Genetic variation of GPLD1 associates with serum GPI-PLD levels: a preliminary study

HDL is a heterogeneous mixture of lipoprotein particles varying in composition, size, and function. We and others have described a small (7.0nm), minor (0.1% of total apolipoprotein AI) particle containing apolipoprotein AI, AIV and glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD) in humans the function of which is not entirely known. Circulating GPI-PLD levels are regulated by multiple factors including genetics. To determine if genetic variation in GPLD1 affects circulating GPI-PLD levels, we examined the relationship between 32 SNPS upstream, within, and downstream of GPLD1 and circulating GPI-PLD levels in Caucasians (n=77) and African-Americans (n=99). The genotype distribution among races differed at 13 SNPs. Nine SNPS were associated with circulating GPI-PLD levels in Caucasians but not African-Americans. These results suggest that genetic variation of GPLD1 appears to associate with circulating GPI-PLD levels. This article is part of a Special Issue entitled Advances in High Density Lipoprotein Formation and Metabolism: A Tribute to John F. Oram (1945-2010).     

Impact of cytokine and cytokine receptor gene polymorphisms on cellular immunity after smallpox vaccination

We explored associations between SNPs in cytokine/cytokine receptor genes and cellular immunity in subjects following primary smallpox vaccination. We also analyzed the genotype–phenotype associations discovered in the Caucasian subjects among a cohort of African-Americans. In Caucasians we found 277 associations (p < 0.05) between gene SNPs and inter-individual variations in IFN-α, IL-12p40, IL-1β, IL-2, and TNF-α secretion levels. A collection of SNPs in the IL1RN, IL2RB, IL4R, IL6, IL10RB, IL12A, and IL12RB2 genes had consistent associations among both Caucasians and African-Americans. A regulatory SNP (rs452204) in the IL1RN gene was significantly associated with higher levels of IL-2 secretion in an allele dose-dependent manner in both race groups (p = 0.05 for Caucasians and p = 0.002 for African-Americans). IL12RB2 polymorphism rs3790567 was associated with a dose-related decrease in IL-1β secretion (p = 0.009 for Caucasians and p = 0.01 for African-Americans). Our results demonstrate that variations in smallpox vaccine-induced cytokine responses are modulated by genetic polymorphisms in cytokine and cytokine receptor genes.     

Population genetic differentiation of Schisandra chinensis and Schisandra sphenanthera as revealed by ISSR analysis

Schisandra chinensis (Turcz.) Baill. and Schisandra sphenanthera Rehd. et Wils. are well-known Chinese medicinal plants. The population genetic variation of the two species was studied using inter simple sequence repeat (ISSR) molecular markers. High levels of genetic diversity are revealed in both S. chinensis (P = 88.36%, h = 0.2894, I = 0.4396) and S. sphenanthera (P = 84.09%, H = 0.2782, I = 0.4280). However, the population genetic differentiation is significantly different between the two species. The S. sphenanthera harbors as high as 27% of the genetic variation among populations but 73% within populations, whereas in S. chinensis 17% of the genetic variation occurs among populations and 83% within populations. Both significant (P < 0.05) heterozygosity excess and shifted mode of allele frequency distribution are detected in four out of six populations of S. chinensis and one out of five populations of S. sphenanthera, suggesting the occurrence of recent population bottlenecks in the two species. The different patterns of genetic variation in S. chinensis and S. sphenanthera are discussed in relation to their differences in pollination mechanism, geographic distribution and historical events, and the level of gene flow and genetic drift.     

GnRH treatment at artificial insemination in beef cattle fails to increase plasma progesterone concentrations or pregnancy rates

