Faecal Egg Counts Research Articles

Reducing fecal egg count through selective breeding alters dorper lamb response to Haemonchus contortus in an artificial challenge trial

Infection by gastrointestinal nematodes (GIN), particularly Haemonchus contortus, can be detrimental to sheep health and performance. Genetic susceptibility to GIN varies between breeds, with those lacking high levels of natural resistance often requiring frequent anthelmintic treatment when facing parasitic challenge. Genetic technology can serve as a tool to decrease GIN susceptibility via selection for sheep with reduced fecal egg count (FEC) estimated breeding values (EBVs). However, the physiological changes that result from implementation of this strategy are not well described. Additionally, there is a need for comparison of animals from recent selective breeding against breeds with inherent GIN resistance. In this study we administered a challenge of H. contortus to Dorper x White Dorper (DWD; n = 92) lambs that have been genetically selected for either low (DWD-) or high (DWD+) FEC EBVs and Barbados Blackbelly x Mouflon (BBM; n = 19) lambs from a genetically resistant breed backgrounds. Lamb FEC, packed-cell volume (PCV) and serum IgG were measured at intermittent levels over 5 weeks. At day 21 and day 35, the selectively bred DWD- had a lower mean FEC compared to DWD+, but were higher than BBM. Reductions in both PCV and serum IgG from initial day 0 levels were observed in DWD lambs, but not in BBM. Furthermore, from a subset of lambs (n = 24) harvested at day 21, DWD- only tended (p = 0.056) to have lower mean worm counts than DWD+, with BBM having the lowest mean worm count. Differentially expressed genes (DEGs) identified via RNA-sequencing of abomasal tissue at day 21 indicate a more pronounced Th2 immune response and more rapid worm expulsion occurred in iBBM than iDWD- and iDWD+ lambs. However, gene expression in DWD- suggests an association between reduced FEC EBV and gastric acid secretion and the ability to limit worm fecundity. Ultimately, selection of Dorper sheep for low FEC EBV can reduce susceptibility to GIN, but it will likely require multiple generations with this trait as a breeding priority before presenting a similar resistance level to Caribbean breeds.

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.

Exploring the potential of phenolic and antioxidant compounds identified and quantified of Caesalpinia coriaria fruits and their impacts on lambs’ performance and health

Abstract This study aimed to assess the impact of the identified phenolic, flavonoid, and fat-soluble vitamin compounds found in Caesalpinia coriaria fruits (EC) aqueous extract on growth performance, helminth parasitic load, feeding behavior, and physiological variables in lambs. The fruits were extracted using water, and three doses of the extract as no extract (EC0 mL/lamb/day), 30 mL of aqueous extract of Caesalpinia coriaria fruits (EC30 mL/lamb/day), or 60 mL of aqueous extract of Caesalpinia coriaria fruits (EC60 mL/lamb/day) were orally administered to 24 growing crossbred lambs weighing 18-20 kg for 60 days. The HPLC analysis revealed that ferulic acid, ellagic acid, syringic acid, quercetin, and hesperidin were the predominant compounds in Caesalpinia coriaria fruits. Additionally, water-soluble vitamin compounds such as thiamine, pantothenic acid, and niacin were detected in the Caesalpinia coriaria fruit extract. The dietary administration of EC improved (P < 0.05) average daily gain and feed and water intake. EC30 lambs spent more time (P < 0.03) eating and less time ruminating. The aqueous extract also showed a dose-dependent reduction (P = 0.048) in fecal parasite egg count, with a steady decrease (P = 0.0001) as the extract was applied. EC0 lambs exhibited the highest (P < 0.0001) respiratory frequency and EC30 the lowest. A strong positive correlation was identified between rectal and abdomen temperature in the morning and afternoon measurements. The presence of phenolic and antioxidants in the aqueous extract of C. coriaria, up to 60 mL, demonstrated beneficial effects, including improved productivity, anti-parasitic activity, and mitigation of body temperature. Thus, farmers without access to synthetic drugs can use this plant extract to treat their animals during fattening to reduce gastrointestinal parasites, improve growth rate, and reduce drug residue in animal products. Further studies need to be carried out on the individual components of Caesalpinia coriaria fruits to ascertain their effect on body temperature/physiology and to know if the effects are individualistic or synergistic.

