INTRODUCTION

Gastrointestinal (GI) parasitism is considered one of the most serious and underestimated problems, which impedes small ruminant productivity [3] by decreasing voluntary feed intake, live weight gain, milk yield and carcass quality [2]. Parasitism of the digestive tract can be described as a nutritional disease, because of the increased nutritional demands, but has additional pathophysiological impacts. It decreases food digestibility, causes disruption of the digestive processes and nutrients absorbed via the digestive tract can be diverted from tissues in order to replace losses caused by GI parasites and to guarantee host survival [9].

Goat (Capra hircus) breeding in Ecuador is principally developed at the Southern Province of Loja in Southwestern Municipality of Zapotillo (4°23′11″S 80°14′37″O), characterized by a semidry climate with temperatures between 27 to 30°C and rainfall levels of 500-750 mm/year. Based on the last governmental census 2010, Zapotillo Municipality has 28,000 goats raised in an extensive way in six localities (Limones, Garza Real, Mangahurco, Paletillas, Bolaspamba, Zapotillo) and constitutes the main economic income for the habitants [10]. According to the last Development and Territorial Plan of the Municipality, goat production has suffered a severe decline in population in the past five years [6]. An outward reason could be the construction throughout years 1999-2014 of an artificial canal from the Chira-Catamayo system [18] which enabled water supplies for agriculture but apparently diminished the available space for feeding of goats. Farmers also reported the drowning of goats when jump into the canal (unpublished data). Although there are no official reports on the impact of the canal in goat breeding, the number of goat population of 71,879 heads dropped up to 61% between 2001 to 2011 [6]. In May 2015, veterinarians from the Ecuadorian Agency for Assuring Quality of the Agriculture (Agrocalidad) suggested that deaths of more than 70 goats in farms from Garza Real locality maybe related to GI parasitism and nutritional stress after a two-year drought (unpublished data).

In this regard, FAMACHA© system was developed in South Africa and uses the estimation of anaemia, based on clinical evaluation of the colour of the lower eyelid mucous membrane, as a morbidity marker for haemonchosis [15] and therefore, indicates the urgency of antihelmintic treatments. It has been used to detect and treat GI parasitism at field in several countries [14, 16, 21, 22]. Although possible variations in the results obtained by the system can occur among management systems, animal breeds, types and ages of animals, system operators, environments and facilities, FAMACHA© would be helpful after training farmers in those localities which are distant to the laboratory or the veterinary services [14, 28], as in the case of goat farms in Ecuador. This type of evaluation has not been done previously in the country and it could be important to improve goat breeding and economic status of the farmers. Also, the present work constitutes a good example of a successful interaction between academic sector, governmental institutions and farmers.

The goal of the present investigation was to record the GI parasitism in goat farms from Garza Real locality in Zapotillo Municipality, Ecuador, and to evaluate the usefulness of FAMACHA© system on infected goats.

MATERIAL AND METHODS

Farms and animals

The locality of Garza Real (369-567 m.s.l.) was selected based on requirements of Agrocalidad related to the levels of mortality in goats. In the absence of data on GI parasitism of goats in Ecuador, results of a non-related qualitative analysis of feces of 128 goats from a neighboring locality of Limones were used to establish sampling number (unpublished data). Based on a population of 3,109 goats in Garza Real locality, 86.3% of prevalence of GI parasites from Limones locality and a confidence limit of 95%, sampling number was calculated in 30 animals (EpiInfo© 7.1.5, Center for Disease Control and Prevention, USA). To guarantee statistical precision, 77 cross-bred goats were sampled (75 females and 2 males, one to four years old) in seven farms with an extensive way of breeding. Only seven farmers gave their acquiescence for sampling.

Animals are allowed to feed in free lands early in the morning and return to the pens at twilight. Farmers informed about treatments with ivermectin 1% by subcutaneous route (1 mL-2 mL depending on the animal size) without veterinary assistance in those cases with notorious loss of body weight or apathy, regardless of the age or physiological state of the animal.

Parasitological analysis

Faecal samples were taken directly from the rectum into plastic bags. Samples were maintained into coolers with blue ice at field and after at 4 °C in laboratory until processing no more than three days later. Qualitative and quantitative parasitological exams were performed by flotation techniques following the standard procedures with sugar as flotation solution (density= 1.20). The identification of eggs was up to genus or order level. Trichuris spp., Moniezia spp. and Eimeria spp. infections were only evaluated by qualitative analysis. The individual faecal eggs counts (FECs) were performed using a modified McMaster method [7] and the eggs per gram (EPG) were calculated for parasites of order Strongylida and Strongyloides spp. The infection levels by nematode infection were established as low (50-799); moderate (800-1,200) and high (>1,200) EPG [1].

