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Compromised placental function can result in fetal growth restriction which is associated with greater risk of neonatal morbidity and mortality. Large increases in transplacental nutrient and waste exchange, which support the exponential increase in fetal growth during the last half of gestation, are dependent primarily on the rapid growth and vascularization of the uteroplacenta. The amplitude of melatonin secretion has been associated with improved oxidative status and altered cardiovascular function in several mammalian species; however, melatonin mediated alterations of uteroplacental capacity in sheep and cattle are lacking. Therefore, our laboratories are examining uteroplacental blood flow and fetal development during maternal melatonin supplementation. Using a mid- to late-gestation ovine model of intrauterine growth restriction, we examined uteroplacental blood flow and fetal growth during supplementation with 5 mg/d of dietary melatonin. Maternal nutrient restriction decreased uterine arterial blood flow, while melatonin supplementation increased umbilical arterial blood flow compared with non-supplemented controls. Although melatonin treatment did not rescue fetal weight in nutrient restricted ewes; we observed disproportionate fetal size and fetal organ development. Elevated fetal concentrations of melatonin may result in altered blood flow distribution during important time points of development. These melatonin specific responses on umbilical arterial hemodynamics and fetal development may be partially mediated through vascular melatonin receptors. Recently, we examined the effects of supplementing Holstein heifers with 20 mg/d of dietary melatonin during the last third of gestation. Uterine arterial blood flow was increased by 25% and total serum antioxidant capacity was increased by 43% in melatonin supplemented heifers vs. non-supplemented controls. In addition, peripheral concentrations of progesterone were decreased in melatonin supplemented heifers vs. non-supplemented controls. Using an in vitro model, melatonin treatment increased the activity of cytochrome P450 2C, a progesterone inactivating enzyme, which was blocked by treatment with the melatonin receptor antagonist, luzindole. Elucidating the consequences of specific hormonal supplements on the continual plasticity of placental function will allow us to determine important endogenous mediators of offspring growth and development.

ObjectivesTo determine the influence of corn supplementation of beef cows during winter and their impact on offspring beef quality attributes.Materials and MethodsForty-seven multiparous Angus beef cows carrying male calves were assigned randomly to two dietary treatments: corn supplementation at 0.2% BW (SUP; n = 24) vs. non-supplementation (NSUP; n = 23) at d 110 d of gestation for 22 wks. Ad-libitum access to low-quality forage was provided to both groups. At 7 d post-calving, a muscle biopsy was collected from the longissimus dorsi muscle (LD) of each calf for muscle fiber typing. Offspring were managed as a single group from nursing through to the backgrounding phase. Thereafter, the steers were placed in the feedlot and assigned to 4 pens (blocks) based on BW and offered ad-libitum access to a 100% corn silage-based ration (76.97% TDN, 11.07% CP), salt and minerals. When the steers reached a final BW of 615 kg (∼16 mo of age), they were slaughtered in a commercial abattoir. A second LD muscle biopsy sample was obtained at 45 min postmortem (PM) for muscle fiber typing. At 96 h PM, striploins (n = 42) were collected, aged for 14 d and samples obtained for Warner Bratzler shear force (WBSF), proximal composition, myofibril fragmentation index (MFI), collagen analysis and objective color evaluation. Data were analyzed as a randomized block design.ResultsImmunofluorescent analysis for the myosin heavy chain (MHC) isoform on the proportion of the fiber type or fiber dimensions was not influenced by maternal dietary treatment at both ages (P > 0.05). However, regardless of maternal dietary treatment, the proportion of fiber type IIA decreased while type IIAX increased in samples from steers at 16 mo of age compared with samples from steers at 7 d of age. No differences were observed between dietary treatment groups in proximate composition (P = 0.8), MFI (P = 0.29), or collagen content (P 0.98); however, WBSF values tended to be higher in steers from SUP cows than steers from NSUP dams (P = 0.07). Maternal dietary treatment had no influence on objective color evaluation at the retail display (P > 0.05). Objectives traits were not affected by dietary treatment × display time interaction (P = 0.92).ConclusionOur findings indicate that corn supplementation of cows during mid to late gestation has minimal effects on muscle fiber type and beef quality of their offspring. Thus, corn supplementation of low-quality forage offered during mid to late gestation did not have detrimental effects on muscle fibers and meat quality of offspring.

