The FAMACHA system for managing haemonchosis in sheep and goats by clinically identifying individual animals for treatment

Association of β-globin polymorphisms and tolerance to haemonchosis in ewes and lambs of different sheep breeds

Gastrointestinal nematodes (GIN), especially Haemonchus contortus, represent a significant challenge for sheep production. Given the global concern about GIN anthelmintic resistance, alternative control methods able to reduce the dependence on these drugs are highly advisable. Since previous studies have shown that sheep carrying the Hb-A allele of β-globin are more resistant to H. contortus, this study aimed to investigate the relationship between the different haplotypes (Hb-AA, Hb-AB and Hb-BB) and phenotypes in Santa Inês (SI), Texel (TX) and White Dorper (DO) breeds infected with H. contortus. Blood samples were collected from 180 ewes and 123 lambs of the three breeds for DNA extraction followed by qPCR using a hydrolysis probe to identify the β-globin haplotypes. Phenotypic data, including fecal egg count (FEC), packed cell volume (PCV), FAMACHA score and body condition score for ewes and lambs, as well as weight gain for lambs, were collected. The genotypic frequencies of β-globin for ewes and lambs were, respectively: 21.7% and 21.4% Hb-AA, 50% and 50% Hb-AB and 28.3% and 28.6% Hb-BB in SI; 0% and 0% Hb-AA, 18.6% and 9.4% Hb-AB and 81.4% and 90.6% Hb-BB in TX; and 0% and 0% Hb-AA, 13.1% and 0% Hb-AB and 86.9% and 100% Hb-BB in DO. In ewes, mean PCV differed (p<0.05) between the three haplotypes, with higher PCV in Hb-AA animals, followed by Hb-AB and Hb-BB. When considering each breed separately, SI Hb-AA ewes presented higher PCV (p<0.05), highlighting that even in a breed already considered resistant, animals with Hb-AA haplotype showed superior performance. Lambs with the Hb-AA haplotype exhibited a higher (p<0.05) mean PCV compared to those with Hb-AB and Hb-BB. The same pattern was found in SI when analyzing each breed separately. No significant association was found between β-globin haplotypes and FEC, FAMACHA score, body condition score, or weight gain. Nevertheless, given that anemia is the major clinical sign of haemonchosis, our findings on PCV reinforce that sheep carrying the Hb-A allele of β-globin are more tolerant to haemonchosis. This study may support the development of a valuable tool, targeting genetic selection for GIN control, reducing the dependence on anthelmintics and boosting sheep production worldwide.

Farmers' and Experts' Knowledge Coping with Sheep Health, Control and Anthelmintic Resistance of Their Gastrointestinal Nematodes

Gastrointestinal nematodes are common in grazing sheep, but the intensity of the infection is not easily appreciated by farmers. For decades, they have relied on anthelmintic treatments to control these gastrointestinal nematodes. This has led to anthelmintic resistance and poor control of infection in most regions of the world. Using face-to-face semidirective interviews with farmers, we recorded their views on gastrointestinal nematode infection and its control. Ten organic and nine conventional meat sheep farmers from central France and 20 milk sheep farmers from the Basque region were interviewed and the data were analysed using a health model based on the importance of the disease and the barriers to implementing control. It was found that gastrointestinal nematodes were not the main health concern, and therefore farmers were not willing to invest too much time and money in their control. The conventional farmers relied on their veterinarians (the experts) to organise and select the anthelmintics, although they complained about the limited investment of their veterinarians in this matter. Organic farmers complained about their lack of knowledge about complementary and alternative medicines. Farmers rarely used faecal egg counts to build control of gastrointestinal nematodes and were unaware of the intensity of their infection. Knowledge of anthelmintic resistance was general (it exists) but farmers did not know if it existed on their farm. Resistance was often considered to have come from elsewhere, so the farmer did not feel at fault and did not take measures to prevent resistance. There is a need for all stakeholders to use faecal egg counts to assess the intensity of infection as well as the level of anthelmintic resistance to establish individual farm control programmes rather than standard blanket treatments.

The groundbreaking impact of digitalization and artificial intelligence in sheep farming

The integration of digitalization and Artificial Intelligence (AI) has marked the onset of a new era of efficient sheep farming in multiple aspects ranging from the general well-being of sheep to advanced web-based management applications. The resultant improvement in sheep health and consequently better farming yield has already started to benefit both farmers and veterinarians. The predictive analytical models embedded with machine learning (giving sense to machines) has helped better decision-making and has enabled farmers to derive most out of their farms. This is evident in the ability of farmers to remotely monitor livestock health by wearable devices that keep track of animal vital signs and behaviour. Additionally, veterinarians now employ advanced AI-based diagnostics for efficient parasite detection and control. Overall, digitalization and AI have completely transformed traditional farming practices in livestock animals. However, there is a pressing need to optimize digital sheep farming, allowing sheep farmers to appreciate and adopt these innovative systems. To fill this gap, this review aims to provide available digital and AI-based systems designed to aid precision farming of sheep, offering an up-to-date understanding on the subject. Various contemporary techniques, such as sky shepherding, virtual fencing, advanced parasite detection, automated counting and behaviour tracking, anomaly detection, precision nutrition, breeding support, and several mobile-based management applications are currently being utilized in sheep farms and appear to be promising. Although artificial intelligence and machine learning may represent key features in the sustainable development of sheep farming, they present numerous challenges in application.

Anaemia in South American camelids - an overview of clinical and laboratory diagnostics

South American camelids (SACs) play an increasing role in veterinary care in Europe. Many alpacas or llamas presented to veterinarians suffer from anaemia, regularly with a packed cell volume (PCV) below 0.10 l/l, which is a life-threatening condition for the animals. This review article presents clinical and laboratory diagnostic tools for the diagnosis of anaemia in SACs. Clinical identification of anaemic animals can be performed by assessing the FAMACHA© score and the Body Condition Score (BCS), since anaemia in alpacas and llamas correlates with pale mucous membranes and a lowered BCS. Haematological examination of a blood sample can provide a more differentiated diagnosis of anaemia in SACs. A common finding is regenerative anaemia with an increased number of reticulocytes that is often caused by blood loss due to Haemonchus contortus. Changes in a blood smear from an alpaca or llama with regenerative anaemia may include normoblasts (nucleated red blood cells), anisocytosis, poikilocytosis, polychromasia, Howell-Jolly bodies or basophilic stippling. Furthermore, non-regenerative anaemia, often caused by trace element deficiency or cachexia, can also occur.

Revisiting anthelmintic resistance in sheep flocks from São Paulo State, Brazil

Haemonchus contortus and Trichostrongylus colubriformis are the most important gastrointestinal nematodes causing serious losses in sheep production of tropical and subtropical regions. Prophylaxis of gastrointestinal nematode infections is based on anthelmintics use, but their frequent administration selects multiple-resistant parasites. To evaluate how the situation has changed over the last decades, the anthelmintic resistance status of gastrointestinal nematodes in sheep flocks was assessed in the current study and compared to previous surveys. In each one of the 15 flocks evaluated, animals (n ≥ 7) were allocated into at least five groups and treated as follows: 1) untreated control; 2) albendazole; 3) levamisole; 4) ivermectin; and 5) monepantel. If more animals were available, two additional groups were included: 6) closantel, and 7) moxidectin. The faecal egg count reduction test (FECRT) was carried out to evaluate the pre- and post-treatment using the SHINY tool. Haemonchus spp. was the most prevalent nematode from faecal cultures. The mean efficacy of albendazole was 40%. Only in two farms, levamisole presented a relatively high percentage of reduction in the FECRT about 90%, while ivermectin and moxidectin presented the worst mean efficacy of 34% and 21% among all farms, respectively. Like other anthelmintics, closantel demonstrated low efficacy (63%) across all farms evaluated. Monepantel presented an overall mean efficacy of 79%, but it was the only anthelmintic that presented efficacy ≥95%, in five farms. The results revealed that gastrointestinal nematodes with multiple anthelmintic resistance were prevalent in all 15 sheep herds. The research suggests that nematodes are becoming more and more resistant to various anthelmintic compounds, which has made the problem worse. This circumstance highlights the necessity to put into practice sustainable and long-lasting methods to prevent gastrointestinal nematode infections in sheep husbandry.

Genome-enabled prediction of indicator traits of resistance to gastrointestinal nematodes in sheep using parametric models and artificial neural networks

This study aimed to assess the predictive ability of parametric models and artificial neural network method for genomic prediction of the following indicator traits of resistance to gastrointestinal nematodes in Santa Inês sheep: packed cell volume (PCV), fecal egg count (FEC), and Famacha© method (FAM). After quality control, the number of genotyped animals was 551 (PCV), 548 (FEC), and 565 (FAM), and 41,676 SNP. The average prediction accuracy (ACC) calculated by Pearson correlation between observed and predicted values and mean squared errors (MSE) were obtained using genomic best unbiased linear predictor (GBLUP), BayesA, BayesB, Bayesian least absolute shrinkage and selection operator (BLASSO), and Bayesian regularized artificial neural network (three and four hidden neurons, BRANN_3 and BRANN_4, respectively) in a 5-fold cross-validation technique. The average ACC varied from moderate to high according to the trait and models, ranging between 0.418 and 0.546 (PCV), between 0.646 and 0.793 (FEC), and between 0.414 and 0.519 (FAM). Parametric models presented nearly the same ACC and MSE for the studied traits and provided better accuracies than BRANN. The GBLUP, BayesA, BayesB and BLASSO models provided better accuracies than the BRANN_3 method, increasing by around 23% for PCV, and 18.5% for FEC. In conclusion, parametric models are suitable for genome-enabled prediction of indicator traits of resistance to gastrointestinal nematodes in sheep. Due to the small differences in accuracy found between them, the use of the GBLUP model is recommended due to its lower computational costs.

