Higher FEC Research Articles

Behavioural assessment of sheep is sensitive to level of gastrointestinal parasite infection

Qualitative behavioural assessment (QBA) was applied to investigate the expressive behaviour of sheep with varying intestinal parasite burdens over two experiments. The expressive behaviour of sheep naturally infected with intestinal parasites was assessed from video footage collected in the paddock, and assessments were compared pre- and post-treatment with anthelmintic drench. The first experiment assessed sheep with a range of parasite burdens (n = 28), and the second compared sheep that expressed clinical symptoms of parasitism (Anaemic, n = 5) with those that did not (Non-anaemic, n = 5). Behavioural expression scores were validated against individual clinical evaluations (faecal egg counts – FEC, faecal consistency and anaemia scores), production parameters (body mass and body condition score), and quantitative locomotive measures (walking speed and return order to paddock). Twenty-two observers scored 28 video clips using QBA in experiment 1, and in the second experiment, 35 observers scored 20 video clips that depicted the 10 focal sheep pre- and post-treatment. QBA scores were analysed using Generalised Procrustes Analysis (GPA), and sheep scores on the main GPA dimensions were evaluated in relation to parasite burden using Spearman Rank correlations and repeated-measures ANOVA for experiment 1 and 2, respectively. In both experiments, observers reached significant (P < 0.001) consensus in their assessment of the behavioural expression of sheep. In experiment 1, sheep with higher FEC had lower anaemia scores (indicative of anaemia), poor body condition, lower body mass, walked slower, ranked lower in return order, and were scored by observers as more docile/at ease, and more assertive/motivated on GPA dimensions 1 and 3, respectively (P < 0.05). In experiment 2, observers scored Anaemic sheep as significantly more unsettled/apprehensive compared to Non-anaemic sheep on GPA dimension 1 (P < 0.05). In addition, observers consistently scored Non-anaemic sheep as more bright/observant following treatment on dimension 2 (P < 0.001). On dimension 3, all animals were scored by observers as less depressed/suspicious post-treatment (P < 0.05). An increase in average walking speed across all sheep was also identified post-treatment (P < 0.05). We conclude that under the conditions tested, QBA could provide information on the behavioural expression of sheep related to varying parasite burdens and the impact of treatment. The data presented herein offers proof of concept that assessments of behavioural expression could aid producers in the monitoring and management of parasitised sheep on-farm in terms of identification of individuals for treatment, and efficacy of anthelmintic treatment.

A PID-FEC mechanism using cross-layer approach for video transmission over multi-hop wireless networks

Multi-hop wireless networks (MWNs) provide an important infrastructure for ubiquitous multimedia content access. However, the accumulated packet losses greatly decrease the quality of multimedia services, particularly video streaming services. In order to overcome packet losses in MWNs, in this paper we propose a proportional integral derivative control-based forward error correction (PID-FEC) mechanism to improve the quality of video streaming services. Our proposed method adopts the cross-layer approach, and leverages the functionalities of different network layers. The automatic repeat request (ARQ) on the media access control (MAC) layer is used as an indicator of packet losses. With the packet loss information, the redundancy rates are adaptively regulated based on the PID control algorithm. Experimental results, presented herein, show that the PID-FEC achieves a better quality of video streaming, as well as a higher FEC efficiency, as compared with conventional FEC schemes, over a variety of network conditions.

Rumen fluke in Irish sheep: prevalence, risk factors and molecular identification of two paramphistome species.

BackgroundRumen flukes are trematode parasites found globally; in tropical and sub-tropical climates, infection can result in paramphistomosis, which can have a deleterious impact on livestock. In Europe, rumen fluke is not regarded as a clinically significant parasite, recently however, the prevalence of rumen fluke has sharply increased and several outbreaks of clinical paramphistomosis have been reported. Gaining a better understanding of rumen fluke transmission and identification of risk factors is crucial to improve the control of this parasitic disease. In this regard, a national prevalence study of rumen fluke infection and an investigation of associated risk factors were conducted in Irish sheep flocks between November 2014 and January 2015. In addition, a molecular identification of the rumen fluke species present in Ireland was carried out using an isolation method of individual eggs from faecal material coupled with a PCR. After the DNA extraction of 54 individual eggs, the nuclear fragment ITS-2 was amplified and sequenced using the same primers.ResultsAn apparent herd prevalence of 77.3 % was determined. Several risk factors were identified including type of pasture grazed, regional variation, and sharing of the paddocks with other livestock species. A novel relationship between the Suffolk breed and higher FEC was reported for the first time. The predominant rumen fluke species found was C. daubneyi. Nevertheless, P. leydeni was unexpectedly identified infecting sheep in Ireland for the first time.ConclusionsAn exceptionally high prevalence of rumen fluke among Irish sheep flocks has been highlighted in this study and a more thorough investigation is necessary to analyse its economic impact. The isolation of individual eggs coupled with the PCR technique used here has proven a reliable tool for discrimination of Paramphistomum spp. This technique may facilitate forthcoming studies of the effects of paramphistomosis on livestock production. The most noteworthy finding was the identification of P. leydeni affecting sheep in Ireland, however further studies are required to clarify its implications. Also, a significant relationship between Suffolk breed and a heavier infection was found, which can be used as a starting point for future research on control strategies of rumen fluke infection.