ObjectivesThe objectives of this study were to investigate the influence of substituting supplemental sucrose with beef on maternal health and fetal development using a sow biomedical model.Materials and MethodsMultiparous crossbred sows (BW = 222 kg; n = 21; rep = 3) were individually housed from d 30 to 111 (± 0.58) of gestation. From d 30 to 39, a complete sow ration (corn-soybean meal-based, CSM) was fed at 1% of d 30 gestational BW. On d 39, daily dietary ration was adjusted to 1% of d 39 gestational BW which was fed daily at 0700 h from d 40 to 110 (± 0.58). Sows were randomly assigned to 1 of 4 isocaloric supplement treatments; 126 g CSM to serve as a control (CON, n = 5), 110 g cooked ground beef (BEEF, n = 6), 85.5 g sucrose (SUCR, n = 5), or 54.8 g BEEF and 42.7 g SUCR (B+S, n = 5). Dietary supplements were fed daily at 1100, 1500, and 1800 h from d 40 to 110 (± 0.58). Blood was collected via jugular venipuncture from sows on d 29 and 111 (± 0.58). Blood chemistry was immediately analyzed, and serum samples were collected for lipid panel and insulin concentrations. Bodyweights were measured on d 30, 39, 54, 68, 82, 96, and 111 (± 0.58). Tenth rib and last rib SQ fat depth were measured on d 35, 70, and 110 (± 0.58) via ultrasound. Sows were euthanized on d 111 (± 0.58). Reproductive tract (RT), pancreas, kidney, liver, heart, heart fat, lung, semimembranosus and abductor (SM), and semitendinosus (ST) weights were collected and recorded from each sow. Two median weight male and female fetuses were selected from each sow for tissue collections. Fetal tissue collection was the same as sows with the addition of testes and no RT weight. A repeated measures design, with sow as the repeated measure, was modeled using the MIXED procedure of SAS using compound symmetry variance covariance matrix. Sow data fixed effects were replicate, sow, and treatment. Fetal data fixed effects were replicate and fetal weight category. Covariates were determined for each individual trait depending on goodness of fit. A treatment by day interaction was used for sow data while a treatment by sex interaction was used for fetal data. Alpha level was 0.05.ResultsDietary treatment did not influence gestational BW (P ≥ 0.99), SQ fat depth (P ≥ 0.09), blood chemistry (P ≥ 0.21), or serum concentrations (P ≥ 0.07). Dietary treatment did not influence sow tissue weight (P ≥ 0.42). Compared with CON, BEEF fetuses had greater fetal BW (P = 0.01), crown to rump length (P = 0.01), nose to crown length (P < 0.01), heart girth (P = 0.02), and abdominal girth (P = 0.05). Dietary treatment did not influence fetal growth characteristics of median weight male and female fetuses (P ≥ 0.23). Compared with BEEF, SUCR fetuses had heavier liver weights (31.43 ± 2.06 and 40.13 ± 2.09, respectively; P = 0.04). There was a dietary treatment by sex interaction for fetal kidney weight with BEEF males having lighter kidney weights compared with all other interactions (P = 0.03). Dietary treatment did not influence any other fetal tissue weight (P ≥ 0.09).ConclusionBeef and/or sucrose supplementation during mid-to-late gestation has minimal effects on swine maternal health and fetal development. Differences in fetal liver and kidney weights should be examined further. Further research is needed to determine the effect of gestational supplementation on human health and development.

Objectives were to determine the effects of advancing gestation, maternal nutrient restriction during early and mid-gestation, and realimentation on fetal liver and jejunal mass and energy use in both dams and fetuses. On day 30 of pregnancy, multiparous, non-lactating beef cows (initial BW=621±11.3 kg and body condition score=5.1±0.1) were assigned to one of the two dietary treatments: control (CON; 100% requirements; n=18) and restricted (R; 60% requirements; n=28). On day 85, cows were slaughtered (CON, n=6; R, n=6), and remaining cows continued on control (CC; n=12) and restricted (RR; n=12) diets, or were realimented to the control diet (RC; n=11). On day 140, cows were slaughtered (CC, n=6; RR, n=6; RC, n=5), remaining cows continued on the control diet (CCC, n=6; RCC, n=5), or were realimented to the control diet (RRC, n=6). On day 254, all remaining cows were slaughtered. Maternal liver O2 consumption linearly increased (P⩽0.04) and jejunal weight (g/kg) linearly decreased (P=0.04) as gestation advanced in CON groups. Fetal BW, and hepatic and small intestinal absolute mass, protein content and O2 consumption linearly increased (P⩽0.04) as pregnancy advanced in CON groups. However, mass and O2 consumption relative to BW linearly decreased (P⩽0.001) in the fetal liver in CON groups. When analyzing the effects of dietary treatment, at day 85, fetal jejunal O2 consumption (mol/min per kg BW) was lower (P=0.02) in the R group when compared with the CON group. At day 140, maternal hepatic weight (g) was lower (P=0.02) in RC and RR cows when compared with CC, and fetal jejunual O2 consumption (mmol/min per mg tissue and mmol/min per g protein) was greater (P⩽0.02) in RC when compared with RR. At day 254, maternal hepatic O2 consumption (absolute and relative to BW) was lower (P⩽0.04) in the RCC cows when compared with RRC. Fetal hepatic weight was lower (P=0.05) in the CCC group when compared with RCC and RRC. The changes in response to nutrient restriction and realimentation in both the dam and fetus may indicate an adaptation to a lower amount of available nutrients by altering tissue mass and metabolism.

