Faecal nematode egg counts in lactating ewes from Romney flocks selectively bred for divergence in lamb faecal egg count

1998 ◽  
Vol 67 (2) ◽  
pp. 283-288 ◽  
Author(s):  
C. A. Morris ◽  
S. A. Bisset ◽  
A. Vlassoff ◽  
C. J. West ◽  
M. Wheeler
Keyword(s):  
Selective Breeding ◽  
Genetic Effects ◽  
Grazing Management ◽  
Phenotypic Correlation ◽  
Correlated Response ◽  
Genetic Changes ◽  
Faecal Samples ◽  
Faecal Egg Count ◽  
Parasite Infections ◽  
Effect Of Age

AbstractFaecal nematode egg counts (FECs) were examined in lactating ewes from divergent flocks of Romney sheep which had been selectively bred from 1979 to 1996 for or against FEC in 4 to 7 month old lambs. Faecal samples were obtained from the ewes while under normal grazing management, 1 to 2 months after lambing in spring for each of 6 years between 1987 and 1996 (no. = 785 records; 298 animals). Analyses were carried out on loge (FEC + 100)–transformed data using animal-model maximum likelihood procedures, accounting for repeated records on ewes, within and between lactations. An examination of non-genetic effects indicated that there was no significant effect of age class of ewe on FEC but ewes which gave birth to single lambs had significantly lower post-parturient FECs than those bearing twins (back-transformed means of 184 v. 276 egg per g, respectively; P < 0·001). In relation to genetic effects, post-parturient FECs were significantly lower in ewes from the flock bred for low lamb-FEC than in their counterparts from the flock bred for high lamb-FEC, with ewes from the most recent birth years (1991 to 1994) showing a nine-fold difference (back-transformed means of 33 and 305 eggs per g faeces respectively; P < 0·001). This was equivalent to 69% of the divergence observed between loge (FEC + 100) in their lambs in the same years. Heritability and repeatability estimates for loge (FEC + 100) in ewes were 0·37 (s.e. 0·06) and 0·46 (s.e. 0·03) respectively. Genetic correlation estimates between a ewe's post-parturient loge (FEC + 200) and her loge (FEC + 100) as a lamb, based on analysis of (co)variance or realized responses, were 0·70 or 0·58 respectively. The phenotypic correlation between a ewe's loge (FEC + 100) and that of her lamb(s) in the same lactation was 0·29 (s.e. 0·06) (P < 0·001). From the results it is clear that substantial genetic changes in post-parturient FECs of breeding ewes can be induced through a correlated response to selective breeding for or against reduced FEC in lambs. This may have important implications for the epidemiology of nematode parasite infections in spring-born lambs, a possibility which is currently being investigated.

scholarly journals The point prevalence of gastro-intestinal parasites in calves, sheep and goats in Magadi division, south-western Keny

2004 ◽  
Vol 71 (4) ◽  
Author(s):  
M.W. Maichomo ◽  
J.M. Kagira ◽  
T. Walker
Keyword(s):  
Animal Species ◽  
Intestinal Parasites ◽  
Economic Loss ◽  
Parasite Control ◽  
Sheep And Goats ◽  
Internal Parasite ◽  
Faecal Samples ◽  
Parasite Infections ◽  
Mcmaster Method ◽  
Semi Arid

Helminths cause great economic loss in livestock in Africa, and can be categorized as either direct or indirect losses. Arid and semi-arid lands (ASAL) in Kenya comprise 71 % of total land area and harbour the largest population of cattle, sheep and goats. However, little information on the distribution and impact of gastro-intestinal (GIT) parasitism in these animals is available. This survey was conducted to establish the prevalence of GIT parasites infecting calves, sheep and goats and their relative importance in Magadi division, which is semi-arid. Faecal samples were obtained directly from the rectum of 109 calves, 133 goats and 20 sheep and submitted to the laboratory for faecal worm egg counts, and coccidial oocysts examination using a modified McMaster method. The significance of differences in mean egg count per gram (epg) between animal species and herds (farms) were assessed using analysis of variance. The overall prevalence of nematodes in the calves, sheep and goats was 69.2 %, 80 % and 82 %, respectively. About 10 % of sheep and goats had epgs higher than 1 000, the remainder having light to moderate infections. The overall prevalence of coccidial oocysts in calves, sheep and goats was 30 %, 44 % and 45 %, respectively. Poor productivity in ASAL areas, where nutrition is often poor, is likely to be pronounced in the presence of parasite infections. These findings indicate that viable internal parasite control should be implemented in the study area in order to increase the productivity of the livestock there.