Validation of targeted selective treatment (TST) methodology for gastrointestinal parasites of adult sheep in different physiological states

We aimed to validate a targeted selective treatment (TST) methodology for treating parasitic gastrointestinal infections in ewes in different physiological states using parasitological and hematological parameters. Forty ewes were monitored from December 2021 to June 2022 and evaluated during various physiological stages in their life cycle. Before starting the experiment, a fecal egg count (FEC) reduction test was performed to evaluate the efficacy of the anthelmintic (AH) treatment. Weekly assessments were performed based on the Famacha© (F) system and body condition score (BCS), and ewes were subjected to AH treatment when necessary, with their physiological states recorded. Ewes were treated when they presented F ≥ 3, BCS ≤ 2.0 (when F = 2), or submandibular edema. Parasitological, i.e., FEC, and hematological, i.e., hematocrit (Ht), parameters were evaluated monthly to determine the efficiency of the TST methodology. Comparisons between the mean Ht and FEC values in ewes subjected to AH treatment and untreated ewes were performed using analysis of variance, followed by Tukey's test. Spearman's correlation was performed to determine the correlation between the variables, i.e., F scores, BCS, Ht, and FEC. All tests were performed at a significance level of 5 %. During the experimental period, 1138 evaluations were performed. The main reason for AH treatment was F ≥ 3. Ewes in early pregnancy, lactation and late pregnancy received comparatively more AH treatments than the other physiological states. Ewes in late pregnancy and lactation exhibited lower mean Ht values (23.5 % and 22.9 %) and higher mean FEC values (3269 and 1426) compared with those in early pregnancy (30.2 % and 727 EPG). In addition, a statistically significant difference was observed in the Ht and FEC values of ewes that presented submandibular edema (P < 0.001) compared with those that did not exhibit submandibular edema. The genus Haemonchus sp. showed a 96.4 % prevalence in coprocultures. A positive correlation existed between F scores and FEC (r = 0.3819) and a negative correlation between F scores and Ht (r = -0.4728). Ewes that needed AH treatment had lower mean Ht values than ewes that did not need the treatment (19.2 % × 29.3 %; P < 0.001) and higher mean FEC values (8747 × 1163; P < 0.001), confirming that these ewes needed AH treatment. The TST methodology based on F scores, BCS, and submandibular edema could effectively identify individuals in the herd needing AH treatment, identifying 13 % additional cases requiring treatment than using only the F score criterion.

Weighted single-step genome-wide association study and functional enrichment analyses for gastrointestinal nematode resistance traits in Santa Ines sheep

This study aimed to identify genomic regions, pathways, and putative candidate genes associated with resistance to gastrointestinal nematode in Santa Ines sheep. The phenotypic information comprised 5529 records from 1703 naturally infected animals. After genomic data quality control, 37,511 SNPs from 589 animals were available. The weighted single-step approach for genome-wide association study was performed to estimate the SNP effects and variances accounted by 10-SNP sliding windows. Confirming the polygenic nature of the studied traits, 20, 22, 21, and 19 genomic windows that explained more than 0.5% of the additive genetic variance were identified for fecal egg counts (FEC), Famacha© (FAM), packed cell volume (PCV), and total plasma protein (TPP), respectively. A total of 81, 122, 106, and 101 protein-coding genes were found in windows associated with FEC, FAM, PCV, and TPP, respectively. Several protein-coding genes related to the immune system and inflammatory response functions were identified within those genomic regions, such as ADCY9, ADRB2, BRAF, CADM1, CCL20, CD70, CREBBP, FNBP1, HTR4, IL16, IL22, IL26, MAPK8, NDFIP1, NLRC3, PAK5, PLCB1, PLCB4, ROCK1, TEK, TNFRSF12A, and VAV1. Functional enrichment analysis by DAVID tool also revealed many significant (P < 0.05) pathways and Gene Ontology terms that could be related to resistance to gastrointestinal nematode in Santa Ines sheep, such as chemokine signaling pathway (oas04062), cAMP signaling pathway (oas04024), cGMP-PKG signaling pathway (Oas04022), platelet activation (Oas04611), Rap1 signaling pathway (oas04015), and oxidoreductase activity, acting on paired donors, with incorporation or reduction of molecular oxygen (GO:0016705). These results contribute to improving the knowledge of the genetic architecture of resistance to gastrointestinal nematode in Santa Ines sheep.

Image analysis to automatically classify anemia based on Famacha score in sheep using ocular conjunctiva images

Haemonchus contortus is the most pathogenic blood-feeding parasitic in sheep, causing anemia and consequently changes in the color of the ocular conjunctiva, from the deep red of healthy sheep to shades of pink to practically white of non-healthy sheep. In this context, the Famacha method has been created for detecting sheep unable to cope with the infection by H. contortus, through visual assessment of ocular conjunctiva coloration. Thus, the objectives of this study were (1) to extract ocular conjunctiva image features to automatically classify Famacha score and compare two classification models (multinomial logistic regression-MLR and random forest-RF) and (2) to evaluate the applicability of the best classification model on three sheep farms. The dataset consisted of 1,156 ocular conjunctiva images from 422 animals. RF model was used to segment the images, i.e., to select the pixels that belong to the ocular conjunctiva. After segmentation, the quantiles (1%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 99%) of color intensity in each image channel (red, blue, and green) were determined and used as explanatory variables in the classification models, and the Famacha scores 1 (non-anemic) to 5 (severely anemic) were the target classes to be predicted (scores 1 to 5, with 162, 255, 443, 266, and 30 images, respectively). For objective 1, the performance metrics (precision and sensitivity) were obtained using MLR and RF models considering data from all farms randomly split. For objective 2, a leave-one-farm-out cross-validation technique was used to assess prediction quality across three farms (farms A, B, and C, with 726, 205, and 225 images, respectively). The RF provided the best performances in predicting anemic animals, as indicated by the high values of sensitivity for Famacha score 3 (80.9%), 4 (46.2%), and 5 (60%) compared to the MLR model. The precision of the RF was 72.7% for Famacha score 1 and 62.5% for Famacha score 2. These results indicate that is possible to successfully predict Famacha score, especially for scores 2 to 4, in sheep via image analysis and RF model using ocular conjunctiva images collected in farm conditions. As expected, model validation excluding entire farms in cross-validation presented a lower prediction quality. Nonetheless, this setup is closer to reality because the developed models are supposed to be used across farms, including new ones, and with different environments and management conditions.

Correlation of Faecal Egg Counts with Clinical Parameters and Agreement between Different Raters Assessing FAMACHA©, BCS and Dag Score in Austrian Dairy Sheep

Gastrointestinal nematodes, most notably trichostrongylids, are known to cause significant losses in sheep production. Previous studies have shown that monitoring parameters (e.g., FAMACHA©, BCS, dag score) change with increasing egg excretion. These parameters are well known and frequently used for targeted selective treatment. Based on the willingness to participate in this study (based on a previous questionnaire distribution among sheep farmers in Austria) we investigated the associations between faecal egg counts and the FAMACHA©, BCS, and dag scores of 1195 dairy ewes. Faecal samples were analysed using the Mini-FLOTAC technique I and larval culture. Three raters assessed the FAMACHA©, BCS, and dag scores in sheep to calculate the inter-rater agreement and intraclass correlation coefficient. The responses to the questionnaire of 23 farms were used for the evaluation, of which 16 farms were visited. Trichostrongylid eggs were detected in 95% of the faecal samples. The BCS was negatively correlated with the eggs per gram of faeces (EpG) (r = -0.156; p < 0.001) and the FAMACHA© score was slightly positively correlated with EpG (r = 0.196; p < 0.001). A small proportion of sheep (25%) shed the majority of eggs (47% to 84%). A moderate to good agreement for the parameters was found between the raters. In conclusion, the clinical parameters showed only weak correlations with faecal egg counts, and we confirmed that a minority of the flock is responsible for the majority of the pasture contamination with trichostrongylid eggs. Clinical raters should be trained before a study to increase the agreement between them.

Control of gastrointestinal helminths in small ruminants to prevent anthelmintic resistance: the Italian experience

Helminth infections are ubiquitous in grazing ruminants and cause significant costs due to production losses. Moreover, anthelmintic resistance (AR) in parasites is now widespread throughout Europe and poses a major threat to the sustainability of modern ruminant livestock farming. Epidemiological data on the prevalence and distribution of gastrointestinal nematodes, cestodes and liver- and rumen-flukes in Italian small ruminants are outdated and fragmentary. However, anthelmintics are commonly used to control these infections and often without prior diagnosis. Compared to other European countries, few reports of AR in small ruminants against levamisole, ivermectin and benzimidazoles have been published in Italy, but recent studies suggest that this phenomenon is spreading. Increased and integrated research efforts in developing innovative approaches to control helminth infections and AR are needed and must be tailored to the peculiarities of each context in order to be effectively implemented. This manuscript provides an overview on helminth prevalence and distribution, sustainable treatment strategies and integrated control approaches in small ruminants in Italy. The implementation of targeted treatments and targeted selective treatments is discussed based on different parameters, such as fecal egg count, degree of anaemia (FAMACHA© method), milk production and body condition score. In addition, several Italian studies have also investigated the implementation of alternative strategies such as the use of different natural bioactive compounds or genetic selection for resistance and resilience to helminth infections. These concrete solutions for helminth management in small ruminant farms in the country are reported and discussed, representing a valid example for other Mediterranean countries.

