Suffolk Ewes Research Articles

281 Changes in satellite cell number in maternal and fetal muscle with 5-hydroxy tryptophan supplementation during late gestation

Abstract Toxic tall fescue contains ergot alkaloids, which induce vasoconstriction in livestock, leading to fescue toxicosis. This condition can impact muscle development due to altered blood flow. Supplementation with 5-HTP may counteract the vasoconstrictive effects of fescue alkaloids. We aimed to investigate the influence of 5-HTP supplementation on satellite cells, myoblast, and preadipocyte numbers in maternal and fetal muscle during late gestation in Suffolk ewes. We hypothesized that 5-HTP supplementation would mitigate the effects of fescue toxicosis on muscle cell populations, potentially promoting muscle development and regeneration in maternal and fetal tissues. Suffolk ewes (n = 75), naïve to toxic tall fescue, were blocked by body condition score and body weight into 10 groups for synchronization. Ewes were confirmed pregnant using transabdominal ultrasound, and lamb number was estimated at gestational day (gd) 60. Pregnant ewes carrying twins (n = 30) were randomly assigned to one of three treatments: 1) negative control (CON, n = 10), 2) toxic tall fescue seed containing 1.77 mg ewe-1ּ d-1 ergovaline/ergovalinine plus 5-HTP (2.5 mg/kg BW) supplement (5HTP, n = 10), or 3) positive control, fed toxic tall fescue seed containing 1.77 mg ewe-1ּ d-1 ergovaline/ergovalinine (E+, n = 10). Ewes were individually fed a total mixed ration from gd 78 to gd 85 of pregnancy and then TMR plus treatment (CON, E+ or 5HTP) from gd 86 to d 111. On gd 112, terminal necropsies were performed, and semimembranosus muscle (SM) from the ewe and fetus was removed. Weights were obtained, and then samples were digested using pronase (1.5mg/mL) to isolate preadipocyte (PP1), myoblasts (PP2) and satellite cell (PP3) fractions using a pre-plating technique. Cells were quantified using a Neubauer-hemocytometer and trypan blue to also assess cell viability and changes in cell number. Fetal SM had a greater (P < 0.05) number of pre-adipocytes, myoblasts, and satellite cells per gram of tissue digested in comparison with the ewes. Pre-adipocyte and myoblast number per gram of tissue digested did not differ (P > 0.05) by treatment. The 5HTP group had the greater (P < 0.05) number of satellite cells per gram of tissue digested in comparison with the CON group. Satellite cell numbers tended (P < 0.10) to be greater in the 5HTP group in comparison to the E+ group. Satellite cell numbers from CON and E+ treatment groups did not differ (P > 0.05). In conclusion, 5-HTP supplementation during late gestation in Suffolk ewes exposed to toxic tall fescue significantly increased satellite cell numbers in maternal and fetal muscle tissues. This suggests a potential mitigation of the impact of fescue toxicosis on muscle cell populations.

Succession of rumen microbiota and metabolites across different reproductive periods in different sheep breeds and their impact on the growth and development of offspring lambs

BackgroundThe microbiota and metabolites in the gastrointestinal tracts of female animals at different reproductive periods are very important to the growth, development, and health of themselves and their offspring. However, the changes in the gastrointestinal microbiota and metabolites throughout reproductive period of different sheep breeds and their effects on the growth and development of offspring lambs are still unclear. Hence, this study presents an assessment of the reproductive hormone levels, immune levels, rumen microbiota, and metabolites in Hu sheep and Suffolk ewes at different reproductive periods and their effects on the growth and development of offspring lambs.ResultsHu sheep and Suffolk during non-pregnancy, pregnancy, and lactation were used as the research objects to determine reproductive and immune indexes of ewes at different periods, analyze rumen microbiome and metabolome, and track the growth performance and development of offspring lambs. The results showed that the reproductive hormone and immune levels of Hu sheep and Suffolk underwent adaptive changes across different reproductive periods. Compared with non-pregnancy, the microbial energy metabolism and lipid metabolism function decreased during Hu sheep pregnancy, and energy metabolism function decreased during lactation. In Suffolk, energy metabolism, glycan biosynthesis, and metabolism function were enhanced during pregnancy, and the metabolism of cofactors and vitamins was enhanced during lactation. Prevotella increased in Suffolk during pregnancy and lactation (P < 0.05) and was positively correlated with the birth weight and body size of the lambs (P < 0.05). Moreover, the abundances of Butyrivibrio and Rikenellaceae_RC9_gut_group during pregnancy were positively correlated with the intestinal immunity of the offspring lambs (P < 0.05), thereby regulating the intestinal immunity level of the lambs. Metabolomic analysis revealed that the protein digestion, absorption, and amino acid metabolism of Hu sheep were enhanced during pregnancy, which provided amino acids for the growth and development of pregnant ewes and fetuses and was significantly correlated with the birth weight, body size, and intestinal immunity of lambs (P < 0.05). Simultaneously, there was an increase in acetate and propionate during the pregnancy and lactation period of both Hu sheep and Suffolk, providing energy for ewes during reproductive period. Moreover, the microbiota during the lactation period was significantly correlated with the milk quality and lambs daily gain (P < 0.05).ConclusionsThis study revealed the characteristic succession changes in the rumen microbiota and its metabolites at different reproductive periods in sheep breeds and their regulation of reproductive hormone and immune levels and identified their potential effects on the growth and development of offspring lambs. The findings provide valuable insights into the health and feeding management of different sheep breeds during the reproductive stage.Cnu7uEJBESQuA-vs1kGzfaVideo

