Search

Objective: Fetuses with single ventricle physiology (SVP) exhibit reductions in fetal cerebral oxygenation, with associated delays in fetal brain growth and neurodevelopmental outcomes. Maternal supplemental oxygen (MSO) has been proposed to improve fetal brain growth, but current evidence on dosing, candidacy and outcomes is limited. In this pilot study, we evaluated the safety and feasibility of continuous low‐dose MSO in the setting of SVP. Methods: This single‐center, open‐label, pilot phase‐1 safety and feasibility clinical trial included 25 pregnant individuals with a diagnosis of fetal SVP. Participants self‐administered continuous MSO using medical‐grade oxygen concentrators for up to 24 h per day from the second half of gestation until delivery. The primary aim was the evaluation of the safety profile and feasibility of MSO. A secondary preliminary analysis was performed to assess the impact of MSO on the fetal circulation using echocardiography and late‐gestation cardiovascular magnetic resonance imaging. Early outcomes were assessed, including perinatal growth and preoperative brain injury, and neurodevelopmental outcomes were assessed at 18 months using the Bayley Scales of Infant and Toddler Development 3rd edition, and compared with those of a contemporary fetal SVP cohort (n = 217) that received the normal standard of care (SOC). Results: Among the 25 participants, the median maternal age at conception was 35 years, and fetal SVP diagnoses included 16 with right ventricle dominant, eight with left ventricle dominant and one with indeterminate ventricular morphology. Participants started the trial at approximately 29 + 2 weeks' gestation and self‐administered MSO for a median of 16.1 h per day for 63 days, accumulating a median of 1029 h of oxygen intake from enrolment until delivery. The only treatment‐associated adverse events were nasal complications that were resolved typically by attaching a humidifier unit to the oxygen concentrator. No premature closure of the ductus arteriosus or unexpected fetal demise was observed. In the secondary analysis, MSO was not associated with any changes in fetal growth, middle cerebral artery pulsatility index, cerebroplacental ratio or head‐circumference‐to‐abdominal‐circumference ratio Z‐scores over gestation compared with SOC. Although MSO was associated with changes in umbilical artery pulsatility index Z‐score over the study period compared with SOC (P = 0.02), this was probably due to initial baseline differences in placental resistance. At late‐gestation cardiovascular magnetic resonance imaging, MSO was not associated with an increase in fetal cerebral oxygen delivery. Similarly, no differences were observed in neonatal outcomes, including preoperative brain weight Z‐score and brain injury, mortality by 18 months of age and neurodevelopmental outcomes at 18 months of age. Conclusions: This pilot phase‐1 clinical trial indicates that low‐dose MSO therapy is safe and well tolerated in pregnancies diagnosed with fetal SVP. However, our protocol was not associated with an increase in fetal cerebral oxygen delivery or improvements in early neurological or neurodevelopmental outcomes. © 2024 International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]

Some studies on neurodevelopmental outcomes after neonatal encephalopathy have suggested that cognitive deficits do not occur in the absence of cerebral palsy. It is increasingly apparent that childhood survivors of overt neonatal encephalopathy may have cognitive impairments, even in the absence of functional motor deficits. The risk of cognitive deficits is related to the severity of neonatal encephalopathy and the pattern of brain injury on neuroimaging, particularly the watershed pattern of injury. A better understanding of the risk factors for cognitive abnormalities after neonatal encephalopathy will ultimately lead to interventions to prevent these deficits. Identifying the full spectrum of neurodevelopmental outcomes after neonatal encephalopathy will also allow care givers to identify children requiring early intervention to maximise their potential for independent function throughout development. [ABSTRACT FROM AUTHOR]

Partial carcass dissection data from 1,031 finished crossbred beef steers were used to calculate heritabilities and genetic correlations among subcutaneous, intermuscular, and body cavity fat percentage and marbling score adjusted to slaughter age-, HCW-, fat depth-, and marbling score-constant endpoints. Genetic correlations were also calculated among these fat partitions with live growth and ultrasound traits evaluated in yearling beef bulls (n = 2,172) and steer carcass measurements. Heritabilities of the different fat partitions ranged from 0.22 (marbling score-constant body cavity fat) to 0.46 (HCW-constant marbling score). Genetic correlations between subcutaneous fat and intermuscular fat (rg = 0.16 to 0.32) and between intermuscular fat and body cavity fat (rg = 0.38 to 0.50) were more highly associated than subcutaneous fat and body cavity fat (rg = -0.08 to 0.05), indicating that fat depots are not under identical genetic control. Adjusting fat depots to different end points affected the magnitude but usually not the sign of the genetic correlations. Bull postweaning gain was associated with intermuscular (-0.24 to -0.35), body cavity (-0.24 to -0.29), and marbling fat (-0.24 to -0.39) in steers. Bull hip height was associated with body cavity (-0.20 to -0.29) and marbling fat (-0.20 to -0.47) in steers. Bull ultrasound fat depth was associated with subcutaneous (0.11 to 0.29), intermuscular (0.05 to 0.36), body cavity (0.27 to 0.49), and marbling fat (0.27 to 0.73) in steers. Bull ultrasound intramuscular fat percentage was associated with subcutaneous (-0.22 to -0.44) and intermuscular fat (-0.06 to 0.31) in steers. Bull ultrasound LM area was associated with body cavity (-0.25 to -0.31) and marbling fat (-0.25 to -0.30) in steers. Ultrasound LM width measurements were negatively correlated with subcutaneous fat (rg = -0.09 to -0.18), intermuscular fat (rg = -0.53 to -0.61), body cavity fat (rg = -0.63 to -0.69), and marbling score (rg = -0.75 to -0.87) at slaughter age-, HCW-, and fat depth-constant endpoints; correlations were generally lower at a marbling score-constant end point (rg = 0.07 to -0.49). Ultrasound indicator traits measured in seedstock may be useful in altering fat partitioning in commercial beef carcasses. [ABSTRACT FROM AUTHOR]

We studied genetic relationships between age-constant live yearling beef bull growth and ultrasound traits and steer carcass traits with dissected steer carcass lean percentage adjusted to slaughter age-, HCW-, fat depth-, and marbling score-constant end points. Three measures of steer carcass lean percentage were used. Blue Tag lean percentage (BTLean) was predicted from HCW, fat depth, and LM area measurements. Ruler lean percentage (RulerLean) was predicted from carcass fat depth and LM depth and width measurements. Dissected lean percentage (DissLean) was based on dissection of the 10-11-12th rib section. Both BTLean (h2 = 0.30 to 0.44) and DissLean (h2 = 0.34 to 0.39) were more heritable than RulerLean (h2 = 0.05 to 0.14) at all end points. Genetic correlations among DissLean and RulerLean (rg = 0.61 to 0.70), DissLean and BTLean (rg = 0.56 to 0.72), and BTLean and RulerLean (rg = 0.59 to 0.90) indicated that these traits were not genetically identical. Adjusting DissLean to different end points changed the magnitude, but generally not the direction, of genetic correlations with indicator traits. Ultrasound scan-age-constant live yearling bull lean percentage estimates were heritable (h2 = 0.26 to 0.42) and genetically correlated with each other (rg = 0.68 to 0.99) but had greater correlations with DissLean at slaughter age (rg = 0.24 to 0.48) and HCW (rg = 0.16 to 0.40) end points than at fat depth (rg = -0.08 to 0.13) and marbling score (rg = 0.02 to 0.11) end points. Scan-age-constant yearling bull ultrasound fat depth also had stronger correlations with DissLean at slaughter age (rg = -0.34) and HCW (rg = -0.25) than at fat depth (rg = -0.02) and marbling score (rg = -0.03) end points. Yearling bull scan-age-constant ultrasound LM area was positively correlated with DissLean at all endpoints (rg = 0.11 to 0.23). Genetic correlations between yearling bull LM method 1 width (rg = 0.38 to 0.56) and method 2 depth (rg = -0.17 to -0.38) measurements with DissLean suggested that LM shape may be a valuable addition to genetic improvement programs for carcass lean percentage at slaughter age, HCW, and fat depth constant end points. At all end points, steer carcass fat depth (rg = -0.60 to -0.64) and LM area (rg = 0.48 to 0.59) had stronger associations with DissLean than did corresponding live yearling bull measurements. Improved methods that combine live ultrasound and carcass traits would be beneficial for evaluating carcass lean percentage at fat depth or marbling score end points. [ABSTRACT FROM AUTHOR]