The Effectiveness of Various Brands of the Drugs Fenbendazole and Ivermectin in Treating Horses with Strongyle Nematodes in Holeta, Oromia, Central Ethiopia

Introduction: Gastrointestinal parasites have always been a problem, and they are likely to continue to be a long-term issue that threatens the livestock industry. Methods: The purpose of this study was to assess the efficacy of various fenbendazole and ivermectin brands against Strongyle nematodes in naturally infected horses in Holeta, central Ethiopia. A total of 120 horses were divided into three groups at random. Group 1 horses were left untreated (n=12), while group 2 horses were given five different brands of ivermectin (SG-Ivermectin 1%, Tecmectin, Ivertong, ivermectin 1%, and Ivervik 1%), and group 3 horses were given four different brands of fenbendazole (Fenbendazole, Fenacure 750 mg, Hunter 22%, and Fenacure 22%). Fecal samples were collected rectally and parasitologically processed using the modified McMaster method and fecal culture, respectively, to determine egg per gram (EPG) and Strongyle species. The efficacy of these anthelmintics was determined by comparing the EPG before (day 0) and after treatment using a fecal egg count reduction test (FECRT) (day 14). Results: The results of this study revealed that the efficacy of ivermectin brands was superior to that of fenbendazole brands. Horses treated with Ivervik 1%, Hunter 22%, SG-Ivermectin 1%, Tecmectin, Ivertong, and Fenacure 22% had the highest reduction in fecal egg counts, followed by horses treated with fenbendazole, ivermectin 1%, and Fenacure 750 mg. Conclusion: Based on the results of this field study, it can be concluded that the various brands of ivermectin and fenbendazole are effective against Strongyle spp. and P. equorum in horses.

Strongyle egg shedding and egg reappearance periods in horses with pituitary pars intermedia dysfunction

Pituitary pars intermedia dysfunction (PPID) is the most common endocrine disorder of older horses. Immune dysfunction in horses with PPID could increase susceptibility to infectious diseases, including strongyle infections; however, few data are available. The aim of this study was to determine if horses with PPID had increased strongyle faecal egg counts (FEC) compared with control horses, over a fourteen-week period in Victoria, Australia. Clinical signs and plasma adrenocorticotropic hormone (ACTH) concentrations were used to categorise horses into PPID (n=14) or control (n=31) groups. Faecal samples were collected for FEC determination prior to anthelmintic treatment, and fortnightly post-treatment for each horse. Generalised linear mixed modelling, using a gamma distribution, was used to compare differences between groups in the repeated measures study. The confounding variable of age was controlled for as a fixed effect. Following anthelmintic treatment, mean FEC was greater for the PPID group compared to the control group on day 56 (405 ± 756 eggs per gram [EPG] vs 40 ± 85 EPG, p=0.05) and day 70 (753 ±1598 EPG vs 82 ±141 EPG, p=0.04). There were no differences in mean FEC between groups on days 84 and 98. Cumulative FEC (day 14 to day 98) was significantly greater for the PPID horses than control horses (2118 ± 4016 EPG vs 798 ± 768 EPG, p<0.0001). Group egg reappearance period was shorter for PPID horses (day 56 post-anthelmintic treatment) compared to control horses (day 70) and 30% of the PPID horses reached a FEC threshold of >200 EPG on day 42, compared to 0% of control horses (p=0.02). These results suggest that the rate of a re-established patent infection between groups could be different due to a comprised immune response in PPID horses or differences in the host-parasite relationship regarding encysted stage larvae. However, despite differences between groups, some horses with PPID consistently had no detectable or low FEC (<200 EPG) during the study period. These findings highlight the importance of individual FEC monitoring to determine if anthelmintic treatment is required, in line with sustainable parasite management practices.

Field testing of recombinant subunit vaccines against Teladorsagia circumcincta in lambing ewes demonstrates a lack of efficacy in the face of a multi-species parasite challenge

IntroductionWe previously demonstrated efficacy of an 8-antigen recombinant subunit vaccine against a single species homologous Teladorsagia circumcincta challenge in lambs and in lambing ewes in pen trials. We subsequently demonstrated efficacy of a simplified, 2-antigen, version of this vaccine in lambs in pen trials. Here, we test both vaccines in lambing ewes in a field setting.MethodsIn the work presented here, 12 adjacent plots were seeded with a mixed infection of several common species of parasitic nematodes of sheep in temperate regions, including T. circumcincta. Ewes (n = 144), in groups of 12, grazed for 2 years on these plots and, in the first year, six of these groups of ewes were vaccinated with a 2-antigen prototype vaccine against T. circumcincta prior to mating and then again prior to lambing. In the following year these ewes were immunised again, this time with the 8-antigen prototype vaccine against T. circumcincta prior to mating and then prior to lambing. Throughout both seasons antigen-specific serum antibody levels in ewes and faecal worm egg counts (FEC) in ewes and their lambs were monitored, along with nematode species diversity at lambing.ResultsImmunised ewes produced elevated serum antibody levels to each of the vaccine antigens following immunisation but their FEC levels were not statistically significantly impacted by vaccination with either vaccine. FEC levels were also not impacted in lambs co-grazing the pastures with these immunised ewes. Nematode species diversity was not significantly impacted by vaccination in either year.DiscussionThe immunosuppressive effects of co-infecting gastrointestinal nematodes, the absence of vaccine cross-protection against co-infecting species and the influence of the periparturient relaxation in immunity probably all contributed to the inability of either vaccine to protect against T. circumcincta infection in field trials in the work presented here.