Inclusion of chia seeds (Salvia hispanica L.) and pumpkin seeds (Cucurbita moschata) in dairy sheep diets.

Chia (Salvia hispanica L.) seed (CS) and Pumpkin (Cucurbita moschata) seed (PS) are used in ruminant diets as energy sources. The current experiment studied the impact of dietary inclusion of CS and PS on nutrient intake and digestibility, milk yield, and milk composition of dairy sheep. Twelve primiparous Texel × Suffolk ewes [70 ± 5 days in milk (DIM); 0.320 ± 0.029 kg milk yield] were distributed in a 4 × 3 Latin square design and fed either a butter-based control diet [CON; 13 g/kg dry matter] or two diets with 61 g/kg DM of either CS or PS. Dietary inclusion of CS and PS did not alter live weight (p >0.1) and DM intake (p >0.1). However, compared to the CON, dietary inclusion of both CS and PS increased the digestibility of neutral detergent fiber (p <0.001) and acid detergent lignin (p < 0.001). Milk production (p = 0.001), fat-corrected milk (p < 0.001), and feed efficiency (p < 0.001) were enhanced with PS, while the highest milk protein yield (p < 0.05) and lactose yield (p < 0.001) were for CS-fed ewes. Compared to the CON diet, the ingestion of either CS and/or PS decreased (p < 0.001) the C16:0 in milk. Moreover, both CS and PS tended to enhance the content of C18:3n6 (p > 0.05) and C18:3n3 (p > 0.05). Overall short-term feeding of CS and/or PS (up to 6.1% DM of diet) not only maintains the production performance and digestibility of nutrients but also positively modifies the milk FA composition.

Genome-wide associations with longevity and reproductive traits in U.S. rangeland ewes.

Introduction: Improving ewe longevity is an important breeding and management goal, as death loss and early culling of mature ewes are economic burdens in the sheep industry. Ewe longevity can be improved by selecting for positive reproductive outcomes. However, the breeding approaches for accomplishing this come with the challenge of recording a lifetime trait. Characterizing genetic factors underpinning ewe longevity and related traits could result in the development of genomic selection strategies to improve the stayability of sheep through early, informed selection of replacement ewes. Methods: Towards this aim, a genome-wide association study (GWAS) was performed to identify genetic markers associated with ewe longevity, reproductive, and production traits. Traits evaluated included longevity (i.e., length of time in the flock), parity and the lifetime number of lambs born, lambs born alive, lambs weaned, and weight of lambs weaned. Ewe records from previous studies were used. Specifically, Rambouillet (n = 480), Polypay (n = 404), Suffolk (n = 182), and Columbia (n = 64) breed ewes (N = 1,130) were analyzed against 503,617 SNPs in across-breed and within-breed GWAS conducted with the Bayesian-information and Linkage-disequilibrium Iteratively Nested Keyway (BLINK) model in R. Results: The across-breed GWAS identified 25 significant SNPs and the within-breed GWAS for Rambouillet, Polypay, and Suffolk ewes identified an additional 19 significant SNPs. The most significant markers were rs411309094 (13:22,467,143) associated with longevity in across-breed GWAS (p-value = 8.3E-13) and rs429525276 (2:148,398,336) associated with both longevity (p-value = 6.4E-15) and parity (p-value = 4.8E-15) in Rambouillet GWAS. Significant SNPs were identified within or in proximity (±50kb) of genes with known or proposed roles in reproduction, dentition, and the immune system. These genes include ALPL, ANOS1, ARHGEF26, ASIC2, ASTN2, ATP8A2, CAMK2D, CEP89, DISC1, ITGB6, KCNH8, MBNL3, MINDY4, MTSS1, PLEKHA7, PRIM2, RNF43, ROBO2, SLCO1A2, TMEM266, TNFRSF21, and ZNF804B. Discussion: This study proposes multiple SNPs as candidates for use in selection indices and suggests genes for further research towards improving understanding of the genetic factors contributing to longevity, reproductive, and production traits of ewes.

Reproductive neuroendocrine defects programmed by prenatal testosterone treatment between gestational days 60-90 are amplified by postnatal obesity in sheep.

