Association between FAMACHA scores and fecal egg counts in katahdin lambs

© 2017 American Society of Animal Science. All rights reserved. The FAMACHA system was introduced to the U.S. just over 10 yr ago to allow selective deworming of lambs with anemia associated with Haemonchus contortus and retard the development of anthelmintic resistance. The FAMACHA system was initially developed as a predictor of packed cell volume (PCV), but correlations between FAMACHA and fecal egg counts (FEC) have also been reported. It is important to understand factors that influence FAMACHA scores among farms to improve management of gastrointestinal nematodes. The objectives of this study were therefore to quantify associations between FAMACHA scores, FEC, BW, and age in Katahdin lambs at 2 different measurement times in 8 flocks in the eastern U.S., and to assess consistency of relationships between FAMACHA and FEC among flocks. Data came from 1,644 Katahdin lambs from 7 flocks sampled at approximately 90 d of age, and 1,295 lambs from 6 flocks sampled at approximately 120 d of age over a 5 yr period. Residual correlations among log-transformed FEC (LFEC), FAMACHA scores, BW, and lamb ages at each measurement time were determined. Repeatability of each variable was also determined as residual correlations among repeated measures. At both 90 and 120 d of age, correlations of FAMACHA scores with LFEC and BW were significant (P \u3c 0.001), but numerically modest (0.25 and -0.16, respectively at 90 d; 0.31 and -0.16, respectively at 120 d), demonstrating that higher FAMACHA scores were associated with higher FEC and more likely to be observed in lighter lambs. A small negative correlation was observed between FAMACHA score and lamb age (r = -0.05, P = 0.05, 90 d; r = -0.11, P \u3c 0.001, 120 d) indicating that younger lambs were more likely to have elevated FAMACHA scores. Thus, younger and lighter lambs will likely be more susceptible to parasitism and may need to be managed more diligently than older or heavier lambs. In addition, FAMACHA scores have potential to improve breeding value estimates in programs designed to genetically improve parasite resistance

Validation of Live Animal Ultrasonic Measurements of Body Composition in Market Lambs

Market lambs from the state fair of Virginia (n = 172) were ultrasonically evaluated by 4 scan technicians and 3 image interpreters to determine accuracy of ultrasonic estimates of loin muscle area (ULMA), backfat thickness (UBF), and body wall thickness (UBW). Lambs were initially scanned at the preferred magnification setting of each technician; 2 chose 1.5× and 2 chose 2.0×. Lambs were then scanned a second time for ULMA and UBF with machine magnification settings changed from 1.5 to 2.0×, or vice versa, midway through the second scan. Lambs were then slaughtered, and analogous measurements [carcass loin muscle area, carcass backfat thickness, and carcass body wall thickness (CBW)] were recorded on chilled carcasses. Pooled, residual correlation coefficients within technicians and interpreters between ultrasonic measurements from the first scan and carcass measurements were 0.66 for loin muscle area, 0.78 for backfat thickness, and 0.73 for body wall thickness, but were reduced to 0.43, 0.69, and 0.50, respectively, by inclusion of linear effects of carcass weight in the model. Mean bias for technicians and interpreters ranged from −1.30 to −2.66 cm2 for loin muscle area, −0.12 to −0.17 cm for backfat thickness, and 0.14 to −0.03 cm for body wall thickness; prediction errors ranged from 1.86 to 2.22 cm2, 0.12 to 0.14 cm, and 0.35 to 0.38 cm, respectively. Pooled correlations between repeated measures were 0.67 for ULMA, 0.79 for UBF, and 0.68 for UBW at the same magnification and 0.73 for ULMA and 0.76 for UBF across different magnification settings. Mean differences between repeated measures were more variable among technicians and interpreters than statistics comparing ultrasound to carcass measures. Standard errors of repeatability ranged from 1.61 to 2.45 cm2 for ULMA, 0.07 to 0.11 cm for UBF, and 0.36 to 0.42 cm for UBW. The effect of changing magnification setting on technician and interpreter repeatability was small for UBF and ULMA. The accuracy of prediction of CBW from UBW was similar to that achieved for backfat thickness; further assessment of the value of ultrasonic measurements of body wall thickness in lambs is warranted. These results indicate that ultrasound scanning can reliably predict carcass loin muscle area and backfat thickness in live lambs and, accordingly, has value in selection programs to improve composition. Development of certification standards for US lamb ultrasound technicians based on results of this study and others is proposed

Genetic parameters for fecal egg counts and their relationship with body weights in katahdin lambs