Resistance of Gastrointestinal Nematodes to Anthelmintics in Sheep Production in Zimbabwe

Introduction: Sheep play a crucial role in enhancing the socio-economic welfare of individuals in numerous nations. Within sub-Saharan Africa, productivity levels are hindered by various factors, such as prevalent diseases, inadequate nutrition, climate variations, predators, severe weather, as well as infestations of both external and internal parasites. The purpose of the present study was to assess the extent of anthelmintic resistance (AR) observed on a sheep farm operating for commercial purposes in Zimbabwe. Materials and methods: Forty female weaner Dorper sheep, averaging 43 kg in body weight, were selected from Ballineety commercial sheep farm in Mashonaland Central, Zimbabwe. These sheep were then divided into four groups of ten each, receiving different treatments including ivermectin, albendazole, levamisole, and no treatment as a control. Each treatment was administered according to the manufacturer’s recommendations. Pre-treatment faecal samples (day zero) and post-treatment (day 14) were collected and subjected to the Faecal Egg Count Reduction Test (FECRT). Anthelminthic resistance was suggested (AR) by the presence of faecal eggs after treatment. Results: All the drugs indicated a decrease in egg counts by less than 90%. The effectiveness of ivermectin, albendazole, and levamisole was measured at 58.5%, 70.1%, and 85.8% respectively. These findings indicate that nematodes have developed resistance to all treatments. The larval cultures of the samples before and after treatment indicated a significant presence of Haemonchus spp. in the pooled samples. In contrast, the quantities of Trichostrongylus spp. and Oesophagostomum spp. were low but present in all treatments. Cooperia spp. was recovered in post-treatment larval cultures of groups that received anthelmintic. The present study reports lower-than-expected efficacy for ivermectin, albendazole, and levamisole based on the reduction of egg excreted post-treatment. Conclusion: A common worms population in sheep are AR in the current study area. Therefore, comprehensive nematode management programs along with complementary eradication strategies are essential for sustainable sheep production.

Validation of the natural sedimentation technique in the diagnosis of chronic fasciolosis

There are various diagnostic techniques available for chronic fasciolosis in ruminants. However, many of them exhibit low specificity and sensitivity, making them impractical for field use and in low-resource laboratories. The present study evaluates the usefulness of the Natural Sedimentation technique in diagnosing chronic fasciolosis in three domestic species conducted at the Laboratorio de Parasitología y Enfermedades Parasitarias, Facultad de Ciencias Veterinas, Universidad Nacional de Cajamarca. Fecal samples were collected from n = 323 cattle, n = 362 sheep, and n = 231 swine for Fasciola hepatica fecal egg counts. The visualization of adult parasites in animal livers post-mortem was considered the gold standard. Additionally, the sensitivity of the technique was evaluated using five different amounts of feces. In cattle, a sensitivity of 0.93 ± 0.03, specificity of 0.91 ± 0.06, positive predictive value of 0.96 ± 0.03, and negative predictive value of 0.86 ± 0.07 were obtained. In sheep, a sensitivity of 0.79 ± 0.05, specificity of 0.83 ± 0.07, positive predictive value of 0.90 ± 0.04, and negative predictive value of 0.66 ± 0.08 were observed. In swine, a sensitivity of 0.92 ± 0.06, specificity of 1.00 ± 0.00, positive predictive value of 1.00 ± 0.00, and negative predictive value of 0.96 ± 0.03 were found. There was no statistical difference in egg counts when using 1, 2, 3, 4, and 5 g of feces (p = 0.907). Furthermore, 1 to 688 fecal eggs of F. hepatica were counted in 1 g of feces. The Natural Sedimentation technique has both qualitative and quantitative applications with satisfactory results when using 1 g of feces in the diagnosis of chronic fasciolosis in domestic animals. Due to its simplicity, it can be implemented in field conditions and low-resource laboratories.

Herbal leys increase forage macro- and micronutrient content, spring lamb nutrition, liveweight gain, and reduce gastrointestinal parasites compared to a grass-clover ley