Faecal samples collected in the farms were pooled and cultured at 27 °C, 70% relative humidity in an incubator (Memmert, model BE-200, Memmert GmbH + Co., Germany) for seven days [7]. After incubation, third stage larvae (L3) were collected by the Baerman technique and identified according to Van Wyck et al. [27] and Roeber et al. [20]. The larval composition was obtained by counting and identifying 100 L3 in each one of the seven cultures under microscope (Axiostar Plus, Zeis . Germany).Hematological analysis

Blood samples were individually collected by jugular venipuncture from each animal by using disposable Vacutainer© system into tubes with EDTA (ethylenediamine tetraacetic acid) (Bencton Dickinson, USA). Packet cell volume (PCV) was measured on the blood samples by the microhaematocrit method (Haematocrit centrifuge model KHT-430B, Gemmy Industrial Corporation, Taiwan) and values were expressed as percentages. The FAMACHA© guide was used through the evaluation of the ocular mucosa membranes classification, performed by comparing with a laminated colour chart bearing pictures of goat classified into five categories ranging from the normal red, through pink to practically white mucous membrane in severe anaemic animals (1: red; 2: red-pink; 3: pink, mildly; 4:pink-white; 5: white) [19, 26].

Statistical analysis

Analysis of variance was used to establish statistical differences between faecal eggs counts in the farms. Level of significance was set at P< 0.05. PCV values and faecal egg counts were also compared and correlated to the score assignment in the FAMACHA© system by a correlation analysis. In all the cases, Prism GraphPad v. 7.0 (GraphPad Software, Inc, USA) was used.

RESULTS AND DISCUSSION

From the total of 77 faecal samples, 91% were found to be infected with GI parasites. A mixed infection with two to four types of GI parasites was found in 87.82% of the animals (12.32, 32.87, 44% and 10.95% with one, two, three or four taxa, respectively). Based on morphology, eggs from order Strongylida (80.5%), genera Strongyloides (59.7%), Trichuris (19.5%), and Moniezia (1.3%) were identified by flotation technique. Unsporulated oocyts of Eimeria were observed in 67.5% of the samples. The mean of FECs of order Strongylida and genus Strongyloides found in the farms are shown in TABLE I. There were not significant differences in FECs between the seven farms (F 1.58; P > 0.05). Considering the mean of type Strongylida eggs, four of the farms have a high infection level (> 1,200 EPG).

These results revealed the critical situation in the farms: a high prevalence of GI parasitism, mainly from order Strongylida, which cause a serious disease; additionally, the goats harbored up to four taxa simultaneously in practically every farm and the symptoms of GI parasitism are similar to a nutritional disease [9, 25]. Additionally, the presence of coccidia in almost all farms with an infection level up to 67.5% is remarkable. The precarious conditions of the pens (no sanitary measures, humidity and darkness) in Garza Real can lead to a clinical coccidiosis due to a massive ingestion of sporulated oocysts in an highly infected environment and a significant asexual multiplication in goats due to a lowered resistance in animals because of prolonged period of alimentary stress [5, 16].

A number of 700 L3 larvae were analyzed from coprocultures. Six genera, mainly from order Strongylida, were identified: Haemonchus contortus (43%), Trichostrongylus spp. (39%), Oesophagostomun spp. (6%), Teladorsagia spp. (1%) and Cooperia spp. (< 1%); Strongyloides larvae was observed in 11% of the cultures. Strongyloides larvae account for 51% of the observed larvae in culture from farm 5 (TABLE II). Based on the results, H. contortus and Trichostrongylus spp. were the most important parasites from order Strongylida as have been reported under tropical conditions [3]. H. contortus is generally considered to be the most prevalent and pathogenic nematode species of small ruminants in tropical and subtropical areas [12, 17, 19]; is associated with anaemia and hypoproteinaemia due to blood- feeding activity. Two species of Trichostrongylus occur in small ruminants: T. axei, living in the abomasum, does not appear to be an important pathogen, but T. colubriformis causes black scours and contributes to parasitic gastroenteritis, ill thrift and diarrhea in kids. Strongyloides also cause disturbances in animal health, quite frequently inducing the sudden death syndrome in young ruminants due to heart failure; the degree of the damage directly correlates with the intensity of the parasitic infection [23].

Mean of the PCV levels and the parasites found in the farms are also shown in TABLE II. Animals of four farms have PCV values lower than normal values [11]. Statistical differences were observed in the PCV values between farms (F 3.196; P< 0.05) and a strong and negative correlation of - 0.9176 (P< 0.001) was found between PCV and FECs.

