fatty acid in estrous and post-estrous urines, appeared to be a volatile in post-estrous urine and estrous cervical mucus. In addition, octanoic and butanoic acids were specific to both estrous urine and cervical mucus, indicating their possible candidature as estrous biomarkers. SDS-PAGE analysis showed pronounced expression of a 98 kDa protein in post-estrous urine, which in matrix-assisted laser desorption ionization-time of flight mass spectrometry was identified as albumin. Our results demonstrate multiple biomarkers in estrous urine and specific volatiles in cervical mucus that offer scope to develop viable estrus detection kits for Kangayam cows.

Identification of potential pheromone source in sows

Pheromones play a pivotal role in intra-species communication for reproduction and social behavior in a variety of mammals, such as boars. For boars, saliva is a rich source of pheromones, however, the identification of additional sources and relative abundance of pheromones in various body fluids of sows is also essential to understand the reproductive behaviors of pigs. The present study was designed to identify the source(s) of pheromones in sows. We collected urine, feces, saliva and cervical mucus/vaginal wash samples from sows at pre-estrus, estrus and post-estrus phases, and from gilts and exposed boars to each of these potential sources of pheromones. All the boars tested spent more time sniffing and hyper-salivating in response to urine from sows in estrus than that from sows not in estrus. The sniffing behavior of boars towards estrus samples differed from that towards the samples from non-estrus sows (P < 0.005) and gilts (P < 0.001). Further, hypersalivation behavior of boars differed between estrus samples and gilt samples (P < 0.05) and estrus samples compared to pre-estrus samples (P < 0.05). This is an indication that pheromones are abundant in the estrus samples. We conclude that urine of estrus sows can be a rich source of pheromones and the same can be used to identify, purify and characterize novel pheromone molecules.