Embryonic mortality in sheep: a review

Chundekkad, Pavitra; B, Błaszczyk; Stankiewicz, Tomasz

doi:10.3906/vet-1907-123

Cited by 8 publications

(6 citation statements)

References 41 publications

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“…In pregnancy, the corpus luteum formed after ovulation does not undergo luteolysis [5]. The detection of early pregnancy is of great importance in the management of a herd, especially since about 30-50% of embryos do not survive this initial period [6]. Early detection of pregnancy also makes it possible to begin the study of intrauterine development as soon as possible, especially since the pregnant sheep is a valuable biomedical model [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Ultrasound parameters of early pregnancy and Doppler indices of blood vessels in the placenta and umbilical cord throughout the pregnancy period in sheep

Brzozowska

Stankiewicz

et al. 2022

BMC Vet Res

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Background Ultrasonography is one of the most important techniques that enable the detection and monitoring of pregnancy. One such study using this technique is the assessment of the hemodynamics of fetal and umbilical blood vessels. However, there is little data on blood flow in the placentomes, which is the basic structural unit of the sheep’s placenta. Therefore, the aim of this study was to determine the Doppler parameters in the arterial vessels of the caruncles, cotyledons and the umbilical cord as well as measuring venous flow rates during the entire gestation period of the sheep. Additionally, the usefulness of various other ultrasound parameters in the early diagnosis of pregnancy in sheep was analyzed. Results Most of the Doppler parameters in umbilical, cotyledonary and caruncular arteries were significantly correlated with the day of pregnancy (p < 0.01). In the early stages of pregnancy, the peak systolic velocity (PSV), regardless of the location of the artery, was significantly lower than that in the later stages of pregnancy (p < 0.01). PSV was also found to be significantly higher in the umbilical artery than in the cotyledonary and caruncular arteries (p < 0.01). Until the 50th day of pregnancy, the end diastolic velocity (EDV) was not found in the umbilical and cotyledonary arteries. EDV was significantly higher in the caruncular arteries than in the cotyledonary and umbilical arteries (p < 0.01). The resistance index (RI) and pulsatility index (PI) in the early stages of pregnancy were found to be significantly higher than that in the later stages of pregnancy (p < 0.01). The RI and PI were significantly lower in the caruncular arteries than in the arteries of the cotyledons and umbilical cord (p < 0.01). In the umbilical vein, all Doppler parameters were observed to be significantly higher than those in the placentomal veins (p < 0.01 or p < 0.05). Using transrectal ultrasound, pregnancy was detected between 20 and 28 days after mating. The ovaries were observed to have corpora lutea, the diameter of which was fairly consistent from the 17th to the 56th day of pregnancy. Conclusions It has been demonstrated that both the location of the arterial vessel in the placental-umbilical circulation and the gestational age have a significant impact on hemodynamic parameters. The results also provide new insights about the blood flow in caruncular and cotyledonary arteries, which could contribute to a more holistic understanding of hemodynamic changes in the placentas of sheep. Analyzing haemodynamic parameters in the umbilical and placental veins are preliminary studies in sheep, but it could inspire further research in this field. Furthermore, the research conducted confirms the practicality and convenience of transrectal ultrasonography in the early diagnosis of pregnancy in sheep and also indicates that the identification and imaging of the corpus luteum using B-mode ultrasonography can be a very early and simple method of confirming effective mating in sheep.

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Section: Introductionmentioning

confidence: 99%

Ultrasound parameters of early pregnancy and Doppler indices of blood vessels in the placenta and umbilical cord throughout the pregnancy period in sheep

Brzozowska

Stankiewicz

et al. 2022

BMC Vet Res

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“…Nevertheless, studies related to embryo quality remained scarce. In contrast, some studies indicated some factors that play a fundamental role in determining the quality of embryos such as the reproductive status of females (Twigg-Flesner et al 2014), nutritional status (Ashworth et al 2009;Chundekkad et al 2020), age (Hammami et al 2013), reasons related to spermatozoa characteristics used in fertilization (Ervandi et al 2013;Chapuis et al 2017), semen quality (Kusumaningrum et al 2015) and the type of protocol used for super ovulation (Sumantri et al 2011).…”

Section: Discussionmentioning

confidence: 99%

Effect of Combination of Follicle Size, FSH and Cysteamine on In Vitro Production of Sheep Embryos