© The Author(s) 2018. Reliance on anthelmintic drugs to control internal parasites in sheep is no longer sustainable because of the development of resistance to these drugs in parasite populations. Genetic selection may offer an alternative long-term solution, as differences in parasite resistance exist both within and among sheep breeds. However, selection for parasite resistance may have correlated effects on other production traits. The objectives of this study were to estimate genetic parameters for weaning (WFEC) and postweaning (PWFEC) fecal egg counts (FEC) and assess their relationship with birth (BWT), weaning (WWT), and postweaning (PWWT) BW in Katahdin lambs. The study used WFEC (n = 2,537), PWFEC (n = 3.421), BWT (n = 12,869), WWT (n = 10,961), and PWWT (n = 7,812) from 12,869 lambs measured between 2003 and 2015 in 13 flocks enrolled in the U.S. National Sheep Improvement Program. Animal and sire models were fitted to the data using the ASReml statistical package. Records were corrected for fixed effects of dam age, joint effect of type of birth and rearing, and management group (defined by joint effects of flock, sex, and birth year and season); lamb age in days at each measurement time was fitted as a covari-ate. Maternal additive and maternal permanent environmental effects were not significant (P \u3e 0.05), but litter effects influenced (P \u3c 0.01) both WFEC and PWFEC. Heritability estimates ranged from 0.18 to 0.26 for WFEC and 0.23 to 0.46 for PWFEC, depending on the model used. Heritability estimates from sire models were higher than estimates from animal models. Direct additive, litter, residual, and phenotypic correlations between WFEC and PWFEC were 0.82, 0.25, 0.15, and 0.29, respectively. Bivariate analyses revealed low to moderate correlations between BW and FEC. Moderate heritabilities for FEC in this study indicated that genetic progress for this trait can be achieved in Katahdin lambs and that selection for low FEC should have little or no effect on BW

The Impact of Nonequilibrium Conditions in Lung Surfactant: Structure and Composition Gradients in Multilamellar Films

The lipid–protein mixture that covers the lung alveoli, lung surfactant, ensures mechanical robustness and controls gas transport during breathing. Lung surfactant is located at an interface between water-rich tissue and humid, but not fully saturated, air. The resulting humidity difference places the lung surfactant film out of thermodynamic equilibrium, which triggers the buildup of a water gradient. Here, we present a millifluidic method to assemble multilamellar interfacial films from vesicular dispersions of a clinical lung surfactant extract used in replacement therapy. Using small-angle X-ray scattering, infrared, Raman, and optical microscopies, we show that the interfacial film consists of several coexisting lamellar phases displaying a substantial variation in water swelling. This complex phase behavior contrasts to observations made under equilibrium conditions. We demonstrate that this disparity stems from additional lipid and protein gradients originating from differences in their transport properties. Supplementing the extract with cholesterol, to levels similar to the endogenous lung surfactant, dispels this complexity. We observed a homogeneous multilayer structure consisting of a single lamellar phase exhibiting negligible variations in swelling in the water gradient. Our results demonstrate the necessity of considering nonequilibrium thermodynamic conditions to study the structure of lung surfactant multilayer films, which is not accessible in bulk or monolayer studies. Our reconstitution methodology also opens avenues for lung surfactant pharmaceuticals and the understanding of composition, structure, and property relationships at biological air–liquid interfaces

Bovine Follicular Dynamics, Oocyte Recovery,and Development of Oocytes Microinjected with a Green Fluorescent Protein Construct

The present study was carried out to 1) evaluate the viability of in vitro fertilized zygotes after microinjection of DNA, 2) assess the influence of oocyte quality upon the development rate of embryos when injected with DNA, and 3) determine the integration frequency of green fluorescent protein DNA into microinjected embryos. Oocytes were aspirated from ovaries of nine nonlactating Holsteins and were categorized into grades A, B, C, and D. At 16 h after in vitro fertilization, approximately half of the pronuclear stage presumptive zygotes were classified as having 1 pronucleus or 2 pronuclei, and they were microinjected with DNA constructs. A potential predictor of DNA integration frequency at d 10 was assessment of the incidence of green fluorescing embryos. The proportion of cleaved embryos that developed to morulae or blastocysts was not different between groups with 1 pronucleus injected (45%), 1 pronucleus uninjected (64%), or 2 pronuclei injected (49%). However, the development of morulae or blastocysts was higher in the group with 2 pronuclei uninjected (69%). The overall developmental score of green fluorescent protein-positive embryos was higher for grade A oocytes (1.3 &#;&#;0.1) than for grade B (0.8 &#; 0.1), C (0.6 &#;&#;0.1), or D (0.3 &#;&#;0.1) oocytes. The results show that production of transgenic bovine blastocysts can occur from the microinjection of a presumptive zygote having only one visible pronucleus. Initial oocyte quality is an important factor in selection of oocytes suitable for microinjection of DNA and for preimplantation development to produce bovine transgenic embryos

Genome-wide association study to identify genetic loci associated with gastrointestinal nematode resistance in Katahdin sheep

