Development of a database of gas chromatographic retention properties of organic compounds.

A comprehensive database of gas chromatographic retention properties of chemical compounds has been developed using multiple literature sources. The National Institute of Standards and Technology (NIST) database of retention data for non-polar and polar stationary phases currently contains 292,924 data records for 42,888 compounds. The database includes data for Kováts indices, linear indices, Lee indices, retention times and retention volumes. The first release of this database for non-polar stationary phases is available with NIST/US Environmental Protection Agency (EPA)/National Institutes of Health (NIH) Mass Spectral Database (June 2005) and through the internet (NIST Chemistry WebBook). The paper describes the database and the process by which it has been compiled. The format of data presentation and the quality control procedures are described. Data sources of gas chromatographic retention data are also discussed.

Induced Effects on Red Imported Fire Ant (Hymenoptera: Formicidae) Forager Size Ratios by Pseudacteon spp. (Diptera: Phoridae): Implications on Bait Size Selection.

Red imported fire ants, Solenopsis invicta Buren, are adversely affected by phorid flies in the genus Pseudacteon by instigating defensive behaviors in their hosts, and in turn reducing the efficiency of S. invicta foraging. Multiple Pseudacteon species have been released in Texas, and research has been focused on the establishment and spread of these introduced biological control agents. Field experiments were conducted to determine bait particle size selection of S. invicta when exposed to phorid populations. Four different particle sizes of two candidate baits were offered to foragers (one provided by a pesticide manufacturer, and a laboratory-created bait). Foragers selectively were attracted to, and removed more 1-1.4-mm particles than any other bait size. The industry-provided bait is primarily made of particles in the 1.4-2.0 mm size, larger than what was selected by the ants in this study. While there was a preference for foragers to be attracted to and rest on the industry-provided blank bait, S. invicta removed more of the laboratory-created bait from the test vials. There was an abundance of workers with head widths ranging from 0.5-0.75 mm collected from baits. This was dissimilar from a previous study wherein phorid flies were not active and in which large workers were collected in higher abundance at the site. This implies that phorid fly activity caused a shift for red imported fire ant colonies to have fewer large foragers.

Effect of field pea level on intake, digestion, microbial efficiency, ruminal fermentation, and in situ disappearance in beef steers fed growing diets.

Effects of increasing level of field pea (variety: Profi) on intake, digestion, microbial efficiency, and ruminal fermentation were evaluated in beef steers fed growing diets. Four ruminally and duodenally cannulated crossbred beef steers (367+/-48 kg initial BW) were used in a 4 x 4 Latin square. The control diet consisted of 50% corn, 23% corn silage, 23% alfalfa hay, and 4% supplement (DM basis). Treatments were field pea replacing corn at 0, 33, 67, or 100%. Diets were formulated to contain a minimum of 12% CP, 0.62% Ca, 0.3% P, and 0.8% K (DM basis). Each period was 14 d long. Steers were adapted to the diets for 9 d. On d 10 to 14, intakes were measured. Field pea was incubated in situ, beginning on d 10, for 0, 2, 4, 8, 12, 16, 24, 36, 48, 72, and 96 h. Bags were inserted in reverse order, and all bags were removed at 0 h. Ruminal fluid was collected and pH recorded at -2, 0, 2, 4, 6, 8, 10, and 12 h after feeding on d 13. Duodenal samples were taken for three consecutive days beginning on d 10 in a manner that allowed for a collection to take place every other hour over a 24-h period. Linear, quadratic, and cubic contrasts were used to compare treatments. There were no differences in DMI (12.46 kg/d, 3.16% BW; P > 0.46). Ruminal dry matter fill (P = 0.02) and mean ruminal pH (P = 0.009) decreased linearly with increasing field pea level. Ruminal ammonia-N (P < 0.001) and total VFA concentrations (P = 0.01) increased linearly with increasing field pea level. Total-tract disappearance of OM (P = 0.03), N (P = 0.01), NDF (P = 0.02), and ADF (P = 0.05) increased linearly with an increasing field pea level. There were no differences in total-tract disappearance of starch (P = 0.35). True ruminal N disappearance increased linearly (P < 0.001) with increasing field pea level. There were no differences in ruminal disappearance of OM (P = 0.79), starch (P = 0.77), NDF (P = 0.21), or ADF (P = 0.77). Treatment did not affect microbial efficiency (P = 0.27). Field pea is a highly digestible, nutrient-dense legume grain that ferments rapidly in the rumen. Because of their relatively high level of protein, including field peas in growing diets will decrease the need for protein supplementation. Based on these data, it seems that field pea is a suitable substitute for corn in growing diets.

Effect of field pea level on intake, digestion, microbial efficiency, ruminal fermentation, and in situ disappearance in beef steers fed forage-based diets.