Primiparous ewes (n=32) were assigned to dietary treatments in a 2×2 factorial arrangement to determine effects of nutrient restriction and melatonin supplementation on maternal and fetal pancreatic weight, digestive enzyme activity, concentration of insulin-containing clusters and plasma insulin concentrations. Treatments consisted of nutrient intake with 60% (RES) or 100% (ADQ) of requirements and melatonin supplementation at 0 (CON) or 5 mg/day (MEL). Treatments began on day 50 of gestation and continued until day 130. On day 130, blood was collected under general anesthesia from the uterine artery, uterine vein, umbilical artery and umbilical vein for plasma insulin analysis. Ewes were then euthanized and the pancreas removed from the ewe and fetus, trimmed of mesentery and fat, weighed and snap-frozen until enzyme analysis. In addition, samples of pancreatic tissue were fixed in 10% formalin solution for histological examination including quantitative characterization of size and distribution of insulin-containing cell clusters. Nutrient restriction decreased (P⩽0.001) maternal pancreatic mass (g) and α-amylase activity (U/g, kU/pancreas, U/kg BW). Ewes supplemented with melatonin had increased pancreatic mass (P=0.03) and α-amylase content (kU/pancreas and U/kg BW). Melatonin supplementation decreased (P=0.002) maternal pancreatic insulin-positive tissue area (relative to section of tissue), and size of the largest insulin-containing cell cluster (P=0.04). Nutrient restriction decreased pancreatic insulin-positive tissue area (P=0.03) and percent of large (32 001 to 512 000 µm2) and giant (⩾512 001 µm2) insulin-containing cell clusters (P=0.04) in the fetus. Insulin concentrations in plasma from the uterine vein, umbilical artery and umbilical vein were greater (P⩽0.01) in animals receiving 100% requirements. When comparing ewes to fetuses, ewes had a greater percentage of medium insulin-containing cell clusters (2001 to 32 000 µm2) while fetuses had more (P

Compromised placental function can result in fetal growth restriction which is associated with greater risk of neonatal morbidity and mortality. Large increases in transplacental nutrient and waste exchange, which support the exponential increase in fetal growth during the last half of gestation, are dependent primarily on the rapid growth and vascularization of the uteroplacenta. The amplitude of melatonin secretion has been associated with improved oxidative status and altered cardiovascular function in several mammalian species; however, melatonin mediated alterations of uteroplacental capacity in sheep and cattle are lacking. Therefore, our laboratories are examining uteroplacental blood flow and fetal development during maternal melatonin supplementation. Using a mid- to late-gestation ovine model of intrauterine growth restriction, we examined uteroplacental blood flow and fetal growth during supplementation with 5 mg/d of dietary melatonin. Maternal nutrient restriction decreased uterine arterial blood flow, while melatonin supplementation increased umbilical arterial blood flow compared with non-supplemented controls. Although melatonin treatment did not rescue fetal weight in nutrient restricted ewes; we observed disproportionate fetal size and fetal organ development. Elevated fetal concentrations of melatonin may result in altered blood flow distribution during important time points of development. These melatonin specific responses on umbilical arterial hemodynamics and fetal development may be partially mediated through vascular melatonin receptors. Recently, we examined the effects of supplementing Holstein heifers with 20 mg/d of dietary melatonin during the last third of gestation. Uterine arterial blood flow was increased by 25% and total serum antioxidant capacity was increased by 43% in melatonin supplemented heifers vs. non-supplemented controls. In addition, peripheral concentrations of progesterone were decreased in melatonin supplemented heifers vs. non-supplemented controls. Using an in vitro model, melatonin treatment increased the activity of cytochrome P450 2C, a progesterone inactivating enzyme, which was blocked by treatment with the melatonin receptor antagonist, luzindole. Elucidating the consequences of specific hormonal supplements on the continual plasticity of placental function will allow us to determine important endogenous mediators of offspring growth and development.