Calpastatin (CAST) is a naturally occurring protein that inhibits the normal tenderization of meat as it ages postmortem. A SNP was identified in the CAST gene (a G to C substitution) and genotyped on crossbred commercially fed heifers (n = 163), steers (n = 226), and bulls (n = 61) from beef feedlots, and steers (n = 178) from a University of Guelph feeding trial. The association of the CAST SNP with carcass and meat quality traits was studied. Carcass traits included fat, lean, and bone yield; grade fat; LM area; and HCW. Meat quality traits included marbling grade; i.m. fat content of LM; tenderness evaluation of LM (Warner-Bratzler shear force) at 2, 7, 14, and 21 d of postmortem aging; and tenderness evaluation of semitendinosus muscle at 7 d of postmortem aging. The mixed model used in the analyses included fixed effects of CAST genotype, sex, slaughter group, and breed composition (linear covariate); sire was a random effect. For the analysis of shear force, i.m. fat content of LM was also included in the model as a linear covariate. Shear force measures were analyzed within days of postmortem aging and by repeated measures analysis. The CAST SNP allele C was more frequent (63%) in the crossbred population than allele G. The CAST SNP was associated with shear force across days of postmortem aging (P = 0.005); genotype CC yielded beef that was more tender than GG (-0.32 kg ± 0.13), and CG had intermediate tenderness. The corresponding average allele substitution effect (G to C substitution) was also highly significant (-0.15 ± 0.05 kg, P = 0.002). A lower percentage of unacceptably tough steaks (shear force >5.7 kg) at 2 and 7 d postmortem was associated with an increasing number of C alleles (P ≤ 0.05). At 7 d postmortem, the percentage of unacceptably tough steaks decreased by 24 and 35%, respectively, for animals carrying 1 and 2 copies of the C allele relative to animals with no C alleles. However, genotype CC had a greater fat yield (+1.44 ± 0.56%; P = 0.037) than genotype GG, with a corresponding allele substitution effect of 0.67 ± 0.27% (P = 0.015). Therefore, the CAST SNP allele C was associated with increased LM tenderness across days of postmortem aging and, importantly for the beef industry, had a significant reduction in the percentage of steaks rated unacceptably tough by consumers based on an assumed threshold level. [ABSTRACT FROM AUTHOR]

Studies with different populations arc required to properly characterize the robustness of associations of polymorphisms in candidate genes with economically important traits across beef cattle populations before this sort of genetic information can be used efficiently in breeding and management decisions. The objective of this study was to evaluate the association of previously reported SNP in the bovine leptin gene with carcass and meat quality traits from a large sample of crossbred beef cattle. Five SNP (UASMSI UASMS2, UASMS3, E2JW, and E2FB) were genotyped on 1,111 crossbred bulls, heifers, and steers. The measured traits included fat, lean, and bone yield (%) by partial rib dissection, grade fat, LM area, HCW, quality grade, LM i.m. fat, and tenderness evaluation of LM and semitendinosus muscle. Only four SNP were analyzed (UASMS1, UASMS2, E2JW, and E2FB), because UASMS1 and UASMS3 were completely linked. A univariate mixed-inheritance animal model was used to evaluate the association of either genotypes or haplotypes with the traits. The two leptin exon 2 SNP were associated with fat and lean yield and grade fat (E2JW, P < 0.01, E2FB, P < 0.05), and they interacted in their effect on LM tenderness (P < 0.01). The leptin promoter SNP were either not associated with any of the traits (UASMS2) or with fat yield only (UASMS1). Three haplotypes (TCAC, CCAT, TTAC) were at high frequency in the population (88%) and had similar effects on all the traits. Compared with the common haplotypes, one haplotype (CCTT) showed a significantly different effect on fat and lean yield and grade fat (P < 0.01), and one haplotype (TTTT) had a different effect on LM tenderness (P < 0.03). Therefore, important associations between SNP within the leptin gene with lean yield, fatness (fat yield and subcutaneous fat), and tenderness were detected. Results confirm some of the previously reported associations, but diverge with respect to others, showing that further efforts are required to validate some prospective associations. [ABSTRACT FROM AUTHOR]

The Crooked Creek Barrens Preserve in the northeastern Knobs region of Kentucky contains an aggregation of species-rich grass and forb-dominated glade openings surrounded by secondary forest. Encroachment of woody species and invasion by non-native species threaten the rare forbs and sedges of the glades. The locations of these plant assemblages are commonly known to correspond to the unique properties of their underlying soils, yet few studies consider how soil factors may influence habitat conservation or restoration. This study describes vegetation and soil properties across the glade-edge-forest transition of three individual glade openings. Juniperus virginiana was the most abundant woody species within the glade openings. Juniperus virginana, Quercus stellata, Fraxinus americana and Cercis canadensis co-dominated the edge-forest boundary. Glade surface soils had dramatically higher pH (2 units) and lower extractable soil P (50% less) than forest soils. Also, total soil N content and net mineralization rates were significantly lower in glades than in forest or edge soils. The highly erodable nature of alkaline shale sediments appears to have contributed to the current location and extent of the glade openings. These findings suggest that management efforts to enhance rare plant habitat by expanding the glade openings should be accompanied by monitoring of soil changes following clearing. Further study should assess whether glade species of conservation concern are restricted to the nutrient-poor alkaline soils within extant glade openings or if they readily colonize the more nutrient-rich habitat of the cleared edge. [ABSTRACT FROM AUTHOR]

Herbaceous communities located within forest openings increase plant species diversity of forests in the Knobs Region of Kentucky. Although these grass-dominated communities are protected and managed for rare plant species conservation, it is unclear how soil conditions may delineate the grassland-forest boundary. We compared soil chemical and physical properties and soil nitrogen pools and transformations of three forest openings with those in the surrounding forest and the wooded edge separating the grassland and forest communities. Soil pH, extractable cations, bulk density and silt content were higher in openings compared to forest soils and extractable phosphorus was lower. In forest-opening grasslands, total soil nitrogen and the availability and production of plant-available N were 25 to 50% of levels in adjacent forest. Soils of the woody edge were similar to the surrounding forest. Our results suggest that the presence of these calcareous glade openings is highly correlated with edaphic conditions, so that efforts to expand rare plant habitat may be constrained by the distinct soils of these forest openings. [ABSTRACT FROM AUTHOR]

Summary • The carbon sink strength of arbuscular mycorrhizal fungi (AMF) was investigated by comparing the growth dynamics of mycorrhizal and nonmycorrhizal Andropogon gerardii plants over a wide range of equivalent tissue phosphorus : nitrogen (P : N) ratios. • Host growth, apparent photosynthesis (A net ), net C gain (Cn ) and P and N uptake were evaluated in sequential harvests of mycorrhizal and nonmycorrhizal A. gerardii plants. Response curves were used to assess the effect of assimilate supply on the mycorrhizal symbiosis in relation to the association of C with N and P. • Mycorrhizal plants had higher Cn than nonmycorrhizal plants at equivalent shoot P : N ratios even though colonization did not affect plant dry mass. The higher Cn in mycorrhizal plants was related to both an increase in specific leaf area and enhanced photosynthesis. The additional carbon gain associated with the mycorrhizal condition was not allocated to root biomass. The Cn in the mycorrhizal plants was positively related to the proportion of active colonization in the roots. • The calculated difference between Cn values in mycorrhizal and nonmycorrhizal plants, Cdiff , appeared to correspond to the sink strength of the AMF and was not an indirect result of enhanced nutrition in mycorrhizal plants. [ABSTRACT FROM AUTHOR]

Abstract1. Two semiaquatic grasses, Panicum hemitomon Schultes and Leersia hexandra Schwartz, were grown for 12 weeks in sterilized soil in experimental mesocosms, with and without the addition of arbuscular mycorrhizal (AM) fungal inoculum (as nonsterilized soil), under the following rooting-zone flood regimes: waterlogged (W), free-draining (D), beginning W and ending D (W–D), and beginning D and ending W (D–W). The purpose of the experiment was to determine whether these controlled water regimes affected both colonization of wetland grasses by AM fungi and the effects of the colonization on various plant parameters. 2. Water regime, addition of inoculum, and their interaction were highly significant effects on total and proportion of root length colonized by AM fungi. Trends were very similar for the two grass species. Colonization was less and plants smaller in the W and W–D than in the D and D–W treatments. The viability of mycorrhiza at the end of the experiment, as measured by vital staining techniques, was not affected by changes in water level. 3. Colonized plants in all water level treatments showed an improvement in phosphorus (P) nutrition over noncolonized plants. Colonized grasses of both species gained consistently more P per plant and had greater tissue P concentrations, with the greatest P concentration in the most heavily colonized plants (from the D and D–W treatments). 4. The effect of flooding on the mycorrhizal association depended largely on the extent to which the association was already established when the flooding occurred. Flooding reduced the initiation of colonization either directly or indirectly, but once the fungi were established in the roots they were able to maintain and expand with the growing root system. [ABSTRACT FROM AUTHOR]