An evaluation of biological and conventional pig selection indices

1989 ◽  
Vol 29 (6) ◽  
pp. 775 ◽  
Author(s):  
RW Ponzoni ◽  
RL Davies
Keyword(s):  
Average Daily Gain ◽  
Selection Criterion ◽  
Conversion Ratio ◽  
Correlated Response ◽  
Feed Conversion ◽  
Genetic Changes ◽  
Lean Meat ◽  
Biological Indices ◽  
Selection Indices ◽  
Daily Gain

Two biological and 4 conventional pig selection indices were compared. The biological indices were lean meat growth (LGRTH) and lean meat feed conversion (LFCR). The conventional indices included average daily gain (ADG) and back fat measured at the P2 site (FP2) as criteria (index OF), or as in OF but with the addition of feed conversion ratio (FCR) as a selection criterion (index BTS). Also, using the same criteria as in BTS and OF, restricted indices were derived setting the genetic change in FP2 at zero (indices BTS.FP2 and OF.FP2). The correlated response in average daily feed intake (ADI) was calculated for all indices. The application of all indices resulted in variable, but desirable, predicted genetic changes in ADG, FCR and FP2. The correlated response in AD1 was positive, except for BTS and LFCR, where it was zero and negative, respectively. The correlations among all indices were high (r > 0.7) except for those restricting FP2. It is concluded that conventional selection indices have advantages over biological indices because they more easily enable the monitoring of changes in the components of overall merit and updating of breeding objectives.

Genetic interactions Between Hatchery and Wild Salmonids: Lessons from the Pacific Northwest

1991 ◽  
Vol 48 (S1) ◽  
pp. 124-133 ◽  
Author(s):  
Robin S. Waples
Keyword(s):  
Pacific Northwest ◽  
Genetic Effects ◽  
Wild Fish ◽  
Genetic Interactions ◽  
Future Research ◽  
Management Options ◽  
Genetic Changes ◽  
The Pacific ◽  
Genetic Risks ◽  
Northwestern North America

The potential for genetic interactions between hatchery and wild populations of salmonids in northwestern North America has increased considerably in recent decades. Efforts to mitigate severe losses to many wild stocks caused by overfishing, destruction of habitat, and blockage of migratory routes have focussed on boosting artificial production in public hatcheries. Opportunities for genetic interactions between hatchery and wild fish will increase if efforts to supplement wild production with hatchery-reared fish continue. Concerns center on three issues: (1) direct genetic effects (caused by hybridization and introgression); (2) indirect genetic effects (principally due to altered selection regimes or reductions in population size caused by competition, predation, disease, or other factors); and (3) genetic changes to hatchery stocks (through selection, drift, or stock transfers), which magnify the consequences of hybridization with wild fish. Strategies for minimizing these genetic risks and monitoring the consequences of various management options are discussed, and some important areas for future research are identified.

Species-specific amplification by PCR of ribosomal DNA from some equine strongyles

Parasitology ◽  
1999 ◽  
Vol 119 (1) ◽  
pp. 69-80 ◽  
Author(s):  
G.-C. HUNG ◽  
R. B. GASSER ◽  
I. BEVERIDGE ◽  
N. B. CHILTON
Keyword(s):  
Ribosomal Dna ◽  
Anthelmintic Resistance ◽  
Pcr Assay ◽  
Strongylus Vulgaris ◽  
Faecal Samples ◽  
Faecal Egg Count ◽  
Specific Amplification ◽  
Internal Transcribed Spacer Sequences ◽  
Second Internal Transcribed Spacer ◽  
Species Specific

The first and second internal transcribed spacer sequences of 28 morphologically-defined species of horse strongyle were characterized, and specific oligonucleotide primers were designed for some species based on the nucleotide differences. Utilizing these primers, a PCR approach was developed for the specific amplification of ribosomal DNA of Strongylus vulgaris, Cyathostomum catinatum, Cylicocyclus nassatus, Cylicostephanus longibursatus or Cylicostephanus goldi. The method allowed the species-specific amplification of parasite DNA derived from faecal samples and/or copro-cultures, demonstrating the potential of the approach for the diagnosis of equine strongyloidosis. The establishment of this PCR assay also has implications for studying the biology and epidemiology of equine strongyles and anthelmintic resistance using faecal egg count reduction tests.