Commercial herbal leys (multispecies swards) are rapidly gaining popularity due to their potential to deliver an enhanced suite of ecosystem services. However, little is known about their impact on lamb production. A 2-ha split-field experiment using an herbal and grass-clover ley (0.33 ha paddock−1, n = 3 per sward) aimed to evaluate the effect of sward-type on forage quality and lamb productivity. Lambs (n = 40 per sward) were rotationally grazed over two experimental seasons: autumn 2020 (males) and spring 2021 (females). Sward quality was measured at the start of each grazing season. Liveweight gain and faecal egg counts (FEC) were measured at week 0, 4 and 6 in autumn and week 0, 4, 9 and 11 in spring. Blood samples were analysed after 11-weeks in spring to assess mineral status. General sward nutritional quality (e.g., crude protein) did not improve under the herbal ley, however, higher sward macro- and micronutrient concentrations were observed in both seasons. Spring liveweight gain was significantly greater in lambs grazing the herbal (172 ± 7 g d−1) vs. grass-clover ley (144 ± 7 g d−1), while autumn liveweight gain showed no difference. Spring lambs grazing the herbal ley compared to the grass-clover ley had elevated plasma cobalt (2.0 ± 0.1 nmol l−1vs. 1.6 ± 0.1 nmol l−1) and selenium (0.7 ± 0.04 µmol l−1vs. 0.5 ± 0.01 µmol l−1), with lower blood urea (7.7 ± 0.3 nmol l−1vs. 10.4 ± 0.4 nmol l−1). Spring FEC scores were reduced by 78 % in herbal grazed lambs; there were no significant differences in autumn FEC from either sward. In conclusion, the herbal ley resulted in seasonal improvements in sward micronutrient content and lamb parasite burden, mineral status, and productivity.

Oxyuris spp. Infection in Green Iguana (Iguana iguana) Under Different Cage Types

The caging system becomes one of the most crucial points in the green iguana (Iguana iguana) husbandry practice since some pathogens are transmitted through ingesting contaminated feed or water in the cage. One of the most common health problems in the green iguana is caused by infection of the gastrointestinal nematode (GIN), Oxyuris spp. Here, we conducted a study to identify Oxyuris spp. infection in the green iguana under different cage types in Malang Raya, East Java. A total of 40 fecal samples were collected and examined through flotation and modified McMaster techniques from three cage types, namely loose cage / extensive (n= 7), terrarium (n= 13), and iron-based cage (n= 20). The results showed that all green iguanas are infected with Oxyuris spp. (40/40 or 100 % prevalence). The highest mean egg per gram (EPG) was found in the green iguana which kept in a loose cage / extensive (mean EPG [CI 95 %] = 14 799.21 [14 442.05 – 15 156.37]), followed by terrarium (mean EPG [CI 95 %] = 8 763.80 [8 436.30 – 9 091.30]), and iron-based cage (mean EPG [CI 95 %] = 1 433.42 [1 303.79 – 1 563.05], respectively. At the same time, there is a significant relationship (P&lt;0,05) between the type of cage and the infection rate of Oxyuris spp. According to this result, we recommend an iron-based cage with routine daily cleaning as prevention for Oxyuris spp. infection among the green iguana.

Enteric parasites in free-living Mediterranean pond turtle (Mauremys leprosa leprosa) in contrasted areas (natural vs polluted) from central-western of Morocco.

The objective of this study is to assess the occurrence of intestinal parasites in Mediterranean pond turtle Mauremys leprosa leprosa collected from three contrasting environments in Morocco. Stool samples from 92 turtles were examined for parasite detection and enumeration. The identified intestinal parasites belong to helminths (oxyurids and ascarid) and protozoa (Entamoebidae). A total of 25 turtles (27.17%) were found to be infected by helminths and/or protozoan parasites. No adult form of these parasites was detected. Eggs of oxyurid and ascarid were detected in individuals of populations studied from Oued Ksob (23.07% and 30.76% of n = 13 turtles) and Oued Zat (34.14% and 24.39% of n = 41 turtles), respectively. For protozoa, Entamoeba cysts were present in turtles in Oued Ksob (15.38% of n = 13turtles), Oued Zat (12.19% of n = 41turtles), and Oued Tensift (5.26% of n = 38turtles) localities. Oxyurid eggs showed the highest intensity at Oued Zat reaching 29.30 ± 59.59 eggs per gram (EPG), versus 12 ± 0.38 EPG for ascaris eggs in Oued Ksob. Entamoeba cysts were detected in lower levels with a maximum of 1.66 ± 1.50 cysts per gram (CPG), in Oued Zat. The prevalence of turtles eliminating eggs was statistically significant between localities for different parasite groups. This study reports for the first time a parasitological characterization of gastrointestinal parasites in wild populations of M. leprosa leprosa from contrasting environments, suggesting a relationship between turtles' infestation and the quality of their habitat.

Differences in colostrum components of Katahdin ewes varies with post-weaning FEC EBV