SummaryIn multi-breed livestock populations, dominance variance is found both between and within breeds for many economically important traits. Mate selection strategies were developed to exploit both types of dominance variation simultaneously, with the aim of maximizing genetic merit of progeny. The extended super-breed model, in which breeds are viewed as groups of related and inbred animals within a ‘super-breed’, was used to predict individual additive and dominance effects for use in mate selection. Performance of mate selection was assessed under a range of relative values of additive and dominance variances for one generation of breeding. Mate selection on total progeny merit, including additive effects, individual dominance effects, and value of heterosis, was the optimal breeding strategy at all values of (co)variance components, with improvements in total progeny performance of up to 12.5 % over truncation selection followed by random mating when dominance variance was large relative to total genetic variance. Improvement in progeny merit from mate selection, relative to truncation selection, followed by random mating or truncation selection, followed by mate allocation, was particularly great (up to 53 %) when there was considerable heterosis. Improvements were small if dominance variance was small relative to total genetic variance, and heterosis was low. If the target population is large, full mate selection on total progeny merit is computationally demanding, and unlikely to be practical. Alternative, less computationally demanding strategies made nearly optimal selection and mating decisions at some parameter estimates. Integrating multi-breed genetic evaluation, using a superbreed model, with mate selection provides a powerful framework for the design of breeding programmes which exploit available sources of genetic merit. [ABSTRACT FROM AUTHOR]

Presents information on a study that investigated the effect of milk yield within three distinct breed groups on beef cattle's biological efficiency and gross margin as an indicator of profit potential. Calf growth rates; Changes in cow weight and fat depth; Means and linear partial regression coefficients on mild yield of dam of biological efficiency to weaning.

Presents a study which estimated the genetic correlation between maternal weaning gain and direct milk yield in a multibreed beef herd. Materials and methods; Results and discussion; Implications.

To enable breeders to select for correct foot and leg structure to increase productive life of beef cattle, the American Angus Association is developing genetic selection tools for these important traits. The Association accepts categorical 1 to 9 scores, with 5 being ideal, from its members for two traits, foot angle and claw set. Objectives were to explore alternative genetic evaluation approaches for these traits and estimate genetic parameters using 5,722 records collected on Angus bulls and heifers ranging from 320 to 460 days of age. Frequency of observations in the 1 to 9 categories, respectively, were 0, 1, 6, 197, 3,845, 1,468, 166, 34, and 5 for foot angle and 0, 0, 5, 263, 3,251, 1,883, 270, 45, and 5 for claw set. All traits were analyzed using a linear animal model with ASREML 3.0. In addition to a model fitting all phenotypes (1 to 9), each of the traits was also analyzed as two independent traits depending on the score to investigate if foot angles 1 to 5 (steep) were different from 5 to 9 (weak) and claw sets 1 to 5 (spread) were different from 5 to 9 (scissor), with 5 being ideal for each trait. A two-trait model for foot angle and claw set (1 to 9) was used to investigate the genetic correlation. All models included contemporary group (customer, scoring date, sex, and diet type) and weaning creep type as fixed effects, age at measurement as a covariate, animal, and error as random effects. Heritability estimates were 0.34, 0.21, 0.16, 0.25, 0.22, and 0.37, respectively, for foot angle, claw set, spread, scissors, steep, and weak, with a low genetic correlation between claw set and foot angle (0.22) determined with the bivariate model. The moderate heritability estimates for these foot score traits indicate that genetic evaluations are warranted. The traits of scissor and weak (5 to 9) appear to have a slightly higher heritability than the respective overall (1 to 9) traits, but it is not clear if splitting the traits is warranted for genetic evaluation. These genetic parameters will play an important role in the American Angus Associations development of genetic evaluations for foot structure. [ABSTRACT FROM AUTHOR]

The American Angus Association (AAA) is currently evaluating two methods to incorporate genomic information into their genetic evaluation program: (1) multi-trait incorporation of an externally produced molecular breeding value as an indicator trait (MT) and (2) single-step evaluation with an unweighted G matrix (SS). Our objective was to quantify bias and accuracy of genomic predictions using these two approaches. Because phenotypic data was limited for actual carcass measures from genotyped bulls in the AAA database, we tested bias and accuracy using data from the germplasm evaluation program (GPE) at the U.S. Meat Animal Research Center. Traits evaluated included birth, weaning, and yearling weight, maternal weaning weight, carcass weight, marbling score, ribeye area, and backfat thickness. The GPE has sampled 197 AAA bulls over 45 years and has typically characterized weight and carcass data on 8 to 15 progeny from each bull. Of these 197 bulls, 128 had been genotyped using high density arrays. From the AAA database, EPDs were derived using MT, SS, and non -genomic (NG) animal model methods. To detect differences in accuracy, these EPD were correlated to multi-breed EPD derived from GPE. These correlations were restricted to bulls that had high-density genotypes. In addition, to quantify bias, breed-specific EPD regression coefficients were derived from GPE. Independent variables for regression analysis were derived by dropping the EPD from sampled bulls proportionally through the pedigree (1/2 reduction in each generation). These EPD regression coefficients were expected to be one if GPE conditions were similar to conditions in breed association databases. Regression coefficients were obtained for GPE progeny born after 1998, as bulls that produced these progeny were generally genotyped. The NG EPD were used as a benchmark for regression comparison, as any bias observed without genomic data was expected to persist with the addition of genomic information. Resulting correlations were very similar for all three methods for weight traits as correlations among MT, SS, and NG EPD were greater than 0.99. For carcass traits, SS and NG EPD were correlated to each other at 0.97 or more while correlations of each with MT were less than 0.93. For all traits, SS correlations were highest with GPE EPD. In regard to bias, SS regressions were always similar to NG regression while MT regressions were always lower. Data from outside sources, such as GPE, can be useful for evaluating alternative genetic prediction models. [ABSTRACT FROM AUTHOR]

Objectives: To characterize, using magnetic resonance imaging (MRI), the distribution of blood flow and oxygen transport in human fetuses with subtypes of congenital heart disease (CHD) that present with neonatal cyanosis.Methods: Blood flow was measured in the major vessels of 152 late-gestation human fetuses with CHD and 40 gestational-age-matched normal fetuses, using cine phase-contrast MRI. Oxygen saturation (SaO2 ) was measured in the major vessels of 57 fetuses with CHD and 40 controls.Results: Compared with controls, we found lower combined ventricular output in fetuses with single-ventricle physiology, with the lowest being observed in fetuses with severe forms of Ebstein's anomaly. Obstructive lesions of the left or right heart were associated with increased flow across the contralateral side. Pulmonary blood flow was reduced in fetuses with Ebstein's anomaly, while those with Ebstein's anomaly and tricuspid atresia had reduced umbilical flow. Flow in the superior vena cava was elevated in fetuses with transposition of the great arteries, normal in fetuses with hypoplastic left heart, tetralogy of Fallot or tricuspid atresia and reduced in fetuses with Ebstein's anomaly. Umbilical vein SaO2 was reduced in fetuses with hypoplastic left heart or tetralogy of Fallot. Ascending aorta and superior vena cava SaO2 were reduced in nearly all CHD subtypes.Conclusions: Fetuses with cyanotic CHD exhibit profound changes in the distribution of blood flow and oxygen transport, which result in changes in cerebral, pulmonary and placental blood flow and oxygenation. These alterations of fetal circulatory physiology may influence the neonatal course and help account for abnormalities of prenatal growth and development that have been described in newborns with cyanotic CHD. © 2021 International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]