To select animals in need for antihelmintic treatment, FAMACHA© system has been found to be a useful tool in many parts of the world [9, 14, 16, 19, 21, 28]. Results of the score of FAMACHA©/percentage of goats in the field were 1 (5.66%); 2 (35.84%); 3 (30.18%); 4 (18.86%) and 5 (9.43%). A strong and negative correlation (-0.9418; P<0.001) was established between PCV values and score assignment in the FAMACHA© system (TABLE III): animals with the highest PCV values had been assigned score 1 and those with lowest PCV value had been assigned score 5. Also, a strong but positive correlation was found (0.9763; P< 0.005) between FECs and FAMACHA© scores (TABLE III), which shows the impact of the parasites in the hematological values.

The percentage of success on the interpretation of FAMACHA© was 65%, mainly due to the fact that score 3 was the most recorded incorrectly to the animals with higher PCV values. However, a high level of infection by GI parasites was found in those animals with an incorrect assignment of score 3, and thus, should be treated. Sotomaior et al. [22] reported that the sensitivity of the test increased when score 3 animals were included as being anemic; Van Wyk and Bath [26] recommended a routine treatment of every animal judged to be in FAMACHA© categories 3–5. The value of success in assignment scores was a reasonable one because it was the first time to apply the system in Ecuador. Vilela et al. [28] achieved a value of 32.6% in Brazil in the first of three months sampling. .Some authors pointed out that applicability of the FAMACHA© method is limited because it requires a percentage of H. contortus in the herd greater than 60% and needs trained technicians to perform the readings [17]. Other studies have shown that animals in greater need of anthelmintic treatment can be identified and treated selectively [19]. However, with a mean of 43% of H. contortus in the Garza Real farms, it represents a good method to demonstrate the need for treatment and control the populations of Strongylida, mainly H. contortus, and improvable if there were trained farmers [14]. Haemonchus females are capable of producing up to 10,000 eggs per day which is a very high reproductive rate and results in rapid contamination of the environment [8]. Certainly, the method could have a disadvantage: if control by treatment is successful and the number of H. contortus diminishes but anaemia is due to malnutrition or another etiology, FAMACHA© method could not be used alone in the quest of an accurate diagnosis.

The high levels of parasitism and anemia found in the farms also suggest a lack of effective treatments and malnutrition due to the long-time drought. In Garza Real, as in many localities of the country, veterinary visits - limited to governmental organisms - may not be as frequent as desirable and there are no regulations about marketing veterinary drugs to the public, so the decision about treatments often relies on the farmers. This indiscriminate use of synthetic anthelmintics cause great economical losses due to the lack of individual evaluations increases the selection pressure towards parasite resistance and leaves residues in meat, milk and in the environment [28]. Any combination of malnutrition and digestive parasitism will lead to uncompensated pathophysiological disturbances and, subsequently, to severe clinical signs (including a high mortality rate) [9]. Under low resource conditions, hosts adopt a tolerance strategy or are simply unable to mount an effective immune response; hence, resource supplementation could increase individual resistance/ resilience and reduce parasite transmission [4, 24].

Shortage in the feeding lands by the canal could also help to concentrate the availability of eggs and larvae to infect the goats or even worst, change the feeding behavior of the animals. Due to browsing, goats may have a natural advantage over grazing sheep, but if the goats are forced to graze or are limited to feeding contaminated pastures may confront burdens of H. contortus– as other parasites [17]. Furthermore, evidence is now accumulating to indicate that, when infected with GI parasites, ruminants can modify either the amount or the type of the food they eat; this may ameliorate the negative impact of parasitic infections, and has been described as self-medication [29].

Summing up, the results from the present investigation suggest the need of a combined strategy of treatments, supplementary food and environment [13] under a well-coordinated and permanent sanitary monitoring over the goat farms of Garza Real locality and maybe over the whole Municipality.

CONCLUSIONS AND RECOMMENDATIONS

This is the first report of GI parasites in goats from Ecuador. The study revealed the high levels of GI parasitism mainly due to H. contortus and Trichostrongylus spp. parasites in the sampled farms. FAMACHA© system could be useful in animals highly infected by Haemonchus, but parasitological methods are also required to evaluate and apply antihelmintic treatments.

Acknowledgements

The authors are thankful to goat farmers from Garza Real locality, Ecuador, who kindly offered their support for the present investigation. To Agrocalidad Loja, Ecuador, for their invaluable technical assistance. To anonymous reviewers who helped to improve the manuscript.

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Author notes

crey@correo.unefm.edu.ve