Using the community-based breeding program (CBBP) model as a collaborative platform to develop the African Goat Improvement Network-Image collection protocol (AGIN-ICP) with mobile technology for data collection and management of livestock phenotypes

Introduction: The African Goat Improvement Network Image Collection Protocol (AGIN-ICP) is an accessible, easy to use, low-cost procedure to collect phenotypic data via digital images. The AGIN-ICP collects images to extract several phenotype measures including health status indicators (anemia status, age, and weight), body measurements, shapes, and coat color and pattern, from digital images taken with standard digital cameras or mobile devices. This strategy is to quickly survey, record, assess, analyze, and store these data for use in a wide variety of production and sampling conditions. Methods: The work was accomplished as part of the multinational African Goat Improvement Network (AGIN) collaborative and is presented here as a case study in the AGIN collaboration model and working directly with community-based breeding programs (CBBP). It was iteratively developed and tested over 3 years, in 12 countries with over 12,000 images taken. Results and discussion: The AGIN-ICP development is described, and field implementation and the quality of the resulting images for use in image analysis and phenotypic data extraction are iteratively assessed. Digital body measures were validated using the PreciseEdge Image Segmentation Algorithm (PE-ISA) and software showing strong manual to digital body measure Pearson correlation coefficients of height, length, and girth measures (0.931, 0.943, 0.893) respectively. It is critical to note that while none of the very detailed tasks in the AGIN-ICP described here is difficult, every single one of them is even easier to accidentally omit, and the impact of such a mistake could render a sample image, a sampling day's images, or even an entire sampling trip's images difficult or unusable for extracting digital phenotypes. Coupled with tissue sampling and genomic testing, it may be useful in the effort to identify and conserve important animal genetic resources and in CBBP genetic improvement programs by providing reliably measured phenotypes with modest cost. Potential users include farmers, animal husbandry officials, veterinarians, regional government or other public health officials, researchers, and others. Based on these results, a final AGIN-ICP is presented, optimizing the costs, ease, and speed of field implementation of the collection method without compromising the quality of the image data collection.

Influence of targeted selective anthelmintic treatment on the productive performance of wool and hair lambs naturally infected with gastrointestinal nematodes in Brazil

Targeted selective treatment (TST) is an alternative method to reduce the use of anthelmintics and delay the development of resistant nematode populations. However, there is limited information on the actual effects of this type of treatment on livestock productivity. The objective of this study was to evaluate the production performance of Santa Ines (hair) and Ile de France (wool) lambs naturally infected with gastrointestinal nematodes (GIN) under TST based on packed cell volume (PCV) versus suppressive anthelmintic treatments. Thirty-eight lambs were divided into two treatment groups: Suppressive treatment, animals were drenched with monepantel every two weeks and TST, animals were treated with the same anthelmintic when they presented PCV ≤ 20%. Feces, blood, and weight were measured weekly to determine eggs per gram of feces, PCV, total plasma protein, and weight gain. After animals were slaughtered, carcasses were weighed to determine carcass yield. In the TST group, substantial productive losses of approximately 21.3% in the wool and 25.9% in the hair lambs were observed in body weight compared to their counterparts. Significant differences in hematological variables occurred over the experimental period, especially in the wool lambs under TST. Favorable environmental conditions enabled infective larvae to survive and thrive on pasture. Haemonchus contortus and intestinal nematodes were the most common parasites found in the Ile de France lambs and the Santa Ines lambs, respectively. Although TST prevented mortality, it did not prevent production losses. Both breeds showed a significant drop in production due to GIN parasitism.

Assessment of the adaptation of Nguni goats to water stress

The recurring drought and limited rainfall patterns occasioned primarily by climate change in sub-Saharan African countries threaten sustainable animal agriculture. The irreversibility of this natural phenomenon calls for an intensive and urgent selection of adaptable breeds that can cope but with minimal compromise on production indices. A water scarcity simulation study was conducted to assess the adaptation potential of Nguni goats to regulated watering by evaluating their growth performance, tolerance to heat and water stress and blood indices during the dry summer months. Eighteen growing Nguni goats (average age: 1 year; BW: 19.25 ± 1.6 kg) were assigned equally to three treatments: W0, without water restriction (WR); W70, WR of 70% ad libitum water intake (WI); and W50, WR of 50% ad libitum WI. The experimental trial lasted for 75 d following a 14-day acclimatisation to the housing condition. Data on growth performance, body thermal gradient, skin temperature (ST) and rectal temperatures, respiratory rate (RR), body condition scores (BCs), linear body indices and blood biochemical indices were taken. The results showed that the final BW was not affected (P > 0.05) by the water restriction levels. The daily gain, DM intake and total BW gain were similar (P > 0.05) in groups W70 and W50. Body thermal gradient and ST were not affected (P > 0.05). The RR and BCs decreased (P < 0.05) with increasing water restriction levels. The body and rump lengths and sternum height were similar (P > 0.05) for groups W70 and W50. There is an haemocentration (W0 < W70 < W50; P < 0.05) of sodium, Chloride, urea, creatinine, total protein, and cholesterol with water restriction levels. Generally, most physiological variables assayed were similar (P > 0.05) in the water-stressed groups (W70 and W50). Overall, Nguni goats showed an adaptive capacity to tolerate limited water intake.

Low-cost molecular methods to characterise gastrointestinal nematode co-infections of goats in Africa

BACKGROUND

Veterinary diagnostics aid intervention strategies, track zoonoses, and direct selective breeding programs in livestock. In ruminants, gastrointestinal nematode (GIN) parasites are a major cause of production losses, but morphologically similar species limit our understanding of how specific GIN co-infections impact health in resource-limited settings. To estimate the presence and relative abundance of GINs and other helminths at the species level, we sought to develop a low-cost and low-resource molecular toolkit applied to goats from rural Malawi smallholdings.

METHODS

Goats were subjected to health scoring and faecal sampling on smallholdings in Lilongwe district, Malawi. Infection intensities were estimated by faecal nematode egg counts with a faecal subsample desiccated for DNA analysis. Two DNA extraction methods were tested (low-resource magbead kit vs high-resource spin-column kit), with resulting DNA screened by endpoint polymerase chain reaction (PCR), semi-quantitative PCR, quantitative PCR (qPCR), high-resolution melt curve analysis (HRMC), and 'nemabiome' internal transcribed spacer 2 (ITS-2) amplicon sequencing.

RESULTS

Both DNA isolation methods yielded comparable results despite poorer DNA purity and faecal contaminant carryover from the low-resource magbead method. GINs were detected in 100% of samples regardless of infection intensity. Co-infections with GINs and coccidia (Eimeria spp.) were present in most goats, with GIN populations dominated by Haemonchus contortus, Trichostrongylus colubriformis, Trichostrongylus axei, and Oesophagostomum columbianum. Both multiplex PCR and qPCR were highly predictive of GIN species proportions obtained using nemabiome amplicon sequencing; however, HRMC was less reliable than PCR in predicting the presence of particular species.

CONCLUSIONS

These data represent the first 'nemabiome' sequencing of GINs from naturally infected smallholder goats in Africa and show the variable nature of GIN co-infections between individual animals. A similar level of granularity was detected by semi-quantitative PCR methods, which provided an accurate summary of species composition. Assessing GIN co-infections is therefore possible using cost-efficient low-resource DNA extraction and PCR approaches that can increase the capacity of molecular resources in areas where sequencing platforms are not available; and also open the door to affordable molecular GIN diagnostics. Given the diverse nature of infections in livestock and wildlife, these approaches have potential for disease surveillance in other areas.

Anthelmintic Treatment and the Stability of Parasite Distribution in Ruminants

Parasites are generally overdispersed among their hosts, with far-reaching implications for their population dynamics and control. The factors determining parasite overdispersion have long been debated. In particular, stochastic parasite acquisition and individual host variation in density-dependent regulation through acquired host immunity have been identified as key factors, but their relative roles and possible interactions have seen little empirical exploration in parasite populations. Here, Taylor's power law is applied to test the hypothesis that periodic parasite removal destabilises the host-parasite relationship and increases variance in parasite burden around the mean. The slope of the power relationship was compared by analysis of covariance among 325 nematode populations in wild and domestic ruminants, exploiting that domestic ruminants are often routinely treated against parasite infections. In Haemonchus spp. and Trichostrongylus axei in domestic livestock, the slope increased with the frequency of anthelmintic treatment, supporting this hypothesis. In Nematodirus spp., against which acquired immunity is known to be strong, the slope was significantly greater in post-mortem worm burden data than in faecal egg counts, while this relationship did not hold for the less immunogenic genus Marshallagia. Considered together, these findings suggest that immunity acting through an exposure-dependent reduction in parasite fecundity stabilises variance in faecal egg counts, reducing overdispersion, and that periodic anthelmintic treatment interferes with this process and increases overdispersion. The results have implications for the diagnosis and control of parasitic infections in domestic animals, which are complicated by overdispersion, and for our understanding of parasite distribution in free-living wildlife. Parasite-host systems, in which treatment and immunity effectively mimic metapopulation processes of patch extinction and density dependence, could also yield general insights into the spatio-temporal stability of animal distributions.