Objective:To examine whether early inflammation is related to cortisol levels at 18 months corrected age (CA) in children born very preterm.Study Design:Infants born 32 weeks of gestational age were recruited in the neonatal intensive care unit (NICU), and placental histopathology, magnetic resonance imaging (MRI) and chart review were obtained. At 18 months CA, developmental assessment and collection of three salivary cortisol samples were carried out. Generalized least squares was used to analyze data from 85 infants providing 222 cortisol samples.Result:Infants exposed to chorioamnionitis with funisitis had a significantly different pattern of cortisol across the samples compared with infants with chorioamnionitis alone or no prenatal inflammation (F(4, 139)=7.3996, P<0.0001). Postnatal infections, necrotizing enterocolitis and chronic lung disease were not significantly associated with the cortisol pattern at 18 months CA.Conclusion:In children born very preterm, prenatal inflammatory stress may contribute to altered programming of the hypothalamic-pituitary-adrenal (HPA) axis. [ABSTRACT FROM AUTHOR]

Ultrasound measurements of muscle depth were analyzed to determine if these traits could be used to increase the rate of genetic gain in breast meat yield (BMY). Two measurements of breast depth, one taken horizontally across both breast lobes and one parallel to the keel, were captured using ultrasound. Heritabilities of muscle depth traits ranged from 0.35 to 0.70. These values were greater than heritabilities of conformation scores, which ranged from 0.25 to 0.47 within sex and line. The ultrasound traits also showed strong genetic correlations to BMY, ranging from 0.43 to 0.75, indicating that selection, using ultrasound depth as a correlated information source, could result in improved BMY. Including each ultrasound trait in a linear regression model predicting BMY increased the proportion of variation explained by the models by 0.08 to 0.17, relative to using conformation score as the only in vivo estimate. Based on results from a sim-ulated turkey breeding program with selection pressure only on BMY, the ultrasound measures could increase the accuracy of a selection index for BMY by 0.02 to 0.16. As a result, ultrasound technology has the poten-tial to improve the rate of genetic gain in BMY in a breeding program. [ABSTRACT FROM AUTHOR]

Genetic parameters for production, survival, and structural fitness traits recorded in pedigreed turkey sire and dam parental lines from a nucleus breeding program were estimated with multiple-trait animal models. Survival and conformation traits were scored in binary terms of health, where 0 = died or affected, and 1 = survived or healthy. Walking ability at 20 wk was subjectively scored from 1 (poor) to 6 (excellent). Body weights and egg production displayed moderate heritability (h² = 0.18 to 0.35). Early survival (to 3 wk) displayed low heritability (h² = 0.02 and 0.04 for the dam and sire lines, respectively). Late survival (3 to 23 wk) and longevity (age at death or cull) had low to moderate heritability (h² = 0.12 to 0.14). Walking ability had moderate heritability (h² = 0.26, 0.25). Leg structure health displayed low heritability (h² = 0.08), as did hip structure, foot, and skin health (h² ≤ 0.02). Crop health displayed moderate heritability (h² = 0.12). Walking ability, hip and leg structures, footpad, and breast skin health had negative genetic correlations with BW (rG = -0.50 to -0.23). Egg production had moderate positive genetic correlation with late survival (rG = 0.61). Genetic correlations between early and late survival were close to zero (rG = 0.10 and 0.03 for the dam and sire lines, respectively). Walking ability had high positive genetic correlations with late survival, longevity, hip structure, and leg structure in both lines (rG = 0.51 to 0.91). These genetic parameters indicate that unchecked selection for growth could decrease survival, walking ability, and hip, leg, footpad, and skin health in turkeys. However, index selection should be effective at improving fitness, survival, and growth simultaneously in commercial turkey lines. Walking ability should be a good indicator trait for selection to improve overall late survival and hip and leg health in turkeys. [ABSTRACT FROM AUTHOR]

Genotype x environment (GxE) interactions can reduce the accuracy of a model to predict the performance of an animal and have an undesirable influence if not accounted for when estimating breeding values. Consequently, identification of these G xE is necessary when considering a turkey breeding program. Reranking based on the genetic prediction of turkey egg production, fertility, and hatchability in different seasons was indicative of a potential GxE interaction. Quantification of the C xE interactions was based on the genetic correlation estimated when traits were expressed in different seasons. Egg production was expressed as the percentage of days with an egg produced; fertility represented the proportion of hatched eggs that contained a fertile embryo; and hatchability was defined as the percentage of fertile eggs that produced a live bird. Variance components and heritability for egg production, fertility, and hatchability were estimated using ASRem1. The heritability (h2) of egg production was calculated to be 0.32 for both lines with the phenotypic (σ2p) and genetic (σ2g) variance, 141.3 and 45.58 (percent days with egg produced)2 and 118.3 and 38.35 (percent days with egg produced)2 for female and male lines, respectively. The h2 estimates for fertility were 0.08 in both lines with and of 293.3%2 and 24.03%2, and 576.9%2 and 48.43%2 for female and male lines, respectively. The hatchability h2, σ2p and σ2gestimates were 0.09, 267.1%2, and 24.44%2, respectively, for the female line and 0.15, 582.2%2, and 90.01%2 for the male line, respectively. Based on an animal model, the variance components were used to calculate estimated breeding values for each trait. The annual fluctuation in estimated breeding values resulted in the need to evaluate egg number, fertility, and hatchability as 2 traits, summer and winter lay. The correlation between the 2 traits was less than unity (female line: r egg production = 0.76, r fertility = –0.20, r hatchability = 0.75 and male line: r egg production = 0.86, r fertility = 0.19, r hatchability = 0.68) suggesting a G xE interaction, and animals will significantly rerank in genetic predictions for these reproductive phenotypes in different seasons of lay. Egg production, fertility, and hatchability in turkeys could be considered as 2 distinct traits in an animal model based on season of lay. [ABSTRACT FROM AUTHOR]

(Co)variance components, direct and maternal breed additive, dominance, and epistatic loss effects on preweaning weight gain of beef cattle were estimated. Data were from 478,466 animals in Ontario, Canada, from 1986 to 1999, including records of both purebred and crossbred animals from Angus, Blonde d'Aquitaine, Charolais, Gelbvieh, Hereford, Limousin, Maine-Anjou, Salers, Shorthorn, and Simmental breeds. The genetic model included fixed direct and maternal breed additive, dominance, and epistatic loss effects, fixed environmental effects of age of the calf, contemporary group, and age of the dam × sex of the calf, random additive direct and maternal genetic effects, and random maternal permanent environment effects. Estimates of direct and maternal additive genetic, maternal permanent environmental and residual variances, expressed as proportions of the phenotypic variance, were 0.32, 0.20, 0.12, and 0.52, respectively. Correlation between direct and maternal additive genetic effects was -0.63. Breed ranking was similar to previous studies, but estimates showed large SE. The favorable effects of direct and maternal dominance (P <0.05) on preweaning gain were equivalent to 1.3 and 2.3% of the phenotypic mean of purebred calves, respectively. The same features for direct and maternal epistatic loss effects were -2.2% (P < 0.05) and -0.1% (P > 0.05). The large SE of breed effects were likely due to multicollinearity among predictor variables and deficiencies in the dataset to separate direct and maternal effects and may result in a less reliable ranking of the animals for across breed comparisons. Further research to identify the causes of the instability of estimates of breed additive, dominance, and epistatic loss genetic effects, and application of alternative statistical methods is recommended. [ABSTRACT FROM AUTHOR]