Genetic parameters and breeding strategies for high levels of iron and zinc in Phaseolus vulgaris L.

One of the current focus of common bean breeding programs in Brazil is to increase iron (FeC) and zinc content (ZnC) in grains. The objectives of this study were to estimate genetic parameters for FeC and ZnC in common bean, verify the need for conducting multi-site evaluation tests, identify elite lines that combine high FeC and ZnC with good adaptability, stability, and agronomic potential, and examine the genetic association between FeC and ZnC. Elite lines (140) were evaluated for important agronomic traits in multiple environments. In one trial, FeC and ZnC were evaluated and genetic parameters were estimated. Based on the high heritability estimates and significant selection gains obtained, the conditions for a successful selection was favorable. Of the 140 evaluated lines, 17 had higher FeC and ZnC, and were included in the validation test (2013, five environments), specifically for the evaluation of FeC and ZnC. The line by environment interaction for FeC and ZnC was detected, but it was predominantly simple. The environmental effect strongly influenced FeC and ZnC . The environment Brasília/rainy season was selected as the best evaluation site for preliminary tests for FeC and ZnC, because it resulted in similar conclusions as the mean of the five environments. The lines CNFP 15701 and CNFC 15865 had higher FeC and ZnC and were highly adaptable and stable, and are recommended for utilization in breeding programs. The lines CNFC 15833, CNFC 15703, and CNFP 15676 showed excellent combined agronomic and nutritional traits, and were selected for the development of biofortified cultivars. Additionally, the genetic association between FeC and ZnC was detected.

Studies on the Realationship between the Speciation Distribution and Si/Fe Ratio of Poly-Silica-Ferric-Chloride

Interactions between ferric species and silica have been shown to play a large part in the coagulation of suspensions. These effects are quite distinct from those associated with polymeric or colloid silica. The interaction of monosilicic acid with Fe ions has been discussed in this paper. Compared with traditional iron salt, poly-silica-ferric-chloride (PFSC) is characterized by having higher molecular weight, less positive charge, lower Feb and higher Fec. In addition, the Si/Fe is higher and the Silica is higher and Silicc is lower. With increasing Si/Fe ratio the effective diameter of PFSC increases. Along with the increase of Si/Fe ratio, more complicated polymers are formed and the particle size distribution is broadened. Resluts show that some co-polymerized species or aggregates between silica and Fe( ) polymers are formed.

Resistance and resilience of West African Dwarf goats of the Nigerian savanna zone exposed to experimental escalating primary and challenge infections with Haemonchus contortus

