Reproductive cycles in Bos indicus cattle

Sartori, Roberto; Barros, C. M.

doi:10.1016/j.anireprosci.2011.02.006

Cited by 88 publications

(63 citation statements)

References 45 publications

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“…It does not appear that a reduction in the diameter of the ovulatory follicle is a determining factor for infertility (Sartori et al 2001;Perry et al 2005) as long as a minimal value close to 10 mm is observed (Martinez et al 1999;Sartori et al 2001). Thus, in Senepol cattle (B. taurus) and Nelore cattle (B. indicus), ovulation of the follicle with a diameter less than 8.5 mm is considered as physiological (Sartori and Barros 2011). Similarly, in the Zebu Nelore, gestations have been observed after ovulation of follicles with a diameter less than 7.5 mm (Sá Filho et al 2010c).…”

Section: Discussionmentioning

confidence: 99%

“…Similarly, in the Zebu Nelore, gestations have been observed after ovulation of follicles with a diameter less than 7.5 mm (Sá Filho et al 2010c). However, reduction in the diameter of the ovulating follicle may be accompanied by progesteronaemia (Sartori and Barros 2011). An increase in the LH effect resulting from the injection of eCG (Sheldon and Dobson 2000;Rostami et al 2011) induces the ovulation of follicles with a smaller diameter (Perry et al 2005).…”

Section: Discussionmentioning

confidence: 99%

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Preovulatory follicle diameter, growth rate and time of ovulation during induced oestrus using a CIDR® in trypanotolerant female Bos taurus N’Dama cattle

Okouyi

Drion

Hanzen

2015

Trop Anim Health Prod

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The aim of this study was to assess the dose (300 to 600 IU) effects of equine chorionic gonadotropin (eCG) on the preovulatory follicle diameter, growth rate and time of ovulation characterized by echography. The eCG was injected at the end (D 0 ) of the 7-day treatment with a controlled internal device release (CIDR®) and a PGF 2α being injected 2 days before the removal of the CIDR® (d −2 ). The 120 N'Dama female were distributed into five experimental groups. The control group (n=26) was treated with physiological saline at the removal of the CIDR®, while the animals in the four treated groups received, respectively, 300 IU (n=25), 400 IU (n=24), 500 IU (n=22) and 600 IU (n=23) of eCG. The diameter of the preovulatory follicle was significantly higher (P<0.05) in the animals treated with 300 IU (10.1±1.4 mm) than in untreated animals (9.3±1.2 mm). Follicle growth rate was significantly (P<0.05) higher in treated animals (1.0± 0.4 mm/day) than in the control group (0.9±0.4 mm/day). The average interval between the time of eCG injection and ovulation was similar in the non-treated (83.7±14.4 h) and treated animals (79.7±11.9). Treated animals showed a significant increase in the percentage of ovulation (94.7 % compared to 73.1 %) (P<0.01). Use of eCG contributed towards synchronising the time of ovulation between 72 to 96 h, which would facilitate the use of systematic insemination.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Preovulatory follicle diameter, growth rate and time of ovulation during induced oestrus using a CIDR® in trypanotolerant female Bos taurus N’Dama cattle

Okouyi

Drion

Hanzen

2015

Trop Anim Health Prod

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“…Secondly, the P4 concentrations in both biopsied groups (B4 and B7) showed a sharp decrease from Days 7-8 to Day 10, without showing a plateau phase (Figueiredo et al, 1997, Sartori andBarros, 2011), followed by fluctuations of P4 between Day 11-to Day 16.…”

Section: Discussionmentioning

confidence: 99%

“…According to Figueiredo et al (1997), P4 concentration increased steadily from the second day post-ovulation and reached a plateau at approximately Days 8 to 16, remaining elevated until luteolysis, which occurred between Days 16 and 19 of the oestrous cycle (Sartori and Barros, 2011). Martin et al (2008) characterised the circulating P4 during the normal oestrous cycle in Nellore heifers.…”

Section: Discussionmentioning

confidence: 99%

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63 Effect of Endometrial Biopsy on Uterine Health of Tropically Adapted Beef Cattle

Ramirez-Garzon

Satake

Lyons

et al. 2017

Reprod. Fertil. Dev.