Objectives: Septo-optic dysplasia (SOD) is a clinical syndrome characterized by varying combinations of optic nerve hypoplasia, pituitary gland hypoplasia and abnormal cavum septi pellucidi. It is suspected on prenatal imaging when there is non-visualization or hypoplasia of the septal leaflets. Long-term postnatal outcomes of fetuses with prenatally suspected SOD have been documented poorly. The aims of this study were to describe the natural history of deficient septal leaflets, to quantify the incidence of postnatally confirmed SOD and to document the visual, endocrine and long-term neurodevelopmental outcomes of these infants.Methods: This was an observational retrospective study of all fetuses with prenatal imaging showing isolated septal agenesis, assessed at a single tertiary center over an 11-year period. Pregnancy, delivery and neonatal outcomes and pre- and postnatal imaging findings were reviewed. Neonatal evaluations or fetal autopsy reports were assessed for confirmation of SOD. Ophthalmologic, endocrine, genetic and long-term developmental evaluations were assessed. Imaging findings and outcome were compared between infants with and those without postnatally confirmed SOD.Results: Of 214 fetuses presenting with septal absence on prenatal ultrasound and magnetic resonance imaging (MRI), 18 (8.4%) were classified as having suspected isolated septal agenesis suspicious for SOD. Uniform prenatal MRI findings in cases with suspected SOD included remnants of the leaflets of the cavum septi pellucidi, fused forniceal columns, normal olfactory bulbs and tracts and a normal optic chiasm. Twelve fetuses were liveborn and five (27.8%) had postnatally confirmed SOD. Only two of these five fetuses had additional prenatal imaging features (pituitary cyst, microphthalmia and optic nerve hypoplasia) supporting a diagnosis of SOD. The other three confirmed SOD cases had no predictive prenatal or postnatal imaging findings that reliably differentiated them from cases without confirmed SOD. Visual and endocrine impairments were present in two (40%) and four (80%) cases with confirmed SOD, respectively. In those with visual and/or endocrine impairment, developmental delay (median age at follow-up, 2.5 (interquartile range, 2.5-7.0) years) was common (80%) and mostly severe. Neonates with isolated septal agenesis and a lack of visual or endocrine abnormalities to confirm SOD had normal development.Conclusions: Only a quarter of fetuses with isolated septal agenesis suggestive of SOD will have postnatal confirmation of the diagnosis. Clinical manifestations of SOD are variable, but neurodevelopmental delay may be more prevalent than thought formerly. © 2020 Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]

The objective of the study was to evaluate utilization of dietary minerals and trace elements in pregnant heifers with distinct residual feed intakes (RFI). Feed intake, body weight (BW), and body composition traits were recorded in 36 crossbred heifers over a period of 37 wk, starting shortly after weaning at 8.3 (0.10; standard deviation) mo of age with an average BW of 276 (7.8) kg. Both BW and body composition were monitored regularly throughout the study, whereas individual feed intake was assessed during the last 84 d of the trial. Data recorded were used to calculate RFI for each heifer. Heifers were ranked based on RFI and assigned to high (n = 14) or low (n = 10) RFI groups. After the RFI study, 24 selected heifers [age 18.2 (0.14) mo; 87.5 (4.74) d in gestation; 497 (8.5) kg of BW] were used in an indirect digestibility trial (lignin as internal marker). Heifers were fed a ration containing corn silage, haylage, and a mineral premix in which Ca, P, K, Na, Mg, S, Cu, Fe, Mn, Mo, Se, Zn, and Co were provided in the diet according to National Research Council requirements of pregnant replacement heifers. The digestibility trial lasted 1 wk, during which samples of feces were gathered twice daily, and blood and liver biopsy samples were collected on the last day. We noted no significant differences between low- and high-RFI heifers in dry matter digestibility. Apparent absorption of Cu, Zn, and Mn was increased in heifers with low RFI, and apparent absorption of Co tended to be greater for these animals. Concentrations of macrominerals and trace elements in serum of pregnant heifers were similar for both groups except for Se, which was increased in the serum of low-RFI heifers. Liver concentrations of Cu, Fe, Mn, Mo, Se, and Zn did not differ between lowand high-RFI heifers. In conclusion, whereas improved absorption of some trace elements (Cu, Zn, Mn, and Co) and increased Se serum concentration appear to be associated with superior feed efficiency in pregnant heifers, further studies are needed to investigate the causality of such relationships. [ABSTRACT FROM AUTHOR]

Genomic prediction for crossbred beef cattle has shown limited results using low- to moderate-density SNP panels. The relationship between the training and validation populations, as well as the size of the reference population, affects the prediction accuracy for genomic selection. Rotational crossbreeding systems require the usage of crossbred animals as sires and dams of future generations, so crossbred animals require accurate evaluation. Here, a novel method for grouping of purebred and crossbred animals (based exclusively on genotypes) for genomic selection was investigated. Clustering of animals to investigate the genetic similarity among different groups was performed using several genomic relationship criteria between individuals. Hierarchical clusters based on average-link criteria (computed as the mean distance between elements of each subcluster) were formed. The accuracy of genomic prediction was assessed using 1,500 bulls genotyped for 54,609 markers. Estimated breeding values based on all available phenotypic records for birth weight, weaning gain, postweaning gain, and yearling gain were calculated using BLUP methodologies and deregressed to ensure unbiased comparisons could be made across populations. A 5-fold validation technique was used to calculate direct genomic values for all genotyped bulls; the addition of unrelated animals in the reference population was also investigated. We demonstrate a decrease in genomic selection accuracy after including animals from disconnected clusters. A method to improve genomic selection for crossbred and purebred animals by clustering animals based on their genotype is suggested. Unlike traditional approaches for genomic selection with a fixed reference population, genomic prediction using clusters (GPC) chooses the best reference population for better accuracy of genomic prediction of crossbred and purebred animals using clustering methods based on genotypes. An overall average gain in accuracy of 1.30% was noted over all scenarios across all traits investigated when the GPC approach was implemented. Further investigation is required to assess this difference in accuracy when a larger genotyped population is available, especially for the comparison of groups with higher genetic dissimilarity, such as those found in industry-wide across-breed genetic evaluations. [ABSTRACT FROM AUTHOR]

The accuracy of genomic predictions can be used to assess the utility of dense marker genotypes for genetic improvement of beef efficiency traits. This study was designed to test the impact of genomic distance between training and validation populations, training population size, statistical methods, and density of genetic markers on prediction accuracy for feed efficiency traits in multibreed and crossbred beef cattle. A total of 6,794 beef cattle data collated from various projects and research herds across Canada were used. Illumina BovineSNP50 (50K) and imputed Axiom Genome-Wide BOS 1 Array (HD) genotypes were available for all animals. The traits studied were DMI, ADG, and residual feed intake (RFI). Four validation groups of 150 animals each, including Angus (AN), Charolais (CH), Angus-Hereford crosses (ANHH), and a Charolais-based composite (TX) were created by considering the genomic distance between pairs of individuals in the validation groups. Each validation group had 7 corresponding training groups of increasing sizes (n = 1,000, 1,999, 2,999, 3,999, 4,999, 5,998, and 6,644), which also represent increasing average genomic distance between pairs of individuals in the training and validations groups. Prediction of genomic estimated breeding values (GEBV) was performed using genomic best linear unbiased prediction (GBLUP) and Bayesian method C (BayesC). The accuracy of genomic predictions was defined as the Pearson's correlation between adjusted phenotype and GEBV (r), unless otherwise stated. Using 50K genotypes, the highest average r achieved in purebreds (AN, CH) was 0.41 for DMI, 0.34 for ADG, and 0.35 for RFI, whereas in crossbreds (ANHH, TX) it was 0.38 for DMI, 0.21 for ADG, and 0.25 for RFI. Similarly, when imputed HD genotypes were applied in purebreds (AN, CH), the highest average r was 0.14 for DMI, 0.15 for ADG, and 0.14 for RFI, whereas in crossbreds (ANHH, TX) it was 0.38 for DMI, 0.22 for ADG, and 0.24 for RFI. The r of GBLUP predictions were greatly reduced with increasing genomic average distance compared to those from BayesC predictions. The results indicate that 50K genotypes, used with BayesC, are more effective for predicting GEBV in purebred cattle. Imputed HD genotypes found utility when dealing with composites and crossbreds. Formulation of a fairly large training set for genomic predictions in beef cattle should consider the genomic distance between the training and target populations. [ABSTRACT FROM AUTHOR]