Severe Anemia in Sprague-Dawley Rats After Roux-en-Y Gastric Bypass Surgery

Roux-en-Y gastric bypass (RYGB) surgery is one of the most commonly performed bariatric procedures for weight loss in humans. However, this procedure is not risk-free, and patients may experience complications that include small bowel obstruction, gastrointestinal bleeding, chronic diarrhea, ulcers, malnutrition, and anemia. In particular, anemia is a recognized long-term complication and can be severe. Rats have been used as a model to study the effects of gastric bypass surgeries. They can experience similar complications as people, but the development of severe anemia has not previously been reported in rats. We observed 2 cases of severe anemia in female Sprague-Dawley rats after RYGB surgery. These cases prompted us to further investigate the frequency and severity of anemia after RYGB in rats. Blood work and necropsies were performed on 9 additional female Sprague-Dawley rats (5 with RYGB, 4 with sham surgery). In these 9 rats, only one had signs of clinical anemia. These 3 anemic rats displayed moderate to severe pallor of the eyes and ears. Necropsy findings in anemic RYGB rats included pale internal organs and eccentric heart enlargement, which led to a significantly higher heart:body weight ratio in RYGB rats as compared with sham controls. Anemic rats had either a macrocytic normochromic anemia, consistent with vitamin B12 or folate deficiency, or microcytic hypochromic anemia, indicative of iron deficiency. Researchers who perform RYGB surgery in rats should be aware of the potential complication of severe anemia. Plans for the diagnosis and management of this complication and the development of criteria for humane endpoints for severe anemia are recommended as a refinement to these studies.

[Five past twelve - the resistance situation in small ruminant gastrointestinal nematodes in Germany]

Anthelmintic resistance has reached alarming levels worldwide and already seriously threatens pasture-based small ruminant production in certain geographic regions. The situation in Europe has also dramatically deteriorated in the last decade. This review provides an overview of the occurrence of anthelmintic resistance in small ruminants with a particular focus on Germany and its neighbouring countries. It also covers mechanisms leading to the development and spread of anthelmintic resistance, and recommendations for a responsible use of anthelmintics in veterinary practice.

Extruded urea levels in lamb supplementation in rainy tropical savanna conditions: the triad host-gastrointestinal nematodes-environment

The objective of this study was to evaluate the influence of increasing levels of extruded urea (EU, Amireia®) in the diet of lambs naturally infected by gastrointestinal nematodes on the interactions in the host-pasture-soil components in edaphoclimatic conditions of the tropical rainy savanna. A total of 60 Texel lambs with a mean initial weight of 20.7 ± 0.87 and mean age of 2.5 ± 0.70 months were distributed in a completely randomized design, in five treatments consisting of different levels of EU supplementation viz., 0, 6, 12, 18, and 24 g 100 kg^-1 live weight (LW). The performance of lambs, parasitological variables, gastrointestinal nematodes (NGIs), and larvae recovery in pasture and soil were evaluated. The highest animal performance was observed in animals that received 0 to 18 g kg^-1 LW (146.0 g day^-1) and the lowest in animals supplemented with 24 g kg^-1 LW (81.0 g day^-1) of EU. The body condition score (BCS) was similar in the animals (P > 0.05). Parasitic infection did not differ as a function of EU level (P > 0.05). Eggs of Haemonchus spp., Trichostrongylus spp., Cooperia spp., and Oesophagostomum spp. were found. The largest amount of larvae in the L1/L2 and L3 stages was recovered in the pastures occupied by the animals that received supplementation 0 g kg^-1 LW of EU (750 larvae), the smallest in those that the animals received 6 g 100 kg^-1 LW of EU (54 larvae). The presence of larvae in the L1/L2 stages changed significantly (P < 0.05) in the soil; in the other stages, it did not differ in the soil. Increasing levels of extruded urea do not influence the eggs per gram of feces (EPG) count. The 0 to 18 g 100 kg^-1 LW level maintains animal performance, BCS and FAMACHA^©. There is less dispersal of NGI larvae in pasture and soil when EU levels increase in the edaphoclimatic conditions of the rainy tropical savannah, which suggests that this supplement can be implemented in the diet of beef lambs, in addition to to be a lower cost nitrogen source.

Mobile app for targeted selective treatment of haemonchosis in sheep

Livestock is an important part of many countries gross domestic product, and sanitary control impacts herd management costs. To contribute to incorporating new technologies into this economic chain, this work presents a mobile application for decision assistance to treatment against parasitic infection by Haemonchus contortus in small ruminants. Based on the Android system, the proposed software is a semi-automated computer-aided procedure to assist Famacha© pre-trained farmers in applying anthelmintic treatment. It mimics the two-class decision procedure performed by the veterinarian with the help of the Famacha© card. The embedded cell phone camera was employed to acquire an image from the ocular conjunctival mucosa, classifying the animal as healthy or anemic. Two machine-learning strategies were assessed, resulting in an accuracy of 83 % for a neural network and 87 % for a support vector machine (SVM). The SVM classifier was embedded into the app and made available for evaluation. This work is particularly interesting to small property owners from regions with difficult access or restrictions on obtaining continuous post-training technical guidance to use the Famacha© method effectively.

Breeding options for nematode resistance in Lacaune dairy sheep

Due to progressing anthelmintic resistance of gastrointestinal nematodes (GIN), supportive measures are needed to control these parasites. In sheep, it has been shown that selection towards an increased nematode resistance is feasible and that faecal egg count (FEC) is the generally acknowledged trait for selection. However, a selection based on FEC would come with certain costs, therefore auxiliary, cheaper resistance traits would be most welcome. FAMACHA©, a colour classification of the eyelid, usually used to determine the manifestation of an infection with Haemonchus contortus, could serve as such. Therefore, we collected FAMACHA©, packed cell volume (PVC) and FEC phenotypes of approx. 1150 naturally infected Lacaune ewes on 15 commercial farms in Switzerland. The Haemonchus-proportion was determined on farm level. Phenotypic correlations of FEC and FAMACHA© as well as FAMACHA© and PCV were 0.25 (SE 0.03) and -0.35 (SE 0.08), respectively, and correspond well with the results of other studies. A multi-trait animal model was applied to estimate genetic parameters with FEC, FAMACHA©, PVC and milk yield as dependent variables. The heritabilities of FEC, FAMACHA©, PCV and milk yield were estimated to be moderate with values of 0.33 (SE 0.08), 0.30 (SE 0.08), 0.36 (SE 0.08) and 0.34 (SE 0.08), respectively. The genetic correlations between FEC and FAMACHA© and between FEC and PCV were estimated to be close to zero with values of 0.03 (SE 0.22) and 0.01 (SE 0.21), respectively. The average Haemonchus-proportion compared to other GIN was found to be 43%. The FAMACHA© classification of the Lacaune ewes seems to indicate a rather high worm challenge, with 38, 14 and 2% of observations classified to scores 3, 4 and 5, respectively. However, the worm challenge according to FEC was moderate. It has been suggested that the genetic correlation between FAMACHA© and FEC is more pronounced when FEC was high. It could therefore be that the lack of genetic correlation was due to an insufficient worm challenge, even though the Lacaune were grazing at least 70 days before phenotyping. The genetic correlation between FEC and milk yield was estimated to be 0.07 (SE 0.22, slightly unfavourable). We conclude that if FEC is used as trait, the Lacaune could be selected for lower susceptibility towards nematode infection. The use of FAMACHA© as an auxiliary trait for FEC is not feasible, due to an inexistent genetic correlation between these two traits.

Practical guide to the diagnostics of ruminant gastrointestinal nematodes, liver fluke and lungworm infection: interpretation and usability of results

The diagnostics of ruminant parasites remains one of the cornerstones for parasite control best practices. Field veterinarians have several techniques at their disposal (fecal egg count, coproculture, FAMACHA®, plasma pepsinogen, ELISA-Ostertagia, ELISA-Fasciola, Baermann and ELISA-Lungworm) for the identification and/or quantification of gastrointestinal nematodes, lungworms and liver fluke infecting small ruminants and cattle. Each of these diagnostic tools has its own strengths and weaknesses and is more appropriate for a specific production operation and/or age of the animal (young and adults). This review focuses on the usability and interpretation of the results of these diagnostic tools. The most advanced technical information on sampling, storage, advantages and limitations of each tool for different types of production operations and animal categories is provided.

Portable near-infrared spectroscopy: A rapid and accurate blood test for diagnosis of Haemonchus contortus infection and for targeted selective treatment of sheep

Haemonchus contortus is the most prevalent and important gastrointestinal nematode (GIN) in small ruminants. Since it reduces the packed cell volume (PCV), causing anemia, early diagnosis can be used for targeted selective treatment (TST) of sheep, reducing antiparasitic drug use and anthelmintic resistance. This study aimed to predict PCV values through near-infrared spectroscopy (NIRS) and to develop a classification and diagnosis model of H. contortus infection using PCV values, eggs per gram of feces (EPG) counts and mean daily weight gain (DWG). A total of 1728 spectra were collected from blood samples of 216 lambs with a portable NIR spectroscope. In parallel, other parameters indicative of infection were measured: PCV by hematocrit, FAffa MAlan CHArt (FAMACHA) scores, EPG and DWG. To evaluate the relationship between NIRS spectra and the evaluated parameters, principal component analysis (PCA) was used for an exploratory analysis, regression by the partial least squares method (PLS) for the prediction of PCV values via NIRS, and PCA linear discriminant analysis (PCA-LDA) as a classification model for diagnosis. The absorption peaks in the NIRS region associated with the excitation of overtones of nitrogen-hydrogen (N-H) functional groups of proteins had a strong impact on the principal components (PCs), indicating that blood proteins, especially hemoglobin, can be estimated by the NIRS technique. The model for predicting PCV by PLS presented a standard error of prediction of 2.53, root-mean-square error of 2.48, and coefficient of determination of 0.84, indicating good correlation between the PCV values predicted by the model and the PCV obtained by hematocrit. The PCA-LDA model presented 93.33% sensitivity and 82.18% accuracy, both higher than those of the FAMACHA method, as was expected for resilient Morada Nova lambs. The multivariate models associated with the NIRS technique reported here can be used in the future as a quick and versatile tool for H. contortus infection diagnosis and TST application in lambs.