Treatment with GnRH at the onset of standing estrus increased pregnancy percentages and circulating concentrations of progesterone in repeat breeder dairy cows. The objective of this study was to determine the effect of treatment with GnRH at AI on concentrations of progesterone and conception rates in beef cattle that exhibited estrus. Two hundred ninety-three heifers at four locations were synchronized with the Select Synch plus CIDR protocol (given GnRH and a CIDR was placed into the vagina, and 7 d later, given PGF_2α and CIDR removed; n = 253) or the 14-19 melengestrol acetate (MGA) protocol (MGA fed at 0.5 mg/head/d for 14 d, with PGF_2α 19 d after MGA withdrawal n = 40) and AI was done after detection of estrus. At Location 1, blood samples were collected on Day 2, 4, 6, 10, 15, and 18 after AI (Day 0 = AI). Two hundred and fifty postpartum cows at two locations were synchronized with the Select Synch plus CIDR protocol, and AI was performed after detection of estrus. At AI, cattle were alternately assigned to one of two treatments: (1) treatment with GnRH (100 μg) at AI (n = 127 heifers and n = 108 cows); or (2) non-treated control (n = 120 heifers and n = 119 cows). Concentrations of progesterone tended to be greater in control heifers compared to GnRH-treated heifers on Days 6 (P = 0.08), 10 (P = 0.07), and 15 (P = 0.11). Overall conception rates were 68% and 66% for GnRH treated and control, respectively, and were not different between treatments (P = 0.72). In summary, treatment with GnRH at time of AI had no influence on conception rates in cattle that had exhibited estrus.     

Genetic diversity of the endangered species Kirengeshoma palmata (Saxifragaceae) in China

In order to investigate the levels of genetic diversity of the endangered species Kirengeshoma palmata (Saxifragaceae), four extant populations were sampled and analyzed using inter-simple sequence repeats (ISSR) markers. We expected a low genetic diversity level, but our results revealed a high level of intraspecific genetic diversity, probably resulting from this species being in a refuge during the last glaciation (at population level: P = 63.25%, A_e = 1.47, H_E = 0.26 and H_O = 0.37; at species level: P = 79.00%, A = 1.5538, H_T = 0.2586 and H_sp = 0.3104). A low level of genetic differentiation among populations was detected based on Nei's genetic diversity analysis (16.69%) and AMOVA (19.36%). Populations shared high levels of genetic identity. Insect pollination and seed dispersal by wind may have facilitated extensive gene flow and are likely responsible for this present structure of genetic variation.     

Chromosomal rearrangements associated with pelagic larval duration in Labridae (Perciformes)

The family Labridae is one of the largest and most important groups of reef fishes in the Southern Atlantic. There is a remarkable ecologic interest in this family because of their complex interactions in the reef environment. Predictions of genetic variability in fish based on biological patterns have often been contradictory. The present work aimed to increase the cytogenetic data about the family and verify the possible correlation between larval pelagic phase and chromosomal rearrangements based on the putative basal Perciformes karyotype (2n = 48a). Therefore, cytogenetic analyses were performed in the species Halichoeres brasiliensis (2n = 48, 48a, FN = 48); Halichoeres radiatus (2n = 48, 48a, FN = 48) and in three populations of Halichoeres poeyi (2n = 48, 4m + 44st-a, FN = 52) from Brazilian coastline. A conserved diploid number was observed in all species and populations. Single NORs were identified in H. brasiliensis and in two populations of H. poeyi (BA and RJ), while multiple NORs were observed in H. radiatus and in H. poeyi from Rio Grande do Norte. The constitutive heterochromatin is reduced and distributed over centromeric and pericentromeric regions. The ribosomal sites allowed differentiating two groups of H. poeyi along the Brazilian coast; one of them comprising the population from RN, bearing multiple NORs, and another representing the populations from BA and RJ, bearing single NORs. The recently separated species, H. brasiliensis and H. radiatus, although presenting similar diploid numbers and chromosomal formulae, could be distinguished by the number of NOR-bearing chromosomes. The results revealed an evolutionary pattern chiefly derived from pericentric inversions. The correlation between larval pelagic phase and cytogenetic data on Labridae indicates that the degree of karyotypic diversification reported within this family, ranging from a highly conserved to a derived pattern, is probably influenced by the species-specific duration of larval pelagic phase.     

