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The present study aimed to assess the relationship of Growth Differentiation Factor 9 (GDF9) genotypes with calving rate, Follicle-stimulating hormone (FSH), and Estradiol (E2) in the Iraqi Holstein-Friesian breed. A number of 15 blood samples were collected from a mother of dizygotic twin birth (DZTB) (with high calving rate records), and another blood sample was collected from 15 single birth (SB) cows. The DNA was extracted and six primers were designed for PCR and sequencing analysis. The FSH and E2 levels were tested through the estrus phase for the two groups (n=10 in each group). The sequence evaluation revealed the presence of two single nucleotide polymorphisms (SNPs) in exon II: A (1109) T and G (1133) A. The genotypic frequency for mutant genotypes was higher significantly (P<0.01) in DZTB cows (with calving rate), as compared to wild genotypes at the same loci. On the other hand, the wild genotypes recorded a significant increment (P<0.01) for SB cows, when compared to mutant genotypes in the same loci. Moreover, a significant rise (P<0.05) was reported in E2 and FSH levels for DZTB cows and mutant genotypes (P<0.01) against SB cows and wild genotypes in 0 and 24 h of estrus phase, respectively. Furthermore, non-significant differences were recorded in E2 concentration among the same genotypes at the same period. In conclusion, the GDF9 exon II SNPs increased the calving rate in Holstein-Friesian cows. The blood FSH and E2 concentrations were higher in the DZTB cows and control the superovulation. Finally, these SNPs can be regarded as markers to accelerate the breeding programs and used in embryo transfer and in vitro embryo production for Iraqi Holstein-Friesian cow breed.

The application of assisted reproductive technology in animal production benefits the economy and conservation of biological resources. Single nucleotide polymorphism (SNPs) was used as predictive markers for breeding and reproduction. In the present study, we examined the association between a SNP of the grb10 gene and superovulation traits in cattle. Sequencing results indicated a point mutation and statistical analysis showed a significant association of the mutation with superovulation traits. The high number of embryos collected from the heterozygotes suggested that the mutation in the grb10 gene exerted a significant effect on the number of embryos recovered although the quality was not affected. The grb10 gene may serve as a useful biomarker for donor selection.

In dairy cows, there is evidence that failure to respond to superovulation protocols is a heritable trait. In women, genotyping for the p.N680S single nucleotide polymorphism (SNP) in the follicle-stimulating hormone receptor (FSHR) gene may help identify poor responders before ovarian stimulation is initiated. Our objectives were to identify SNPs in the coding region of the bovine FSHR gene and to investigate the effect of FSHR genotypes on superovulatory response in Holstein cattle. Sequencing of FSHR exons 1-10 revealed seven SNPs. Three were non-synonymous mutations (c.337C>G, c.871A>G and c.1973C>G). SNP c.337C>G encodes for a proline-to-alanine (p.Pro113Ala) amino acid replacement in the extracellular ligand-binding domain of the receptor. PCR-RFLP analyses showed that homozygous GG Holstein cows present a higher percentage of viable embryos, whereas GG and CG animals have less unfertilised oocytes. SNP c.871A>G results in an isoleucine-to-valine (p.Ile291Val) modification, and homozygous AA animals present lower embryo yield after superovulatory treatments. SNP c.1973C>G corresponds to a threonine-to-serine (p.The658Ser) modification in the intracellular carboxyl-terminal domain of the FSHR protein, and homozygous GG Holstein cows were associated with a lower embryo yield and a higher percentage of unfertilised oocytes. Our results suggest that specific alleles of the bovine FSHR gene are associated with variations in embryo yield and in the number of unfertilised oocytes., (© 2012 The Authors, Animal Genetics © 2012 Stichting International Foundation for Animal Genetics.)

To identify a predictor to forecast superovulation response on the basis of associations between superovulation performance and gene polymorphism, variation in the bovine follicle stimulating hormone receptor (FSHR) gene was investigated using PCR-single-strand conformational (PCR-SSCP) and DNA sequencing. One single nucleotide polymorphism (SNP) of G-278A located in the 5' upstream region of bovine FSHR gene was found in 118 Chinese Holstein cows treated for superovulation. Two SNPs of G-278A (GU253337) and A-320T (rs43676359) were analyzed. In polymorphic locus -278, all cows without superovulation response were mutations with genotypes of CD and DD. Cows with CC genotype had a significant increase in the total number of ova (TNO) (P<0.01), and produced more transferable embryos (NTE) than those of the CD and DD genotypes (P<0.01). At this locus, the additive effects seemed to be highly significant (P<0.01) and allele C was associated with an increase in the TNO and NTE. These results indicated that the FSHR is a potential marker for superovulation response and can be used as a predictor for superovulation in Chinese Holstein cows., (Copyright (c) 2010 Elsevier B.V. All rights reserved.)