Polycystic ovary syndrome (PCOS) is the leading cause of anovulatory infertility in women of reproductive age, and obesity can increase the severity and development of the PCOS phenotype. Prenatal testosterone (T) treatment between gestational days 30-90 advanced puberty and disrupted the reproductive and metabolic phenotype in female sheep, recapitulating attributes of women with PCOS, with postnatal obesity amplifying its severity. On the other hand, prenatal T treatment from gestational days 60-90 led to a much milder phenotype. We hypothesized that reproductive neuroendocrine defects programmed by prenatal T treatment between gestational days 60-90 are amplified by postnatal obesity in sheep. Suffolk ewes received T propionate (T; 100mg) or corn oil (C; vehicle) twice weekly from gestational days 60-90. At 5months of age, T lambs were assigned to either a maintenance (100% of NRC requirements) or overfed (130% NRC) diet and C lambs were fed the maintenance diet. We compared the timing of puberty (n = 15/group) determined by twice weekly measurement of progesterone concentrations, estradiol positive feedback responsiveness (n = 8/group) determined by assessing LH secretion in response to exogenous estradiol, periovulatory LH dynamics during the second breeding season (n = 8/group) following synchronization with two injections of PGF2α, and progesterone negative feedback (n = 8/group) determined by characterizing LH pulses during the mid-luteal phase between C, T-maintenance and T-overfed groups. Our findings indicate that postnatal obesity: 1) exacerbated reproductive defects and further deteriorated reproductive cyclicity during the second breeding season (adulthood); 2) did not amplify the impairment in estradiol positive feedback in delaying the timing and amplitude of the LH surge, although it reduced the total amount of LH secreted during the preovulatory LH surge; 3) amplified the reduced responsiveness to progesterone negative feedback manifested as an increase in LH pulse amplitude and peak. These observations, in addition to supporting our previous findings that prenatal T treatment results in reproductive neuroendocrine dysfunction and periovulatory disruptions, provide evidence that these neuroendocrine defects programmed between gestational days 60-90 are amplified by postnatal obesity in female sheep.

Effects of Dam and Sire Breeds on Lamb Carcass Quality and Composition in Pasture-Based Systems.

This study explored the impacts of sire and dam breed on carcass quality and composition in a pasture-based system and the use of DXA to rapidly rank carcasses for leanness. Southdown (SD) and Suffolk (SF) ewes were mated to Texel (TX) or SD rams to produce seventy-nine lambs. Lambs were raised on pasture-based systems with limited grain supplementation. Lamb birth weight was greater (p < 0.01) for TX, regardless of dam breed. Lambing rate was lower (p < 0.01) for SD than SF ewes. Circulating myostatin concentrations were greater (p < 0.05) on d 42 than d 75 or d 110 but did not differ by sire breed. Texel-sired lambs had greater (p < 0.01) carcass weight, ribeye area and quality grade compared to SD-sired. Total and primal fat mass as predicted from DXA was higher (p < 0.05) in carcasses from SD than TX sires. Muscles from TX lambs had greater (p < 0.05) polyunsaturated fatty acid (PUFA) composition than SD-sired. Shear force values were influenced (p < 0.01) by dam breed, muscle cut and postmortem age but not by sire breed. The use of TX sires in pasture-based systems improved carcass leanness and muscle PUFA concentrations without altering tenderness.

344 Incorporation of Hemp Hulls and Screenings as Alternative Feed Sources for Ruminants

Abstract Currently there are no legal markets for feeding hempseed hulls or screenings to ruminants in Canada. This represents a significant wastage of high-quality feed that could be utilized in ruminant production. Therefore, the objectives of this project were to 1) evaluate the in situ rumen digestibility of hemp hulls and screenings; 2) evaluate the effect of including hemp hulls and screenings on the growth performance of feedlot lambs, and 3) assess if there are cannabinoids within the carcasses of growing lambs, and the milk of lactating ewes. Three ruminally cannulated Angus × Hereford heifers were used to determine the in situ degradability of hemp hulls and screenings. Wheat screenings, hemp hulls, and hemp screenings were weighed into polyester bags and incubated in the rumen for 0, 2, 4, 8, 12, 24, 48, 96, 120, and 240 h. The kinetics of in situ DM disappearance were estimated using a non-linear regression procedure of SAS. Wheat screenings had a similar soluble fraction to hemp hulls and screenings; however, hemp screenings had a greater (P &amp;lt; 0.01) soluble fraction than hemp hulls. The rapidly degradable fraction, total potentially degradable fraction, and ruminal degradability were greatest (P &amp;lt; 0.01) for wheat screenings, followed by hemp screenings, and then hemp hulls. Study 2 was conducted using twelve Canadian Arcott x Suffolk ram lambs randomly allocated to one of three treatments: control (Wheat screenings), hemp hulls, and hemp screenings. By-products were included at 20% dietary dry matter, and lambs were fed ab libitum until they reached 50 kg. To test for cannabinoid residues, samples of muscle, adipose tissue, liver, and kidney were taken post-mortem. Study 3 was conducted using fifteen lactating Canadian Arcott x Suffolk ewes with twins, fed the same treatments as in Objective 2. Hulls and screenings were included at 15% DM, and ewes were fed dietary treatments for 30 d, with dry matter intake and body weight recorded weekly. On d 15 and 30, ewes were hand milked to obtain samples for cannabinoid analysis. This research will have an important role in supporting Canadian approval for feeding industrial hemp by-products to ruminant livestock.