Genetic diversity of Aegiceras corniculatum (Myrsinaceae) revealed by amplified fragment length polymorphism (AFLP)

Aegiceras corniculatum is a cryptoviviparous mangrove tree distributed in the Indo-West Pacific. The genetic structure of 13 populations of A. corniculatum from South China, Malay Peninsula, Sri Lanka, and North Australia, was assessed by amplified fragment length polymorphism (AFLP) markers. Our results showed a relatively high level of genetic variation at the species level (P = 92%, H_E = 0.294 and H_s = 0.331 ± 0.001). The value of G_ST was 0.698, suggesting significant genetic differentiation among populations. At the population level, however, genetic diversity was low (P = 24%, H_E = 0.086 and H_s = 0.127 ± 0.001). When populations were grouped according to geographic regions, i.e., South China, Malay Peninsula and Sri Lanka, it was inferred from analysis of molecular variance (AMOVA) that about half the total variation (49%) was accounted for differentiation between regions. A UPGMA dendrogram based on genetic distance also revealed five major clades corresponding to geographical regions within the distribution of A. corniculatum, although the precise relationships among the clades were not fully concordant with expected geographical delineations and need further study.     

Combined effects of four SNPs within goat PRLR gene on milk production traits

Xinong Saanen (SN, n = 323) and Guanzhong (GZ, n = 197) goat breeds were used to detect single nucleotide polymorphisms (SNPs) in the coding regions with their intron–exon boundaries of prolactin receptor (PRLR) gene by DNA sequencing, primer-introduced restriction analysis-polymerase chain reaction (PIRA-PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP). Four novel SNPs (g.40452T > C, g.40471G > A, g.61677G > A and g.61865G > A) were identified. The g.61677G > A and g.61865G > A SNPs caused amino acid variations p.Ser485Asn and p.Val548Met, respectively. Both g.40452T>C and g.40471G>A loci were closely linked in SN and GZ goat breeds (r² > 0.33). In addition, there was also a close linkage between g.61677G>A and g.61865G>A loci in both goat breeds. Statistical results indicated that the g.40452T > C, g.61677G > A and g.61865G > A SNPs were significantly associated with milk production traits in SN and GZ breeds. Further analysis revealed that combinative genotype C1 (TTAAGGGG) was better than the others for milk yield in SN and GZ goat breeds. These results are consistent with the regulatory function of PRLR in mammary gland development, milk secretion, and expression of milk protein genes, and extend the spectrum of genetic variation of the caprine PRLR gene, which might contribute to goat genetic resources and breeding.     

Marinobufagenin is an upstream modulator of Gadd45a stress signaling in preeclampsia

Preeclampsia (PE) is a hypertensive disorder of pregnancy, in which marinobufagenin (MBG), a circulating cardiotonic steroid, is increased. The Gadd45a stress sensor protein is an upstream modulator of the pathophysiological changes observed in PE. However, the effects of MBG on Gadd45a stress signaling remain unknown. We examined the expression of Gadd45a, the sFlt-1 receptor, and p38, as well as caspase 3 and 8 activities in placental samples from four groups of rats. These were: normal pregnant (NP, n = 8); pregnant rats which received weekly injections of desoxycorticosterone acetate and 0.9% saline as their drinking water (PDS, n = 9); normal pregnant rats injected with MBG (NPM, n = 8); and PDS rats injected with resibufogenin (RBG), an in vivo antagonist of MBG (PDSR, n = 8). Utilizing human cytotrophoblast (CTB) cells, we examined the effect of MBG on these stress signaling proteins in vitro. Placental Gadd45a expression, caspase 3 and 8 activities, sFlt-1 concentrations, and sFlt-1 receptor expression were significantly higher in PDS and NPM compared to NP and PDSR rats. Gadd45a protein was significantly upregulated in the CTB cells when MBG was present in concentrations ≥1 nM. Treatment with MBG (≥ 1 nM) also significantly arrested cell cycle progression and activated the expression of the Gadd45a-mediated stress signaling proteins. Inhibition of Gadd45a through RNAi-mediation attenuated MBG-induced CTB cell stress signaling. In conclusion, MBG is involved in the alteration in Gadd45a stress signaling both in vivo and in vitro and RBG prevents these changes when administered in vivo.     