Four ruminally and duodenally cannulated crossbred beef steers (397+/-55 kg initial BW) were used in a 4 x 4 Latin square to evaluate the effects of increasing level of field pea supplementation on intake, digestion, microbial efficiency, ruminal fermentation, and in situ disappearance in steers fed moderate-quality (8.0% CP, DM basis) grass hay. Basal diets, offered ad libitum twice daily, consisted of chopped (15.2-cm screen) grass hay. Supplements were 0, 0.81, 1.62, and 2.43 kg (DM basis) per steer daily of rolled field pea (23.4% CP, DM basis) offered in equal proportions twice daily. Steers were adapted to diets on d 1 to 9; on d 10 to 14, DMI were measured. Field pea and grass hay were incubated in situ, beginning on d 10, for 0, 2, 4, 8, 12, 16, 24, 36, 48, 72, and 96 h. Ruminal fluid was collected and pH recorded at -2, 0, 2, 4, 6, 8, 10, and 12 h after feeding on d 13. Duodenal samples were taken for three consecutive days beginning on d 10 in a manner that allowed for a collection to take place every other hour over a 24-h period. Linear, quadratic, and cubic contrasts were used to evaluate the effects of increasing field pea level. Total DMI and OMI increased quadratically (P = 0.09), whereas forage DMI decreased quadratically (P = 0.09) with increasing field pea supplementation. There was a cubic effect (P < 0.001) for ruminal pH. Ruminal (P = 0.02) and apparent total-tract (P = 0.09) NDF disappearance decreased linearly with increasing field pea supplementation. Total ruminal VFA concentrations responded cubically (P = 0.008). Bacterial N flow (P = 0.002) and true ruminal N disappearance (P = 0.003) increased linearly, and apparent total-tract N disappearance increased quadratically (P = 0.09) with increasing field pea supplementation. No treatment effects were observed for ruminal DM fill (P = 0.82), true ruminal OM disappearance (P = 0.38), apparent intestinal OM digestion (P = 0.50), ruminal ADF disappearance (P = 0.17), apparent total-tract ADF disappearance (P = 0.35), or in situ DM disappearance of forage (P = 0.33). Because of effects on forage intake and ruminal pH, field peas seem to act like cereal grain supplements when used as supplements for forage-based diets. Supplementing field peas seems to effectively increase OM and N intakes of moderate-quality grass hay diets.

Effect of high-selenium wheat on visceral organ mass, and intestinal cellularity and vascularity in finishing beef steers.

Twelve crossbred steers (351 +/- 24 kg initial BW) were used to determine effects of high-Se wheat on visceral tissue mass, intestinal cell growth, and intestinal cellularity and vascularity. Steers were allotted randomly by BW to one of two treatments consisting of 75% concentrate diets that supplied 1) adequate Se concentration (7 to 12 microg x kg x BW(-1) x d(-1)) or 2) high-Se concentration (60 to 70 microg x kg x BW(-1) x d(-1)). Diets were similar in composition, including 25% grass hay, 25% wheat, 39% corn, 5% desugared molasses, and 6% wheat middlings supplement on a DM basis. In the Se treatment, high-Se wheat (10 ppm Se, DM basis) was replaced with low-Se wheat (0.35 ppm Se, DM basis). Diets were formulated to be similar in CP and energy (14.0% CP, 2.12 Mcal of NEm/kg, and 1.26 Mcal NEg/kg of DM) and were offered daily (1500) to individual steers in an electronic feeding system. Diets were fed at 2.38% BW. After 126 d, steers were slaughtered, and individual visceral tissue weights determined. Concentrations of DNA, RNA, and protein of duodenum, ileum, and total small intestine were not affected (P > or = 0.33) by treatment. Similarly, RNA:DNA and protein:DNA ratios in duodenum, jejunum, ileum, and whole small intestine were not (P > or = 0.33) affected by feeding high-Se wheat. Conversely, jejunal weight was greater (P < 0.002) in steers fed high-Se wheat than in controls (916 vs. 1,427 +/- 84 g). Jejunal DNA was increased (P < 0.04) in steers fed high-Se wheat (2.95 vs. 3.56 +/- 0.19 mg/g), suggesting increased cell number. Concentrations of jejunal RNA and protein were not altered by treatment; however, because the jejunal weight increased in high-Se steers, DNA, RNA, and protein contents (grams) were greater than in control steers (P < 0.05). Vascularity of jejunal tissue decreased (P < 0.10) with high-Se wheat; however, because jejunal mass was greater for the high-Se wheat treatment, total microvascular volume was not affected by treatment. Percentage of jejunal crypt cell proliferation was not affected (P = 0.48) by treatment; however, total number of cells proliferating within the jejunum was increased in steers fed high-Se wheat. Data indicate that the lower jejunal vascularity in the diet high in Se (provided from wheat) may have resulted in increased jejunal mass to meet physiological nutrient demand. Therefore, negative effects of Se level used in this study on productive performance of feedlot steers are not expected.

Cohen's weighted kappa with Turbo Pascal (FORTRAN).

A microcomputer based Turbo Pascal and FORTRAN program for Cohen's weighted kappa (kappa w) is given. Three clinical applications for kappa w are also presented. A typical data file, the Pascal and FORTRAN program listing and corresponding output are given.