Residual feed intake (RFI) is a measure of the efficiency of animals in feed utilization. The accuracies of GEBV for RFI could be improved by increasing the size of the reference population. Combining RFI records of different breeds is a way to do that. The aims of this study were to 1) develop a method for calculating GEBV in a multibreed population and 2) improve the accuracies of GEBV by using SNP associated with RFI. An alternative method for calculating accuracies of GEBV using genomic BLUP (GBLUP) equations is also described and compared to cross-validation tests. The dataset included RFI records and 606,096 SNP genotypes for 5,614 Bos taurus animals including 842 Holstein heifers and 2,009 Australian and 2,763 Canadian beef cattle. A range of models were tested for combining genotype and phenotype information from different breeds and the best model included an overall effect of each SNP, an effect of each SNP specific to a breed, and a small residual polygenic effect defined by the pedigree. In this model, the Holsteins and some Angus cattle were combined into 1 "breed class" because they were the only cattle measured for RFI at an early age (6-9 mo of age) and were fed a similar diet. The average empirical accuracy (0.31), estimated by calculating the correlation between GEBV and actual phenotypes divided by the square root of estimated heritability in 5-fold cross-validation tests, was near to that expected using the GBLUP equations (0.34). The average empirical and expected accuracies were 0.30 and 0.31, respectively, when the GEBV were estimated for each breed separately. Therefore, the across-breed reference population increased the accuracy of GEBV slightly, although the gain was greater for breeds with smaller number of individuals in the reference population (0.08 in Murray Grey and 0.11 in Hereford for empirical accuracy). In a second approach, SNP that were significantly (P < 0.001) associated with RFI in the beef cattle genomewide association studies were used to create an auxiliary genomic relationship matrix for estimating GEBV in Holstein heifers. The empirical (and expected) accuracy of GEBV within Holsteins increased from 0.33 (0.35) to 0.39 (0.36) and improved even more to 0.43 (0.50) when using a multibreed reference population. Therefore, a multibreed reference population is a useful resource to find SNP with a greater than average association with RFI in 1 breed and use them to estimate GEBV in another breed. [ABSTRACT FROM AUTHOR]

Interest in genetic improvement of carcass and tenderness traits of beef cattle using genome-based selection (GS) and marker-assisted management programs is increasing. The success of such a program depends on the presence of linkage disequilibrium between the observed markers and the underlying QTL as well as on the relationship between the discovery, validation, and target populations. For molecular breeding values (MBV) predicted for a target population using SNP markers, reliabilities of these MBV can be obtained from validation analyses conducted in an independent population distinct from the discovery set. The objective of this study was to test MBV predicted for carcass and tenderness traits of beef cattle in a Canadian-based validation population that is largely independent of a United States-based discovery set. The discovery data set comprised of genotypes and phenotypes from >2,900 multibreed beef cattle while the validation population consisted of 802 crossbred feeder heifers and steers. A bivariate animal model that fitted actual phenotype and MBV was used for validation analyses. The reliability of MBV was defined as square of the genetic correlation (R²g) that represents the proportion of the additive genetic variance explained by the SNP markers. Several scenarios involving different starting marker panels (384, 3K, 7K, and 50K) and different sets of SNP selected to compute MBV (50, 100, 200, 375, 400, 600, and 800) were investigated. Validation results showed that the most reliable MBV (R²g) were 0.34 for HCW, 0.36 for back fat thickness, 0.28 for rib eye area, 0.30 for marbling score, 0.25 for yield grade, and 0.38 for Warner-Bratzler shear force across the different scenarios explored. The results indicate that smaller SNP panels can be developed for use in genetic improvement of beef carcass and tenderness traits to exploit GS benefits. [ABSTRACT FROM AUTHOR]

Genotyping with lower density but lower cost panels enables more animals to be genotyped for genomic selection. Imputation enables the determination of missing SNP genotypes in animals genotyped with a low-density panel by using information from a reference population genotyped with a higher density panel, which should increase accuracy of genomic EBV. In this study, population imputation, using linkage disequilibrium among markers, was implemented using the software BEAGLE, FIMPUTE 2.2, and IMPUTE2 in a multibreed, crossbred taurine beef cattle population genotyped with the Illumina SNP50. Different combinations of reference populations and imputed animals were defined based on breed composition. Number of animals (n = 250 to 4,932) and the presence of closer relatives in the reference population (only for Angus animals) were investigated. The overall average imputation accuracy for purebred animals ranged from 94.20 to 97.93% using FIMPUTE, from 95.35 to 98.31% using IMPUTE2, and from 90.02 to 96.38% when BEAGLE software was used. Imputation accuracy of crossbred animals ranged from 54.15 to 97.53% (FIMPUTE), from 57.04 to 97.46% (IMPUTE2), and from 54.35 to 95.64% (BEAGLE). Higher imputation accuracies were obtained when closer relatives along with the breed composition of imputed animals was well represented in the reference population. Within breed imputation from 6K to 50K did not improve when an additional purebred population was added to the reference population. FIMPUTE reduced the run time by 13 to 52 times compared to BEAGLE and 51 to 108 times compared to IMPUTE2. [ABSTRACT FROM AUTHOR]

In mid-to-late gestation, nutrient demand increases to meet the growth requirements of the conceptus and cows may alter metabolism in response to energy demands of pregnancy. By better understanding the metabolic role of pregnancy, there may be opportunities to better understand maintenance energy costs and improve overall feed efficiency. Eighteen mature Simmental/Angus crossbred cows, pregnant (PREG; n = 9) and nonpregnant (OPEN; n = 9), were used to investigate the effect of pregnancy on BW change, carcass traits, visceral organ mass, and circulating serum metabolites. Cows were blocked by day of expected parturition such that each block was slaughtered 4 to 5 wk before parturition. Cows were individually fed for ad libitum intake using Calan gates for 89 to 105 d. Cows were weighed, ultrasounded for rib (over the 12th and 13th rib) and rump fat, and a serum sample obtained at d 1, 56, and 3 to 5 d before slaughter. At slaughter, organs were removed, trimmed of fat, and weighed. Serum was analyzed for β-hydroxybutyrate (BHBA), NEFA, glucose, urea, total cholesterol, and triiodothyronine T3. Tissue samples from liver, kidney, sternomandibularis muscle, ruminal papillae, pancreas, and small intestinal muscosa were collected at slaughter and snap frozen in liquid N. Western blots were conducted to quantify abundance of: proliferating cell nuclear antigen (PCNA), ATP synthase, ubiquitin, and Na(+)/K+ ATPase for all tissues; PPARγ, PPARγ coactivator 1α (PGC1-α), 5'-adenosine monophosphate-activated protein kinase (AMPK) and phosphorylated-AMPK (pAMPK) for liver, muscle, and rumen; phosphoenolpyruvate carboxykinase (PEPCK) for liver and kidney; and uncoupling protein 2 (UCP2) for liver. Data were analyzed using PROC MIXED in SAS as a replicated randomized complete block. Liver weights (actual, relative to BW, relative to HCW) were heavier (P ≤ 0.02) in OPEN. Rumen mass and kidney fat weight, both relative to BW, were also greater (P ≤ 0.04) in OPEN. On d 56 and at preslaughter, PREG cows had greater (P ≤ 0.04) BHBA, NEFA and urea concentrations and lower (P = 0.04) cholesterol concentration. Hepatic Na+/K+ ATPase abundance was greater (P = 0.04) in PREG cows. In rumen papillae, abundance of pAMPKα was increased (P = 0.006) in PREG cows. These data indicate that PREG cows may metabolize energy reserves and alter their metabolism to meet the energetic demands of the growing fetus. [ABSTRACT FROM AUTHOR]

Twenty-two nonlactating multiparous pregnant beef cows (639 ± 68 kg) were used to investigate the effect of dietary restriction on the abundance of selected proteins regulating cellular energy metabolism. Cows were fed at either 85% (n = 11; LOW) or 140% (n = 11; HIGH) of total NE requirements. The diet consisted of a haylage-based total mixed ration containing 20% wheat straw. Cows were slaughtered by block (predicted date of parturition), beginning 83 d after the initiation of dietary treatments and every week thereafter for 6 wk, such that each block was slaughtered at approximately 250 d of gestation. Tissue samples from liver, kidney, sternomandibularis muscle, ruminal papilli (ventral sac), pancreas, and small intestinal muscosa were collected at slaughter and snap frozen in liquid N2. Western blots were conducted to quantify abundance of proliferating cell nuclear antigen (PCNA), ATP synthase, ubiquitin, and Na/K+ ATPase for all tissues; PPAR?, PPAR? coactivator 1 a (PGC-1a), and 5'-adenosine monophosphate-activated protein kinase (AMPK) and the activated form phosphorylated-AMPK (pAMPK) for liver, muscle, and rumen; phosphoenolpyruvate carboxykinase (PEPCK) for liver and kidney; and uncoupling protein 2 (UCP2) for liver. Statistical analysis was conducted using Proc Mixed in SAS and included the fixed effects of dietary treatment, cow age, block, and the random effect of pen. Dietary treatments resulted in cows fed HIGH having greater (P = 0.04) ADG and final BW than cows fed LOW. Abundance of ubiquitin in muscle was greater (P = 0.009) in cows fed LOW, and PCG-1 a in liver was greater (P = 0.03) in cows fed HIGH. Hepatic O2 consumption was greater in HIGH (P = 0.04). Feed intake can influence the abundance of important metabolic proteins and suggest that protein degradation may increase in muscle from moderately nutrient restricted cows and that energy metabolism in liver increases in cows fed above NE requirements. [ABSTRACT FROM AUTHOR]