ObjectivesA diet high in sucrose is reflective of a Western diet that the average American consumes. When consuming a Western diet, individuals consume roughly 20 teaspoons of sucrose per day. The Western diet has been previously linked to metabolic disorders such as diabetes and obesity, which may be prevented by replacing dietary sucrose with a healthy protein alternative like beef. The objectives of this study were to investigate the impact of substituting dietary sucrose with beef supplementation on maternal health and fetal development utilizing the sow as a biomedical model. Materials and MethodsMultiparous pregnant sows (Landrace × Yorkshire; BW = 222 kg; n = 21) were fed a complete sow gestation diet (corn-soybean meal-based, CSM; NRC 2017) at 1 percent of BW on sow d 30 of gestation at 700 h daily from d 30 to 39 of gestation. Sows were then fed CSM at 1 percent of BW on d 39 of gestation at 700 h daily from d 40 to 110 (± 0.58) of gestation. Sows were randomly assigned to 1 of 4 isocaloric dietary supplements consisting of 126 g CSM (CON, n = 5); 110 g cooked ground beef (CGB; BEEF, n = 6); 54.8 g CGB and 42.7 g sucrose (B+S, n = 5); or 85.5 g sucrose (SUCROSE, n = 5). Dietary supplements were fed 3 times daily from d 40 to 110 (± 0.58) of gestation. Sows were housed in gestation crates from d 30 to 111 (± 0.58) of gestation and euthanized on d 111 (± 0.58) of gestation. Blood was collected via jugular venipuncture from sows on d 29 and 111 (± 0.58) of gestation. Blood chemistry was immediately analyzed using iSTAT point-of-care device. Bodyweights were measured on d 30, 39, 54, 68, 82, 96, and 111 (± 0.58) of gestation. Tenth rib and last rib fat depth were measured on d 35, 70, and 110 (± 0.58) of gestation utilizing an ALOKA SSD-500V ultrasound. Fetal growth measurements were recorded for all fetuses. Two median weight male and female fetuses were selected from each sow for tissue collections which included pancreas, kidney, liver, heart, heart fat, lung, empty body weight, semimembranosus, and semitendinosus weights. A repeated measures design, using sow as the repeated measure, was modeled using the MIXED procedure of SAS (SAS Inst. Inc., Car, NC) using compound symmetry variance covariance matrix. Alpha level was 0.05. ResultsDietary treatment did not influence blood metabolites of sows on d 29 or 111 of gestation (P = 0.09 and P = 0.20, respectively). Sow weight throughout gestation was not influenced by dietary treatment (P = 0.74). Dietary treatment did not influence tenth rib or last rib fat depth on d 35, 70, or 110 of gestation (P = 0.27). Compared to CON and SUCROSE, fetuses from sows supplemented with BEEF had greater nose to crown lengths (6.03 ± 0.29, 6.02 ± 0.28, and 7.33 ± 0.36 cm, respectively; P = 0.04). Compared to CON, fetuses from sows supplemented with sucrose had respectively greater BW (1296 ± 73.6 vs. 1556 ± 68.8 g; P = 0.02); heart girths (22.90 ± 0.39 vs. 24.13 ± 0.39 cm; P = 0.03), and liver weights (36.48 ± 2.19 vs. 43.44 ± 2.05 g; P = 0.04). Dietary treatment did not influence other fetal characteristics or organ weights (P ≥ 0.05). ConclusionBeef supplementation during mid to late pregnancy had minimal effects on maternal blood metabolites, bodyweight, or backfat depth or fetal growth. The increase in fetal weight due to sucrose supplementation should be further explored.

Objectives were to determine the effects of maternal dietary supranutritional Se and nutritional plane during gestation on capillary surface density, capillary area density, and angiogenic factor expression in the developing mammary gland of primiparous ewes. Selenium treatments were initiated at breeding [adequate Se (ASe; 9.5 μg/kg of body weight) vs. high Se (HSe; 81.8 μg/kg of body weight)] and nutritional planes at d 50 of gestation [Low, 60%; moderate (Mod), 100%; and High, 140% of requirements). Mammary glands were collected within 24h postpartum. Vascular development was assessed in the glandular portion of the mammary gland. Vascularity was determined for mammary tissue with the following measurements taken: the cross-sectional capillary area density (total capillary area as a proportion of tissue area) and capillary surface density (CSD; total capillary circumference per unit of tissue area). High-Se ewes had greater capillary surface and area densities compared with ASe ewes. A tendency existed for an Se × plane of nutrition interaction for CSD with maternal diet not affecting CSD in HSe ewes, but Low ewes had a decreased CSD compared with Mod ewes, with High being intermediate in ASe ewes. Moreover, HSe-Low and HSe-High ewes had increased CSD compared with ASe-Low and ASe-High, respectively. Although Se status did not influence angiogenic factor mRNA expression, mammary glands from Low ewes tended to have increased VEGF and FLT1 mRNA expression compared with High ewes, with Mod being intermediate. Maternal plane of nutrition did not affect mammary gland glutathione peroxidase activity, but it was increased in HSe compared with ASe ewes. Increased mammary capillary nutrient exchange area may contribute to previously observed changes in colostrum quality.