NLF2 gene expression in the endometrium of patients with implantation failure after IVF treatment

The aim of this study was to analyze the expression of microfibril-associated protein 2 (MFAP2), microfibril-associated protein 5 (MFAP5) and nuclear localized factor 2 (NLF2) genes in patients with repeated IVF failure and compare with fertile population. Total RNA was isolated from 38 patients (repeated implantation failure, group 1, n = 22; fertile patients, group 2, n = 16). mRNA expression levels were measured quantitatively using real-time polymerase chain reaction. Our results showed that mRNA expression of NLF2 significantly decreased in the infertility group as compared to control group (P = 0.023). In addition a marked decrease was observed in the expression of MFAP2 in women with repeated implantation failure. In conclusion, NLF2 gene expression levels and differences in MFAP2 and MFAP5 gene expressions (albeit being insignificant) between infertile group and control group draw attention to a genetic basis under implantation failure.     

Phosphorylation decreases trypsin activation and apolipoprotein al binding to glycosylphosphatidylinositol-specific phospholipase D.

Glycosylphosphatidylinositol-specific phospholipase D (GPI-PLD) is present in plasma as an apolipoprotein and as a cell-associated lipase. GPI-PLD mRNA levels are regulated, but it is unclear if posttranslational mechanisms also regulate GPI-PLD function. We examined the effect of protein kinase A phosphorylation on human serum GPI-PLD activity, trypsin activation, and apolipoprotein AI binding. Protein kinase A phosphorylation did not activate GPI-PLD activity in vitro, nor did phosphorylated GPI-PLD cleave a GPI-anchored protein from intact porcine erythrocytes. Trypsin cleaves the C-terminal beta propeller of purified human serum GPI-PLD to generate three immunodetectable fragments (75, 28, and 18 kDa) in association with a 12-fold increase in enzyme activity. After phosphorylation, the amounts of 28- and 18-kDa fragments were markedly decreased with trypsin treatment, and activity was only increased five-fold. Phosphorylation also inhibits binding of GPI-PLD to apolipoprotein AI. These data are the first demonstrating that phosphorylation may regulate GPI-PLD interaction with other proteins.     

Genetic diversity and biogeography of the traditional Chinese medicine, Gardenia jasminoides, based on AFLP markers

Gardenia jasminoides Ellis is used in traditional Chinese medicine (TCM) in China. Levels of genetic variation and patterns of population structure within and among eight wild or cultivated populations of G. jasminoides Ellis in China were investigated using amplified fragment length polymorphism (AFLP) markers. Of the 11 primers screened, four produced highly reproducible AFLP bands. Using these primers, 244 discernible DNA fragments were generated with 165 bands (67.6%), were polymorphic, indicating considerable genetic variation at the species level. In contrast, there were relatively low levels of polymorphism at the population level with the percentage of polymorphic bands (PPB) ranging from 36.89% to 59.43%. Genetic diversity within populations ranged from 0.2086 to 0.3108, averaging 0.2392 at the species level. A high level of genetic differentiation among populations was detected based on Nei's genetic diversity analysis (76.59%), Shannon's index analysis (64.8%) and AMOVA analysis (72.75%). No significant statistical differences (analysis of molecular variance [AMOVA], p = 0.0639) in AFLP variation were found between regions. However, the variance among populations and within populations differed significantly (p < 0.001). An indirect estimate of historical levels of gene flow (N_m = 1.7448) was consistent with the high mean genetic identity (mean I = 0.9263) found among populations. There is an association between geographic and genetic distances between populations. Presently gene change exists between populations.     

Evidence of expression variation and allelic imbalance in Crohn's disease susceptibility genes NOD2 and ATG16L1 in human dendritic cells