289 Postnatal Obesity Amplifies the Effect of Prenatal Testosterone Excess in Reducing the Progesterone Negative Feedback Sensitivity in First-Generation Ewes

Abstract Polycystic ovary syndrome (PCOS) is the leading cause of anovulatory infertility in women of reproductive age. Women with PCOS exhibit reduced sensitivity of the GnRH neuronal system to the inhibitory effects of both progesterone and estradiol. Additionally, obesity amplifies the severity of the PCOS phenotype. In sheep, testosterone (T) excess during gestational days (GD) 30-90 and 60-90 reduces neuroendocrine sensitivity to the progesterone negative feedback and recapitulates the PCOS phenotype. This study investigated the contribution of postnatal obesity in amplifying or mitigating the effects of mid-gestational T excess in disrupting the responsiveness to progesterone negative feedback in sheep. Suffolk ewes received T propionate (T; 100 mg i.m.) or corn oil (CO; vehicle) twice weekly from GD 60-90 (term = 147 d). At 5 mo of age, F1 T lambs were assigned randomly to either a maintenance (100% of NRC requirements) or overfed diet (130% of NRC requirements) and control lambs were fed the maintenance diet. At 22 mo of age, F1 ewes (n = 8/group) were synchronized with two injections of PGF2α 11 d apart. After the second PGF2α administration, blood samples were collected daily for 14 d and progesterone concentrations were determined via radioimmunoassay. Ewes that were confirmed to be cycling and in the mid-luteal phase based on progesterone concentrations (progesterone ≥ 1 ng/ml on day 10 and ≥ 0.5 ng/ml on days 8-9 and 11-12) were used for LH pulse characterization. On day 10 after PGF2α synchronization (mid-luteal phase), blood samples were collected every 15 min for 6 h to characterize LH pulsatile secretion via radioimmunoassay. Data were analyzed as one-way ANOVA with Tukey's HSD post-hoc analysis. Frequency of LH pulses was greater (P &amp;lt; 0.05) in T maintenance (3.75 ± 0.41 pulses/6h) and T overfed ewes (3.50 ± 0.34 pulses/6h) compared with controls (2.00 ± 0.37 pulses/6 h). Luteinizing hormone pulse amplitude was greater (P &amp;lt; 0.05) in T overfed (2.03 ± 0.15 ng/mL) compared with T maintenance (1.44 ± 0.17 ng/mL), but not to controls (1.74 ± 0.21 ng/mL). Also, average LH concentration was greater (P &amp;lt; 0.05) in T overfed (2.03 ± 0.24 ng/mL), but not T maintenance (1.31 ± 0.35 ng/mL), compared with controls (0.93 ± 0.30 ng/mLl). In conclusion, these findings demonstrate the activational role of postnatal obesity in amplifying prenatal T-induced alterations in tonic LH secretion during progesterone negative feedback. The activational effect of postnatal obesity in increasing LH secretion and consequently thecal androgen production is likely a contributor to the severity of hyperandrogenic status in women with PCOS. Research support: NIH-NICHD (R01HD099096).

PSIV-17 Postnatal Obesity Amplifies Gnrh-Induced Lh Release in Prenatal Testosterone-Treated Female Sheep