Selection of Merino sheep for resistance to Haemonchus contortus: genetic variation

1996 ◽  
Vol 62 (3) ◽  
pp. 451-460 ◽  
Author(s):  
R. R. Woolaston ◽  
L. R. Piper
Keyword(s):  
Haemonchus Contortus ◽  
Genetic Correlations ◽  
Heritability Estimate ◽  
Phenotypic Correlation ◽  
Cube Root ◽  
Selection Line ◽  
Pooled Data ◽  
Heterogeneity Of Variance ◽  
Root Transformation ◽  
Faecal Egg Count

AbstractAn animal model was used to estimate heritabilities of faecal egg count (FEC) and packed cell volume decline (PCVD) in lines of Merinos selected for divergent levels of resistance to Haemonchus contortus. The estimated heritability of FEC was 0·23 (s.e. 0·03) and of PCVD was 0·21 (s.e. 0·03). A cube root transformation was found to be effective in normalizing FEC data and reducing the range of within selection line-birth year variances from 118-fold to 10-fold. Transforming FEC data increased the heritability estimate to 0·29 (s.e. 0·03) and reduced selection bias due to heterogeneity of variance, but the further step of pre-adjusting the transformed data to a common variance had only a trivial effect. Heritability estimates for FEC in years with high means and variances were similar, as were estimates for transformed FEC. The estimated genetic correlations between measurements in years with high and low means and variabilities were 0·77 to 0·91.PCVD and pre-adjusted transformed FEC had a phenotypic correlation of 0·48. Estimates for the genetic correlation ranged from 0·76 in the decreased resistance line to 1·00 in the increased resistance line and 0·87 with pooled data. Other effects on resistance included birth type and dam age, with twins and progeny of maiden dams being more resistant than their cohorts. Sex effects were unimportant for FEC but males had higher PCVD than females in most, but not all, years. Younger animals had higher FEC and PCVD than older animals. Maternal genetic effects were found to be unimportant, as were the effects of low levels of inbreeding.

scholarly journals Worm-control practices and prevalence of anthelmintic resistance using in vivo FECRTs on smallholder sheep farms in Lithuania

2016 ◽  
Vol 53 (1) ◽  
pp. 24-30 ◽  
Author(s):  
T. Kupčinskas ◽  
I. Stadalienė ◽  
A. Šalomskas ◽  
P. Trusevičius ◽  
M. Varady ◽  
...  
Keyword(s):  
Anthelmintic Resistance ◽  
Gastrointestinal Nematodes ◽  
Parasitic Nematodes ◽  
Future Studies ◽  
Faecal Samples ◽  
Two Samples ◽  
Faecal Egg Count ◽  
Worm Control

SummaryThis study determined the prevalence of anthelmintic resistance (AR) in parasitic nematodes on smallholder sheep farms in Lithuania from April to November 2014. Faecal samples were collected from two groups of 10-15 sheep treated with fenbendazole (FBZ) or ivermectin (IVM) on 18 sheep farms. Two samples were collected from each group: on day zero (T1) and 10-14 days after treatment. Faecal egg counts (eggs per gramme, EPG) were determined using a modified McMaster technique. Animals with < 140 EPG on day zero were removed from the analysis. The prevalence of AR was estimated using the in vivo faecal egg count reduction test. AR to FBZ was detected on three of 15 farms where FBZ was used (20 %) and was suspected on one farm (6.7 %). AR to IVM was detected on two of 16 farms where IVM was used (12.5 %). The main species of resistant gastrointestinal nematodes (GINs) identified after treatment were Teladorsagia spp. and Trichostrongylus spp. A questionnaire surveying 71 sheep farmers estimated that 71.8 % of sheep farmers used anthelmintics against GINs. IVM was the most frequently (68.6 %) applied anthelmintic, and 62.7 % of the respondents reported treating their animals twice a year. This study confirmed the presence of AR to GIN infections on sheep farms in Lithuania. Future studies should assess the prevalence of AR to GIN infection using in vitro methods.