Human dendritic cells (DCs) play an important role in induction and progression of Crohn's disease (CD). Accumulating evidence suggests that viral infection is required to trigger CD pathogenesis in genetically predisposed individuals. NOD2 and ATG16L1 are among the major CD susceptibility genes implicated in impaired immune response to bacterial infection. In this study, we investigated gene expression and allelic imbalance (AI) of NOD2 and ATG16L1 using common variants in human monocyte-derived DCs. Significant AI was observed in ~ 40% and ~ 70% of NOD2 and ATG16L1 heterozygotes, respectively (p < 0.05). AI of NOD2 was inversely associated with its expression level (p = 0.015). No correlation was detected between gene expression and AI for ATG16L1. When infected with Newcastle Disease Virus (NDV), NOD2 expression in DCs was induced about four-fold (p < 0.001), whereas ATG16L1 expression was not affected (p = 0.88). In addition, NDV infection tended to lower the variance in AI among DC populations for the NOD2 gene (p = 0.05), but not the ATG16L1 gene (p = 0.32). Findings of a simulation study, aimed to verify whether the observed variation in gene expression and AI is a result of sample-to-sample variability or experimental measurement error, suggested that NOD2 AI is likely to result from a deterministic event at a single cell level. Overall, our results present initial evidence that AI of the NOD2 and ATG16L1 genes exists in populations of human DCs. In addition, our findings suggest that viral infection may regulate NOD2 expression.     

Rates of luteolysis and pregnancy in dairy cows after treatment with cloprostenol or dinoprost

Our objective was to determine whether rates of luteolysis or pregnancy differed in lactating dairy cows of known progesterone status and either known or unknown luteal status after either cloprostenol or dinoprost was injected as part of a timed-insemination program. In Experiment 1, 2358 lactating dairy cows in six herds were given two injections of PGF_2α 14 d apart (Presynch), with the second injection given 12 to 14 d before the onset of a timed AI protocol (Ovsynch). Cows (n = 1094) were inseminated when detected in estrus after the Presynch PGF_2α injections. Cows not inseminated (n = 1264) were enrolled in the Ovsynch protocol and assigned randomly to be treated with either cloprostenol or dinoprost as part of the timed-AI protocol. In cows having pretreatment concentrations of progesterone ≥ 1 ng/mL and potentially having a functional corpus luteum (CL) responsive to cloprostenol (n = 558) or dinoprost (n = 519), dinoprost increased (P < 0.05) luteal regression from 86.6 to 91.3%. Despite a significant increase in luteolysis, pregnancies per AI did not differ between luteolytic agents (dinoprost = 37.8% and cloprostenol = 36.7%). Fertility was improved in cows of both treatments having reduced concentrations of progesterone at 72 h and in cows showing signs of estrus. In Experiment 2, an ovulation-resynchronization program was initiated with GnRH or saline in 427 previously inseminated lactating dairy cows of unknown pregnancy status in one herd. Seven days later, pregnancy was diagnosed and nonpregnant cows were blocked by number of CL and assigned randomly to be treated with cloprostenol or dinoprost. Compared with cloprostenol, dinoprost increased (P < 0.05) luteal regression from 69.1 to 78.5%, regardless of the number of CL present or the total luteal volume per cow. Pregnancies per AI did not differ between dinoprost (32.8%) and cloprostenol (31.3%). Although dinoprost was more effective than cloprostenol at inducing luteolysis in lactating dairy cows exposed to an Ovsynch or ovulation-resynchronization protocol, resulting fertility did not differ between products.     

Lack of association between LXRα and LXRβ gene polymorphisms and prevalence of metabolic syndrome: A case–control study of an Iranian population

The metabolic syndrome (MetS) is considered to be a major risk factor for type 2 diabetes mellitus and cardiovascular diseases. It is characterized by central adiposity, high blood pressure, glucose intolerance and abnormalities of lipoprotein metabolism. The cause of MetS is likely to be due to a complex interaction between genetic and environmental factors. Liver X receptors alpha (NR1H3) and beta (NR1H2) play a key role in lipid and carbohydrate metabolism. The aim of this study was to investigate the contribution of genetic polymorphisms in the LXRs to risk of MetS and related traits. Two common SNPs in NR1H3 (rs11039155 and rs2279238) and in NR1H2 (rs17373080 and rs2695121) were genotyped using TaqMan assays in MetS patients (n = 265) and controls (n = 219). Logistic regression analyses were performed to calculate the odds ratios (ORs) as a measure of association of genotypes with the presence of MetS and related phenotypes. Although The NR1H2 polymorphism rs2695121 was nominally associated with MetS but correction for multiple-testing and adjustment for age, sex and number of MetS criteria, failed to identify any significant interactions associated with prevalence of MetS. However in the haplotype analysis, a LXRα haplotype AC, was more common in controls and was associated with a significant protective effect for MetS (OR [95% CI] = 0.25 [0.07–0.88], p = 0.031). In conclusion, this study suggests that the above-named variants in LXRα and LXRβ genes are not potential contributors to the risk of MetS and related traits in an Iranian population.     