Abstract Polycystic ovary syndrome (PCOS) is the most common hormonal disorder in females of reproductive age. Hypersecretion of luteinizing hormone (LH), partly due to increased pituitary sensitivity to gonadotrophin-releasing hormone (GnRH), is a significant cause of infertility in women with PCOS. Moreover, obesity amplifies the severity of reproductive dysfunction in PCOS. In sheep, testosterone (T) excess during gestational days (GD) 30 to 90 results in GnRH-mediated LH hypersecretion and recapitulates the PCOS phenotype. This study investigated 1) if mid-gestation (GD 60 to 90) is the susceptibility window for programming pituitary hypersensitivity to GnRH, and 2) the contribution of postnatal obesity in modulating LH responsiveness to GnRH. Suffolk ewes received T propionate (T; 100 mg i.m.) or corn oil (C; vehicle) twice weekly from GD 60 to 90 (term = 147 d). At 5 mo of age, T lambs were assigned randomly to either a maintenance (100% of NRC requirements) or overfed diet (130% of NRC requirements), and Control lambs were fed the maintenance diet. During the anestrous period (late summer), ewes (n = 8/group; ~17 mo of age) received a GnRH bolus injection (2 ng/kg) intravenously every 1.5 h and blood samples were collected at 15-min intervals for a 6-h period. Despite animals being in seasonal anestrous, few endogenous LH pulses were evident during the 6 h-sampling period. To avoid confounding, only clear responses to GnRH challenge that occurred within 15 to 45 min after each GnRH injection were considered for further analyses. Mean number of exogenous GnRH-induced LH responses that met these criteria did not differ between groups and averaged 1.81 ± 0.27 pulses/animal. The parameters of these GnRH-induced responses were analyzed as one-way ANOVA with Tukey’s HSD post-hoc analysis. Mean LH pulse peak was greater (P &amp;lt; 0.05) in T overfed ewes (4.59 ± 0.49 ng/mL) compared with T maintenance (2.19 ± 0.61 ng/mL) and Control ewes (2.58 ± 0.53 ng/mL). Additionally, amplitude of LH pulses was greater (P &amp;lt; 0.05) in T overfed ewes (2.66 ± 0.39 ng/mL) compared with T maintenance (1.03 ± 0.48 ng/mL) and tended (P = 0.089) to be greater in T overfed compared with Control ewes (1.41 ± 0.42 ng/mL). LH pulse peak and amplitude in T maintenance did not differ from Control ewes. In conclusion, failure of GD 60 to 90 T treatment to increase GnRH responsiveness as opposed to our earlier finding of increased responsiveness in GD 30 to 90 T-treaded sheep indicates that the susceptibility window for programming pituitary hypersensitivity to GnRH lies between GD 30 to 60. Postnatal obesity may act as an independent activational signal in amplifying the pituitary sensitivity to GnRH in female sheep. This premise is supported by observations that obesity exacerbates pituitary-mediated LH hypersecretion in women with PCOS. Research support: NIH-NICHD (R01HD099096).

Use of a Visual Scoring System to Assess External Udder Conformation and Its Relationship to Colostrum Quality and Lamb Growth Rates.

In sheep raised for meat production, the relationship between external udder conformation, colostrum quality, and lamb growth rates has not received much attention. We hypothesized that ewes with a more desirable udder conformation at lambing would have greater colostrum quality and greater growth rates in lambs. Fifty Suffolk ewes were used in this study. Within 6-8 h of parturition, colostrum samples from both halves of the udder were collected and visual scoring of the udder was conducted. Colostrum quality was measured for total proteins using both optical and Brix refractometers. On day 2, day 45, and day 60 after parturition, lamb weights were recorded, and udder conformation measurements were repeated. A visual scoring system evaluating udder floor (scale 1-4), udder depth (scale 1-9), teat placement (scale 1-9), teat/mammary lesions (present or absent), and the presence of wool (present or absent) was used to assess the external udder conformation. Normal udder parameters included udder depth scores of 5 or 6; udder floor scores of 1 or 2; teat placement scores of 4, 5, or 6; and the absence of teat/mammary lesions and wool. All ewes not meeting normal parameters were considered to have an abnormal udder. The data were analyzed using the GLM procedure. Mean total colostrum protein was greater (p = 0.03) in ewes displaying a 'normal' udder conformation compared with those with an 'abnormal' conformation (14.82 ± 0.5 and 13.31 ± 0.3 mg/dL, respectively). Mean Brix values were also greater (p = 0.03) for ewes with a 'normal' udder compared to an abnormal udder confirmation (21.70 ± 0.8 and 19.54 ± 0.5, respectively). On day 2 after parturition, the mean lamb body weight was not different between ewes with 'normal' and abnormal udders (5.38 ± 0.26 vs. 5.46 ± 0.15). No differences (p > 0.05) in lamb weights were detected between ewes with normal and abnormal udder conformations on day 45 and 60 after parturition. These data provide evidence of greater colostrum total protein values and greater Brix values present in ewes with a 'normal' udder conformation. There were no differences in the weights of lambs born to ewes with normal or abnormal udder conformations.

Regulation of synthesis of polyamines by progesterone, estradiol, and their receptors in uteri of cyclic ewes†.