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In cattle, early embryonic loss during the first two to three weeks after fertilisation is recognised as the major cause of reproductive failure, with consequent significant impacts on business performance of beef and dairy farms. Inadequate endometrial receptivity is considered an important cause of early embryonic mortality in cattle. A pilot experiment was conducted to compare the outcome of performing different endometrial sampling procedures in tropically adapted (Bos indicus x Bos taurus) heifers, and to select the most suitable method to collect samples for investigation of endometrial gene expression. Endometrial biopsy (EB) using a biopsy device with a diameter similar to an artificial insemination gun (10366L Karl Storz®, Germany) was found to be the most reliable method of collecting endometrial samples in these heifers, with the samples recovered yielding a mean concentration of RNA of 72.9 ±39.3 ng/µl and mean RNA integrity number (RIN) of 7.3 ±1.1.To assess the likely safety of conducting EB in cattle a systematic review of published information assessing the impact of EB on subsequent pregnancy rates was conducted. Using the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) protocol, online searches identified 1164 possible studies. After applying the exclusion criteria, six studies allowed the comparison of pregnancy rates between sampled (n= 1,208) and non-sampled cows (n=2,393). The results showed that EB can be performed before breeding without adversely affecting the likelihood of cows becoming pregnant.A major objective of the research was to determine whether EB and evaluation of endometrial gene expression could be used to identify tropically adapted embryo transfer (ET) recipients more likely to become pregnant. Three potential EB scenarios were investigated, 1) EB on Day 7 of the oestrous cycle prior to the cycle when ET would be performed, 2) EB on Day 4 of the oestrous cycle in which ET would be performed i.e. EB 3 days before ET, and 3) EB on the same day when ET would be performed.The first study assessed the morphological and inflammatory changes induced by endometrial biopsy. Pre-synchronised heifers underwent EB from the horn ipsilateral to the corpus luteum (CL) either at Day 7 of the previous cycle (Group 1 n=10) followed by administration of a luteolytic dose of prostaglandin F2α or at Day 4 (Group 2, n=7) of the present cycle. All heifers were slaughtered on Day 7 of the present cycle. The site of EB was visually evident in 40% (4/10) of Group 1 and 42% (3/7) of Group 2 heifers. Histological assessment revealed no evidence of changes indicative of endometritis in either the biopsied or non-biopsied horns in both groups. The histological iii changes observed included mild mononuclear infiltration of the epithelium and mild vascular changes associated with haemorrhage and congestion.Initial investigation of the endometrial expression of the pro-inflammatory cytokine IL1β and wound healing cytokine TGFβ genes found no significant difference betwe...

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The methylation patterns of the IGF2 and IGF2R genes in bovine spermatozoa are not affected by flow‐cytometric sex sorting

Carvalho

Michalczechen-Lacerda

Sartori

et al. 2011

Molecular Reproduction Devel

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The objectives of this study were to investigate the effect of sexing by flow cytometry on the methylation patterns of the IGF2 and IGF2R genes. Frozen-thawed, unsorted, and sex-sorted sperm samples from four Nellore bulls were used. Each ejaculate was separated into three fractions: non-sexed (NS), sexed for X-sperm (SX), and sexed for Y-sperm (SY). Sperm were isolated from the extender, cryoprotectant, and other cell types by centrifugation on a 40:70% Percoll gradient, and sperm pellets were used for genomic DNA isolation. DNA was used for analyses of the methylation patterns by bisulfite sequencing. Methylation status of the IGF2 and IGF2R genes were evaluated by sequencing 195 and 147 individual clones, respectively. No global differences in DNA methylation were found between NS, SX, and SY groups for the IGF2 (P = 0.09) or IGF2R genes (P = 0.38). Very specific methylation patterns were observed in the 25th and 26th CpG sites in the IGF2R gene. representing higher methylation in NS than in the SX and SY groups compared with the other CpG sites. Further, individual variation in methylation patterns was found among bulls. In conclusion, the sex-sorting procedure by flow cytometry did not affect the overall DNA methylation patterns of the IGF2 and IGF2R genes, although individual variation in their methylation patterns among bulls was observed.

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Reproductive cycles in Bos indicus cattle

Cited by 88 publications

References 45 publications

Preovulatory follicle diameter, growth rate and time of ovulation during induced oestrus using a CIDR® in trypanotolerant female Bos taurus N’Dama cattle

Preovulatory follicle diameter, growth rate and time of ovulation during induced oestrus using a CIDR® in trypanotolerant female Bos taurus N’Dama cattle

63 Effect of Endometrial Biopsy on Uterine Health of Tropically Adapted Beef Cattle

The methylation patterns of the IGF2 and IGF2R genes in bovine spermatozoa are not affected by flow‐cytometric sex sorting

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