Stayability to consecutive calvings was selected as a measure of cow longevity in the Canadian Simmental population. Calving performance data on 188,579 cows and culling information from the Total Herd Reporting System were used to determine whether a cow stayed in a herd for her second and later (up to the eighth) calvings, given that she had calved as 2 yr old. Binary records («=1,164,319) were analyzed with animal linear and threshold models including fixed effects of year of birth by season of birth by parity number and age of cow at first calving by parity number and random effects of contemporary group (CG) defined as herd of birth within year by season, animal additive genetic effect, and a cow permanent environmental (PE) effect. All random effects were Legendre polynomial regressions of the same order, defined on the scale from second to the eighth calving. Bayesian methods with Gibbs sampling were used to estimate covariance components and genetic parameters for random effects of models and selected variables on the longitudinal scale. Bayes factors and analyses of mean squared error and correlation between observed and predicted observations indicated that the linear model with regressions of order 3 was most plausible for generating the current data compared with a fixed regression and other random regression (both linear and threshold) models of order up to 4. Estimates of variances for all random effects from the best fitting model changed with the calving number. Estimates of heritability decreased in time: from 0.35 (SD = 0.006) for stayability to second calving to 0.13 (SD = 0.004) for stayability to the eighth calving. Variance due to PE effect constituted the largest part of the total variance of stayability for all longitudinal points followed by genetic and CG components. Genetic effects of stayability to different calvings were relatively highly correlated, from 0.62 (SD = O.oTl) to 0.99 (SD = 0.001), and correlation decreased with the time span between calvings. Correlations for PE and CG effects showed similar trends. Animal genetic effect seemed to be less variable on the longitudinal scale compared with other random effects of the model. The first 2 principal components explained from 95% (PE effects) to 99% (genetic effect) of the total variance. The overall level of genetic stayability curve correlated well (from 0.87 to 0.99, with SD < 0.006) with genetic stayability to different calvings and therefore could be used as a single criterion in selection for stayability. [ABSTRACT FROM AUTHOR]

Discovery of genetic mutations that have a significant association with economically important traits would benefit beef cattle breeders. Objectives were to identify with an in silico approach new SNP in 8 genes involved in digestive function and metabolic processes and to examine the associations between the identified SNP and feed efficiency and performance traits. The association between SNP and daily DMI, ADG, midpoint metabolic weight (MMWT), residual feed intake (RFI), and feed conversion ratio (FCR; the ratio of average daily DMI to ADG) was tested in discovery and validation populations using a univariate mixed-inheritance animal model fitted in ASReml. Substitution effect of the T allele of SNP rs41256901 in protease, serine, 2 (trypsin 2; PRSS2) was associated with FCR (-0.293 ± 0.08 kg DMI kg-1 BW gain; P < 0.001) and RFI (-0.199 ± 0.08 kg; P < 0.01) and although not significant in the validation population, the phase of association remained. In the cholecystokinin B receptor (CCKBR) gene, genotypes in rs42670351 were associated with RFI (P < 0.05) whereas genotypes in rs42670352 were associated with RFI (P = 0.002) and DMI (P < 0.05). Substitution of the G allele in rs42670352 was associated with DMI (-0.236 ± 0.12 kg; P = 0.055) and RFI (-0.175 ± 0.09 kg; P = 0.05). Substitution of the G allele of SNP rs42670353 was associated with ADG (0.043 ± 0.02 kg/d; P < 0.01) and FCR (0.114 ± 0.05 kg BW gain kg-1 DMI; P < 0.05). In the validation dataset, SNP rs42670352 in gene CCKBR was significant for RFI and DMI and had the same phase of associations; SNP rs42670353 was significantly associated with FCR with same phase of association and the C allele in SNP rs42670351 was validated as decreasing DMI, RFI, and FCR. Substituting the G allele of SNP rs42670352 in CCKBR2 was associated with decreasing DMI and RFI in the validation study. New SNP were reported in genes PRSS2 and CCKBR, being associated with feed efficiency and performance traits in beef cattle. The association between these SNP with fertility, carcass, and meat quality traits must still be tested. [ABSTRACT FROM AUTHOR]

Four crossbred steers (average BW = 478 ± 33 kg) were used in a 4 x 4 Latin square design to determine the effects of dietary concentration of dry com distillers grains plus solubles (DDGS) in whole corn-based finishing diets on total tract digestion and nutrient balance and excretion. The DDGS were fed at 0% (control), 16.7%, 33.3%, and 50% of dietary DM. All diets contained 10% (DM basis) alfalfa/grass haylage and were formulated to meet or exceed the estimated requirements for CP. Steers were fed the experimental diets ad libitum for a 14-d adaptation period followed by a 5-d period for fecal and urine collection. Increasing concentration of DDGS in diets from 0 to 50% of DM linearly decreased (P < 0.05) total tract DM and starch digestibility (from 77.8 to 72.9%>, and 89.2 to 81.5%, respectively). Daily N and P intakes linearly increased (P = 0.06 and P = 0.01, respectively) with increasing DDGS concentration. Fecal and urinary N, P, S, Mg, and K excretion linearly increased (P < 0.05) with increasing DDGS concentration; however, Se and Na excretion did not differ (P > 0.38) among treatments. Retention (g/d; intake minus urinary and fecal excretion) of N did not differ (P > 0.16) among treatments. Retention of P tended (P = 0.07) to linearly increase and retention of S (g/d) linearly increased (P = 0.004), with increasing DDGS concentration. There were no effects (P > 0.16) of dietary treatment on digestion and retention of Se, Mg, K, and Na. Plasma P and S concentrations increased (P = 0.03 and 0.01, respectively) with increasing DDGS concentration. These data indicate that feeding DDGS up to 50% of dietary DM in whole corn grain-based finishing diets does not have a negative effect on nutrient retention but decreases digestibility. Total excretion of N, P, Ca, Mg, S, and K increased as DDGS concentration increased. [ABSTRACT FROM AUTHOR]

There is concern in the beef industry that selecting bulls for feed efficiency based on residual feed intake (RFI) may have a negative impact on bull repro-ductive performance and fertility. Here we investigated the impact of selection of bulls for low RFI on breeding soundness evaluation (BSE), reproductive performance, and fertility of bulls under natural service in multisire mating groups on pasture. Of the 412 RFI-tested bulls available, 98 (23.8%) were culled for performance, type, temperament, or other reasons, and 88 (21.4%) were culled for failing BSE, for an overall cull rate of 45.1%. From among the 314 bulls subjected to BSE, 32 (10.2%), 20 (6.4%), and 36 (11.4%) were culled for poor feet and legs, scrotal circumference, and semen quality, respectively. The BSE traits were not different (P > 0.10) between bulls categorized as either inefficient (+RFI) or efficient (-RFI), but the proportion of bulls that failed to meet the 60% minimum sperm motility requirement tended (P = 0.07) to be greater in the -RFI group than in the +RFI group (10.2% vs. 4.4%, respectively). In a subpopulation of 115 bulls, individual progressive spenn motility was greater {P < 0.05) in +RFI (85%) than -RFI (80%) bulls. A multisire natural mating experiment was conducted during 2 consecutive breeding seasons (2006 to 2007 and 2007 to 2008) using 18 +RFI and 18 -RFI bulls. The overall calving rate (calves born/cows exposed) was 72.9%. Mean number of progeny per sire was significantly greater (P <0.01) in -RFI bulls (18.3) than in +RFI bulls (11.8). Selection for feed efficiency based on RFI appears to have no detrimental impact on reproductive performance and fertility in beef bulls bred in multisire groups on pasture. However, the decreased sperm motility and the greater number of progeny per sire associated with -RFI status need further investigation. [ABSTRACT FROM AUTHOR]