Progesterone (P4), estradiol (E2), and expression of their receptors (PGR and ESR1, respectively) by cells of the uterus regulate reproductive performance of mammals through effects on secretion and transport of nutrients into the uterine lumen. This study investigated the effect of changes in P4, E2, PGR, and ESR1 on expression of enzymes for the synthesis and secretion of polyamines. Suffolk ewes (n = 13) were synchronized to estrus (Day 0) and then, on either Day 1 (early metestrus), Day 9 (early diestrus), or Day 14 (late diestrus) of the estrous cycle, maternal blood samples were collected, and ewes were euthanized before obtaining uterine samples and uterine flushings. Endometrial expression of MAT2B and SMS mRNAs increased in late diestrus (P < 0.05). Expression of ODC1 and SMOX mRNAs decreased from early metestrus to early diestrus, and expression of ASL mRNA was lower in late diestrus than in early metestrus (P < 0.05). Immunoreactive PAOX, SAT1, and SMS proteins were localized to uterine luminal, superficial glandular, and glandular epithelia, stromal cells, myometrium, and blood vessels. Concentrations of spermidine and spermine in maternal plasma decreased from early metestrus to early diestrus and decreased further in late diestrus (P < 0.05). The abundances of spermidine and spermine in uterine flushings were less in late diestrus than early metestrus (P < 0.05). These results indicate that synthesis and secretion of polyamines are affected by P4 and E2, as well as the expression of PGR and ESR1 in the endometria of cyclic ewes.

Creatine metabolism at the uterine-placental interface throughout gestation in sheep†.

The placenta requires high levels of adenosine triphosphate to maintain a metabolically active state throughout gestation. The creatine-creatine kinase-phosphocreatine system is known to buffer adenosine triphosphate levels; however, the role(s) creatine-creatine kinase-phosphocreatine system plays in uterine and placental metabolism throughout gestation is poorly understood. In this study, Suffolk ewes were ovariohysterectomized on Days 30, 50, 70, 90, 110 and 125 of gestation (n = 3-5 ewes/per day, except n = 2 on Day 50) and uterine and placental tissues subjected to analyses to measure metabolites, mRNAs, and proteins related to the creatine-creatine kinase-phosphocreatine system. Day of gestation affected concentrations and total amounts of guanidinoacetate and creatine in maternal plasma, amniotic fluid and allantoic fluid (P < 0.05). Expression of mRNAs for arginine:glycine amidinotransferase, guanidinoacetate methyltransferase, creatine kinase B, and solute carrier 16A12 in endometria and for arginine:glycine amidinotransferase and creatine kinase B in placentomes changed significantly across days of gestation (P < 0.05). The arginine:glycine amidinotransferase protein was more abundant in uterine luminal epithelium on Days 90 and 125 compared to Days 30 and 50 (P < 0.01). The chorionic epithelium of placentomes expressed guanidinoacetate methyltransferase and solute carrier 6A13 throughout gestation. Creatine transporter (solute carrier 6A8) was expressed by the uterine luminal epithelium and trophectoderm of placentomes throughout gestation. Creatine kinase (creatine kinase B and CKMT1) proteins were localized primarily to the uterine luminal epithelium and to the placental chorionic epithelium of placentomes throughout gestation. Collectively, these results demonstrate cell-specific and temporal regulation of components of the creatine-creatine kinase-phosphocreatine system that likely influence energy homeostasis for fetal-placental development.

139 Post-natal anti-Müllerian hormone profiles for Australian Merino and Suffolk ewe lambs

139 Post-natal anti-Müllerian hormone profiles for Australian Merino and Suffolk ewe lambs

Potential role for human menopausal gonadotropin in ovine superovulatory regimens during the breeding season.

Human menopausal gonadotrophin (hMG) has been reported to produce a comparable superovulatory response to that of follicle stimulating hormone (FSH). Furthermore, hMG has a long half-life as compared with FSH. The present study was designed to compare hMG administered once daily and FSH administered twice daily over a 4 - day period on superovulatory response of Suffolk ewes. During the mid-luteal phase, twenty-four Suffolk donor ewes received intravaginal sponges at day 0 for 12 days. The superovulatory regimens in the Control group (n=12) and the Treatment group (n=12) consisted of eight injections of FSH given at twice daily and four injections of hMG given at once daily, respectively. At day 13, the donor ewes were subjected to laparoscopic insemination. Embryos were recovered, classified, and transferred to recipient ewes at day 19. Pregnancy status was determined by ultrasound examination 40 days after transfer. Lambing rate was calculated after all the ewes had delivered. No significant differences were observed between the two groups in terms of the structures recovered, transferable embryos, degenerated embryos, unfertilized oocytes, pregnancy rate and lambing rate. The results showed that once daily injection of hMG can produce a comparable superovulatory response and embryo transfer outcomes to those obtained by twice daily injection of FSH over a 4 - day period. It is feasible that hMG is used to replace FSH and reduce the number of injection treatments in ovine superovulatory regimens.

Reproductive performance of European-breed ewes in different seasons of the year under mid-latitude.