Scholljegerdes, E. J., Lekatz, L. A. and Vonnahme, K. A. 2011. Effects of short-term oilseed supplementation on reproductive performance in beef heifers. Can. J. Anim. Sci. 91: 221–229. The objective of this experiment was to evaluate the role of a short-term increase in linolenic acid around the timed artificial insemination (TAI) on plasma fatty acid concentrations, estrous behavior, and pregnancy. Therefore, 96 cross-bred heifers (Initial BW=394±18.1 kg) fed chopped grass hay were allotted to one of three dietary treatments: no supplement (CON); 1.8 kg head−1 d−1 (DM basis) of a soybean-based pellet (SOY) high in linoleic acid (C18:2n-6); or 1.5 kg head−1 d−1 (DM basis) of a flaxseed-based pellet (FLX) high in linolenic acid (C18:3n-3). On day −9, relative to TAI, supplementation began, and heifers received a controlled internal drug-releasing (CIDR) device and gonadotropin releasing hormone (GnRH; 100 µg). On day −2, CIDRs were removed and heifers received 25 mg prostaglandin F2α (PGF2α). Heifers were bred by TAI (day 0) 54 h after CIDR removal and received GnRH. Estrous behavior was monitored throughout the feeding period by radiotelemetry. Supplementation ended on day 18 relative to TAI. Plasma concentrations of C18:2n-6 were greater by day 0 and day 18 (P

The objectives were to investigate effects of nutritional plane and Se supply during gestation on yield and nutrient composition of colostrum and milk in first parity ewes. Rambouillet ewe lambs (n = 84, age = 240 ± 17 d, BW = 52.1 ± 6.2 kg) were allocated to 6 treatments in a 2 × 3 factorial array. Factors included Se [adequate Se (ASe, 11.5 µg/kg of BW) or high Se (HSe, 77.0 µg/kg of BW)] initiated at breeding, and nutritional plane [60 (RES), 100 (CON), or 140% (HIH) of requirements] initiated at d 40 of gestation. Ewes were fed individually from d 40, and lambs were removed at parturition. Colostrum was milked from all ewes at 3 h postpartum, and one-half of the ewes (n = 42) were transitioned to a common diet meeting lactation requirements and mechanically milked for 20 d. Colostrum yield was greater (P = 0.02) for HSe ewes than ASe, whereas CON had greater (P < 0.05) colostrum yield than RES and HIH. Colostrum Se (%) was greater (P < 0.01) for HSe than ASe. Colostrum from ewes fed HSe had less (P = 0.03) butterfat (%), but greater (P ≤ 0.05) total butterfat, solids-not-fat, lactose, protein, milk urea N, and Se than ASe. Colostrum from HIH ewes had greater (P ≤ 0.02) solids-not-fat (%) than RES, whereas RES had greater (P ≤ 0.04) butterfat (%) than CON and HIH. Colostrum from ewes fed the CON diet had greater (P = 0.01) total butterfat than HIH. Total solids-not-fat, lactose, and protein were greater (P < 0.05) in colostrum from CON than RES and HIH. Ewes fed HSe had greater (P < 0.01) milk yield (g/d and mL/d) than ASe, and CON and HIH had greater (P < 0.01) yield than RES. Milk protein (%) was greater (P ≤ 0.01) in RES compared with CON or HIH. Ewes fed HSe had greater (P < 0.01) milk Se (µg/g and mg/d) than ASe on each sampling day. Milk from CON and HIH ewes had greater (P < 0.01) total solids-not-fat, lactose, protein, and milk urea N than RES. Total Se was greater (P = 0.02) in milk from ewes fed the CON diet compared with RES. Somatic cell count and total somatic cells were greater (P ≤ 0.05) in milk from CON than RES. A cubic effect of day (P ≥ 0.01) was observed for milk yield (g and mL). Butterfat, solids-not-fat, lactose, milk urea N, and Se concentration responded quadratically (P ≤ 0.01) to day. Protein (%), total butterfat, and total Se, and somatic cells (cells/mL and cells/d) decreased linearly (P < 0.01) with day. Results indicate that gestational nutrition affects colostrum and milk yield and nutrient content, even when lactational nutrient requirements are met.

To examine the impact of corn supplementation of cows on carcass outcomes of their offspring, forty-seven multiparous Angus beef cows carrying male calves were assigned randomly to two dietary treatments. Treatments were control (CON; n=23) receiving ad libitum access to a low quality, forage-based diet (57.54% TDN, 6.4% CP) TMR, and a supplemented group (SUP; n= 24) receiving corn at 0.02% BW (94.5% TDN, 7.64% CP) in addition to ad libitum access to the basal TMR. Dietary treatments started on d 110 of gestation for 22 wks. Following parturition, cows with their offspring were placed on pasture and managed as a single group. Calves were weaned (~159 d of age) and backgrounded for 250 d. Thereafter, the steers were placed in the feedlot, assigned to 4 pens (blocks) based on BW and offered a 57% corn silage/ 38% barley grain-based ration with growth performance measured at 28-day intervals. Pens 1 through 4 were fed for 69, 83, 96, and 137 d, respectively, to reach a final BW of 615 kg (~16 mo of age) and then sent to a commercial abattoir. Steers from SUP and CON cows did not differ in initial BW, final BW, and ADG, during the finishing period (P > 0.05). No significant difference in carcass quality and yield traits, including subprimal cut yields, bone, lean and fat trim, was observed between treatments (P > 0.05). In addition, differences in the frequency distribution of the Canadian quality and yield grades (P > 0.05) were not observed. Warner-Bratzler shear force values tended to be higher in steers from SUP dams than steers from CON dams (P = 0.07). Overall the results indicate that corn supplementation of cows during the mid to late gestation does not affect growth performance and carcass outcomes of their offspring.