Mardenli¹,

Mohammad

Alolo

2020

JITV

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The participatory relationship among the follicle size, follicle stimulating hormone (FSH), and cysteamine (antioxidant agent) contribute to the production of embryos characterized by abundance and good quality. The aim of this study was to evaluate the efficacy of FSH, cysteamine and follicle size on <em>in vitro</em> embryo production of Awassi sheep oocytes. Follicles sizes were determined into two groups: small follicles (1-2 mm) and large follicles (> 2 mm). Oocytes were matured across two increasingly shared levels of FSH and cysteamine: A (40 ng/ml + 50 μM) and B (60 ng/ml + 100 μM). Results of the bilateral interaction showed significant differences across the follicle size (large follicles group) and the maturation treatment (B medium) in the rates of fertilization (highest value: 67.51%; p= 0.02), cleavage (highest value: 65.41%; p= 0.01), 2-16 cell stage (lowest value: 2.29%; p= 0.0001), blastocyst stage (highest value: 44.82%; p= 0.04), down to morula stage arrest (lowest value: 55.17%; p= 0.04) and Type I embryos (highest value: 52.87%; p= 0.03). Likewise, matured oocytes of small follicles group (B medium) attained the highest rate of morula stage (56.60%; p= 0.03). No significant differences were observed in Type II and Type III embryos. In order to obtain high yields of good quality embryos, it is advised to add FSH and cysteamine with levels of 60 ng/ml and 100 μM respectively to maturation medium of ovine oocytes obtained from follicles with a diameter > 2 mm.

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“…Lack of fertilization accounts for only 5–10% of reproductive losses. Most of the losses are associated with embryonic deaths, which occur after Day 12 of pregnancy, prolonging the inter-estrous interval, and most ewes cannot mate again within the same season [ 26 ]. The main source of pre-implantation embryonal losses in ewes is associated with inadequate luteal function, and progesterone supplementation may prevent pregnancy losses in this context [ 27 ].…”

Section: Introductionmentioning

confidence: 99%

“…The present study aimed to demonstrate the effectiveness of the first resynchronization in ewes during anestrus. Accordingly, for the purposes of the present study, the second sponge was implanted in the resynchronization groups 14 days after the removal of the first and was retained in the vagina for 12 days, including the period when PGF2α was intensively released in order to prevent losses caused by pre-implantation luteal insufficiencies without a pregnancy diagnosis [ 26 ]. We aimed to reinforce implantation by means of a second sponge and, at the same time, to provide a chance for a second stimulation without delay when pregnancy did not occur.…”

Section: Introductionmentioning

confidence: 99%

Stimulation of Estrus and Ovulation by Resynchronization in Kangal Sheep during Early Anestrus

TAKCI

Dinç

2023

Veterinary Sciences

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A total of 100 Kangal sheep were divided into four groups with the aim of investigating the effectiveness of resynchronization during anestrus for the first time in the literature. The groups were then divided into two further subgroups, namely the resynchronization subgroup group (hCG+resynch) and group (resynch)) and the no resynchronization subgroup (Group (hCG) and group (control)). All the groups started with progesterone-containing sponge insertion on Day 7. The sponge was removed after 7 days (on Day 0), and 600 IU eCG + 131.5 µg PGF2α was injected. The animals in group (hCG+resynch) and group (hCG) received hCG injection at the time of sponge administration. Accordingly, four different groups were established, i.e., resynchronization + hCG administration group (hCG+resynch); n:25), no resynchronization + hCG administration (group (hCG); n:25), resynchronization + no hCG administration (group (resynch); n:25), and no resynchronization + no hCG administration (Group (control); n:25). Estrus rates at the first application in group (hCG+resynch), group (hCG), group (resynch), and group (control) groups were 76%, 88%, 96%, and 76%, respectively, and pregnancy rates were 52%, 64%, 72%, and 60%, respectively; there were no intergroup statistical differences in the two parameters above. It was concluded that resynchronization performed with two consecutive stimulations during anestrus could help save time and provide a pregnancy rate at a level that can provide economic returns.

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Embryonic mortality in sheep: a review

Cited by 8 publications

References 41 publications

Ultrasound parameters of early pregnancy and Doppler indices of blood vessels in the placenta and umbilical cord throughout the pregnancy period in sheep

Ultrasound parameters of early pregnancy and Doppler indices of blood vessels in the placenta and umbilical cord throughout the pregnancy period in sheep

Effect of Combination of Follicle Size, FSH and Cysteamine on In Vitro Production of Sheep Embryos

Stimulation of Estrus and Ovulation by Resynchronization in Kangal Sheep during Early Anestrus

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