We assessed the resilience and resistance to infection with Haemonchus contortus of savanna West African Dwarf (WAD) goats from northern Nigeria. Adult male goats ( n = 32) were given an escalating immunizing infection, comprising 5 weekly infections with increasing numbers of larvae. On day (D) 56 they were segregated into low (LFEC) and high (HFEC) faecal egg count phenotypes, and within each phenotype 7 goats were treated with anthelmintic and seven received no treatment. Four goats were culled for worm counts. Fourteen additional goats acted as naïve controls until D56. All, except seven naïve, were challenged with 6000 L3 of H. contortus on D63 and culled on D81, together with the seven naïve goats. The escalating infections had no effect on body weight of the goats. Neither deworming, nor challenge infection and previous experience of infection influenced body weight post-challenge (pc). There was no effect of the escalating infection on packed cell volume (PCV) of blood cells, however, the HFEC phenotypes tended to have lower values than their LFEC counterparts and controls towards the end of immunization. Virtually all goats maintained normal PCV values (28–32%) throughout, without clinical evidence of anaemia. After challenge infection the HFEC phenotypes had significantly lower PCV than the LFEC goats and naïve controls but without other symptoms of anaemia. Anthelmintic treatment had no influence on PCV pc. The anthelmintic-treated LFEC group harboured fewer worms on D18 pc than the untreated LFEC group with the superimposed challenge. In contrast anthelmintic treatment made only a small difference to the worm burdens of the HFEC group pc. In week 7 there was a strong correlation between FEC and PCV among all the goats that experienced the immunizing infection. With anthelmintic treatment taken into account, higher FEC and lower PCV in week 7 predicted higher worm burdens at the end of the experiment, but both relationships were dependent on and differed between the anthelmintic treatment groups. Overall, we found no parasitological evidence of attenuation or loss of resistance and resilience of the Nigerian savanna WAD goat ecotype to H. contortus, suggesting that significant introgression of genes from parasite-susceptible Sahelian breeds into this WAD goat population has so far not occurred.

Effects of Teladorsagia ( Ostertagia) circumcincta infection on lambs selected for high fleece weight

The physiological processes leading to the expression of the resilient phenotype, which allow animals to maintain a relatively higher production level during infection, have been investigated in lambs from a closed flock selected for 40 generations for high fleece weight (HFW), but with higher FEC and worm burdens than their unselected control (C) flock run in parallel. After recovery from surgery to implant abomasal cannulae, eight parasite-naïve lambs from each flock were infected intraruminally at 4.5 months-of-age with 50,000 Teladorsagia circumcincta L3. Blood, abomasal fluid and faecal samples were collected daily for measurement of serum gastrin and pepsinogen concentrations, blood eosinophils, abomasal pH and FEC. Four lambs from each flock were euthanased on Day 8 post-infection and the other four on Day 28 post-infection. At necropsy, abomasal contents and tissues were collected for worm counts, abomasal lymph nodes and fundic tissue for cytokine gene expression and fundic tissue for histopathology. Expression of resilience appeared to be age-dependent as there were no significant differences in either FEC or worm burden between lambs from the two flocks, unlike older HFW lambs in a previous study. Abomasal secretion did not differ between flocks. Histopathological changes were typical of parasitism: inflammatory cells, mainly eosinophils and lymphocytes, were numerous in nodular areas and there were fewer TGF-α positive parietal cells, many of which were vacuolated. By Day 28 p.i., globule leucocytes were present. Mucosal thickness was significantly greater on Day 8 than Day 28 p.i. ( p = 0.000) and in C than HFW lambs. There were fewer parietal cells on Day 28 than on Day 8 p.i. ( p = 0.003) for pooled data. Circulating eosinophil counts increased moderately in both groups, significantly less in the HFW lambs. Fewer tissue and blood eosinophils in the HFW than C group on Day 8 p.i. were consistent with cytokine gene expression patterns, particularly lower IL-5 levels. Worm count decreased by 90% by Day 28 p.i., along with declining tissue eosinophil counts and IL-13 gene expression and increasing IL-10 and IL-4 gene expression. Food intake was depressed less in the HFW lambs, suggesting that maintenance of appetite could be an important aspect of the physiological basis for resilience. Although the resilient phenotype was not apparent at the younger age, lesser effects on food intake, differences in ALN cytokine profiles and lower blood and tissue eosinophil numbers in the HFW lambs may lead to the expression of resilience when older.

Pathophysiology in Teladorsagia (Ostertagia) circumcincta-infected sheep selected for high fleece weight