Analyzing the performance of diagnostic tests.

When a single diagnostic test is used to assess the disease state of a patient, the classic univariate measures of sensitivity and specificity are used. When combining two or more diagnostic tests, other methods provide alternative methods for assessing the utility of combining these tests. We have written and tested a program in FORTRAN that computes the univariate statistics and bivariate concordant/discordant statistics analyses of all possible combinations of diagnostic tests as compared with the 'gold standard'.

Effectiveness comparison of multiple sticky-trap configurations for sampling Pseudacteon spp. phorid flies (Diptera: Phoridae).

A variety of traps have been developed for monitoring introduced populations of Pseudacteon spp. phorid flies (Diptera: Phoridae) across their established range in the United States. Such traps typically exploit common aspects of phorid fly biology and behavior, such as their attraction to live or dead red imported fire ants, Solenopsis invicta Buren (Hymenoptera: Formicidae), as well as the perching behavior of these parasitoids. However, populations of multiple species of phorid flies have been established in the United States to serve as biological control agents against S. invicta, and it is unclear if all trap designs are equally effective in sampling this variety of phorid species. This study investigated the effectiveness of six trap designs simultaneously during three sampling events in south-central Texas. Interactions between two species of phorid flies (Pseudacteon tricuspis Borgmeier and P. curvatus B.) and their hosts have been intensively studied at this location for over eight years. When analyzed independently, there were no significant differences in the mean number of P. curvatus or P. tricuspis phorids collected by any of the trap designs during any of the sampling events. However, when the total number of phorids collected were combined, significant trap performance differentials were observed during the October 2010 sampling event. Furthermore, there were significant differences among male flies during the September 2012 observation. Additionally, a trap component cost comparison is provided. The consistent and relatively equivalent performance of the phorid traps investigated in these trials suggests that all are appropriate for phorid surveillance, and cost and ease-of-use considerations may be the most important criteria when selecting a trap design.

Maternal nutritional plane and selenium supply during gestation impact visceral organ mass and intestinal growth and vascularity of neonatal lamb offspring.

To investigate effects of nutritional plane and Se supply during gestation on neonatal offspring visceral organ mass and intestinal growth and vascularity, 84 nulliparous Rambouillet ewes (age = 240 ± 17 d, BW = 52.1 ± 6.2 kg) were allocated to a 2 × 3 factorial design. Ewes were fed 1 of 2 Se diets [adequate Se (ASe, 11.5 µg/kg BW) or high Se (HSe, 77.0 µg/kg BW)], initiated at breeding, and 1 of 3 nutritional planes [60% (restricted; RES), 100% (control; CON), or 140% (high; HIH) of NRC requirements], initiated at d 40 of gestation. Ewes were fed individually and remained on treatments through parturition. All lambs were removed from their dams at birth and fed milk replacer. At 20.6 ± 0.9 d of age, lambs were necropsied, visceral organs dissected, and jejunal samples collected. Lambs born to ewes fed CON and HIH had greater (P < 0.05) BW, gastrointestinal tract, stomach complex, and liver masses at necropsy than RES. Large intestinal and pancreatic masses, as well as stomach complex, large intestinal, and liver proportional masses, demonstrated (P ≤ 0.08) a nutritional plane × Se supply interaction. Proportional pancreatic mass was greater (P = 0.03) for lambs born to RES ewes than HIH. Although small intestinal mass was not affected (P ≥ 0.18) by gestational treatments, lambs born to HIH-fed ewes had greater (P ≤ 0.09) jejunal DNA concentration than RES and CON, and greater (P = 0.01) total DNA than RES. Nutritional plane and Se supply interacted to affect (P ≤ 0.003) jejunal percent proliferation and total proliferating small intestinal cells, although jejunal crypt depth and villus length were not affected by gestational treatment (P ≥ 0.17). Jejunal glucagon-like peptide-2 mRNA expression was greater (P ≤ 0.07) in lambs born to ewes fed RES compared with CON and HIH. Jejunal capillary size was affected (P = 0.09) by the interaction of nutritional plane × Se supply. Lambs from CON ewes had greater (P ≤ 0.04) jejunal capillary surface density than RES. Nutritional plane and Se supply interacted to affect (P = 0.07) jejunal soluble guanylate cyclase mRNA expression in a manner opposite of capillary size. In conclusion, neonatal lamb visceral organ mass was affected by gestational nutrition, even when lambs had ad libitum intake and similar management postnatally. Despite similar small intestinal mass at 20 d of age, jejunal growth, vascularity, and gene expression were altered by maternal nutrition during gestation.

Impacts of maternal selenium supply and nutritional plane on visceral tissues and intestinal biology in 180-day-old offspring in sheep.