Variation in post-weaning fecal egg count (PFEC) estimated breeding values (EBV) has revealed effects beyond the reduction of parasitism. Previous work demonstrated lambs with a PFEC of < −50 (Low-PFEC) have higher survivability to weaning than lambs with a PFEC of > +50 (High-PFEC). In response to clostridial vaccination, Low-PFEC lambs also generate a more robust and rapid antibody response. These findings prompted curiosity of the maternal influence underpinning differences observed in lamb survivability based upon PFEC genotype. Thus, this study aimed to assess the impact of dam PFEC EBV on IgG concentration, Brix values, and color within colostrum. For Year 1 (YR1), Katahdin ewes from the Virginia Tech SWAREC were selected based on the following criteria: age (3–6 years), have a Katahdin Hair Index EBV (>104, pre-genomic EBV), and be twin bearing. Ewes fitting those criteria were sorted by their PFEC EBV into two groups: Low-PFEC (PFEC < −50; n=20) and High-PFEC (PFEC > +50; n=18) and sampled at three distinct time points, early (within 24-hr post-partition), mid (30-d post-parturition) and late (60-d post-parturition) lactation. For Year 2 (YR2), all lactating ewes at the SWAREC were analyzed and were sorted into three groups: Low-PFEC (PFEC < −50; n=39), Mid-PFEC ( −49 < PFEC < +49; n=38), and High-PFEC (PFEC > +50; n=23) and colostrum samples were taken within 6-hrs post-partition. All colostrum and milk samples were collected by milking 10 mL from each half of the ewes' udder. Total IgG within colostrum and milk was measured using an ovine-specific enzyme-linked immunosorbent assay (ELISA). In YR1, main effects of ewe genotype revealed that Low-PFEC ewes had a greater concentration of IgG across all lactation time points (631 ng/mL vs 222 ng/mL; P < 0.0001). This was primarily driven by IgG differences within colostrum, where a 2.5 fold difference in IgG were observed between Low-PFEC and High-PFEC groups (937 ng/mL vs. 319 ng/mL, P < 0.0001). In YR2, a stepwise decrease in average colostrum IgG concentration from Low-PFEC to High-PFEC groups was observed (825 ng/mL, 513 ng/mL, and 258 ng/mL, respectively; P < 0.0429). Likewise, a stepwise decrease in yellow to blue hue or b* value occurs from Low-PFEC to High-PFEC groups (18.97, 16.91, and 15.22, respectively; P < 0.0459). No correlations were found between IgG and Brix values within the Low-PFEC and High-PFEC grouping; remarkably, Mid-PFEC ewes have a slightly positive correlation between IgG and Brix (r= 0.34, P = 0.0334). These data indicate that Low-PFEC Katahdin ewes generate colostrum with greater antibody concentration and more yellow color. Lambs born to these ewes would have a significant advantage in passive immunity from their dams, which may explain some component of the enhanced lamb survivability observed pre-weaning.

Hide ‘n seek: individual behavioural responses of cattle excreting different amounts of nematode eggs—potential threshold for pasture contamination assessment

The aim of this study was to investigate how the activity of cattle under natural grazing conditions is related to their individual parasite contribution (IPC). Potentially, the individuals contributing the most to the contamination of the pasture with gastrointestinal nematodes (GIN) could then be identified and selectively treated based on sensor data thresholds. A total of 58 steers of the dairy breeds Swedish Red (SR, n = 19) and Swedish Holstein (SH, n = 39) were used for sensor-based data collection that lasted for a total of 10 weeks from 4 May to 13 July 2022. All steers were inoculated with a priming dose of nematode larvae and weighed in conjunction with the pasture release. The animals were then divided into four experimental groups and treated with ivermectin (IVM PO, Boehringer Ingelheim, 0.5 mg/kg BW) at different intervals to obtain an exposure contrast (Group A was left untreated, Group B/IVM PO-4w was treated after 4 weeks, Group C/IVM PO-8w was treated after 8 weeks, and Group D/IVM PO-4&amp;amp;8w was treated after 4 weeks and then after 8 weeks). The steers were weighed on four further occasions, during which faecal samples were also taken for parasite testing. Activity data were collected using leg-mounted IceQube sensors and body weight data and faecal samples were collected bi-weekly. The new threshold metric (IPC) was proposed for individuals with different faecal egg count (FEC) levels [NO (no contribution) &amp;lt;20 EPG, LO (low contribution) = 20–150 EPG, ME (medium contribution) = 150–250 EPG, and HI (high contribution) ≥250 EPG] The effects of IPC on activity patterns were analysed stepwise using a Generalised Estimating Equations model implemented in Python programming language. Results showed significant effects of different IPC values on motion index and number of steps taken (adjusted p-value of 0.008, 0.018, 0.041, and 0.001 for individuals with NO, LO, ME, and HI IPC values, respectively). There were some breed effects on the average number of steps and minutes spent lying. The results also provide alternative threshold methods aimed at finding more sustainable ways of using anthelmintics and integrating individual data into future parasite control strategies.

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.