Resilience to parasitism is considered to be the maintenance of growth and production during infection, probably associated with an immune response with lesser detrimental effects on the host relative to adverse effects on the parasite. Resilience to infection with Teladorsagia circumcincta was investigated in lambs from a flock selected for forty generations for high fleece weight (HFW), but with higher FEC and worm burdens than their unselected control (C) flock run in parallel. After recovery from surgery to implant abomasal cannulae, four parasite-naïve lambs from each flock were infected intraruminally at 6.5 months-of-age with 50,000 T. circumcincta L3, then from Day 35 to 70 post infection with 10,000 larvae at weekly intervals. Blood, abomasal fluid and faecal samples were collected daily to Day 35 and thence twice weekly for measurement of serum gastrin and pepsinogen concentrations, blood eosinophils, abomasal pH and FEC. Abomasal worm counts were made after necropsy on Day 94. Skin biopsies were collected weekly for estimation of the percentage of wool follicles containing paracortical cells. Total serum immunoglobulin and IgG1, IgG2, IgA and IgM titres specific for T. circumcincta antigens were estimated twice weekly to Day 42 p.i., then weekly. After the primary challenge, FEC were higher in the HFW lambs, whereas neither group shed many eggs during the 5-week trickle infection; worm burdens were small at post mortem. Resilient HFW lambs showed a lesser inflammatory response, but relatively small differences in abomasal secretion. Circulating eosinophil counts increased moderately in both groups, less in the HFW lambs, during the primary infection and more markedly during the subsequent trickle infection, when the increase in the C lambs became significantly greater. All measured serum antibody titres were low in both groups throughout. Selection for HFW altered the wool characteristics of parasite-naïve lambs (fewer follicles containing paracortical cells). There was a slower increase in the percentage of follicles containing these cells after primary infection. Abomasal function was similar in the two groups, both exhibiting typical increases in abomasal pH and serum gastrin and pepsinogen concentrations. The most marked differences in the HFW lambs were a greater rise in serum pepsinogen during the primary infection and the 2-day delay in onset of hypoacidity. Resilience to parasitism in this flock is consistent with maintenance of wool quality and small differences in abomasal secretion resulting from an attenuated immune response causing fewer detrimental effects on host tissues.

Effect of a diet high in energy and protein on growth, carcase characteristics and parasite resistance in goats

The effects of a high-energy and high-protein diet on growth, parasite resistance and carcase characteristics were studied using local goats with an average initial body weight (BW) of 12.0 (SD = 0.7) kg. Thirty-two animals were allocated to a completely randomized factorial design, with four animals of each sex per treatment. The factors were: two diets (diet H with high content of crude protein (CP) and metabolizable energy (ME), and diet L with low content of CP and ME) and deworming (DW) or non-deworming (NDW). The highest dry matter (DM) intake was obtained for goats fed diet H combined with DW, but there was no significant difference between DW or NDW for goats fed diet H. The goats fed diet L and DW had significantly better total DM intake than NDW goats. The average daily gain of animals fed diet H was 86 and 92 g/day compared to 27 and 40 g/day for diet L, for NDW and DW animals, respectively. Feeding diet H resulted in higher slaughter weight and consequently also higher empty BW, carcase weight and dressing percentage and lower feed conversion ratio. Dewormed animals had significantly higher empty BW than NDW animals. There were significant effects of diet and parasite control on Faecal egg count (FEC: number of parasite eggs per gram of faeces (e.p.g.)), with NDW animals fed diet L having higher FEC than animals fed diet H.

Discrimination of wide-field images as a test of a peripheral-vision model.

In order to test a model of peripheral vision, various contrast sensitivity functions (CSF's) and fundamental eccentricity constants (FEC's) [see J. Opt. Soc. Am. A 8, 1762 (1991)] were applied to real-world, wide-field (6.4 degrees-32 degrees eccentricity) images. The FEC is used to model the change in contrast sensitivity as a function of retinal eccentricity. The processed test images were tested perceptually by determining the threshold FEC for which the observers could discriminate the test images from the original image. It was expected that higher CSF sensitivity would be associated with higher FEC's; and in fact, for images processed with low-pass (variable-window stimuli) CSF's, the threshold FEC's were larger for the higher-sensitivity (pattern-detection) CSF than for the lower-sensitivity (orientation detection) CSF. When two higher-sensitivity CSF's were compared, the bandpass (constant-window stimuli) CSF resulted in essentially the same FEC threshold as did the low-pass (variable-window stimuli) CSF. The fact that the FEC compensated for complex differences in the form of the CSF suggested that the discrimination task was mediated by a limited range of spatial frequencies over which the two CSF's were similar. Image contrast was then varied in order to extend the range of spatial frequencies tested. The FEC's estimated with the lower-contrast test images were unchanged for test images obtained with the high-sensitivity, bandpass CSF but increased for test images obtained with the high-sensitivity, low-pass CSF. These results suggest that peripheral contrast sensitivity as used in the present discrimination task is based on a high-sensitivity, bandpass CSF. The peripheral-vision model validated by the present analysis has practical applications in the evaluation of wide-field simulator images as well as area-of-interest or other foveating systems.