Ovine placentomes vary in shape, with type A placentomes being concave, type D convex, and types B and C intermediate in morphology. It has been speculated that as placentomes advance in type they differ in vascularity and nutrient transport capacity. Our objective was to determine cellularity and vascularity measurements, angiogenic factor expression, and arterial vasoactivity within different morphologic types of placentomes. On Day 130 of gestation, placentomes were collected from multiparous ewes (n = 38) and were evaluated for size, cellularity estimates, angiogenic factor mRNA expression, capillary vascularity (capillary size, capillary surface density [CSD], capillary number density [CND], and capillary area density [CAD]), and vasoreactivity to potassium chloride and angiotensin II. The average weight and size of type A and B placentomes were less (P < 0.01) than those of type C and D placentomes. Placentome morphology did not affect (P ≥ 0.24) cotyledonary or caruncular cellularity estim...

To examine the effects of maternal metabolizable protein (MP) restriction during late gestation on uterine and umbilical blood flows, conceptus size, and amino acid concentrations in the uterine and umbilical vessels, 11 ewes with singleton pregnancies were assigned to one of three isocaloric diets formulated to provide 60% of MP (MP60), 80% of MP (MP80), or 100% of MP (MP100) requirements from days 100 to 130 of gestation. On day 130 of gestation, intraoperative uterine and umbilical blood flows were obtained as well as serum samples from the uterine artery, uterine vein, umbilical artery, and umbilical vein. Ewes on the MP60 diet had lighter (P=0.04) and smaller (P≤0.05) fetuses, but increased (P=0.02) uterine blood flow relative to fetal weight compared with MP100 ewes, with MP80 being intermediate. Umbilical blood flow was similar (P=0.70) across treatments. Glutamine, glycine, isoleucine, leucine, ornithine, serine, and valine concentrations were impacted (P≤0.02) by maternal treatment. While uterine flux of total serum nitrites was greater (P=0.03) in MP60 and MP80 ewes compared with MP100 ewes, fetal flux did not differ. Decreased maternal protein intake resulted in less (P

Vonnahme,K.A.,Zimprich,R.C.,Harris,E.K.,Berg,E.P.,Newman,D.J.andBuchanan,D.S.2010.Linseedmealduringearlypregnancyincreaseslittersizeinpigswithoutaffectingpost-natalgrowth.Can.J.Anim.Sci.90:491 493.Todeterminehowfeedinglinseedmeal(LSM)duringgestationinfluenceslittersize,placentalweight,andpigletgrowth,sows(n 30) received a phytoestrogen-free Control diet throughout gestation; 12.5% LSM diet throughout gestation(LSM114);or12.5%LSMdietfromday1today15ofgestationandcontroldietuntilparturition(LSM15).Maternaldietdidnotaffectbirthweight,placentalweight,orpostnatalgrowth.Thenumberoffullyformedpigletswasincreased(P 0.05)inLSM15sowscomparedwithControlandLSM114sows(13.5vs.10.1and11.691.0,respectively).FeedingLSMduringthefirst2wkafterbreedingmayenhancelittersize.Key words: Littersize,linseedmeal,pigVonnahme,K.A.,Zimprich,R.C.,Harris,E.K.,Berg,E.P.,Newman,D.J.etBuchanan,D.S.2010.Letourteaudelinende´butdegrossesseaugmentelatailledesporte´eschezlesporcssansaffecterlacroissancepost-natale.Can.J.Anim.Sci.90:491 493.Afindede´terminercommentnourritureavecfarinedesgrainesdelin(LSM)pendantlagestationinfluencetaille de litie`re, poid placentaire, et croissance des porcelets, truies (n 30) ont recu un re´gime de controˆle sans-phytoestrogenpendanttoutelagestation;alimentationLSMde12,5%toutesagestation(LSM114);ou12,5%LSMDie`tedejour1a`15dure´gimedegestation,etcontroˆlejusqu’a`laparturition(LSM15).Alimentationmaternellen’affectaitpasnaissance, poids placentaire ou croissance postnatale. Porcelets entie`rement forme´se´te´augmente´es (P 0,05) dans lestruies LSM15 par rapport a`la commande et LSM114 truies (13,5 VS 10.1 et 11,691.0, respectivement). AlimentationLSMpendantlesdeuxpremie`ressemainesapre`sreproductionpeutame´liorerlatailledelalitie`re.Mots cle´s: Tailledelitie`re,farinedesgrainesdelin,porc

