High environmental temperature and humidity decrease oocyte quality in but not in cows

Rocha, Aristides Almeida; Randel, R.D.; Broussard, J.R.; Lim, Jeeyoung; Blair, R.; Roussel, J.D.; Godke, R.A.; Hansel, William

doi:10.1016/s0093-691x(98)00016-8

Cited by 158 publications

(114 citation statements)

References 32 publications

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“…Other studies, however, have shown that European cattle (Bos taurus) differ from zebu cattle (Bos indicus) in various aspects of their reproductive biology ( Chenoweth, 1994, Rocha et al, 1998and Visintin et al, 2002. Many attempts have been made in developing the reproductive technologies for zebu cattle, especially because these animals are economically important to Brazil.…”

Section: Introductionmentioning

confidence: 99%

Morphometric and ultrastructural characterization of Bos indicus preantral follicles

Kacinskis¹,

Lucci²,

Luque³

et al. 2005

Animal Reproduction Science

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Morphometric and ultrastructural characterization of Bos indicus preantral folliclesMirella Ávila Kacinskis Carolina Madeira Lucci Maria Carolina Aquino Luque Sônia Nair Báo AbstractThe aim of the present study was to characterize the ultrastructure of zebu cow preantral follicles (PAFs). Ovarian cortex samples were processed for light and transmission electron microscopy. Primordial follicles consisted of an oocyte surrounded by one layer of flattened or flattened-cuboidal granulosa cells. The oocyte contained a large and usually eccentric nucleus. Most organelles were located at the perinuclear ooplasm. Round shaped mitochondria, which contained electron-dense granules, smooth and rough endoplasma reticulum and a Golgi apparatus were also observed. Vesicles and coated pits were often observed in the cortical ooplasm. In primary follicles, the oocyte was surrounded by one layer of cuboidal granulosa cells. Short microvilli were observed on the oolema. Secondary follicles consisted of an oocyte surrounded by a variable number of layers of cuboidal granulosa cells. Small secondary follicles had an ultrastructure very similar to that observed in primary follicles. At this follicular stage, the zona pellucida was beginning to form around the oocyte. In large secondary follicles, the zona pellucida was totally developed around the oocyte. Several granulosa cell projections could be detected that were encroaching into the zona pellucida and protruding towards the oocyte, where gap junctions were observed between oocyte and granulosa cell membranes. Organelles within the oocyte were located at the periphery of the ooplasm, and clusters of cortical granules were observed. Round mitochondria were abundant in all developmental stages. In conclusion, this study described the ultrastructure of zebu cow PAFs, and some unique characteristics could be observed as compared with what has been reported for follicles of Bos taurus cattle.

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Section: Introductionmentioning

confidence: 99%

Morphometric and ultrastructural characterization of Bos indicus preantral follicles

Kacinskis¹,

Lucci²,

Luque³

et al. 2005

Animal Reproduction Science

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“…Only few reports focusing on possible differences among breeds have also been reported (15). Individual variations as a result of specific and unspecific factors (5) limit the attainment of a satisfactory number of oocytes as well as oocytes with enough quality to develop in vitro after in vitro fertilization (16).…”

Section: Discussionmentioning

confidence: 99%

164 Influence of Lineage of Oocyte Donor on the Yield and Morphology of Oocytes Recovered by Ultrasound-Guided Follicular Aspiration in Nellore Cows

Martins

Calegari

Paschoal

et al. 2012

Reprod. Fertil. Dev.

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The objective of this study was to investigate the influence of lineage of oocytes donors on the number and quality of oocytes obtained through ultrasound-guided follicular aspiration in Nellore breed cows derived from two lineages of bulls (Karvadi; K and Taj-Mahal; T). Both maternal (Km and Tm) and paternal (Kp and Tp) lineages, as well as their combinations were investigated. Oocyte aspirations were repeatedly performed with an aspiration interval of 15 days in 56 donor females. Recovered cumulus oocyte-complexes (COCs) were counted, morphologically examined and classified into seven categories (grades from I to VII) according to the number of layers of the cumulus oocyte and cytoplasm appearance. 5.9±0.42 and 3.64±0.25, respectively) than for lineage Karvadi, with similar results for oocytes of grades IV, V, VI, and VII. Similarly to the paternal lineage, the number of oocytes of grade III was superior (P<0.05) when compared to other categories for both lineages. In conclusion, we demonstrate here a direct influence of lineage of oocyte donor on the production and quality of oocytes obtained through ultrasound-guided follicular aspiration in Nellore cows. Keywords