The study evaluated the reproductive performance of Ile de France, Texel, Suffolk and crossbred ewes in different seasons, considering season of mating, age, body condition score and breed. The herd was located at geographic coordinates -25.66114429S, -49.27262198W, in Fazenda Rio Grande, Paraná State, southern Brazil, in a semi-intensive system. 643 mating were evaluated, under natural estrus conditions in 10 consecutive breeding seasons (2015-2019), under a body condition score between 2.5 and 3.5 in 93.9%. Data were analyzed using chi-square tests, binary logistic regression, ANOVA and T test. Considering the breeds and crossbred animals, a pregnancy rate (PR) of 83% (winter), 91% (autumn) and 89% (summer) with no differences between them was obtained, except for 77% PR in spring (p<0.05). Ile de France and crossbred ewes showed similar PR in all four seasons. Suffolk ewes showed similar fertility rates in summer, autumn and winter, but reduced in spring (p<0.05); Texel ewes showed lower PR in summer and spring compared to autumn and winter (p<0.05). The twin PR (TPR) in autumn, winter and spring showed no differences, except for summer (p<0.05). Age did not influence the PR of ewes <2 years, 2 to 8 years and > 8 years in the seasons, except in summer. It was concluded that the reproduction of European ewes breeds under medium latitude, combined with the use of constant management and feeding conditions, resulted in a fertility rate above 77% in all seasons, resulting in constant production of lambs.

Phosphate, calcium, and vitamin D signaling, transport, and metabolism in the endometria of cyclic ewes

BackgroundRecent evidence suggests important roles for progesterone (P4) and interferon tau in the regulation of calcium, phosphate, and vitamin D signaling in the uteri of pregnant sheep. However, the effects of P4 and estradiol (E2), with respect to the expression of their receptors PGR and ESR1, respectively, in uterine epithelia on mineral signaling during the estrous cycle has not been investigated. Estrous cycles of mature Suffolk ewes were synchronized, prostaglandin F2α was administered, and ewes were observed for estrus (designated as Day 0) in the presence of vasectomized rams. On Days 1, 9, or 14 of the estrous cycle, hysterectomies were performed.Results25-hydroxyvitamin D was more abundant in plasma from ewes on Day 14 than Day 1 (P < 0.05). Expression of fibroblast growth factor receptor 2 (FGFR2), a disintegrin and metalloprotease 17 (ADAM17), and parathyroid hormone-related protein (PTHrP) mRNAs was greater in endometria on Day 9 compared to Days 1 and 14 (P < 0.01). Similarly, expression of transient receptor potential cation channel subfamily V member 6 (TRPV6) mRNA was greater in endometria on Day 9 than Day 1 (P < 0.05). ATPase plasma membrane Ca2+ transporting 4 (ATP2B4) and S100 calcium binding protein G (S100G) mRNA expression was greater in endometria on Day 14 than on Days 1 and 9 (P < 0.01). In contrast, endometrial expression of vitamin D receptor (VDR) mRNA was lower on Days 9 and 14 than Day 1 (P < 0.01). Expression of klotho (KL) (P < 0.05) and cytochrome P450 family 24 subfamily A member 1 (CYP24) (P < 0.01) mRNAs was lower on Day 14 than Days 1 and 9. ADAM17, FGF23, CYP2R1, CYP27B1, KL, and VDR proteins immunolocalized to the uterine myometrium, blood vessels, and uterine luminal (LE), superficial glandular (sGE), and glandular (GE) epithelia. S100A9 protein was weakly expressed in the uterine myometrium, LE, sGE, and GE. Immunoreactivity of CYP2R1 and KL proteins in uterine LE and sGE was less on Day 1 than on Days 9 and 14. In contrast, S100G protein was expressed exclusively by GE, and immunoreactive S100G protein was less on Day 9. S100A12 protein localized to stromal cells of the uterine stratum spongiosum and blood vessels, but not by uterine epithelial cells.ConclusionCollectively, these results implicate E2, P4, and PGR in the regulation of phosphate, calcium, and vitamin D signaling in cyclic ewes.

The ovine conceptus utilizes extracellular serine, glucose, and fructose to generate formate via the one carbon metabolism pathway.

Highly proliferative cells rely on one carbon (1C) metabolism for production of formate required for synthesis of purines and thymidine for nucleic acid synthesis. This study was to determine if extracellular serine and/or glucose and fructose contribute the production of formate in ovine conceptuses. Suffolk ewes (n = 8) were synchronized to estrus, bred to fertile rams, and conceptuses were collected on Day 17 of gestation. Conceptuses were either snap frozen in liquid nitrogen (n = 3) or placed in culture in medium (n = 5) containing either: 1) 4mM D-glucose + 2mM [U-13C]serine; 2) 6mM glycine + 4mM D-glucose + 2mM [U-13C]serine; 3) 4mM D-fructose + 2mM [U-13C]serine; 4) 6mM glycine + 4mM D-fructose + 2mM [U-13C]serine; 5) 4mM D-glucose + 4mM D-fructose + 2mM [U-13C]serine; or 6) 6mM glycine + 4mM D-glucose + 4mM D-fructose + 2mM [U-13C]serine. After 2h incubation, conceptuses in their respective culture medium were homogenized and the supernatant analyzed for 12C- and 13C-formate by gas chromatography and amino acids by high performance liquid chromatography. Ovine conceptuses produced both 13C- and 12C-formate, indicating that the [U-13C]serine, glucose, and fructose were utilized to generate formate, respectively. Greater amounts of 12C-formate than 13C-formate were produced, indicating that the ovine conceptus utilized more glucose and fructose than serine to produce formate. This study is the first to demonstrate that both 1C metabolism and serinogenesis are active metabolic pathways in ovine conceptuses during the peri-implantation period of pregnancy, and that hexose sugars are the preferred substrate for generating formate required for nucleotide synthesis for proliferating trophectoderm cells.