To examine the effects of maternal metabolizable protein (MP) supplementation during late gestation on serum hormone and metabolites and organ masses, multiparous ewes (n = 45) carrying singletons or twins were allotted randomly (within pregnancy group) to 1 of 3 treatments: 60% (MP60), 80% (MP80), or 100% (MP100) of MP requirements. Blood samples were drawn before the initiation of diets (day 100) and before slaughter (day 130) for chemistry panel analysis and weekly for hormone analysis including progesterone (P4) and estradiol-17β (E2). At day 130, ewe organ masses were recorded. Despite being fed isocaloric diets, MP60 ewes gained less weight throughout pregnancy compared with MP80 and MP100 ewes which were similar. Although diet did not impact E2 or P4 concentrations, ewes carrying twins had greater (P < 0.05) concentrations of both as gestation advanced. Albumin, aspartate aminotransferase, and total protein were reduced (P < 0.05) in MP60 compared with MP100 ewes near term. There was a diet by fetal number interaction (P = 0.03) for lactate dehydrogenase. Twin-carrying MP80 ewes had greater lactate dehydrogenase compared with all other groups on day 130 of gestation. Ewes that were fed MP80 had greater body weight on day 130 of gestation compared with MP60 ewes. Kidney and heart weights were lighter in MP60 ewes compared with MP80 ewes. There was a maternal diet by fetal number interaction (P = 0.05) on fetal weight per unit empty ewe body weight. In ewes carrying singletons, MP60 ewes supported less fetal weight compared with MP100. In contrast, MP60 ewes supported more fetal mass compared with MP100 ewes when carrying twins. The level of protein, and not just total energy, in the diet appears to impact some aspects of the maternal system. Moreover, it appears some measurements of mobilizing maternal body resources are enhanced in ewes carrying twins.

Ovine placentomes vary in shape, with type A placentomes being concave, type D convex, and types B and C intermediate in morphology. It has been speculated that as placentomes advance in type they differ in vascularity and nutrient transport capacity. Our objective was to determine cellularity and vascularity measurements, angiogenic factor expression, and arterial vasoactivity within different morphologic types of placentomes. On Day 130 of gestation, placentomes were collected from multiparous ewes (n = 38) and were evaluated for size, cellularity estimates, angiogenic factor mRNA expression, capillary vascularity (capillary size, capillary surface density [CSD], capillary number density [CND], and capillary area density [CAD]), and vasoreactivity to potassium chloride and angiotensin II. The average weight and size of type A and B placentomes were less (P0.01) than those of type C and D placentomes. Placentome morphology did not affect (Por = 0.24) cotyledonary or caruncular cellularity estimates or percentage of cellular proliferation. Placentome morphology affected (Por = 0.41) neither caruncular CAD, CND, CSD, or capillary size nor cotyledonary CND, CSD, or capillary size. Cotyledonary CAD was increased (P0.01) in type B and D placentomes compared with type A placentomes. Furthermore, placentome type did not affect (Por = 0.06) angiogenic factor gene expression in the cotyledon or the caruncle. Size, but not morphologic type of placentome, was associated with greater caruncular artery contractility to potassium chloride and angiotensin II (P0.01 for both). Placentome size, but not morphologic type, may be important for vascularity and nutrient transfer in the placenta of the pregnant ewe.

Establishment of pregnancy in the pig is accompanied by a localized uterine acute inflammatory response and increase in uterine blood flow. Following rapid trophoblast elongation on Day 12 of pregnancy there is an increase in tissue kallikrein activity and release of bradykinin into the uterine lumen, suggesting the kallikrein-kininogen-kinin system is active in the porcine uterus. The present study investigated endometrial expression and presence of the various factors of the kallikrein-kininogen-kinin system. Endometrial L- and H-kininogen gene expression as well as presence of kininogens in the uterine flushings was evaluated throughout the estrous cycle and early pregnancy in the pig. The possible involvement of plasma kallikrein and Factor XII, activators of the kallikrein-kininogen-kinin system, were evaluated through analysis of gene expression in endometrial and conceptus tissues. Gene expression for plasma kallikrein, Factor XII, and H-kininogen were detected in endometrium but not early conceptus tissues. Factor XII and H-kininogen gene expression were similar across the days of the estrous cycle and early pregnancy. Endometrial plasma kallikrein gene expression was low but increased on Day 15 of the estrous cycle, whereas expression was similar across the days of early pregnancy. In comparison to cyclic gilts, endometrial L-kininogen gene expression increased fourfold on Days 15 and 18 of pregnancy. Both L- and H-kininogen were detected in the uterine flushings of cyclic and pregnant gilts. Presence of L- and H-kininogen in the porcine uterus and endometrial gene expression of plasma kallikrein and Factor XII provide evidence that the kallikrein-kininogen-kinin system is biologically active during establishment of pregnancy in the pig.

