Direct Evidence on the Contribution of a Missense Mutation in GDF9 to Variation in Ovulation Rate of Finnsheep

peer-reviewedThe Finnish Landrace (Finnsheep) is a well known high-prolificacy sheep breed and has been used in many countries as a source of genetic material to increase fecundity of local breeds. Analyses to date have indicated that mutations with a large effect on ovulation rate are not responsible for the exceptional prolificacy of Finnsheep. The objectives of this study were to ascertain if: 1) any of 12 known mutations with large effects on ovulation rate in sheep, or 2) any other DNA sequence variants within the candidate genes GDF9 and BMP15 are implicated in the high prolificacy of the Finnish Landrace breed; using material from lines developed by divergent selection on ovulation rate. Genotyping results showed that none of 12 known mutations (FecBB, FecXB, FecXG, FecXGR, FecXH, FecXI, FecXL, FecXO, FecXR, FecGE, FecGH, or FecGT) were present in a sample of 108 Finnsheep and, thus, do not contribute to the exceptional prolificacy of the breed. However, DNA sequence analysis of GDF9 identified a previously known mutation, V371M, whose frequency differed significantly (P<0.001) between High and Low ovulation rate lines. While analysis of ovulation rate data for Finnsheep failed to establish a significant association between this trait and V371M, analysis of data on Belclare sheep revealed a significant association between V371M and ovulation rate (P<0.01). Ewes that were heterozygous for V371M exhibited increased ovulation rate (+0.17, s.e. 0.080; P<0.05) compared to wild type and the effect was non-additive (ovulation rate of heterozygotes was significantly lower (P<0.01) than the mean of the homozygotes). This finding brings to 13 the number of mutations that have large effects on ovulation rate in sheep and to 5, including FecBB, FecGE, FecXO and FecXGR, the number of mutations within the TGFβ superfamily with a positive effect on prolificacy in the homozygous state

Functional Analysis of MicroRNA Pathway Genes in the Somatic Gonad and Germ Cells During Ovulation in \u3cem\u3eC. Elegans\u3c/em\u3e

MicroRNAs (miRNAs) are post-transcriptional regulators of gene expression that play critical roles in animal development and physiology, though functions for most miRNAs remain unknown. Worms with reduced miRNA biogenesis due to loss of Drosha or Pasha/DGCR8 activity are sterile and fail to ovulate, indicating that miRNAs are required for the process of oocyte maturation and ovulation. Starting with this penetrant sterile phenotype and using new strains created to perform tissue specific RNAi, we characterized the roles of the C. elegans Pasha, pash-1, and two miRNA-specific Argonautes, alg-1 and alg-2, in somatic gonad cells and in germ cells in the regulation of ovulation. Conditional loss of pash-1activity resulted in a reduced rate of ovulation and in basal and ovulatory sheath contractions. Similarly, knockdown of miRNA-specific Argonautes in the cells of the somatic gonad by tissue-specific RNAi results in a reduction of the ovulation rate and in basal and ovulatory sheath contractions. Reduced miRNA pathway gene activity resulted in a range of defects, including oocytes that were pinched upon entry of the oocyte into the distal end of the spermatheca in about 42% of the ovulation events observed following alg-1 RNAi. This phenotype was not observed on worms exposed to control RNAi. In contrast, knockdown of alg-1 and alg-2 in germ cells results in few defects in oocyte maturation and ovulation. These data identify specific steps in the process of ovulation that require miRNA pathway gene activity in the somatic gonad cells

Reproductive management in pigs: emphasis on the different roles of the boar and on optimal insemination management