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“…If follicular dynamics, FSH secretion and steroidogenesis are altered by heat stress, this would create an abnormal environment for oocyte development. In that regard, Rocha et al (1998) reported a marked decline in oocyte quality (as assessed by ooplasm and cumulus cell morphology) and developmental competence after in vitro fertilization in oocytes aspirated from Bos taurus cattle during the hot versus the cool season. However, this was not true for oocytes recovered from Bos indicus cattle.…”

Section: Heat Stressmentioning

confidence: 99%

Factors affecting embryo survival and strategies to reduce embryonic mortality in cattle

Bilodeau‐Goeseels¹,

Kastelic²

2003

Can. J. Anim. Sci.

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Bilodeau-Goeseels, S. and Kastelic, J. P. 2003. Factors affecting embryo survival and strategies to reduce embryonic mortality in cattle. Can. J. Anim. Sci. 83: 659-671. Embryonic mortality in cattle is the death of the conceptus before Day 42 of pregnancy. Estimates of embryonic mortality varied greatly, ranging from 10 to 40% in first-service cattle to 65% in repeat-breeder cows. This paper reviews endogenous causes of embryonic mortality, including chromosomal abnormalities, inadequate corpus luteum function and the influence of follicular development on fertility. External causes of embryonic mortality, including heat stress and nutrition, are also reviewed; these factors act by modifying the follicular environment (thereby affecting oocyte quality) or by creating a hostile uterine environment. Strategies to reduce embryonic mortality, including good management practices and supplementation with progesterone or interferon-tau, are discussed. From a practical perspective, improved knowledge of the causes of embryonic mortality and regulation of follicular growth and corpus luteum function should result in the development of improved, cost-effective hormonal regimes that effectively synchronize estrus and ovulation and reduce embryonic mortality, thereby benefiting the cattle industry.Key words: Cattle, reproduction, fertility, embryo development, embryo mortality Bilodeau-Goeseels, S. et Kastelic, J. P. 2003. Les facteurs affectant la survie de l'embryon et les stratégies pour réduire la mortalité embryonnaire chez la vache. Can. J. Anim. Sci. 83: 659-671. Chez la vache, la mortalité embryonnaire se définie comme étant la perte de l'embryon avant le Jour 42 de la gestation. Les estimations de la mortalité embryonnaire varient grandement, allant de 10 à 40 % chez les vaches à fertilité normale jusqu'à 65 % chez les vaches à fertilité réduite. L'article que voiçi examine les causes endogènes de la mortalité embryonnaire incluant les anomalies chromosomales, le fonctionnement inadéquat du corpus luteum ainsi que l'influence du développement folliculaire sur la fertilité. Des causes externes telles que le stress thermique et la nutrition sont aussi passées en revue; ces facteurs agissent en modifiant l'environnement folliculaire ce qui conduit à une diminution de la qualité de l'ovocyte; ou en créant un environnement utérin hostile pour l'embryon. Des stratégies pour réduire la mortalité embryonnaire telles que la bonne gestion et la supplémentation avec de la progestérone ou de l'interféron-tau sont aussi discutées. Du point de vue pratique, l'augmentation des connaissances sur les causes de la mortalité embryonnaire ainsi que sur la régulation de la croissance folliculaire et du fonctionnement du corpus luteum permettra le développement de régimes hormonaux améliorés et économiques produisant des hauts niveaux de synchronization de l'estrus et/ou de l'ovulation et qui réduiront la mortalité embryonnaire, ce don't bénéficieront les industries laitières et bovines. Mots clés:Bovin, reproduction, fertilité, dévelo...

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High environmental temperature and humidity decrease oocyte quality in but not in cows

Cited by 158 publications

References 32 publications

Morphometric and ultrastructural characterization of Bos indicus preantral follicles

Morphometric and ultrastructural characterization of Bos indicus preantral follicles

164 Influence of Lineage of Oocyte Donor on the Yield and Morphology of Oocytes Recovered by Ultrasound-Guided Follicular Aspiration in Nellore Cows

Factors affecting embryo survival and strategies to reduce embryonic mortality in cattle

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