Determination of Breeding Seasonality in Rusa Deer (Rusa timorensis) Stags via Serum Testosterone Profiling (original) (raw)
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Breeding seasonality in mammals is influenced by the environmental changes and the endocrine response of the animals to that changes. Comprehension in breeding seasonality enables better reproductive management consequently maximizing the reproductive potential of the stags. Despite that, the study in breeding seasonality in Rusa deer (Rusa timorensis) is still scarce. Five healthy and matured stags were selected for this experiment. Semen were collected using electroejaculator at a monthly interval from April to September 2012. Semen motility is determined using a percentage. Meteorological data were obtained from the nearest weather station located in Petaling Jaya. Serum was utilized for the radioimmunoassay determination of serum testosterone profile. The warmest condition was in June and it's coolest in November of 2012. There was a strong, positive correlation between testosterone concentration and general motility (p<0.05) with a correlation coefficient, r s = 0.943. Meteorological data alone; temperature, relative humidity and rainfall are insufficient to determine the breeding seasonality in Rusa deer, bearing no significant correlation with serum testosterone concentration and sperm motility. Rusa deer stags is reproductively active from April to July, low in August and starts to rise again in September. Therefore, this study demonstrates that breeding seasonality in Rusa deer stags can be determined via serum testosterone profiling.
Annual Changes in Serum LH and Testosterone Concentrations in Male Sika Deer (Cervus nippon)
Journal of Reproduction and Development, 2002
Although sika deer is valuable for deer farming in Japan, little is understood about the reproductive endocrinology of the male. Especially, there is no information on the blood LH concentration in male sika deer. The present study aimed to determine the annual changes of serum LH and testosterone (T) secretion in male sika deer. Blood samples were collected monthly from three stags for 3 years (1998-2000). Serum LH and T concentrations were determined using a secondantibody enzyme immunoassay and a time-resolved fluorescent immunoassay, respectively. The serum LH and T concentrations fluctuated obviously in an annual fashion. The LH concentrations peaked in May, June and July, while the T concentrations peaked in September and October. These results suggest that LH and T secretion in adult male sika deer are mainly controlled by annual rhythm in the same manner as in other temperate cervids.
Theriogenology, 2005
The purpose of this study was to validate noninvasive endocrine monitoring techniques for Pampas deer and to evaluate seasonal changes in testicular steroidogenic activity and their correlation to reproductive behavior, antler cycle and group size. Thus, fecal samples, behavioral data and observations of antler status were collected at monthly intervals during 1 year from free-ranging Pampas deer stags (three radio-collared individuals and 15 random individuals) living in Emas National Park, Brazil (188S latitude). Fecal steroids were extracted using 80% methanol and steroid concentrations were quantified by a commercial enzyme immunoassay (EIA). Fecal testosterone concentrations peaked in December-January (summer), March (early autumn) and in August-September (winter-spring), with minimal values from April-July. Reproductive behavior had two peaks, the first in December-January, characterized by predominately anogenital sniffing, flehmen, urine sniffing, chasing and mounting behavior, and the second peak in July-September (behavior primarily related to gland marking). There were significant correlations between fecal testosterone and reproductive behavior (r = 0.490), and between fecal testosterone and antler phases (r = 0.239). Antler casting and regrowth occurred under low testosterone concentrations, whereas velvet shedding was associated with high concentrations of testosterone. We inferred that Pampas deer stags exhibited a seasonal cycle that modulated sexual behavior and the antler cycle, and we concluded that fecal steroid analysis was a practical and reliable non-invasive method for the evaluation of the endocrine status of free-ranging Pampas deer.
Reproduction in Domestic Animals, 2010
In this article, we aimed to describe the changes related to mating season in red deer, especially those related to antler growth, body condition score, testosterone and cortisol. Antler growth was studied in 17 Iberian red deer males, including body weight, antler length, biometric measures and testosterone and cortisol determination during 15 months. Body weight, body condition score, thoracic perimeter (TP), neck perimeter (NL) and testicular diameter (TD) showed the highest values immediately before mating season (autumn), decreased during it and remained constant at winter. Antler growth lasted 158 days and produced antlers with a final length of 80.8 ± 2.0 cm. Testosterone and cortisol showed seasonal changes with maximum values at September and May, respectively. Final antler size was related positively to cranial longitude, TP, NL, TD and body weight at casting time. No relationship between weight loss during precedent mating season and current antler size was found, but spring recovery weight was positively related to final antler size. Final length was related to the descent in testosterone values during previous mating season and to body weight before it. Spring recovery weight was related to relative weight loss during previous mating season. These results suggest that there is no relationship between the reproductive effort performed during one season and the next year size of the antler. In contrast, antler size was positively related to spring recovery weight, in the sense that those deer that recover a higher percentage of body weight at the early stages of antler growth develop higher antlers.
Journal of experimental zoology. Part A, Comparative experimental biology, 2005
The growth and mineralization of antlers correlate with the seasonal variation of serum androgens. Whereas seasonal levels of testosterone (T) in plasma are well established, steroid concentrations have not yet been determined in the tissues of growing antlers. Therefore, RIA was used to determine T and 17beta estradiol (E2) in serum, and three areas (tip, middle, and base) of the antler bone and the antler skin, called velvet. Blood and antler tissues of white-tailed deer (Odocoileus virginianus) were collected from May to August. The difference between levels of T and E2 among the sites was calculated using the square root transformation followed by a mixed model analysis with individual deer and an interaction of individual and year (individual(*)year) as a random factor. Concentrations of T in serum (799+/-82 pg/ml) were higher than T values in the velvet (589+/-58 pg/ml, P<0.01) and in the antler bone (538+/-58 pg/ml, P<0.001). Estradiol concentrations differed among antl...
Seasonal Changes of Reproductive Behavior and Fecal Steroid Concentrations in Père David's Deer
Hormones and Behavior, 2001
, we studied reproductive behaviors of Pè re David's deer in Dafeng, China. During the field behavioral observations, we collected fresh voided fecal samples from the Pè re David's stags and hinds periodically and kept those samples under ؊20°C until laboratory analysis. We analyzed the fecal testosterone, estradiol, and progesterone concentrations in those samples using radioimmunoassay. During this study, we also recorded 17 types of male reproductive behaviors and nine types of female reproductive behaviors. Reproductive behaviors and the fecal steroid concentrations showed overt seasonal fluctuations. There were statistically significant correlations between some male reproductive behaviors, such as anogenital sniffing, urine sniffing, urine spraying, wallowing, bellowing, antler adorning, Antler swags mud, chasing, herding hinds, chin resting, mounting and copulating, with the fecal testosterone concentrations. These results suggested that seasonal reproductive behaviors in stags are strongly associated with circulating testosterone. We also found that some female reproductive behaviors fluctuate corresponding with changes in fecal estrogen concentrations. Although there was no direct evidence to confirm the correlations between female reproductive behaviors and fecal estrogen in our experiment, we could not rule out that reproductive activities of hinds were largely related to ovarian estrogen secretion, and estrogen is necessary for inducing female reproductive behaviors.