Boars have different roles in the reproductive management in pigs. Boar contact can stimulate follicle development and thereby induce oestrus, both in gilts and sows. Boar contact during oestrus is essential for good oestrus expression, which is essential for the correct timing of insemination and the proper use of boar contact during insemination can stimulate sperm transport and thereby fertilisation. Stimulation by boars clearly has an olfactory component (the boar smell), but can also have an auditory, visual and evn tactile component. The background of the different roles and some of these different components of the boar are discussed. To enable a good farrowing rate and litter size, sows should be inseminated between 0 and 24h before ovulation. However, it is not possible to accurately predict the time of ovulation in sows. Although ovulation takes place at a relatively fixed 60-75% of the duration of oestrus, the duration of oestrus varies considerably between sows and between farms, resulting in a variable ovulation time from onset of oestrus. Therefore, most farmers inseminate their sows every day of oestrus to ensure insemination within the optimal period. Since post-ovulation inseminations should be avoided, it is adviced to only inseminate sows while they still show an optimal standing respons

A Comparison of the Ovulation Method With the CUE Ovulation Predictor in Determining the Fertile Period

The purpose of this study was to compare the CUE Ovulation Predictor with the ovulation method in determining the fertile period. Eleven regularly ovulating women measured their salivary and vaginal electrical resistance (ER) with the CUE, observed their cervical-vaginal mucus, and measured their urine for a luteinizing hormone (LH) surge on a daily basis. Data from 21 menstrual cycles showed no statistical difference (T= 0.33, p= 0.63) between the CUE fertile period, which ranged from 5 to 10 days (mean = 6.7 days, SD = 1.6), and the fertile period of the ovulation method, which ranged from 4 to 9 days (mean = 6.5 days, SD = 2.0). The CUE has potential as an adjunctive device in the learning and use of natural family planning methods

Ovarian Dynamic in Ongole Grade Cattle After GnRH Injection in Ovsynch Protocol Based on Progesterone Device

PO cattle have weaknesses to show clear estrus signs which cause difficulty in artificial insemination implementation. The present study was designed to obtain ovarian dynamic as effect of GnRH injection in ovsynch protocol based on progesterone intravaginal device. Heifers (18) and cows (n= 12) were allocated to one of three groups. Cuemate-PGF2α (CP) group inserted with a Cuemate on day 0-7 and injected with prostaglandin on day 7. Cuemate-PGF2α-GnRH (CPG) group was treated as CP group with the addition of GnRH injection on day 9. GnRH-Cuemate-PGF2α-GnRH (GCPG) group was treated as CPG group with addition of GnRH injection on day 0. Ultrasonography was performed on days 0-3, day 7 until ovulation and 7 days after ovulation. Percentage of ovulation synchronization increased significantly (P&lt;0.01) between CP, CPG, and GCPG, respectively, both in heifers (16%, 50%, and 85%, respectively) and cows (0%, 60%, and 100%, respectively), on day 11. Preovulatory follicle diameters between CP, CPG, and GCPG treatments were not different significantly both in heifers (11.9±0.5, 11.9±0.5, and 12.1±0.6 mm, respectively) and cows (11.7±0.4, 11.8±0.7, and 11.1±0.6 mm, respectively). This study concluded that GCPG protocol increased the synchrony of ovulation rate both in cows and heifers, without affecting the follicle preovulatory and CL diameters

Accuracy of the Peak Day of Cervical Mucus as a Biological Marker of Fertility

The (PD) peak day of cervical mucus is an important biologic marker for the self-determination of the optimal time of fertility in a woman’s menstrual cycle. The purpose of this article is to provide evidence (literature and empiric) for the accuracy of the PD of cervical mucus as a biologic marker of peak fertility and the estimated day of ovulation. An analysis of data from four published studies that compared the self-determination of the PD of cervical mucus with the urinary luteinizing hormone (LH) surge was conducted. The four studies yielded 108 menstrual cycle charts from 53 women participants. The 108 cycles ranged in length from 22 to 75 days (mean 29.4 SD 6.0). Ninety-three of the 108 cycles had both an identified PD and LH surge. Data charts showed that 97.8% of the PD fell within ±4 days of the estimated day of ovulation. Use of a standardized mucus cycle scoring system indicated that the peak in cervical mucus ratings was highest on the day of the LH surge. Self-determination of the PD of cervical mucus is a very accurate means of determining peak fertility and a fairly accurate means of determining the day of ovulation and the beginning of the end of the fertile time