A SURVEY OF ANTHELMINTIC EFFICACY IN DAIRY GOAT FARMS IN SOUTH-EAST FRANCE

Goat’s milk production is an important activity in France. Gastrointestinal nematodes (GIN) remain a main threat for grazing goats, usually controlled using anthelmintic drugs (AH). However, 1) eprinomectin (EPN) is the sole molecule yet available without withdrawal time for milk in France; 2) nematodes AH resistances increase dramatically. First, a survey was performed on 13 farms in the Auvergne-Rhône-Alpes (AURA) region to evaluate the efficacy of 2 AH authorized for dairy goats: a benzimidazole (BZ) and a macrocyclic lactone (EPN pour-on). Fecal Egg Count Reduction Tests (FECRT) were carried out using 3 groups of 10 goats per farm: a control group, one treated with BZ (oxfendazole) and one treated with EPN. The results indicate a resistance to BZ in 11 out of 13 farms (84.6%) and a lack of efficacy for EPN pour-on in at least 10 farms (76.9%). Secondly, EPN was given orally or subcutaneously in 4 farms of the previous trial showing a lack of efficacy to EPN pour-on. A resistance to EPN was confirmed in 3 out of 4 farms. Although based on a few farms, these results confirm the high prevalence of resistance of GIN to BZ in dairy goat farms. They also highlight a high level of resistance to EPN and the lack of efficacy of EPN when used pour-on. Given the level of resistance to marketed drugs, there is an urgent need to explore alternative options to AH to prepare integrated, sustainable control of GIN.

136 Evaluation of internal parasite burden in grazing beef cattle in North Carolina over a production lifecycle

Abstract Gastrointestinal nematode (GIN) parasite infections can be detrimental to not only cattle health and immunity, but also result in economic loss and poor performance. Cattle grazing in the southeast are challenged even further by the favorable environmental conditions for parasite development, especially those animals who have yet to develop an immunity to combat parasitism. To diminish potential economic and performance-based losses, many beef producers treat animals for GIN parasites with anthelmintics on a regular basis without proper diagnosis. Anthelmintic resistance(AR) develops when deworming products are overused and misused. To minimize the development of AR, selective deworming and sustainable management practices should be implemented. However, the severity of parasite burden over the production cycle needs to be better understood in beef cattle herds before recommendations can be made. Thus, the objective was to investigate the rates of GIN parasite infections through fecal egg counts (FEC) and the impact on body weight (BW) and body condition score (BCS). Angus-based cattle (6 mo-13 yr, n = 1,154) on a were utilized from five different research and educational herds across North Carolina. Cattle were categorized based on their age at the start of the project as either calves (n = 446), yearling heifers (n = 205), 2 year old (n = 260), 3-5 year old (n = 501), or 6+ year old (n = 206). Starting in September, FEC, BW, and BCS were collected and analyzed every 90 d at critical production timepoints (calving, breeding, weaning, and 90d post-weaning) to monitor the severity of GIN parasite challenge. Cattle on study were not treated with anthelmintics regardless of parasite load, with the exception of calves at four of the locations at the time of weaning. All data were analyzed using Proc MIXED in SAS with repeated measures. Statistical significance was declared at P ≤ 0.05 and a trend at 0.10 &amp;gt; P &amp;gt; 0.05. Age of cattle had an impact on FEC overall (P &amp;lt; 0.05), however, there was no difference between FEC of mature cattle over 3 yr (4.29 ± 4.9 eggs/gm). Calves had the greatest FEC (120.59 ± 4.2 eggs/gm) while cattle 6+ yr had the least (3.68 ± 4.5 eggs/gm). Cattle age at each location affected BCS and BW (P &amp;lt; 0.05). Between age groups across locations, time had an impact on FEC, BW, and BCS (P &amp;lt; 0.05). There was also a tendency (P = 0.6) for location to impact FEC. Calf sex did not affect (P &amp;gt; 0.05) FEC. Further FEC analysis of cattle under 2 yrof age is required to better understand when a natural immune response to GIN parasite infections develops.

66 Effect of copper oxide wire particles on parasitism and growth in Katahdin lambs divergently selected for fecal egg count estimated breeding value

Abstract Internal parasites are one of the greatest threats to small ruminant production across the United States and parasitic resistance to anthelmintics continues to increase. Genetic selection and copper oxide wire particles (COWP) are two tools that could help reduce effects of parasites in small ruminants. The objective of this project was to determine the effects and interactions of COWP and genetic selection based on fecal egg count (FEC) estimated breeding value (EBV) on gastrointestinal nematode (GIN) infection and performance in naturally infected Katahdin lambs. Spring-born Katahdin ram lambs (n = 52) selected for extremely high FEC EBV (HighFEC, PFEC EBV = +100%) or low FEC EBV (LowFEC, PFEC EBV = -81%) were managed on a fescue-based pasture at the Southwest Virginia Agricultural Research and Extension Center (Glade Spring, VA). At weaning (June 29), lambs were dewormed with a three-combination treatment and rested for 21 d. At the start of the project (July 18), a random subset of lambs (HighFEC, n = 11; LowFEC, n = 15) were given a 2 g copper oxide wire particle bolus, while an equal number of remaining lambs were managed as controls without a copper bolus. All lambs were managed as one contemporary group. Fecal egg counts, FAMACHA scores, body weights, and packed cell volume (PCV) were measured bi-weekly for 10 weeks. Statistical analysis was performed using PROC Mixed Procedure of SAS (SAS Institute, Cary, NC) and FEC data were log transformed for normality. There were no effects of COWP treatment on FEC (P = 0.18). However, LowFEC-selected lambs had less FEC than HighFEC-selected lambs (230 vs. 565 eggs/g, respectively; P &amp;lt; 0.01). There was no interaction of COWP treatment and FEC genotype (P = 0.37). Copper oxide wire particle treatment had no effect on lamb body weight (P = 0.21), PCV (P = 0.69), FAMACHA score (P = 0.41), or overall ADG (P = 0.12). Lamb FEC genotype did not affect FAMACHA score or overall ADG (P = 0.10 and P = 0.22, respectively). LowFEC-selected lambs had lighter body weights (27.7 vs. 30.6 kg, respectively) and PCV (29.2% vs. 30.4%, respectively) than the HighFEC-selected lambs (P &amp;lt; 0.05). None of the 52 lambs met the requirement for deworming (FAMACHA ≥ 3) during the study. These results indicate that lamb FEC genotype may have a greater effect on parasitism than COWP treatment when given once during the post-weaning period. Even so, multiple tools should be considered, in addition to selection, for an integrated parasite management plan.