The objective was to examine the effect of maternal nutrient restriction followed by realimentation during midgestation on uterine blood flow (BF). On Day 30 of pregnancy, lactating, multiparous Simmental beef cows were assigned randomly to treatments: control (CON; 100% National Research Council; n = 6) and nutrient restriction (RES; 60% of CON; n = 4) from Day 30 to 140 (period 1), and thereafter, realimented to CON until Day 198 of gestation (period 2). Uterine BF, pulsatility index (PI), and resistance index (RI) were obtained from both the ipsilateral and contralateral uterine arteries via Doppler ultrasonography. Generalized least square analysis was performed. Ipsilateral uterine BF in both groups increased quadratically (P < 0.01) during period 1 and linearly (P < 0.01) during period 2. There was a treatment (P = 0.05) effect during period 2; where RES cows had greater ipsilateral BF versus CON. Ipsilateral uterine PI and RI decreased linearly (P ≤ 0.01) during period 1 across treatments. Contralateral uterine BF in CON cows tended (P < 0.09) to be greater versus RES in both periods. Contralateral PI in both groups increased linearly (P ≤ 0.01) during period 1. Contralateral uterine RI was increased (P ≤ 0.05) in RES cows versus CON in both periods. There was no interaction or treatment effect (P ≥ 0.24) for total BF during either period. Nutrient restriction does not alter total uterine BF, but it may increase vascular resistance. However, up on realimentation, local conceptus-derived vasoactive factors appear to influence ipsilateral uterine BF.

We investigated the temporal association between placental vascular endothelial growth factor (VEGF), a potent stimulator of angiogenesis and vascular permeability, and changes in placental/endometrial vascularity on selected days throughout gestation in the pig. Placental and endometrial tissues were collected from sows on Days 25 (n = 4), 36 (n =6), 44 (n = 6), 70 (n =5), 90 (n =5 ), and 112 (n = 7) of gestation. Cross sections of the placental/endometrial interface of each conceptus were used to estimate the number of blood vessels per unit area via image analysis and the intensity of VEGF staining via immunohistochemistry. Placental tissues were also collected on these days to evaluate VEGF mRNA expression. Placental VEGF mRNA expression and the numbers of blood vessels per unit area of placental and adjacent endometrial tissue were low and decreasing from Day 25 to Day 44, before increasing (P0.05) markedly and progressively through Day 112. These data are consistent with the marked increase in VEGF immunostaining in the chorionic and uterine luminal epithelium from early to late gestation. Further, these increases in placental VEGF mRNA were positively correlated with fetal weight (r = 0.73; P0.0001) and placental efficiency (fetal weight/placental weight ratio; r = 0.66, P0.0001). These data are consistent with a role for VEGF in increasing the number of blood vessels at the placental endometrial interface, resulting in an increased capacity for nutrient transfer from the maternal to the fetal compartment.

Porcine conceptuses rapidly elongate within the uterine horns prior to the period of placental attachment. During the time of elongation, secretion of estrogen by the developing conceptuses occurs for the establishment of pregnancy through maintenance of corpora lutea and facilitation of placental attachment. Factors associated with the uterine luminal epithelium accentuate embryo attachment by allowing close contact between the conceptus and the uterine epithelium. Kallikrein, a serine protease, may be involved with the timing of conceptus expansion and placental attachment to the uterine surface. The objective of this study was to evaluate kallikrein enzymatic activity, protein, and gene expression in the pig during the estrous cycle and early pregnancy. Enzymatic activity was first detected in uterine flushings (UTF) on Day 12 of the estrous cycle and pregnancy. Activity was enhanced on Day 12 of pregnancy compared to that in cyclic gilts, with a reversal of increased kallikrein activity in cyclic compared to pregnant flushings on Day 15. Western blot analysis with antiserum to human plasma kallikrein detected a 50-kDa product similar to human plasma kallikrein from Day 10 to Day 15 of the estrous cycle and pregnancy. Kallikrein enzymatic activity in UTF was associated with the presence of a 23-kDa reactive product. Gene expression of kallikrein as determined by reverse transcription-polymerase chain reaction indicated the presence of kallikrein mRNA in the porcine endometrium and conceptuses. Results indicate that an increase in uterine luminal kallikrein activity occurs during the estrous cycle at a period that corresponds to rapid conceptus elongation during pregnancy of the pig. The present information suggests that kallikrein may play a role in opening the window for establishment of pregnancy in the pig.