Farmers' Views and Tools Compared with Laboratory Evaluations of Parasites of Meat Goats in French West Indies

Gastrointestinal nematodes (GINs) are a major health problem in tropical goat husbandry. The control of GIN has been nearly exclusively reliant on the use of anthelmintic treatments. Their wide use has provoked the appearance and diffusion of anthelmintic resistance. Therefore, there is a need to use anthelmintics only when they are really needed. This strategy of targeted selective treatment (TST) has been recommended. The selection of animals to be treated has been based either on the objective measures of GIN intensity (fecal nematode egg counts) performed in the laboratory or on indirect assessment such as anemia (FAMACHA©), diarrhea score or weight gains, particularly in sheep. The roughness of hair has also been proposed in goats. These indicators can be handled by the farmer. Their opinion on the importance of GINs, and the indicators that they are ready to accept and use have very rarely been studied. Goat for meat production is important in the French West Indies (especially in Guadeloupe) and GIN infection may significantly alter this production. Eighteen farmers participated in semi-directive interviews in order to appreciate their relation to goat GIN infection and the solutions they considered. Seventeen farms were investigated for fecal nematode egg counts, FAMACHA©, body score, and roughness of hair. The average infection by GINs was high (average fecal egg count 1562 and standard deviation 2028) with a wide range from one farm to another (from 0 to 25,000 eggs of GIN per gram of feces). The Haemonchus genera was predominant (54%), followed by Trichostrongylus (37%) and Oesophagostomum (9%). Young goats were less infected than adult goats since they were not yet grazing; males were more infected than females; and the Creole breed was more infected than the other breeds. Among the farming types, the professional ones were less infected compared with the traditional or mixed agriculture and husbandry farms. Those using targeted selective treatment did not have a significantly higher GIN infection than those treating the whole herd. Most of the characteristics were related and multivariate analysis could not match the intensity of GIN infection with any parameter. The frequency of anthelmintic treatments was negatively related to the use of body score, FAMACHA©, and hair roughness. The use of semi-directive interviews provided a wider understanding of the strategies and problems of farmers. The farmers valued their animals very much and diseases, in general, were a preoccupation, whereas parasites were not a major issue for traditional farmers. This is due to the important use of indicators and the belief in their value that gives comfort to the farmers that the parasites are being controlled. The extension services have well diffused the practice of indicators to the goat farmers of Guadeloupe, with some depending less on anthelmintics to control the gastrointestinal nematodes by using targeted selective treatments.

Classification Performance of Machine Learning Methods for Identifying Resistance, Resilience, and Susceptibility to Haemonchus contortus Infections in Sheep

This study investigated the feasibility of using easy-to-measure phenotypic traits to predict sheep resistant, resilient, and susceptible to gastrointestinal nematodes, compared the classification performance of multinomial logistic regression (MLR), linear discriminant analysis (LDA), random forest (RF), and artificial neural network (ANN) methods, and evaluated the applicability of the best classification model on each farm. The database comprised 3654 records of 1250 Santa Inês sheep from 6 farms. The animals were classified into resistant (2605 records), resilient (939 records), and susceptible (110 records) according to fecal egg count and packed cell volume. A random oversampling method was performed to balance the dataset. The classification methods were fitted using the information of age class, the month of record, farm, sex, Famacha© degree, body weight, and body condition score as predictors, and the resistance, resilience, and susceptibility to gastrointestinal nematodes as the target classes to be predicted considering data from all farms randomly. An additional leave-one-farm-out cross-validation technique was used to assess prediction quality across farms. The MLR and LDA models presented good performances in predicting susceptible and resistant animals. The results suggest that the use of readily available records and easily measurable traits may provide useful information for supporting management decisions at the farm level.

Genotype by environment interaction and heteroscedasticity influence the expression of parasite resistance in Katahdin sheep

Increasingly, sheep producers are choosing breeds that express resistance to gastrointestinal parasites due to reduced efficacy of anthelminthic drugs. One such breed is Katahdin. Katahdins are raised in various climates and management systems in the United States, which can be combined into eco-management clusters to describe production environments more holistically. The objectives of this study were to determine if genotype by environment interaction (G × E) and heteroscedasticity existed across these eco-management clusters for traits indicative of parasite resistance. Body weights (BW), FAMACHA scores (FAM), and fecal egg counts (FEC) were collected at around 90 d in 3,527 Katahdin lambs delineated into nine eco-management clusters. A tri-variate animal model including birth-rearing type, sex, and dam age (as a quadratic covariate) as fixed effects, and eco-management cluster, direct additive, uncorrelated maternal environmental (for BW), and residual as random effects, was fitted with ASReml. Heritability estimates for BW, FEC, and FAM were 0.36 ± 0.07, 0.31 ± 0.07, and 0.26 ± 0.05, respectively. The genetic (additive) correlation between BW with FEC was -0.26 ± 0.08 and with FAM was -0.16 ± 0.08, and thereby favorable. Heritabilities were also estimated univariately within eco-management clusters and ranged from 0.30 ± 0.05 to 0.37 ± 0.05 for BW, 0.18 ± 0.12 to 0.50 ± 0.13 for FEC, and 0.07 ± 0.06 to 0.40 ± 0.19 for FAM. Significant genetic and phenotypic heteroscedasticity among eco-management clusters was detected in FEC and FAM. A sire by eco-management cluster interaction term was added to the initial model fitted to evaluate G × E. This interaction defined substantial variation (P < 0.01) in all traits and explained 12% (FEC) to 20% (BW) of the phenotypic variation. Accounting for G × E and heteroscedasticity in the design and implementation of breeding programs may introduce operational challenges. Still, doing so would improve the efficacy of selection programs to improve parasite resistance.

Finisher lamb growth and rumen fermentation responses to the plane of nutrition and naturally occurring coccidiosis

The objective of the present study was to investigate the interaction of plane of nutrition and naturally occurring coccidiosis on finisher lamb growth performance, FAMACHA score, and rumen volatile fatty acid profile. The study included 30 Suffolk, Dorset or Suffolk x Dorset lambs and were divided into 2 groups based on their initial body weight and assigned to 2 feeding groups differing in dietary energy intake to create lambs representing divergent growth curves due to differing nutritional management. Lambs with naturally occurring coccidiosis and healthy lambs were present in both feeding groups making a 2 × 2 factorial arrangement of treatments, (a) high plane of nutrition (HPN) lambs with no clinical coccidiosis diagnosis (HPNH), (b) HPN lambs with clinical coccidiosis (HPNC), (c) low plane of nutrition (LPN) lambs with no clinical coccidiosis diagnosis (LPNH), (d) LPN lambs with clinical coccidiosis (LPNC). Body weight and FAMACHA scores were recorded once every 2 weeks. On d 65 of feeding, lambs were slaughtered, and rumen fluid samples were collected and analyzed for volatile fatty acid concentrations. All response variables were analyzed statistically using a linear mixed effects model with fixed effects for plane of nutrition, health status, and a random effect for initial body weight nested within the pen. The total and average weight gain were not associated with planes of nutrition, health status, or the interaction. Health status had an impact on FAMACHA© score (P = 0.047) and concentration of isobutyrate (P = 0.037) and tended to affect total VFA (P = 0.085) and acetate (P = 0.071) concentrations. The interaction between the plane of nutrition and the health status tended to affect butyrate concentration (P = 0.058). These data support the conclusion that coccidiosis infection impacted on rumen fermentation in a manner independent of the plane of nutrition; however, the translation of these rumen level impacts did not translate to the production responses.

Ovine gastrointestinal parasite burden and the impact of strategic anthelmintic treatment in community-based breeding sites in Ethiopia

Introduction

In Ethiopia, small ruminants contribute significantly to livelihoods and food security but productivity is low with high disease burden and essential endoparasite control not widely practiced. The current study assessed worm burden and its control in three districts in Ethiopia.

Methods

All sheep older than 3 months in nine villages were treated en-masse with albendazole and triclabendazole twice a year from 2018 to 2021. Treatments were administered under field conditions by animal health workers. Pre- and post-treatment data were assessed looking at fecal egg presence/absence and fecal egg per gram (EPG) count.