Objectives were to investigate the effects of maternal Se supply and nutritional plane during gestation on offspring visceral tissues and indices of intestinal growth, vascularity, and function at 180 d of age. Rambouillet ewe lambs (n = 82, approximately 240 d of age; 52 ± 0.8 kg BW at breeding) were allocated to a 2 × 3 factorial arrangement of treatments. Treatments included dietary Se [adequate Se (ASe, 9.5 µg/kg BW) or high Se (HSe, 81.8 µg/kg BW)] initiated at breeding and nutritional plane [60% (restricted, RES), 100% (control, CON), and 140% (high, HI) of requirements] initiated at d 50 of gestation. Ewes were fed pelleted diets and housed individually indoors. At parturition, lambs were immediately removed and fed artificial colostrum for the first 20 h followed by ad libitum access to milk replacer. At 180 ± 2 d of age, lambs were euthanized and tissues were harvested. Birth weight was affected by nutritional treatments (P < 0.001), with decreased birth weight in RES and HI compared with CON. Offspring from RES and HI ewes had decreased (P = 0.07) blood volume compared with CON, and those born to HSe ewes had increased (P < 0.04) total visceral adiposity. Within offspring from CON ewes, those from HSe ewes had greater (P < 0.02) intestinal mass compared with ASe ewes. Within offspring from HSe ewes, both RES and HI had reduced (P ≤ 0.05) intestinal mass compared with CON. Jejunal capillary area density was greater (P = 0.08) in offspring from ewes fed HSe compared with ASe. In addition, area per capillary was greater (P ≤ 0.09) in CON compared with RES. Maternal nutritional plane tended (P ≤ 0.11) to alter total small intestinal vascularity, with lambs from CON being greater than RES. Expression of most mRNA for measured angiogenic factors and receptors was not altered (P ≤ 0.13) by maternal treatments; however, expression of glucagon-like peptide-2 (GLP-2) was decreased (P = 0.07) in offspring from RES compared with CON ewes. Offspring from ewes fed HI diets had increased (P = 0.08) jejunal mucosal maltase activity. In conclusion, maternal Se supply and nutritional plane during gestation resulted in measurable changes in offspring visceral tissues and intestinal biology, including perirenal fat, blood volume, intestinal mass, total jejunal crypt cell proliferation, area per capillary in jejunal villi, GLP-2 mRNA expression, and maltase activity at 180 d. Additional work is needed to determine impacts on intestinal function and nutrient uptake.

Effects of nutritional plane and selenium supply during gestation on visceral organ mass and indices of intestinal growth and vascularity in primiparous ewes at parturition and during early lactation.

Objectives were to investigate effects of nutritional plane and Se supply during gestation on visceral organ mass and intestinal growth and vascularization in ewes at parturition and during early lactation. Primiparous Rambouillet ewes (n = 84) were allocated to 2 × 3 × 2 factorial arrangement of treatments. Factors included dietary Se [adequate Se (ASe, 11.5 µg/kg BW) or high Se (HSe, 77.0 µg/kg BW)], nutritional plane [60% (restricted; RES), 100% (control; CON), or 140% (high; HIH)], and physiological stage at necropsy (parturition or d 20 of lactation). At parturition, lambs were removed and 42 ewes (7 per treatment) were necropsied. Remaining ewes were transitioned to a common diet which met lactation requirements and mechanically milked for 20 d. In the absence of interactions (P > 0.10), main effects are reported. At parturition, stomach complex and liver masses were greatest for HIH, intermediate for CON, and least for RES (P < 0.02). Small intestinal mass was greater (P ≤ 0.002) for HIH than RES and CON, and greater (P < 0.01) for ASe than HSe. During early lactation, RES and CON gastrointestinal masses increased disproportionally to BW (P < 0.05). At parturition, jejunal mucosal density was less (P ≤ 0.01) for RES than CON and HIH, whereas CON had greater (P < 0.003) jejunal mucosal RNA concentration and RNA:DNA than RES and HIH. Although there were no differences (P > 0.17) at parturition, jejunal cell percent proliferation was greatest in RES, intermediate in CON, and least in HIH (P ≤ 0.09) at d 20 lactation. At both stages, RES had less (P = 0.01) jejunal capillary area density than HIH and less (P ≤ 0.03) capillary surface density than CON and HIH. During lactation, jejunal capillary size was greater (P = 0.04) for ewes previously fed HSe compared with ASe. At parturition, ASe-HIH had greater (P < 0.02) jejunal mucosal endothelial nitric oxide synthase 3 mRNA than all other treatments and greater (P = 0.10) vascular endothelial growth factor (VEGF) than all treatments, except ASe-RES. In addition, CON had less (P ≤ 0.08) jejunal VEGF receptor-1 (FLT1) mRNA compared with RES and HIH, and ASe had greater (P = 0.003) FLT1 than HSe at parturition. Ewes fed HIH had greater (P = 0.04) jejunal VEGF receptor-2 mRNA compared with RES. Results indicate that maternal intestinal growth and vascularization are responsive to nutritional plane and dietary Se during gestation and undergo changes postpartum when under similar lactational management.

Nutritional plane and selenium supply during gestation affect yield and nutrient composition of colostrum and milk in primiparous ewes.