scholarly journals Cattle gastrointestinal nematode egg-spiked faecal samples: high recovery rates using the Mini-FLOTAC technique

2020 ◽  
Author(s):  
Alessandra Amadesi ◽  
Antonio Bosco ◽  
Laura Rinaldi ◽  
Giuseppe Cringoli ◽  
Edwin Claerebout ◽  
...  
Keyword(s):  
Recovery Rate ◽  
Gastrointestinal Nematode ◽  
Mean Value ◽  
Reading Levels ◽  
Accuracy And Precision ◽  
Faecal Samples ◽  
Significant Difference ◽  
Faecal Egg Count ◽  
Flotac Technique ◽  
Higher Sensitivity

Abstract Background: Faecal egg count (FEC) techniques are commonly used to detect gastrointestinal nematode (GIN) in cattle and to determine anthelmintic efficacy/resistance through the faecal egg count reduction test (FECRT). Mini-FLOTAC is one of the techniques recommended for a standardised FEC/FECRT of helminth eggs in cattle. However, only one paper evaluated the recovery rate of GIN eggs by Mini-FLOTAC (compared to McMaster and modified-Wisconsin) in cattle, using only the level of contamination of 200 eggs per gram (EPG) of faeces and using GIN eggs collected from goat faeces to spike faecal samples from cattle. To further study the recovery rate of added GIN eggs from cattle, this study was conducted in two laboratories, one in Belgium and one in Italy to evaluate sensitivity, accuracy, precision and reproducibility of Mini-FLOTAC and McMaster (at two reading levels: grids and chambers) for the detection of GIN eggs in spiked bovine faecal samples. Methods: In both countries, spiked cattle faecal samples with five different levels of egg contamination (10, 50, 100, 200 and 500 EPG) of GINs were used. The study was performed in both laboratories by the same expert operator and using the same standard operating procedures (SOPs) for Mini-FLOTAC and McMaster. Sensitivity, accuracy and precision were calculated for each technique and for each level of contamination. Moreover, statistical analyses were performed to evaluate differences between performances of techniques used. Results: Mini-FLOTAC had a higher sensitivity (100% at all EPG levels for Mini-FLOTAC vs 0-66.6% for McMaster chambers and grids at levels <100 EPG), a higher accuracy (98.1% mean value for Mini-FLOTAC vs 83.2% for McMaster grids and 63.8% for McMaster chambers) and a lower coefficient of variation (10.0% for Mini-FLOTAC vs 47.5% for McMaster grids and 69.4% for McMaster chambers) than McMaster. There was no significant difference between the recovery of GIN eggs from the two studies performed in Belgium and in Italy. Conclusions: The high GIN eggs recovery rate detected by Mini-FLOTAC and the similar results obtained in Belgium and in Italy indicated that the diagnostic performance of a FEC technique was not regard to the laboratory environment.

scholarly journals Cattle gastrointestinal nematode egg-spiked faecal samples: high recovery rates using the Mini-FLOTAC technique

2020 ◽  
Author(s):  
Alessandra Amadesi ◽  
Antonio Bosco ◽  
Laura Rinaldi ◽  
Giuseppe Cringoli ◽  
Edwin Claerebout ◽  
...  
Keyword(s):  
Recovery Rate ◽  
Gastrointestinal Nematode ◽  
Mean Value ◽  
Reading Levels ◽  
Accuracy And Precision ◽  
Faecal Samples ◽  
Significant Difference ◽  
Faecal Egg Count ◽  
Flotac Technique ◽  
Higher Sensitivity