Results

A total of 1,928 and 735 sheep were examined before and after deworming, respectively. Before treatment worms were detected in 54.4% (95% CI: 52.2-56.6) of sheep. Strongylid (30.4%) and Fasciola (18.2%) were the most frequently identified parasites. Animals living in wet mid-highland environments were more than 23 times more likely to have strongylid eggs in their feces and 5 times more likely to have eggs from any gastrointestinal tract (GIT) parasites detected, as compared to animals living in moist highland agro-ecology. Over the course of the 2018-2021 community intervention there was total elimination of animals with a high worm burden (EPG > 1,500), and elimination of a third of those with moderate infections. Mild infections remained, largely accounted for by strongylid, which remains at low levels in healthy sheep. However, there were signs of emerging drug resistance.

Conclusion

Generally, sheep in smallholder systems in Ethiopia experience a needlessly large economic burden from GIT worms. Routine therapy reduces this burden but smart strategies are needed to limit the onset of drug resistance.

Genetic parameters for resistance to gastrointestinal nematodes in sheep: a meta-analysis

Gastrointestinal nematodes (GINs) are damaging parasites of global sheep populations. The key weapons in fighting GINs have been anthelmintic drugs, but the emergence of drug-resistant parasites has meant that alternative control methods are needed. One of these alternatives is to breed for enhanced host resistance to GINs, and decades of research have estimated the genetic contribution to different measures of resistance to GINs and their genetic correlations with other desirable performance traits. It is clear that parasite resistance is a heritable trait that can be selected for. Despite this consensus, estimates of both heritability of resistance and genetic correlations with other traits vary widely between studies, and the reasons for this variation have not been examined. This study provides a comprehensive and quantitative meta-analysis of genetic parameters for resistance to GINs in sheep, including measures of worm burden (faecal egg counts, FECs), anti-parasite immunity (GIN-specific antibodies), and parasite-induced pathology (FAMACHA© scores). Analysis of 591 heritability estimates from 121 studies revealed a global heritability estimate for resistance to GINs of 0.25 (95% confidence interval (CI) = 0.22-0.27) that was stable across breeds, ages, geographical location and analytical methods. Meanwhile, analysis of 559 genetic correlations from 54 studies revealed that resistance to GINs overall has a positive genetic correlation of +0.10 (95% CI = 0.02-0.19) with performance traits, and that this was consistent across breeds, ages, sexes and analytical methods. Importantly, the direction of the genetic correlation varied with the resistance trait measured: while FECs and FAMACHA© scores were favourably correlated with performance traits, adaptive immune markers were unfavourably correlated, suggesting that selection for enhanced immune responses to GINs could reduce animal performance. Overall, the results suggest that breeding for resistance to GINs should continue to form part of integrated management programs to reduce the impact of parasites on health and performance, but that selection for enhanced immune responses should be avoided.

Trichostrongyle infections in domestic ruminants from Egypt: A systematic review and meta-analysis

Trichostrongylid nematodes can cause serious loss in the livestock economy; nevertheless, infections with these ubiquitous nematodes in animals from developing countries are largely neglected. The present paper provides a systematic review and meta-analysis to evaluate the status of trichostrongyle infections in domestic ruminants from Egypt. Out of 626 collected publications, 118 were defined suitable for inclusion in this review and represented trichostrongyle infections in 5 ruminant species (sheep, goats, cattle, buffaloes and camels) from Egypt. Published surveys have mostly focused on sheep, which had the highest (44.8%) pooled prevalence of trichostrongyle infections based on 95% confidence interval (35.9-53.6%) with no significant variations among sheep in different Egyptian regions. Goats had lower infection prevalence (31.2%, 21.5-40.8%) in comparison to sheep, and no significant regional differences were also found. The management and marketing practices likely account for the wide distribution of infection among small ruminants across Egypt. Variable trichostrongyle infection rates were estimated for camels (38.8%, 28.9-48.7%), cattle (27.4%, 14.4-40.3%) and buffaloes (12.2%, 8.0-16.4%). The prevalence of infection was significantly high during winter (52.1%, 32.2-72.1%), which provide favorable conditions for development and survival of larvae on pastures. The most common trichostrongyle identified in infected animals was Haemonchus contortus. The parasite was detected in 38.8% (29.9-47.6%) of infected sheep, 35.3% (24.8-45.7%) of infected goats and in 40.6% (18.6-62.5%) of infected camels. Clinical infections have been reported in a limited number of studies. Analysis of fecal egg counts (FECs) revealed that more than half (52.7%, 30.4-75.0%) of the tested sheep had low counts (<500 eggs per gram EPG), whereas only a few sheep (6.1%, 3.5-8.7%) had high counts >2000 EPG, implying that subclinical infections are common; however, the clinical infections cannot be completely ruled out. Anthelmintic resistance does not appear to be serious in trichostrongyle populations infecting ruminants from Egypt; nonetheless there have been a few cases of albendazole resistance in trichostrongyles infecting sheep. This paper contributes to a better understanding of the epidemiology and economic implications of trichostrongyle infections in ruminants from Egypt, which is crucial for establishing effective control strategies against these ubiquitous nematodes.

Prevalence, risk factors, and infection intensity of fasciolosis in dairy cattle in Boyolali, Indonesia

Background and Aim: Fasciolosis is a significant problem in veterinary and public health, causing huge economic losses. Epidemiological studies of fasciolosis in dairy cattle in Indonesia are few and existing reports primarily focus on prevalence. This study aimed to determine the prevalence, risk factors, and infection intensity of fasciolosis in dairy cattle in Boyolali, Indonesia. Materials and Methods: This cross-sectional study included 400 dairy cattle from 72 household farms in eight subdistricts. Fecal samples (n=400) were examined using the Flukefinder® kit and the simple sedimentation technique was the gold standard for fasciolosis. In-person interviews using questionnaires collected data on farmers, farms, and animal characteristics. Chi-square and logistic regression analyses were performed to evaluate the associated risk factors for fasciolosis, and p < 0.05 was considered statistically significant. Results: The overall prevalence of fasciolosis in dairy cattle in Boyolali, Indonesia, was 16.50% (95% confidence interval [CI] 12.85-20.15) at the animal level (n = 400), whereas 40.28% at household farms (n = 72) level (95% CI 18.67-51.88). The relative sensitivity and specificity of the Flukefinder® kit compared with those of the gold standard were 79.49% and 92.52%, respectively, with a moderate agreement (kappa=0.59; p < 0.001). Fasciolosis was more likely in cattle originating from the Mojosongo subdistrict than from other subdistricts (odds ratio (OR)=5.28, 95% CI 1.22-22.94); from farms that did not process manure versus from those that did (OR = 3.03, 95% CI 1.43-4.71); and with farmers that had never attended extension programs compared with those who had (OR = 4.72, 95% CI 1.99-11.19). Studied cattle were mostly affected by light Fasciola spp. infections (92.4%, 95% CI 77.8-100%) followed by moderate (6.1%, 95% CI 0-22.2%) and heavy (1.5%, 95% CI 0-5.6%) infections. Conclusion: Fasciolosis is prevalent in dairy cattle in Boyolali, Indonesia. Control efforts should target the high-risk Mojosongo subdistrict, emphasize the importance of processing manure, and encourage farmers to attend extension programs. Flukefinder® is a practical on-site diagnostic kit for fasciolosis in Indonesian dairy farms. Parasite species identification and a malacological survey of intermediate hosts of Fasciola spp. in the farming environment are required for further research.

A Review: Haemonchus contortus Infection in Pasture-Based Sheep Production Systems, with a Focus on the Pathogenesis of Anaemia and Changes in Haematological Parameters

Simple Summary

Infection with Haemonchus contortus parasites (haemonchosis) is an important cause of anaemia in sheep. Haemonchosis is a global problem, although sheep that are kept in warm, high rainfall environments are at the greatest risk of infection due to the favourable conditions for H. contortus survival. Following ingestion, the parasites develop in the abomasum of sheep. Various factors such as age, breed, health, nutritional status, and larval challenge influence the severity of clinical disease. Hyperacute, acute, and chronic haemonchosis are reviewed, focusing on the pathophysiology of haemonchosis, associated clinical signs, and haematological and biochemical findings.

Abstract

Haemonchosis is an important cause of anaemia in sheep worldwide, particularly those that are kept in pasture-based systems in warm, high rainfall environments. Potential outcomes vary based on the severity of infection and the sheep’s immune response, however, in some sheep infection can lead to death. The consequences of Haemonchus contortus infection mean that it has been well-studied in a range of different farming systems. However, to our knowledge, there has not been a recent review focused on the pathophysiology of anaemia caused by haemonchosis. Thus, this review provides an in-depth discussion of the literature related to the pathophysiology of haemonchosis and associated clinical signs for hyperacute, acute, and chronic haemonchosis. Additionally, haematological and biochemical findings are presented, and various diagnostic methods are assessed.

Case Report: Severe Anemia Associated With an Abomasal Fibrosarcoma in a Goat

A 10-year-old female goat was presented to the clinic with lethargy, emaciation, and pale mucous membranes. Laboratory diagnosis revealed severe anemia with regenerative character as well as melena. Blood transfusions were administered, but the animal's condition continued to deteriorate, so it was euthanized. The main finding in the necropsy was an abomasal neoplasia with two metastases in the mesenterium which was positive for vimentin, but negative for smooth muscle actin and c-kit using immunohistochemistry, indicating a fibrosarcoma that might have contributed to gastrointestinal blood loss. Further pathological findings consisted of changes in the liver cells as well as a cervical leiomyoma. These findings illustrate that intestinal blood loss due to neoplasia should also be considered in older goats with anemia.