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.

Effects of maternal selenium supply and plane of nutrition during gestation on passive transfer of immunity and health in neonatal lambs.

To investigate the influence of maternal Se supply and plane of nutrition on lamb morbidity, mortality, and passive transfer of IgG, pregnant ewe lambs were used in 2 experiments with 2 × 3 factorial treatment arrangements. Supplementation of Se began at breeding and was either adequate Se (ASe, 9.5 µg/kg of BW) or high Se (HSe, 81.8 µg/kg of BW) in Exp. 1 or ASe (11.5 µg/kg of BW) or HSe (77.0 µg/kg of BW) in Exp. 2. On d 50 or 40 of gestation for Exp. 1 or 2, respectively, ewes were assigned randomly to 1 of 3 nutritional planes: 60% (RES), 100% (control, CON), or 140% (HI) of NRC requirements. This resulted in the following treatments: ASe-RES, ASe-CON, ASe-HI, HSe-RES, HSe-CON, and HSe-HI. Upon parturition, lambs were separated from their dams and serum samples obtained. Lambs were fed artificial colostrum for the first 20 h and then placed on milk replacer and grain pellets until completion of the study (Exp. 1, 57 d; Exp. 2, 21 d). Twenty-four hours after parturition, lamb serum samples were collected for IgG analysis. All lambs were reared similarly and morbidity and mortality assessed. Main effects were considered significant when P ≤ 0.05. In Exp. 1, there was a Se × plane of nutrition interaction (P ≤ 0.01) for lamb morbidity from birth to weaning and for 24-h IgG concentration. Lambs from ASe-RES and HSe-HI ewes were treated more frequently (P < 0.01) for respiratory and gastrointestinal disease, and lambs from HSe-HI ewes had the smallest (P < 0.01) 24-h serum IgG concentration. In Exp. 1, lambs from HI ewes also had the greatest (P < 0.01) mortality rates from birth to weaning compared with lambs from CON and RES ewes. In Exp. 2, there was an effect (P < 0.01) of maternal plane of nutrition with lambs from RES ewes having increased 24-h IgG compared with lambs from CON and HI ewes. There was no effect of maternal Se supplementation on lamb 24-h IgG in Exp. 2; however, there was a Se × plane of nutrition interaction (P < 0.01) for morbidity. From birth to 21 d of age, lambs from ASe-CON ewes had fewer (P < 0.01) treatment days compared with lambs from any of the other treatment groups. There also tended (P = 0.08) to be an effect of maternal Se supplementation on lamb mortality with increased mortality observed in lambs from HSe ewes. Results from the studies show a restricted maternal plane of nutrition can increase lamb serum IgG concentration. Selenium results were not consistent between the 2 experiments and may be due to differences in maternal Se.

Effects of stage of gestation and nutrient restriction during early to mid-gestation on maternal and fetal visceral organ mass and indices of jejunal growth and vascularity in beef cows.

The objectives were to evaluate effects of maternal nutrient restriction and stage of gestation on maternal and fetal visceral organ mass and indices of jejunal growth and vascularity in beef cows. Thirty multiparous beef cows (BW = 571 +/- 63 kg; BCS = 5.4 +/- 0.7) carrying female fetuses (d 30 of gestation) were allocated to receive a diet of native grass hay (CON; 12.1% CP, 70.7% IVDMD, DM basis) to meet NRC recommendations for BW gain during early gestation or a nutrient-restricted diet of millet straw (NR; 9.9% CP, 54.5% IVDMD, DM basis) to provide 68.1% of NE(m) and 86.7% of MP estimated requirements. On d 125 of gestation, 10 CON and 10 NR cows were killed and necropsied. Five remaining CON cows received the CON diet, and 5 NR cows were realimented with a concentrate supplement (13.2% CP, 77.6% IVDMD, DM basis) and the CON hay to achieve a BCS similar to CON cows by d 220 of gestation. Remaining cows were necropsied on d 245 of gestation. Cow BW and eviscerated BW (EBW) were less (P < 0.01) for NR than CON at d 125 but did not differ (P > 0.63) at d 245. Cows fed the CON diet had greater (P < 0.09) total gastrointestinal (GI) tract, omasal, and pancreatic weights. Stomach complex, ruminal, and liver weights were greater for CON than NR cows (P < 0.09) on d 125. Total GI, stomach complex, and pancreatic weights increased (P < 0.001) with day of gestation. Restricted cows had decreased (P = 0.09) duodenal RNA:DNA compared with CON. Duodenal DNA was less (P = 0.01) and jejunal RNA:DNA (P = 0.09) was greater for cows at d 125 vs. 245. Cow jejunal capillary area density increased with day of gestation (P = 0.02). Fetal BW and EBW were unaffected by dietary treatment (P > or = 0.32). Total GI tract and all components increased in mass with day of gestation (P < 0.001). Fetuses from NR dams had greater (P = 0.003) reticular mass at d 245 than CON fetuses. Fetuses from NR cows had greater (P = 0.02) percent jejunal proliferation at d 125 and greater (P = 0.03) total intestinal vascularity (mL) at d 245. Fetal jejunal DNA decreased (P = 0.09), RNA:DNA increased (P = 0.05), and total jejunal proliferating cells increased (P < 0.001) with day of gestation. Jejunal capillary area density, number density, and surface density were greater (P < 0.008) during late gestation. Results indicate that maternal and fetal intestines undergo changes during gestation, which can be affected by nutrient restriction and may partially explain differences observed in fetal development and postnatal performance.