GnRH administration after estrus induction protocol decreases the pregnancy rate of recipient ewes following transfer of frozen-thawed embryos

The objective of this study was to investigate the effects of GnRH on the pregnancy rate and the embryo survival rate of recipient ewes following embryo transfer. Estrus was synchronized in 83 nulliparous Huyang ewes using intravaginal sponges impregnated with 45 mg flurogestone acetate. The sponge was left in the vagina for 12 days followed with an injection of 330 IU of eCG at sponge removal. The treatment group (n = 34) was subjected 48 h after sponge removal to intramuscular administration with 16 μg of the GnRH agonist triptorelin and the control group (n = 49) with 1 mL of saline solution. Embryo transfer was performed by laparoscopy on day 8 after sponge removal, which transferred frozen-thawed embryos of Suffolk ewes directly to the anterior third of the corpus luteum ipsilateral uterine horn of the recipient ewe.Each recipient with at least one normal corpus luteum received one grade I embryo. The proportion of ewes with at least one normal corpus luteum in the control group was significantly lower compared to the treatment group (73.5 % vs 91.2 %, P < 0.05). In total, 62 embryos were transferred into 62 ewes and 29 lambs were born. The pregnancy rate (59.4 % vs 33.3 %, P < 0.05) and the embryo survival rate (56.3 % vs 30.0 %, P < 0.05) in the control group were significantly higher compared to the treatment group. In conclusion, a single dose of GnRH administered 48 h after sponge removal significantly decreased the pregnancy rate and the embryo survival rate of recipient ewes following transfer of frozen-thawed embryos.

Evaluation of herbal choline in productive performance and blood metabolites of ewes

Objective: To evaluate the effect of different levels of protected herbal choline (CHP) on productive performance, carcass characteristics, and serum metabolites in ewes. Design/Methodology/Approach: Fifty-two Hampshire × Suffolk ewes (29.95 ± 3.90 kg of initial live weight, PV) were randomly assigned to one within four treatments: 0, 0.3, 0.6 and 0.9% choline kg-1 dry matter (MS). The experimental design was complete randomized, in order to detect linear or quadratic trends. Results: No treatment effects were detected in the production variables, GD and AML with the addition of protected herbal choline in the diet (p&gt;0.05). CHP linearly increased the concentration of cholesterol, glucose, albumins, globulins, total proteins (p≤0.05) and phosphatidylcholine (p≤0.10). The triglyceride concentration had a quadratic response (p≤0.05) to the addition of CHP. Study limitations/Implications: The level of choline supplementation in sheep depends on whether the source is herbal or synthetic. Findings/Conclusions: The addition of CHP in ewe diets raised the concentration of phosphatidylcholine, modified the concentration of protein and lipid metabolites. However, no improvements in production were found.

Characterizing the vaginal microbiota of high and low producing Poll Merino and White Suffolk ewes.

There is a substantial, and growing, body of research focused on manipulating gastrointestinal microbes to affect health and production. However, the maternal vaginal microbiota and its effects on neonatal inoculation and lifetime production have received little attention. We aimed to characterize the vaginal microbes of domesticated sheep to determine whether they differ across sheep breeds with differing meat and wool growth potentials and to determine a link between vaginal microbes and high and low producing animals. A flock of White Suffolk (n = 136) and Poll Merino (n = 210) ewes were sorted by the Australian Sheep Breeding Values (ASBV), for yearling fleece weight in the Merino and by post-weaning weight in the Suffolk ewes. The top and bottom ASBV sheep were selected for sampling and the resulting treatment groups were; High Suffolk (n = 12), Low Suffolk (n = 12), High Merino (n = 12), and Low Merino (n = 12) ewes. A double guarded culture swab was used to sample from the surface of the vaginal epithelium. Diversity profiling analysis of vaginal bacterial communities was conducted using 16S rRNA amplicon sequencing. Breed and ASBV group differences in bacterial communities were tested. Within breed, there were no significant differences in ewe vaginal bacterial communities associated with ewe production parameters; however, there was a significant difference in ewe vaginal bacterial communities between breeds. We have been able to characterize the normal vaginal microbiota of nonpregnant ewes and demonstrate a rich microbial community.