Status of gastrointestinal nematode infections and associated epidemiological factors in sheep from Córdoba, Colombia

Gastrointestinal nematodes cause serious economic losses in sheep production systems. To determine the prevalence and risk factors associated with these parasites, a study was conducted on 595 sheep in Córdoba, Colombia. Prevalence and parasite burden were determined using the McMaster technique. Larvae were cultured from feces to identify the nematode genera. For the analysis of associated factors and parasite burden, data means, medians, and confidence intervals were compared. A georeferenced data analysis was performed and an epidemiological map was constructed. An overall prevalence of 88.2% was found, with the highest prevalence and parasite burden for Strongylida (83.2%) and Strongyloides (41%) nematodes. The mean parasite burden was 1255 eggs per gram. The gastrointestinal nematode genera identified were Trichostrongylus, Strongyloides, Haemonchus, Oesophagostomum, Bunostomum, and Cooperia. In general, a significant association was found between parasite burden and dewormed animals, anthelmintic used, date of last deworming, and breeds. The FAMACHA® method and body condition showed a significant association with the Strongylida parasite burden. Clusters with higher intensity of gastrointestinal nematode burden and high prevalence were observed in the regions of Bajo Sinú, Sinú Medio, and San Jorge.

Anthelmintic resistance in ruminants: challenges and solutions

Anthelmintic resistance (AR) is a growing concern for effective parasite control in farmed ruminants globally. Combatting AR will require intensified and integrated research efforts in the development of innovative diagnostic tests to detect helminth infections and AR, sustainable anthelmintic treatment strategies and the development of complementary control approaches such as vaccination and plant-based control. It will also require a better understanding of socio-economic drivers of anthelmintic treatment decisions, in order to support a behavioural shift and develop targeted communication strategies that promote the uptake of evidence-based sustainable solutions. Here, we review the state-of-the-art in these different fields of research activity related to AR in helminths of livestock ruminants in Europe and beyond. We conclude that in the advent of new challenges and solutions emerging from continuing spread of AR and intensified research efforts, respectively, there is a strong need for transnational multi-actor initiatives. These should involve all key stakeholders to develop indicators of infection and sustainable control, set targets and promote good practices to achieve them.

Suppressive treatment with monepantel and the fast selection for phenotypically resistant trichostrongylids of sheep

Gastrointestinal parasite control has been a major challenge to livestock due to the failure of anthelmintic treatments. Monepantel (MNT) was introduced in 2009 as an alternative treatment option showing a new mechanism of action against nematode parasites. To study the response of MNT in a suppressive regime, 45-Suffolk and White Dorper naturally infected sheep were divided into one of three groups, G1: control – with no treatment, G2: MNT at 2.5 mg kg−1 live weight (LW) PO every 30 days, and G3: MNT at 4.0 mg kgLW−1 PO every 30 days for 6 months. Every 15 days, the animals were individually weighed (body weight, BW) and checked for Famacha (FMC) and body condition score (BCS). The efficacy of MNT was evaluated weekly by fecal egg count (FEC) every month. FEC showed >97% efficacy at the start of the experiment, revealing a significant reduction for G2 (28%) and G3 (39%) in the following months. There was no treatment, BW or BCS effect between treatments; however, there was a period (P < 0.0001) and a treatment vs period interaction (P < 0.0001) for BW. The data revealed that MNT at a therapeutic and suppressive dose had a non-linear polynomial efficacy regression (R2) of 0.988 and 0.992, respectively. This original experiment demonstrates how short-interval and suppressive MNT treatments would rapidly select Haemonchus contortus, showing a fast susceptible-resistance phenotypic population replacement. Therefore, it is suggested that MNT might be carefully used in parasite control programmes alongside other management strategies (i.e. FMC, BCS) to reduce treatment frequency and the selection process for resistance.

Cluster analysis to explore additive-genetic patterns for the identification of sheep resistant, resilient and susceptible to gastrointestinal nematodes

Infection caused by gastrointestinal nematodes is an important issue for animal health and production. Controlling worm infections improves the sustainability of the sheep industry. Genetic selection of animals that are resistant to gastrointestinal nematodes is another strategy to render sheep production more sustainable by decreasing the use of anthelmintics. The aims of this study were (1) to explore the additive-genetic pattern of EBVs for Famacha© (FAM), packed-cell volume (PVC), and fecal egg counts (FEC) of Santa Ines sheep, (2) to propose a classification of animals that are resistant, resilient and susceptible to gastrointestinal nematodes based on their additive-genetic patterns, and (3) to identify the most suitable animals for selection based on their genetic pattern. A dataset of 2,241 records from 747 animals was used to predict the breeding values for indicator traits of resistance to gastrointestinal nematodes with THRGIBBS1F90 and to carry out cluster analyses was used R software. Three clusters of animals were found in the population using hierarchical cluster analysis of the breeding values for FAM, PCV and FEC. Each cluster was characterized by different additive-genetic patterns identified by k-means non-hierarchical cluster analysis. Among a total of 747 animals, 196 were classified as resistant, 288 as resilient, and 263 as susceptible. Cluster analysis is a valuable tool for data screening that permits to evaluate only selection candidates based on their additive-genetic pattern for gastrointestinal nematode resistance. EBVs for FEC were decisive to divide the population into resilient, resistant and susceptible animals. It is also important to include the EBVs for PCV and FAM to adequately distinguish resistant from resilient animals. Finally, the resistant cluster consisted of the most desirable animals to be used as selection candidates in order to genetically improve resistance to infection with gastrointestinal nematodes. This cluster contained animals with the most appropriate additive-genetic pattern to achieve the breeding goal, with positive breeding values for PCV and negative breeding values for FAM and FEC.

Weaning and concentrate supplementation on the characteristics of carcass cuts and longissimus muscle of Suffolk lambs finished on pasture

The aim of this study was to evaluate the influence of weaning and concentrate supplementation on the characteristics of carcass cuts and longissimus muscle of Suffolk lambs finished on a Tifton 85 (Cynodon spp.) pasture. Weaning and concentrate supplementation strategies were evaluated in four finishing systems: i) non-weaned and non-supplemented lambs; ii) non-weaned lambs supplemented with concentrate in creep feeding; iii) weaned and non-supplemented lambs; and iv) weaned lambs supplemented with concentrate. In the systems with weaning, lambs were weaned at 46 ± 6 days of age. In the systems with supplementation, the concentrate was offered daily at 2% of lambs’ body weight. Weaning led to a decrease, whereas supplementation led to an increase in carcass cut weights. Supplemented lambs had lower yields of neck and uncovered ribs, and higher yields of breast + flank and loin. The characteristics of loin eye and fat thickness over the longissimus muscle presented lower values in weaned lambs and higher values in supplemented lambs. Keeping lambs with their dams and offering concentrate supplementation until slaughter are strategies recommended to obtain heavier cuts with increased muscularity and fat content.

Helminth Infections in Cattle and Goats in Kanchanaburi, Thailand, with Focus on Strongyle Nematode Infections

Gastrointestinal helminths are major enteric parasites affecting the health of important livestock ruminants, such as cattle and goats. It is important to routinely survey these animals for helminth infections to allow effective management and control programs to be implemented. A cross-sectional helminth survey carried out in Kanchanaburi Province, Thailand, revealed the infection rate of gastrointestinal helminths in cattle (n = 157) and goats (n = 117) to be 35.7% and 88%, respectively, by microscopic fecal examination, and a 100% herd prevalence was observed in goats. Eggs of strongyle nematodes, Strongyloides spp., Trichuris spp., Capillaria spp., Paramphistomum spp., and Moniezia spp. were detected, with a relatively high rate of strongyle nematode infection in both cattle (28.7%) and goats (86.3%). Mixed infections were observed in 14.3% and 35.9% of egg-positive samples from cattle and goats, respectively. Risk factor analysis showed that dairy cattle were 5.1 times more likely to be infected with strongyles than meat cattle. In contrast, meat goats were 9.3 times more likely to be infected with strongyles than dairy goats. The inverse findings in cattle and goats are discussed. Female gender was associated with a higher risk of strongyle infection in goats. DNA sequencing and in-house semi-nested PCR with primers specific to a region in the internal transcribed spacer 2 (ITS2) were successfully used to identify strongyle genera in randomly selected egg-positive cattle (n = 24) and goat (n = 24) samples. Four strongyle genera, i.e., Cooperia spp., Haemonchus spp., Oesophagostomum spp., and Trichostrongylus spp. were identified by DNA sequencing. By semi-nested PCR, Cooperia spp. were detected as a major parasite of cattle (70.8%), whereas Haemonchus spp. were abundant in goats (100%). The majority of samples from cattle (58.3%) and goats (95.8%) were found to coinfect with at least two strongyle genera, suggesting that coinfection with multiple strongyle genera was more common than single infection in these animals.