Maternal dietary restriction and selenium supply alters messenger ribonucleic acid expression of angiogenic factors in maternal intestine, mammary gland, and fetal jejunal tissues during late gestation in pregnant ewe lambs.

The objectives of this study were to evaluate effects of maternal dietary restriction and Se supply on angiogenic factor mRNA expression in intestinal and mammary tissues, and jejunal crypt cell proliferation and vascularity in late-term fetal intestines. In Exp. 1, pregnant ewe lambs (n = 32; initial BW = 45.6 +/- 2.3 kg) were allotted randomly to 1 of 4 treatments. Treatments (initiated d 50 +/- 5 of gestation) were control (3.5 microg of Se.kg of BW(-1).d(-1)), Se-wheat (75 microg of Se.kg of BW(-1).d(-1)), selenate (Se3; providing 75 microg of Se.kg of BW(-1).d(-1)), selenate (Se15; providing 375 microg of Se.kg of BW(-1).d(-1)). Diets (DM basis) were similar in CP (15.5%) and ME (2.68 Mcal/kg). In Exp. 2, pregnant ewe lambs (n = 36; initial BW 53.8 +/- 1.3 kg) were allotted randomly to treatments in a 2 x 2 factorial arrangement. Factors were nutrition (control, 100% of requirements vs. restricted nutrition, 60% of controls) and dietary Se (adequate Se; 6 microg of Se.kg of BW(-1).d(-1) vs. high Se; 80 microg of Se.kg of BW(-1).d(-1)). Selenium treatments were initiated 21 d before breeding, and nutritional treatments were initiated on d 64 of gestation. Diets (DM basis) were 16% CP and 2.12 Mcal/kg of ME. In Exp. 1, Se15 increased (P = 0.07) vascular endothelial growth factor (VEGF) mRNA expression, whereas Se supplementation decreased (P = 0.06) kinase insert domain receptor (KDR) mRNA in maternal mucosal scrape on d 134 of gestation. Expression of VEGF mRNA was decreased by Se (P = 0.10) in fetal jejunum. In mammary tissue, fms-related tyrosine kinase 1 and KDR mRNA were greater in Se-wheat compared with Se3, and KDR expression was increased (P = 0.10) in Se15 compared with Se3. In Exp. 2, dietary restriction increased (P < or = 0.07) expression of mRNA for VEGF, fms-related tyrosine kinase 1, KDR, neuropilin 1, neuropilin 2, and hypoxia-inducible factor 1, alpha subunit in mucosal scrapes from maternal jejunum. In fetal jejunum, soluble guanylate cyclase, was decreased (P = 0.01) by maternal dietary restriction from d 64 to 135 of gestation. Total microvascularity in fetal jejunum was reduced (P = 0.002) by maternal dietary restriction. Mammary gland expression of VEGF, neuropilin 1, angiopoietin receptor (endothelial tyrosine kinase), and endothelial nitric oxide synthase 3 increased (P < or = 0.09), whereas angiopoietin 1 decreased (P = 0.05) due to nutrient restriction. Data indicate that expression of angiogenic factors and receptors in maternal intestine, mammary gland, and fetal jejunum are responsive to maternal nutrition and likely explain observed changes in tissue vascularity.

Effects of plane of nutrition and selenium supply during gestation on ewe and neonatal offspring performance, body composition, and serum selenium.

To investigate the effects of nutritional plane and Se supply during gestation on ewe and offspring performance and body composition, 84 Rambouillet ewe lambs (age = 240 +/- 17 d, BW = 52.1 +/- 6.2 kg) were allocated to a 2 x 3 x 2 factorial arrangement of treatments. Factors included Se [adequate Se (ASe, 11.5 microg/kg of BW) or high Se (HSe, 77.0 microg/kg of BW)] initiated at breeding, nutritional plane [60% (restricted, RES), 100% (control, CON), or 140% (high, HIH) of NRC requirements] initiated at d 40 of gestation, and physiological stage at necropsy [3 to 24 h postpartum or d 20 of lactation]. Ewes were fed and housed individually in a temperature-controlled facility. At parturition, all lambs were removed and artificially reared until necropsy on d 20.6 +/- 0.9 of age. Ewes assigned to the treatment at d 20 of lactation were transitioned to a common diet meeting lactation requirements and were mechanically milked. From d 95 of gestation through parturition and d 20 of lactation, ewe BW and BCS were least (P

Ovine offspring growth and diet digestibility are influenced by maternal selenium supplementation and nutritional intake during pregnancy despite a common postnatal diet.