117 Supplementation with soy hull during late gestation and lactation on parasite indicators in hair sheep ewes

Abstract Before lambing and up to 8 wk during lactation, ewes experience a temporary loss of immunity to gastrointestinal nematodes (GIN). This can result in a periparturient increase in fecal egg counts (FEC) along with clinical symptoms of parasitism. This increase in FEC can lead to greater larval numbers on pasture, consequently exposing lambs to a greater level of infection that can impair production. Adequate supplementation during late gestation and lactation has been shown to reduce the impact of this temporary loss in immunity and decrease GIN infection levels in ewes. This study evaluated the supplementation of an agro-byproduct (soy hull) on GIN infection parameters in hair sheep ewes. Pregnant ewes (n = 36) were allocated, balanced by breed, parity and fetal numbers to either corn/soybean (CS) or soy hull (SH) supplementation during the last trimester of pregnancy. Ewes rotationally grazed predominantly fescue pastures subdivided into 6 sections (0.13 ha) using electro-netting (3 sections of 6 ewes/supplement type). Ewes were supplemented at either 0.75% BW (late gestation) or 1.5% BW (lactation) using a single feeder per section. Ewes lambed on pasture and lambs were weaned at approximately 63 d. Lambs had access to the supplement provided to their dams. Blood and fecal samples were collected in prepartum, postpartum and at weaning for determination of packed cell volume (PCV) and FEC. Pooled treatment group feces were also collected and cultured to determine GIN genera. Body condition scores (BCS) were also recorded at each sampling. Data were analyzed in a model with supplement type and breed as the main effects and FEC were log transformed before analysis. There was a mixed population of GIN throughout the study with H. contortus (49.5%) and Tricostrongylus spp. (46.6%) being the most common. Supplement type had no effect on ewe BCS prepartum, postpartum or at weaning (averaging 2.6 ± 0.1, 2.3 ± 0.1 and 2.0 ± 0.1, respectively). Supplement type influenced PCV at weaning only, with ewes supplemented with CS having a greater (P &amp;lt; 0.03) PCV than those supplemented with SH (33.0 ± 0.7% and 30.8 ± 0.7%, respectively). PCV was similar between treatments prepartum (38.4 ± 1.3%) and postpartum (34.4 ± 0.9%). Ewe FEC was similar between CS and SH supplemented ewes prepartum (271.6 ± 0.5 epg) and at weaning (298.5 ± 80.5 epg); however, at postpartum sampling CS ewes tended (P = 0.09) to have reduced FEC (234.1 ± 62.0 epg) compared with SH (414.1 ± 59.6 epg) supplemented ewes. At weaning, lamb FEC was not influenced by supplementation or breed and averaged 502.3 ± 83.2 epg. Data indicate that substituting SH for a more traditional corn-based supplement in landrace hair sheep ewes managed in a pasture-based system had no influence on GIN infection. Agro-byproduct supplementation should be explored further for their use in sustainable, forage-based sheep production systems.