Anthelmintic activity of methanol extract of Dennettia tripetala G. Baker (Annonaceae) fruits against Haemonchus contortus in red Sokoto goats

Haemonchosis is a gastrointestinal parasitic disease of economic importance in ruminants especially sheep and goats. In view of the rising costs of conventional veterinary anthelmintics and the development of resistance by Haemonchus contortus, there is a need to develop alternative ethnoveterinary therapies for the treatment and management of Haemonchosis. This study investigated the anthelmintic activity of Dennettia tripetala G. Baker (Annonaceae) fruits against Haemonchus contortus in red Sokoto goats. The maximum tolerated dose was determined in adult albino rats administered, 3000, 4000, and 5000 mg/kg body weight of the crude methanol extract (CME) fraction, and observed over a period of 48 h for signs of toxicity and mortality. The in vivo anthelmintic activity was evaluated using 20 kids infected with H. contortus and randomly allocated into 5 groups (1, 2, 3, 4, and 5). Kids in groups 1, 2, and 3 were treated with CME at doses of 1250, 2500, and 5000 mg/kg respectively for 3 consecutive days per os. Groups 4 and 5 were treated with albendazole (7.5 mg/kg) once and distilled water (5 ml) respectively and served as treated and untreated controls. Blood samples were collected for haematology. The maximum tolerated dose of the CME of D. tripetala did not produce observable signs of toxicity or death in all the rats given up to 5000 mg/kg. There was significant (P < 0.05) reduction in faecal egg count by CME at doses of 1250 mg/kg (91.6%), 2500 mg/kg (98.5%), and 5000 mg/kg (100%) at day 14 post-treatment. The total plasma protein (TPP) and FAMACHA© scoring values were significantly improved (P < 0.05) in the treated groups. These results indicate that methanol extract and fractions of D. tripetala fruits possess beneficial anthelmintic activity against H. contortus and may be a suitable alternative anthelmintic candidate for the control of haemonchosis in goats.

Comparison between methods for measuring fecal egg count and estimating genetic parameters for gastrointestinal parasite resistance traits in sheep

Fecal egg count (FEC) is an indicative measurement for parasite infection in sheep. Different FEC methods may show inconsistent results. Not accounting for inconsistencies can be problematic when integrating measurements from different FEC methods for genetic evaluation. The objectives of this study were to evaluate the difference in means and variances between two fecal egg counting methods used in sheep-the Modified McMaster (LMMR) and the Triple Chamber McMaster (LTCM); to estimate variance components for the two FEC methods, treating them as two different traits; and to integrate FEC data from the two different methods and estimate genetic parameters for FEC and other gastrointestinal parasite resistance traits. Fecal samples were collected from a commercial Rideau-Arcott sheep farm in Ontario. Fecal egg counting was performed using both LMMR and the LTCM methods. Other parasite resistance trait records were collected from the same farm including eye score (FAMACHA), body condition score (BCS), and body weight (WT). The two FEC methods were highly genetically (0.94) and phenotypically (0.88) correlated. However, the mean and variance between the two FEC methods were significantly different (P < 0.0001). Therefore, re-scaling is required prior to integrating data from the different methods. For the multiple trait analysis, data from the two fecal egg counting methods were integrated (LFEC) by using records for the LMMR when available and replacing missing records with re-standardized LTCM records converted to the same mean and variance of LMMR. Heritability estimates were 0.12 ± 0.04, 0.07 ± 0.05, 0.17 ± 0.06, and 0.24 ± 0.07 for LFEC egg count, FAMACHA, BCS, and WT, respectively. The estimated genetic correlations between FEC and the other parasite resistance traits were low and not significant (P > 0.05) for FAMACHA (r = 0.24 ± 0.32) and WT (r = 0.22 ± 0.19), and essentially zero for BCS (r = -0.03 ± 0.25), suggesting little to no benefit of using such traits as indicators for LFEC.

A journey through 50 years of research relevant to the control of gastrointestinal nematodes in ruminant livestock and thoughts on future directions

This review article provides an historical perspective on some of the major research advances of relevance to ruminant livestock gastrointestinal nematode control over the last 50 years. Over this period, gastrointestinal nematode control has been dominated by the use of broad-spectrum anthelmintic drugs. Whilst this has provided unprecedented levels of successful control for many years, this approach has been gradually breaking down for more than two decades and is increasingly unsustainable which is due, at least in part, to the emergence of anthelmintic drug resistance and a number of other factors discussed in this article. We first cover the remarkable success story of the discovery and development of broad-spectrum anthelmintic drugs, the changing face of anthelmintic drug discovery research and the emergence of anthelmintic resistance. This is followed by a review of some of the major advances in the increasingly important area of non-pharmaceutical gastrointestinal nematode control including immunology and vaccine development, epidemiological modelling and some of the alternative control strategies such as breeding for host resistance, refugia-based methods and biological control. The last 50 years have witnessed remarkable innovation and success in research aiming to improve ruminant livestock gastrointestinal nematode control, particularly given the relatively small size of the research community and limited funding. In spite of this, the growing global demand for livestock products, together with the need to maximise production efficiencies, reduce environmental impacts and safeguard animal welfare - as well as specific challenges such as anthelmintic drug resistance and climate change- mean that gastrointestinal nematode researchers will need to be as innovative in the next 50 years as in the last.

Changes in Serum Thiol-Disulphide Homeostasis in Sheep with Gastrointestinal Nematodes

Simple Summary

Parasitism with gastrointestinal nematodes represents a significant risk to the health of livestock populations. Besides the local oxidative damage caused by the parasite, the host reacts by increasing the production of oxidants. The study of thiol-disulphide homeostasis can be of help in the evaluation of the oxidative status of sheep during this type of parasitism. In this study, the thiol-disulphide homeostasis, together with other biomarkers of oxidative stress and inflammation, were assessed in the serum of lambs infected with gastrointestinal nematodes and were evaluated after 70 days of integrated crop-livestock system and anthelmintic treatment. This study showed that the thiol-disulphide balance was impaired in the infected lambs and the changes were correlated with the parasite load, which therefore could indicate their potential use as a tool to evaluate and monitor the disease in sheep.

Abstract

This work aimed to evaluate the thiol-disulphide homeostasis in serum of lambs naturally infected by gastrointestinal nematodes presenting different levels of parasite load indirectly indicated by faecal worm egg counts (EPG). Furthermore, the possible changes in the thiol-disulphide dynamic after different procedures to reduce the parasitic charge, such as the integrated crop-livestock system or anthelmintic treatment, were assessed. The results were compared with a panel of various oxidative stress and inflammatory biomarkers. The lambs were divided into three groups: animals highly infected (EPG higher than 5000) and packed cell volume (PCV) lower than 24% (G1); animals highly infected (EPG higher than 5000) and normal PCV (>24%) (G2); and animals presenting EPG lower than 5000 and normal PCV (>24%) (G3). The highly infected lambs (G1 and G2) showed lower total thiol (TT) and native thiol (SH) (p ≤ 0.01) than those from G3. After treatment, TT and SH increased significantly in all groups (p ≤ 0.01), and the disulphide (SS)/TT and SS/SH ratios decreased significantly (p < 0.01) in G1 and G2. These results show that the thiol-disulphide balance was impaired in lambs infected by gastrointestinal nematodes and that it could be potentially used as a biomarker to monitor this disease.

Evaluation of resistance to gastrointestinal helminth nematodes in two naturally infected indigenous Nigerian goat breeds

Tropical goat breeds often have at least modest resistance to gastrointestinal nematode parasites (GIN), but enhancement of GIN resistance is important for breed improvement. This study compared changes in fecal egg count (FEC), packed cell volume, and body weight in Red Sokoto (RS) and Sahelian (SH) male and female weaner kids and adult goats. The RS is found throughout Nigeria, but the SH is found only in the arid Sahel. Goats were evaluated fortnightly for 20 times (MT) under normal grazing conditions and natural GIN infection over 9.5 months, beginning in the dry season (November) and ending at the end of the subsequent wet season (August). Animals were dewormed at the start of the study and during the rainy season (MT 18). Breed differences in FEC and PCV were not observed in weaners. Weaner females had lower FEC than males but were rapidly re-infected after deworming, perhaps in association with attainment of puberty. Adult SH goats of both sexes had lower FEC than RS goats in MT 8 through 17, suggesting a stronger acquired immune response. The FEC in lactating females of both breeds increased rapidly after deworming, to ≥ 3000 eggs per gram of feces at MT 19 and 20. The optimal time to evaluate GIN resistance in weaners was during the early rainy season, but the decision to focus on the initial high FEC near MT 15 or wait until mobilization of the acquired immune response near MT 17 requires further consideration.

Differences in burden of gastrointestinal nematode infestations in indigenous does foraging in grassland and forestland vegetation types

Gastrointestinal nematode (GIN) infestations remain a major challenge to the health, productivity and reproductive performance of small ruminants. A longitudinal study was conducted to assess the effect of vegetation type, season and parity on the burden of GIN in indigenous does that were foraging in grassland and forestland vegetation types. Body condition scores (BCS), packed cell volume (PCV), FAMACHA score and faecal egg counts (FEC) were determined in Xhosa lob-eared does (n = 165) during the cool-dry, hot-wet and post-rainy seasons in both vegetation types. Faecal samples were collected from the rectum and analysed using the modified McMaster technique. There was a significant association between vegetation type and season on the recorded BCS, body weight (BW), FEC, PCV and FAMACHA scores. Xhosa lob-eared does in the forestland had higher (P < 0.05) BCS as compared to those in grassland. Higher FEC (P < 0.05) were observed in Xhosa lob-eared does in the grassland vegetation compared to those in forestland. Body condition scores, FEC and FAMACHA scores were significantly higher in the hot-wet season than cool-dry and post-rainy seasons, while PCV was significantly higher during the cool-dry compared to hot-wet season in forestland. Strongyles and Strongyloides eggs were higher in does grazing in the grassland than those in the forestland during the hot-wet season. Strategies for the effective control of GIN in goats should consider that infestation levels differ with vegetation type, season and parity. Controlling of GIN in goats, therefore, requires an integrated control strategy that should consider the vegetation type that the goats are reared on.