Lambs born from feed-restricted or overfed ewes can be lighter at birth, whereas maternal Se supplementation can increase fetal size near term. We hypothesized that birth weight would be inversely related to feed efficiency and growth rates during postnatal development. To examine the effects of maternal dietary Se and nutrient restriction or excess on postnatal lamb growth, diet digestibility, and N retention, 82 ewe lambs (52.2 ± 0.8 kg) were allotted randomly to 1 of 6 treatments in a 2 × 3 factorial arrangement. Factors were dietary Se [adequate Se (9.5 µg/kg of BW; ASe) vs. high Se (Se-enriched yeast; 81.8 µg/kg of BW; HSe)] and maternal nutritional intake [60% (restricted, RES), 100% (control, CON), or 140% (high, HI) of NRC requirements]. Selenium treatments began at breeding. Nutritional treatments began on d 50 of gestation. Lambs were immediately removed from their dams at parturition, provided artificial colostrum, and fed milk replacer until weaning. After weaning, lambs were maintained using common management and on common diets until necropsy at 180 d. Male and female lambs from RES-fed ewes were lighter (P ≤ 0.03) at birth than lambs from CON-fed ewes, with lambs from HI-fed ewes being intermediate. Although maternal nutritional intake influenced (P < 0.06) BW gain before weaning on d 57, both maternal nutritional intake and sex of offspring influenced (P ≤ 0.09) BW gain from d 57 to 180. Although maternal nutritional intake did not influence (P ≥ 0.35) female lamb BW gain, male lambs from RES-fed ewes were lighter (P ≤ 0.09) than those from CON-fed ewes until d 162. By d 180, male lambs from RES- and HI-fed ewes were lighter (P ≤ 0.09) than those from CON-fed ewes. In a subset of lambs used in a feed efficiency study, namely, those born to ASe ewes, HI maternal nutritional intake decreased (P ≤ 0.09) ADG and G:F compared with lambs born to RES- and CON-fed ewes, which did not differ (P ≥ 0.60). Conversely, when lambs were born to HSe ewes, HI maternal nutritional intake increased (P ≤ 0.01) ADG and G:F compared with CON, with RES being intermediate. Moreover, lambs born to ASe-HI ewes had decreased (P < 0.01) ADG and G:F compared with lambs born to HSe-HI ewes. Furthermore, male lambs had a greater (P < 0.01) G:F than female lambs. Maternal diet did not affect (P ≥ 0.11) N retention in male lambs. These data indicate that maternal nutrition during gestation and sex of the offspring alter postnatal growth and efficiency of growth in offspring despite similar postnatal management.

Effects of maternal nutrition and stage of gestation on body weight, visceral organ mass, and indices of jejunal cellularity, proliferation, and vascularity in pregnant ewe lambs.

Peripubertal ewe lambs (44.3 +/- 1.1 kg of initial BW) were used in a 2 x 3 factorial design to test the effects of plane of nutrition (diet) and stage of gestation on maternal visceral tissue mass, intestinal cellularity, crypt cell proliferation, and jejunal mucosal vascularity. Singleton pregnancies to a single sire were established by embryo transfer, and thereafter ewes were offered a control (Control) or high (High) amount of a complete diet (2.84 Mcal/kg and 15.9% CP; DM basis) to promote slow or rapid maternal growth rates. After d 90 of gestation, feed intake of the Control group was adjusted weekly to maintain BCS and meet the increasing nutrient demands of the gravid uterus. Ewes were slaughtered at 50 d (n = 6 Control; n = 5 High), 90 d (n = 8 Control; n = 6 High), or 130 d (n = 8 Control; n = 6 High) of gestation. Ewes were eviscerated and masses of individual organs were recorded. The jejunum was sampled and processed for subsequent analyses. Final ewe BW for Control-fed ewes was similar at d 50 and 90 and increased (P = 0.10) from d 90 to 130 (46.0, 48.9, and 58.2 +/- 1.6 kg, respectively), whereas final BW increased (P

Effects of dietary selenium supply and timing of nutrient restriction during gestation on maternal growth and body composition of pregnant adolescent ewes.