114 The efficacy of a natural fungus (Duddingtonia flagrans) in reducing gastrointestinal nematode indicators in lambs

Abstract Sustainable and profitable small ruminant production in the US is affected by infections with gastrointestinal nematodes (GIN), especially the blood sucking GIN, Haemonchus contortus. The overuse and misuse of available drug classes has led to multi-drug resistant GIN that pose significant challenges to parasite control on many farms. The objective of this study was to evaluate the effectiveness of a natural fungus (Duddingtonia flagrans; Bioworma, International Animal Health) in reducing GIN larval counts and other GIN indicators in hair sheep wethers. Eighteen St. Croix (n = 9) and Barbados Blackbelly (n = 9) wethers (227 ± 1.4 days of age and 29.7 ± 0.6 kg BW) were dewormed (d 0) with a combination of levamisol (Prohibit; 8 mg/kg BW) moxidectin (Cydectin; 0.2 mg/kg BW) and albendazole (Valbazen; 7.5 mg/kg BW) prior to the start of feeding according to the manufacturer’s recommendations for feeding BioWorma. At this time, lambs were separated into two treatment groups (n = 9/group), split into 3 replications per treatment group and placed on six pasture paddocks (0.06 ha; n = 3 per paddock) after accounting for breed, initial fecal egg count (FEC) and BW. Lambs were then fed daily either a grain supplement ration (corn and soybean meal) with Livamol with Bioworma (LIV) or without (CON) at 2% of their BW for 98 d. LIV was added to the ration based on total lamb BW/paddock. To evaluate the effect of LIV treatment, BW and body condition scores (BCS) were recorded every 2 wk for 98 d. Blood and fecal samples were also collected for determination of packed cell volume (PCV) and FEC. Pooled treatment group feces (d 0 – 98) were collected and cultured to determine GIN genera. A subset of animals/treatment (n = 3) will be harvested to determine abomasal worm counts. Data were analyzed using repeated measures in a mixed model, and FEC were log transformed before analysis. Following deworming (d 0), FEC were reduced by 100% by d 14. There was a mixed population of GIN at the start of the study (averaging 54%, 42%, 1.2% and 1.8% for H. contortus, Tricostrongylus spp., Oesphagostomum spp. and Nematodirus spp., respectively). LIV with Bioworma supplementation had no impact on BW, BCS, PCV or FEC in this study averaging 34.2 ± 0.3 kg, 2.5 ± 0.04, 34.7 ± 0.5% and 150.9 eggs per gram, respectively. Under the conditions of this study, Bioworma® supplementation had no influence on GIN indicators measured up to 100 d of grazing. This research will be continued during subsequent grazing seasons to determine the effect of continued supplementation on lamb parasite load and performance as well as pasture infestation levels.

73 Deworming to improve growth in early-weaned spring born hair sheep lambs

Abstract In lambs, the stress of weaning and the lack of a fully developed immune system can increase susceptibility to gastrointestinal nematodes (GIN). Lack of an effective GIN control strategy around this time can have a significant impact on lamb growth, productivity and mortality. The objective of this study was to determine the influence of deworming at weaning on growth performance in hair sheep lambs. St. Croix (STX) and Barbados Blackbelly (BB) lambs used in the study were born on pasture, weaned at 60.2 ± 0.4 d of age, and transitioned in pens for 87 d post-weaning before turning out to pasture. After accounting for initial FAMACHA eyelid color score, breed, and birth type (single or multiple) at weaning, 54 STX (n = 32) and BB (n = 22) lambs weighing 11.7 ± 0.4 kg were dewormed (DEW) or not (CON) with a combination of levamisol (Prohibit; 8 mg/kg BW) moxidectin (Cydectin; 0.2 mg/kg BW) and albendazole (Valbazen; 7.5 mg/kg BW). To evaluate the effect of deworming treatment, BW and body condition scores (BCS; scale 1-5) were recorded at weaning and at end of transition to pasture. Blood and fecal samples were also collected for determination of packed cell volume (PCV) and fecal egg counts (FEC). Pooled treatment group feces (d 0 – 98) were collected and cultured to determine GIN genera at weaning. Data were analyzed using repeated measures in a mixed model, and FEC were log transformed prior to analysis. There was a mixed population of GIN at weaning averaging 65% and 35% for H. contortus and Tricostrongylus spp. At weaning, BCS, PCV, and FEC were similar between treatment groups and averaged 1.6 ± 0.07, 36.5 ± 0.6%, and 399 ± 54.4 epg, respectively. Combination deworming reduced FEC by 99%. At turnout, DEW lambs (2.3 ± 0.1) tended (P = 0.08) to have greater BCS than CON lambs (2.0 ± 0.1) and PCV was greater (P &amp;lt; 0.001) in DEW versus CON lambs (37.2 ± 0.9 and 33.3 ± 0.8%, respectively). There was also a tendency (P = 0.09) for breed to influence BCS (2.3 ± 0.1 and 2.0 ± 0.1 for BB and STX, respectively). The FEC at turnout was not influenced by treatment or breed (496.7 ± 75.1 epg). Additionally, DEW lambs (131.8 ± 5.2) tended (P = 0.09) to grow faster than CON (119.9 ± 4.7 g/d) lambs, a difference more pronounced in STX DEW (g/d) than STX CON lambs (136 ± 6.1 vs 110 ± 6.5 g/d; P &amp;lt; 0.05). Even though deworming tended to promote faster growth rates in lambs used in this study, alternative, more sustainable, parasite control strategies should be considered in the wake of increasing dewormer resistance.