Genetic diversity of silver pomfret (Pampus argenteus) populations from the China Sea based on mitochondrial DNA control region sequences

The genetic diversity of silver pomfret (Pampus argenteus) from the Bohai, East China, and South China Seas was investigated using mitochondrial DNA (mtDNA) control region sequence data. We found high levels of variation with 17 haplotypes among the 45 individuals (h = 0.88, π = 0.006). AMOVA analysis detected significant structuring among China Sea silver pomfret (P < 0.05, F_ST = 0.050), which indicates significant genetic differentiation. No significant differentiation between Bohai Sea and East China Sea samples was detected (P > 0.05). Whether silver pomfret from the South China Sea exhibit a different demographic history than those from the Bohai and East China Seas remains to be determined.     

Fixed-time AI pregnancy rate following insemination with frozen-thawed or fresh-extended semen in progesterone supplemented CO-Synch protocol in beef cows

The objective of this study was to compare fixed-time AI pregnancy rate in Angus crossbred beef cows inseminated with frozen-thawed or fresh-extended semen. Two ejaculates from each of two Angus bulls were collected by artificial vagina and pooled for each bull. The pooled semen from each bull was divided into two aliquots; Aliquot 1 was extended using Caprogen^® (LIC, Hamilton, New Zealand) to a concentration of 3 × 10⁶ sperm/straw and Aliquot 2 was extended using egg-yolk-glycerol extender to a concentration of 20 × 10⁶ sperm/straw. Semen extended with Caprogen^® was maintained at ambient temperature and semen extended with egg-yolk-glycerol extender was frozen and maintained at −196 °C until insemination. In each of two breeding seasons (Fall 2007 and Spring 2008), Angus-crossbeef cows (N = 1455) at 12 locations were randomly assigned within location to semen type [Fresh (N = 736) vs. Frozen (N = 719)] and sire [1 (N = 731) vs. 2 (N = 724)]. All cows were synchronized with 100 μg of GnRH im and a progesterone Controlled Internal Drug Release insert (CIDR) on Day 0, and on Day 7, 25 mg of PGF2_α im and CIDR removal. All cows received 100 μg of GnRH im and were inseminated at a fixed-time on Day 10, 66 h after CIDR removal. Timed-AI pregnancy rates were influenced by season (P < 0.05), cows detected in estrus prior to and at AI (P < 0.001), and dam age (P < 0.01). Pregnancy rates were not affected by semen type (Fresh = 51.5% vs. Frozen = 50.4%; P = 0.66) and there were no significant interactions of semen type by estrus expression, semen type by sire, or semen type by season (P > 0.1). In conclusion, commercial beef cows inseminated with fresh-extended semen (3 × 10⁶ sperm/straw) yielded comparable pregnancy rates to conventional frozen-thawed semen in a progesterone supplemented, CO-Synch fixed-time AI synchronization protocol and may provide an alternate to frozen semen for more efficient utilization of superior genetics.     

Analysis of the genetic structure of Rhodiola rosea (Crassulaceae) using inter-simple sequence repeat (ISSR) polymorphisms

The genetic diversity and differentiation of eleven R. rosea populations from different parts of its wide area of occurrence were studied by ISSR markers. Using eight primers, 252 DNA fragments were generated, and 243 of those DNA fragments were found to be polymorphic, indicating a high genetic variability at the species level (P = 96.4%, h = 0.176, SI = 0.291). Relatively low levels of diversity were determined at the population level (P 30.6-59.1%, h 0.088-0.165, SI 0.137-0.257). AMOVA analysis revealed that the majority of the genetic variation was within populations (65.42%), and the variance among populations was 34.58%. Cluster analysis revealed two groups of R. rosea populations; these groups likely represent distinct evolutionary lines in the species, which are different in genetic structure, evolutionary history and chorological migration routes.     