Abstract Background: Faecal egg count (FEC) techniques are commonly used to detect gastrointestinal nematode (GIN) in cattle and to determine anthelmintic efficacy/resistance through the faecal egg count reduction test (FECRT). Mini-FLOTAC is one of the techniques recommended for a standardised FEC/FECRT of helminth eggs in cattle. However, only one paper evaluated the recovery rate of GIN eggs by Mini-FLOTAC (compared to McMaster and modified-Wisconsin) in cattle, using only the level of contamination of 200 eggs per gram (EPG) of faeces and using GIN eggs collected from goat faeces to spike faecal samples from cattle. To further study the recovery rate of added GIN eggs from cattle, this study was conducted in two laboratories in Belgium and Italy to evaluate sensitivity, accuracy, precision and reproducibility of Mini-FLOTAC and McMaster (at two reading levels: grids and chambers) for the detection of GIN eggs in spiked bovine faecal samples. Methods: In both countries, spiked cattle faecal samples with five different levels of egg contamination (10, 50, 100, 200 and 500 EPG) of GINs were used. The study was performed in both laboratories by the same expert operator and using the same standard operating procedures (SOPs) for Mini-FLOTAC and McMaster. Sensitivity, accuracy and precision were calculated for each technique and for each level of contamination. Moreover, statistical analyses were performed to evaluate differences between performances of techniques used. Results: Mini-FLOTAC had a higher sensitivity (100% at all EPG levels for Mini-FLOTAC vs 0-66.6% for McMaster chambers and grids at levels <100 EPG), a higher accuracy (98.1% mean value for Mini-FLOTAC vs 83.2% for McMaster grids and 63.8% for McMaster chambers) and a lower coefficient of variation (10.0% for Mini-FLOTAC vs 47.5% for McMaster grids and 69.4% for McMaster chambers) than McMaster. There was no significant difference between the recovery of GIN eggs from the two studies performed in Belgium and in Italy. Conclusions: The high GIN eggs recovery rate detected by Mini-FLOTAC and the similar results obtained in Belgium and in Italy indicated that the diagnostic performance of a FEC technique was not regard to the laboratory environment.

scholarly journals Religious Attendance Moderates the Environmental Effect on Prosocial Behavior in Nigerian Adolescents

2019 ◽  
Vol 22 (1) ◽  
pp. 42-47 ◽  
Author(s):  
Yoon-Mi Hur ◽  
Hoe-Uk Jeong ◽  
Frances Ajose ◽  
Ariel Knafo-Noam
Keyword(s):  
Prosocial Behavior ◽  
Environmental Influences ◽  
Model Fitting ◽  
Interaction Model ◽  
Genetic Effects ◽  
Religious Attendance ◽  
Phenotypic Correlation ◽  
Phenotypic Variance ◽  
Environmental Variance ◽  
Frequent Attenders

AbstractThere is a growing body of literature linking religious attendance to prosocial behavior (PB). The main purposes of the present study were to estimate genetic and environmental influences on the frequency of religious attendance (FRA) and to explore whether and how FRA moderates genetic and/or environmental influences on PB. As part of the Nigerian Twin and Sibling Study, 2860 (280 monozygotic male, 417 monozygotic female, 544 dizygotic male, 699 dizygotic female, and 920 opposite-sex dizygotic) twins (mean age = 14.2 years; SD = 1.7 years; age range = 12–18 years) completed a questionnaire regarding FRA and a PB scale. Similar to the findings from western twin samples, FRA showed substantial shared environmental influences of 74% (95% CI = 69%, 78%), with absence of genetic effects. The phenotypic correlation between FRA and PB was modest but positive and significant (r = .12; p < .01), suggesting that PB is higher among more frequent attenders than among less frequent attenders. The results of gene–environment (G × E) interaction model-fitting analysis revealed that FRA changed individual environmental experiences rather than genetic effects on PB such that while genetic variance was stable, non-shared environmental variance declined, leading the total phenotypic variance of PB to decrease with increasing levels of religious attendance.

scholarly journals The genetic analysis of the direct and correlated response to selection for chaetae in Drosophila melanogaster

1973 ◽  
Vol 22 (1) ◽  
pp. 1-7
Author(s):  
W. R. Scowcroft
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Analysis ◽  
Genetic Correlation ◽  
Statistical Approach ◽  
Correlated Response ◽  
Minor Importance ◽  
Response To Selection ◽  
Genetic Changes ◽  
Selection For ◽  
Selection Of

SUMMARYThe direct and correlated response to selection of scutellar microchaetae and scutellar bristles has been analysed by determining the contribution of the three major chromosomes, alone and in combination with each other, to the overall response. The results of the analysis confirm a previous finding, based on a formal statistical approach, that response to selection for microchaetae had highly pleiotropic effects on scutellar bristles. In lines selected, each for high and low microchaetae, genetic changes in the 2nd and 3rd chromosomes are pre-eminent and essentially equal. Inter-chromosomal interactions are of relatively minor importance in interpreting the response to selection for microchaetae but assume greater importance with respect to the correlated character. The results are discussed in terms of the genetic correlation between fitness and the character measured.

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