Replication-competent oncolytic viruses hold great potential for the clinical treatment of many cancers. Importantly, many oncolytic virus candidates, such as reovirus and myxoma virus, preferentially infect cancer cells bearing abnormal cellular signaling pathways. Reovirus and myxoma virus are highly responsive to activated Ras and Akt signaling pathways, respectively, for their specificity for viral oncolysis. However, considering the complexity of cancer cell populations, it is possible that other tumor-specific signaling pathways may also contribute to viral discrimination between normal versus cancer cells. Because carcinogenesis is a multistep process involving the accumulation of both oncogene activations and the inactivation of tumor suppressor genes, we speculated that not only oncogenes but also tumor suppressor genes may have an important role in determining the tropism of these viruses for cancer cells. It has been previously shown that many cellular tumor suppressor genes, such as p53, ATM and Rb, are important for maintaining genomic stability; dysfunction of these tumor suppressors may disrupt intact cellular antiviral activity due to the accumulation of genomic instability or due to interference with apoptotic signaling. Therefore, we speculated that cells with dysfunctional tumor suppressors may display enhanced susceptibility to challenge with these oncolytic viruses, as previously seen with adenovirus. We report here that both reovirus and myxoma virus preferentially infect cancer cells bearing dysfunctional or deleted p53, ATM and Rb tumor suppressor genes compared to cells retaining normal counterparts of these genes. Thus, oncolysis by these viruses may be influenced by both oncogenic activation and tumor suppressor status. [ABSTRACT FROM AUTHOR]

Ninety-three crossbred steer calves (BW + SD = 385 ± 50 kg) were used (n = 48 steers in yr 1, n 45 steers in yr 2) to examine the relationship among carcass traits, lean, bone, and fat proportions, visceral tissue weights, and pancreatic digestive enzyme activity with DM1, ADG, G:F, and residual feed intake. Calves were progeny from crossbred dams predominantly of Angus and Simmental breeding and were sired by Angus, Simmental, crossbred (predominantly of Angus and Simmental breeding), Charolais, or Piedmontese bulls. Steers were fed a high-moisture corn-based diet for an average of 112 d. Partial correlation analysis accounting for year, pen within year, week of slaughter within year, and sire breed was conducted. Gain:feed was negatively correlated (P ≤ 0.04) with back~at thickness (r = -0.38), marbling score (r = -0.32), and trim and kidney fat weight proportion (g/kg of BW; r = -0.42). Residual feed intake (P = 0.008; g/kg of BW; r = 0.34) and backfat-corrected residual feed intake (P = 0.005; r = 0.29) were positively correlated with trim and kidney fat weight proportion. Gain:feed was negatively correlated (P < 0.001) with total fat weight proportion (g/kg of rib; r = -0.45) and positively correlated (P ≤ 0.03) with lean weight proportion (g/kg of rib; r = 0.30) and bone weight proportion (g/kg of rib; r = 0.28). Gain:feed was negatively correlated (P < 0.01) with subcutaneous fat weight proportion (g/kg of rib; r = -0.32) and intramuscular fat weight proportion (g/ kg of rib; r = 0.37). Gain:feed was negatively correlated (P < 0.001) with total visceral weight proportion (g/kg of BW; r = -0.44) and visceral fat weight proportion (g/kg of BW; r = -0.41) but was positively correlated (P = 0.02) with spleen weight proportion (g/kg of BW; r = 0.30). There were no significant correlations (P> 0.10) between performance measures and the pancreat-, ic proportional content of ct-amylase and trypsin activity (units/kg of BW). These data indicate that carcass fatness traits and changes in the proportional weight of total viscera may be negatively associated with G:F and that visceral fat weight proportion and trim and kidney fat weight proportion may be important factors influencing this relationship. [ABSTRACT FROM AUTHOR]

Glucokinase (GK) is expressed in the pancreatic beta-cells and liver, and plays a key role in the regulation of glucose homeostasis. The enzymatic activity and thermal stability of wild-type (WT) GK and several mutant forms associated with maturity-onset diabetes of the young type 2 (MODY-2) were determined by a steady-state kinetic analysis of the purified expressed proteins. The eight MODY-2 mutations studied were Ala53Ser, Val367Met, Gly80Ala, Thr168Pro, Arg36Trp, Thr209Met, Cys213Arg, and Val226Met. These missense mutations were shown to have variable effects on GK kinetic activity. The Gly80Ala and Thr168Pro mutations resulted in a large decrease in Vmax and a complete loss of the cooperative behavior associated with glucose binding. In addition, the Gly80Ala mutation resulted in a sixfold increase in the half-saturating substrate concentration (S0.5) for ATP, and Thr168Pro resulted in eight- and sixfold increases in the S0.5 values for ATP and glucose, respectively. The Thr209Met and Val226Met mutations exhibited three- and fivefold increases, respectively, in the S0.5 for ATP, whereas the Cys213Arg mutation resulted in a fivefold increase in the S0.5 for glucose. These mutations also led to a small yet significant reduction in Vmax. Of all the mutations studied, only the Cys213Arg mutation had reduced enzymatic activity and decreased thermal stability. Two mutants, Ala53Ser and Val367Met, showed kinetic and thermal stability properties similar to those of WT. These mutants had increased sensitivities to the known negative effectors of GK activity, palmitoyl-CoA, and GK regulatory protein. Taken together, these results illustrate that the MODY-2 phenotype may be linked not only to kinetic alterations but also to the regulation of GK activity. [ABSTRACT FROM AUTHOR]

Purpose: Cells derived from individuals in which the ataxia telangiectasia ( ATM ) gene is mutated are hypersensitive to ionizing radiation. Whether differences in ATM protein levels exist among human malignant glioma cell lines and whether such differences are correlated with cellular radiosensitivity were determined. Materials and methods: Polyclonal antibodies were raised to separate regions of the ATM protein. ATM protein expression in human malignant glioma cell lines, SV40 transformed normal human fibroblasts and SV40 transformed AT fibroblasts was analysed by Western blotting. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to assess the presence of ATM transcript. Results: While ATM protein was detected in all cell extracts, significant differences in the level of expression were observed. There was no apparent correlation between cellular radiosensitivity and differences in ATM protein levels in these human glioma cells. Extremely low levels of ATM protein were observed in M059J cells, which provide the only example of DNA-dependent protein kinase (DNA-PKcs) deficiency in a cell line of human origin. Conclusions: Variations in the levels of ATM protein are insufficient to explain the differences in cellular radiosensitivity observed in a panel of human malignant glioma cell lines. [ABSTRACT FROM AUTHOR]

Transmission ratio distortion (TRD) is the deviation from the expected Mendelian inheritance of alleles from heterozygous parents. This phenomenon has been reported in a broad range of organisms and can be caused by various biological mechanisms including meiotic drive, embryo or fetal failure, germline selection, gametic competition, imprint resetting error and differential survival of offspring. Within this context, we investigated TRD in cattle aiming to identify genomic regions showing altered deviations in segregation that could contain potential causal mutations directly affecting economically important traits, such as reproduction. A Bayesian approach was implemented in order to uncover TRD across the whole genome using SNP-by-SNP and haplotypes of 2-SNP sliding windows using 79,238 genotyped trios of Holstein. From a total of 44,369 autosomal SNP, 942 were significantly detected with TRD that exceeded a Bayes factor (BF) ≥ 10 (strong evidence) and 408 with BF ≥ 100 (decisive evidence) from SNP-by-SNP analyses. The number of SNP with parent-unspecific TRD were 270 whereas 393 and 271 SNP were detected as either sire- or dam-TRD, respectively. By using the approximate empirical null distribution of TRD, results potentially generated by chance were discarded, resulting in 555, 307 and 92 SNP significantly detected with a probability of error of 5%, 1% and 0.1%, respectively. From the SNP-by-SNP approach, regions with moderate-to-high |TRD| (≥ 0.15) were less polymorphic (minor allele frequency, MAF < 0.027), providing evidence of TRD selection and unravelling rare variants as candidate lethal alleles. In contrast, slightly more polymorphic regions with moderate-to-high |TRD| were identified by the haplotype approach (MAF ~ 0.045). The number of regions identified by haplotype approach after correction (at 0.1% probability of error) were 1,047, 421 and 683 for overall, sire- and dam-TRD, respectively. The preliminary functional analysis of detected regions with TRD identified positional genes associated with regulation of embryonic development. Moreover, the identification of alleles with TRD in chromosomal regions around haplotypes well known to be associated with recessive disorders in Holstein or affecting fertility traits in other cattle breeds highlighted important biological implications of TRD. In conclusion, the prevalence of TRD was extended across the whole genome and an in-depth deeper study of these candidate regions and alleles will be further investigated to better understand this phenomenon in cattle. [ABSTRACT FROM AUTHOR]