Resistance to gastrointestinal nematodes has previously been shown to be a moderately heritable trait in some breeds of sheep, but the mechanisms of resistance are not well understood. Selection for resistance currently relies upon faecal egg counts (FEC), blood packed cell volumes and FAMACHA visual indicator scores of anaemia. Identifying genomic markers associated with disease resistance would potentially improve the selection process and provide a more reliable means of classifying and understanding the biology behind resistant and susceptible sheep. A GWAS was conducted to identify possible genetic loci associated with resistance to Haemonchus contortus in Katahdin sheep. Forty animals were selected from the top and bottom 10% of estimated breeding values for FEC from a total pool of 641 sires and ram lambs. Samples were genotyped using Applied BiosystemsTM AxiomTM Ovine Genotyping Array (50K) consisting of 51 572 SNPs. Following quality control, 46 268 SNPs were included in subsequent analyses. Analyses were conducted using a linear regression model in PLINK v1.90 and a single-locus mixed model in SNP AND VARIATION SUITE. Genome-wide significance was determined by a Bonferroni correction for multiple testing. Using linear regression, loci on chromosomes 2, 3, 16, 23 and 24 were significantly associated at the genome level with FEC estimated breeding values, and we identified a region on chromosome 2 that was significant using both statistical analyses. We suggest a potential role for the gene DIS3L2 for gastrointestinal nematode resistance in Katahdin sheep, although further research is needed to validate these findings

Variants Within Genes \u3ci\u3eEDIL3\u3c/i\u3e and \u3ci\u3eADGRB3\u3c/i\u3e are Associated With Divergent Fecal Egg Counts in Katahdin Sheep at Weaning

Gastrointestinal nematodes (GIN) pose a severe threat to sheep production worldwide. Anthelmintic drug resistance coupled with growing concern regarding potential environmental effects of drug use have demonstrated the necessity of implementing other methods of GIN control. The aim of this study was to test for genetic variants associated with resistance or susceptibility to GIN in Katahdin sheep to improve the current understanding of the genetic mechanisms responsible for host response to GIN. Linear regression and casecontrol genome-wide association studies were conducted with high-density genotype data and cube-root transformed weaning fecal egg counts (tFEC) of 583 Katahdin sheep. The casecontrol GWAS identified two significant SNPs (P-values 1.49e-08 to 1.01e-08) within introns of the gene adhesion G protein-coupled receptor B3 (ADGRB3) associated with lower fecal egg counts. With linear regression, four significant SNPs (P-values 7.82e-08 to 3.34e-08) were identified within the first intron of the gene EGF-like repeats and discoidin domains 3 (EDIL3). These identified SNPs were in very high linkage disequilibrium (r2 of 0.996–1), and animals with alternate homozygous genotypes had significantly higher median weaning tFEC phenotypes compared to all other genotypes. Significant SNPs were queried through public databases to identify putative transcription factor binding site (TFBS) and potential lncRNA differences between reference and alternate alleles. Changes in TFBS were predicted at two SNPs, and one significant SNPwas found to bewithin a predicted lncRNA sequencewith greater than 90% similarity to a known lncRNA in the bovine genome. The gene EDIL3 has been described in other species for its roles in the inhibition and resolution of inflammation. Potential changes of EDIL3 expression mediated through lncRNA expression and/or transcription factor binding may impact the overall immune response and reduce the ability of Katahdin sheep to control GIN infection. This study lays the foundation for further research of EDIL3 and ADGRB3 towards understanding genetic mechanisms of susceptibility to GIN, and suggests these SNPs may contribute to genetic strategies for improving parasite resistance traits in sheep

Reflections on a 'virtual' practice development unit: changing practice through identity development

Aims. This paper draws together the personal thoughts and critical reflections of key people involved in the establishment of a ‘virtual’ practice development unit of clinical nurse specialists in the south of England. Background. This practice development unit is ‘virtual’ in that it is not constrained by physical or specialty boundaries. It became the first group of Trust-wide clinical nurse specialists to be accredited in the UK as a practice development unit in 2004. Design and methods. The local university was asked to facilitate the accreditation process via 11 two-hour audio-recorded learning sessions. Critical reflections from practice development unit members, leaders and university staff were written 12 months after successful accreditation, and the framework of their content analysed. Findings and discussion. Practice development was seen as a way for the clinical nurse specialists to realize their potential for improving patient care by transforming care practice in a collaborative, interprofessional and evolutionary manner. The practice development unit provided a means for these nurses to analyse their role and function within the Trust. Roberts’ identity development model for nursing serves as a useful theoretical underpinning for the reflections contained in this paper. Conclusions. These narratives provide another example of nurses making the effort to shape and contribute to patient care through organizational redesign. This group of nurses began to realize that the structure of the practice development unit process provided them with the means to analyse their role and function within the organization and, as they reflected on this structure, their behaviour began to change. Relevance to clinical practice. Evidence from these reflections supports the view that practice development unit participants have secured a positive and professional identity and are, therefore, better able to improve the patient experience