The objectives were to examine effects of dietary Se supplementation and nutrient restriction during defined periods of gestation on maternal adaptations to pregnancy in primigravid sheep. Sixty-four pregnant Western Whiteface ewe lambs were assigned to treatments in a 2 x 4 factorial design. Treatments were dietary Se [adequate Se (ASe; 3.05 microg/kg of BW) vs. high Se (HSe; 70.4 microg/kg of BW)] fed as Se-enriched yeast, and plane of nutrition [control (C; 100% of NRC requirements) vs. restricted (R; 60% of NRC requirements]. Selenium treatments were fed throughout gestation. Plane of nutrition treatments were applied during mid (d 50 to 90) and late gestation (d 90 to 130), which resulted in 4 distinct plane of nutrition treatments [treatment: CC (control from d 50 to 130), RC (restricted from d 50 to 90, and control d 90 to 130), CR (control from d 50 to 90, and restricted from d 90 to 130), and RR (restricted from d 50 to 130)]. All of the pregnant ewes were necropsied on d 132 +/- 0.9 of gestation (length of gestation approximately 145 d). Nutrient restriction treatments decreased ewe ADG and G:F, as a result, RC and CR ewes had similar BW and maternal BW (MBW) at necropsy, whereas RR ewes were lighter than RC and CR ewes. From d 90 to 130, the HSe-CC ewes had greater ADG (Se x nutrition; P = 0.05) than did ASe-CC ewes, whereas ADG and G:F (Se x nutrition; P = 0.08) were less for HSe-RR ewes compared with ASe-RR ewes. The CR and RR treatments decreased total gravid uterus weight (P = 0.01) as well as fetal weight (P = 0.02) compared with RC and CC. High Se decreased total (g; P = 0.09) and relative heart mass (g/kg of MBW; P = 0.10), but increased total and relative mass of liver (P < or = 0.05) and perirenal fat (P < or = 0.06) compared with ASe. Total stomach complex mass was decreased (P < 0.01) by all the nutrient restriction treatments, but was reduced to a greater extent in CR and RR compared with RC. Total small intestine mass was similar between RC and CC ewes, but was markedly reduced (P < 0.01) in CR and RR ewes. The mass of the stomach complex and the small and large intestine relative to MBW was greater (P = 0.01) for RC than for CR ewes. Increased Se decreased jejunal DNA concentration (P = 0.07), total jejunal cell number (P = 0.03), and total proliferating jejunal cell number (P = 0.05) compared with ASe. These data indicate that increased dietary Se affected whole-body and organ growth of pregnant ewes, but the results differed depending on the plane of nutrition. In addition, the timing and duration of nutrient restriction relative to stage of pregnancy affected visceral organ mass in a markedly different fashion.

Effects of selenium supply and dietary restriction on maternal and fetal metabolic hormones in pregnant ewe lambs.

The objective of these studies was to evaluate the effects of dietary restriction and Se on maternal and fetal metabolic hormones. In Exp. 1, pregnant ewe lambs (n = 32; BW = 45.6 +/- 2.3 kg) were allotted randomly to 1 of 4 treatments. Diets contained (DM basis) either no added Se (control), or supranutritional Se added as high-Se wheat at 3.0 mg/kg (Se-wheat), or sodium selenate at 3 (Se3) and 15 (Se15) mg/kg of Se. Diets (DM basis) were similar in CP (15.5%) and ME (2.68 Mcal/kg). Treatments were initiated at 50 +/- 5 d of gestation. The control, Se-wheat, Se3, and Se15 treatments provided 2.5, 75, 75, and 375 microg/kg of BW of Se, respectively. Ewe jugular blood samples were collected at 50, 64, 78, 92, 106, 120, and 134 d of gestation. Fetal serum samples were collected at necropsy on d 134. In Exp. 2, pregnant ewe lambs (n = 36; BW 53.8 +/- 1.3 kg) were allotted randomly to treatments in a 2 x 2 factorial arrangement. Factors were nutrition (control, 100% of requirements vs. restricted nutrition, 60% of control) and dietary Se (adequate Se, 6 microg/kg of BW vs. high Se, 80 microg/kg of BW). Selenium treatments were initiated 21 d before breeding, and nutritional treatments were initiated on d 64 of gestation. Diets were 16% CP and 2.12 Mcal/kg of ME (DM basis). Blood samples were collected from the ewes at 62, 76, 90, 104, 118, 132, and 135 d of gestation. Fetal blood was collected at necropsy on d 135. In Exp.1, dietary Se source and concentration had no effect (P > 0.17) on maternal and fetal serum IGF-I, triiodothyronine (T(3)), or thyroxine (T(4)) concentrations. Selenium supplementation increased (P = 0.06) the T(4):T(3) ratio vs. controls. In Exp. 2, dietary Se had no impact (P > 0.33) on main effect means for maternal and fetal serum IGF-I, T(3), or T(4) concentrations from d 62 to 132; however, at d 135, high-Se ewes had lower (P = 0.01) serum T(4) concentrations than adequate-Se ewes. A nutrition by Se interaction (P = 0.06) was detected for the T(4):T(3) ratios; ewes fed restricted and adequate-Se diets had greater (P = 0.10) T(4):T(3) ratios compared with the other treatments. Nutrient-restricted ewes had lower (P < 0.05) serum IGF-I, T(3), and T(4) concentrations. Fetal serum IGF-I concentrations were lower (P = 0.01) in restricted-vs. control-fed ewes; however, fetal T(3) and T(4) concentrations were unaffected (P > 0.13) by dietary Se or maternal plane of nutrition. These data indicate that dietary Se may alter maternal T(4):T(3) ratios. In addition, nutrient restriction during gestation reduces maternal IGF-I, T(3), and T(4) and fetal IGF-I concentrations.