Ovarian follicular dynamics and hormonal secretory profiles in guanacos (Lama guanicoe)

Riveros, José Luis; Schuler, Gerhard; Bonacic, Cristián; Hoffmann, Bernd; Chaves, Marı́a Graciela; Urquieta, Bessie

doi:10.1016/j.anireprosci.2009.11.005

Cited by 15 publications

(25 citation statements)

References 13 publications

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“…In addition, the low level of progesterone detected in the 1 st day postpartum concur with previous studies during postpartum females in camels [18] and other species [19] . Similar changes in the hormonal levels were observed during pregnancy, parturition and postpartum in llama [20,21] . The ultrasonographic examination was performed twice previous studies by Abu-Seida [22] , Derar, Ali [23] , who found that the uterine involution was completed in female camels from 25 th until 30 th days postpartum.…”

Section: Discussionsupporting

confidence: 58%

Monitoring the Changes in Certain Hematological and Biochemical Parameters in Camels (Camelus Dromedaries) during Postpartum Period

El-Zahar

Zaher

Alkablawy

et al. 2017

JFB

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Section: Discussionsupporting

confidence: 58%

Monitoring the Changes in Certain Hematological and Biochemical Parameters in Camels (Camelus Dromedaries) during Postpartum Period

El-Zahar

Zaher

Alkablawy

et al. 2017

JFB

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“…In addition, studies in guanacos (Riveros et al. ) reported that only 60% of follicular waves overlapped. Moreover, the degree of overlapping observed in llamas of the present study was greater than that reported by other researchers in anovulatory llamas (1–4 days) and bactrian camels (2–5 days) (Chen and Yuen ; Bravo et al.…”

Section: Discussionmentioning

confidence: 99%

“…Conversely, research in guanacos (93%; Riveros et al. ), vicuñas (77%; Miragaya et al. ) and alpacas/llamas (81%; Bravo et al.…”

Section: Discussionmentioning

confidence: 99%

Ultrasonographic and Endocrine Characterization of Follicular Waves in Llamas with a Special Reference to the Overlapping Phenomenon During Successive Waves

Cavilla¹,

Bianchi²,

Maistruarena³

et al. 2013

Reprod Domestic Animals

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Ovarian follicular growth in non-mated llamas occurs in successive waves that generally superimpose their origin on the regression of the preceding wave (overlapping), originating prolonged sexual receptivity in the species. The aim of this study was to perform an ultrasonographic and endocrine characterization of individual and successive waves in non-mated llamas with a special interest on the overlapping phenomenon. Twelve llamas were examined daily by transrectal ultrasonography for at least two consecutive waves. In six females, blood samples were collected daily at the end of each examination. The development of the largest follicle (F) showed a wavelike pattern with a mean duration of 25 days. All waves evaluated were partially overlapped on the preceding wave and emerged at a mean interval of 15.8 ± 0.5 days. This interwave interval determines a mean overlapping degree of 32% of the wave length. Similarly, mean plasma oestradiol-17β (E2 ) concentrations followed a wavelike pattern. However, E2 concentrations started to decline before the structural regression of the F was observed. Mean basal E2 concentrations remain higher than 10.9 ± 0.6 pmol/l. In conclusion, follicular activity in non-mated llamas is characterized by continuous emergence of successive waves that always overlap the preceding wave with variable degrees. E2 production during the follicular wave is shorter in duration than the morphological development of the F. Finally, the overlapping phenomenon maintains increased plasma E2 concentrations persistently and this could explain the prolonged periods of sexual receptivity registered in llamas.

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“…These observations are in agreement with Mayor et al (2006), who suggested the existence of follicular waves in this species, based on the size and number of antral follicles and corpus luteum. The follicle recruiting, selection, and dominance phases are observed in other species of artiodactyls, such as buffaloes and South American camelids (Baruselli et al 1997, Riveros et al 2010, vaughan 2011; however, their morpho-physiological mechanism is yet little understood (Fortune 1994, Rodgers et al 1999, Gougeon & Busso 2000, Monniaux et al 2009). …”

Section: Discussionmentioning

confidence: 99%

Ovarian folliculogenesis in collared peccary, <i>Pecari tajacu</i> (Artiodactyla: Tayassuidae).

Guimarães

Garcia

Ferreira

et al. 2012

RBT

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Abstract:The sustainability and production of collared peccary (Pecari tajacu) has been studied in the last few years; however, further information on its reproduction is necessary for breeding systems success. Understanding folliculogenesis aspects will contribute to effective reproductive biotechniques, which are useful in the preservation and production of wildlife. The aim of this study was to evaluate the ovarian folliculogenesis in collared peccary. Ovaries from six adult females of collared peccary were obtained through ovariectomy and analyzed. These were fixed in aqueous Bouin's solution and sectioned into 7µm slices, stained with hematoxilin-eosin and analyzed by light microscopy. The number of pre-antral and antral follicles per ovary was estimated using the Fractionator Method. The follicles, oocytes and oocyte nuclei were measured using an ocular micrometer. Results showed that the length, width, thickness, weight, and the gross anatomy of the right and left ovaries were not significantly different. However, the mean number of corpora lutea was different between the phases of the estrous cycle (p<0.05), with the highest mean in the luteal phase. Primordial follicles were found in the cortex; the oocytes were enveloped by a single layer of flattened follicular cells. In the primary follicles, proliferation of the follicular cells gave rise to cuboidal cells (granulosa cells). The secondary follicle was characterized by two or more concentric layers of cuboidal cells (granulosa), beginning of antrum formation, and the presence of pellucid zone and theca cells. Antral follicles were characterized by a central cavity (antrum), the presence of cumulus oophorus and theca layers (interna and externa). In the right ovary, the values of the primordial and primary follicles were similar, but significantly different from the secondary ones (p<0.05). In the left ovary, significant differences were observed between all follicles in the follicular phase (p<0.05); the mean number of primordial and primary follicles was similar in the luteal phase. The mean number of pre-antral follicles and antral follicles in the follicular phase was higher in the left ovary (p<0.05). The mean number of antral follicles in the luteal phase was similar in both ovaries. We also found significant differences in mean diameter of preantral follicles, oocyte, granulosa layer and oocyte nucleus during the estrous cycle. In the antral follicles a significant difference was observed only in follicular diameter (p<0.05). The predominance of active primordial and primary follicles was found in both phases; otherwise the secondary follicles and antral follicles showed a high degree of degeneration. The results obtained in the present work will strengthen the development of biotechnology programs to improve the productive potential and conservation of the collared peccary. Rev. Biol. Trop. 60 (1): 437-445. Epub 2012 March 01.

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Ovarian follicular dynamics and hormonal secretory profiles in guanacos (Lama guanicoe)

Cited by 15 publications

References 13 publications

Monitoring the Changes in Certain Hematological and Biochemical Parameters in Camels (Camelus Dromedaries) during Postpartum Period

Monitoring the Changes in Certain Hematological and Biochemical Parameters in Camels (Camelus Dromedaries) during Postpartum Period

Ultrasonographic and Endocrine Characterization of Follicular Waves in Llamas with a Special Reference to the Overlapping Phenomenon During Successive Waves

Ovarian folliculogenesis in collared peccary, <i>Pecari tajacu</i> (Artiodactyla: Tayassuidae).

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