Pregnancy rates in heifers and cows with cryopreserved sexed sperm: Effects of sperm numbers per inseminate, sorting pressure and sperm storage before sorting

Field trials were conducted to increase fertility with AI of flow-sorted, sexed bovine sperm. In the first trial, a novel competitive fertilization approach was used to compare pressures (30 psi vs 50 psi) for sorting sperm. Both X- and Y-sperm were sorted to approximately 95% purity at 30 and at 50 psi; X-50 + Y-30 (and the converse) were mixed in equal numbers for AI of heifers. Fetal sex divulged which treatment produced the pregnancy; 82% of pregnancies resulted from the 30 psi treatment (P < 0.05). Based on a similar approach, a new-pulsed laser did not damage sperm any more than the previous standard continuous wave laser. In a large field trial, sorting sperm at 40 psi increased pregnancy rates in heifers relative to 50 psi (42.3% vs 34.1%, n = 367/group, P < 0.05). Storing sperm for 20 h before sorting at 40 psi decreased pregnancy rates from 42.3% (n = 367) to 36.8% (n = 368; P < 0.05). Breeding heifers with sexed sperm 55-56 h after CIDR removal and PGF_2α resulted in 34% (n = 32) pregnant, compared to 49% (n = 35) with fixed-time insemination 67-68 h after CIDR removal (P > 0.1). Lactating dairy cows pre-screened for normal reproductive tracts when OvSynch injections (GnRH, prostaglandin, GnRH) were initiated, had similar (P > 0.1) pregnancy rates to timed AI, with 10 × 10⁶ sexed sperm (43.9%, n = 57), 2 × 10⁶ sexed sperm (40.5%, n = 57) and 10 × 10⁶ unsexed control sperm (55.6%, n = 58). A final field trial with unselected, lactating dairy cows resulted in similar pregnancy rates for 2 × 10⁶ sexed sperm in 0.25 mL straws (25.0%, n = 708) and 0.5 mL straws (24.4%, n = 776), but lower (P < 0.05) than unsexed control sperm (37.7%, n = 713). Younger cows and those >84 days in milk had the highest pregnancy rates for both sexed and unsexed sperm. These studies improved sperm sexing procedures, and provided insight into appropriate commercial use of sexed sperm.     

Effects of equine chorionic gonadotropin and type of ovulatory stimulus in a timed-AI protocol on reproductive responses in dairy cows

The objectives were to evaluate the effects of equine chorionic gonadotropin (eCG) supplementation (with or without eCG) and type of ovulatory stimulus (GnRH or ECP) on ovarian follicular dynamics, luteal function, and pregnancies per AI (P/AI) in Holstein cows receiving timed artificial insemination (TAI). On Day 0, 742 cows in a total of 782 breedings, received 2 mg of estradiol benzoate (EB) and one intravaginal progesterone (P4) insert (CIDR). On Day 8, the CIDR was removed, and all cows were given PGF2α and assigned to one of four treatments in a 2 × 2 factorial arrangement: (1) CG: GnRH 48 h later; (2) CE: ECP; (3) EG: eCG + GnRH 48 h later; (4) EE: eCG + ECP. There were significant interactions for eCG × ovulatory stimulus and eCG × BCS. Cows in the CG group were less likely (28.9% vs. 33.8%; P < 0.05) to become pregnant compared with those in the EG group (odds ratio [OR] = 0.28). There were no differences in P/AI between CE and EE cows (30.9% vs. 29.1%; OR = 0.85; P = 0.56), respectively. Thinner cows not receiving eCG had lower P/AI than thinner cows receiving eCG (15.2% vs. 38.0%; OR = 0.20; P < 0.01). Treatment with eCG tended to increase serum progestesterone concentrations during the diestrus following synchronized ovulation (P < 0.10). However, the treatment used to induce ovulation did not affect CL volume or serum progesterone concentrations. In conclusion, both ECP and GnRH yielded comparable P/AI. However, eCG treatment at CIDR removal increased pregnancy rate in cows induced to ovulate with GnRH and in cows with lower BCS.