A STUDY ON THE RELATIONSHIP BETWEEN FAMACHA SCORES AND PACKED CELL VOLUME, FECAL EGG COUNTS AND ADULT HAEMONCHUS COUNTS IN RED SOKOTO GOATS AT SLAUGHTER IN ZARIA, NIGERIA.

A STUDY ON THE RELATIONSHIP BETWEEN FAMACHA SCORES AND PACKED CELL VOLUME, FECAL EGG COUNTS AND ADULT HAEMONCHUS COUNTS IN RED SOKOTO GOATS AT SLAUGHTER IN ZARIA, NIGERIA.

 

Abstract:

The FAMACHA^© system was developed to assist farmers in identifying small ruminants clinically infected by haemonchosis and therefore in need of treatment with anthelmintics, against the blanket treatment of all animals irrespective of their worm burdens, resulting in anthelmintic resistance. This study was aimed at carrying out a preliminary evaluation of the sensitivity and specificity of the FAMACHA^©. The colour of the ocular conjunctivae of 300 goats presented for slaughter was scored on a 1-5 scale using the FAMACHA^© card and blood samples were collected from each animal for determination of Packed Cell Volume (PCV) and biochemical analyses. Fecal sample and abomasum were collected from each animal for determination of fecal egg counts (FEC) and the abomasum worm (adult Haemonchus) counts respectively. The accuracy of the chart was evaluated by using PCV as the gold standard for anemia, that is PCV≤ 18%.The mean PCV for animals with FAMACHA^© scores (FS) 1,2,3,4, and 5 were 32.1±0.42, 31.3±0.36, 28.3±0.43, 23.8±0.66 and 18.1±1.69 respectively. Correlation between FS and PCV was negative (r = -0.6184) and highly significant (P<0.0001). The mean adult worm counts for animals with FS of 1, 2, 3, 4, and 5 were 9.76±5.56, 41.50±7.76, 119.89±14.16, 332.54±61.67 and 833.90±412.67 respectively. There was a highly significant (P<0.0001) positive correlation between FS and adult worm count (r = 0.3216). The mean FEC for animals with FS 1, 2, 3, 4, and 5 were 269.47±110.37, 926.49±228.30, 1757.57±240.65, 2488.50±394.04 and 5923.26±2387.50 respectively. The correlation between FS and FEC was positive (r=0.3191) and highly significant (P<0.0001). The mean FEC for goats with PCV ranges of 7-29, 15-39, 12-39, 24-38 and 25-38 were 5923.26±2387.50, 2488.50±394.04, 1757±240.65, 926.49±228.30 and 269.47±110.37 respectively. The mean Body Condition scores (BCS) for goats with FS of 1, 2, 3, 4, and 5 were 4.87±0.064,4.23±0.057, 3.43±0.064, 2.28±0.11 and 1.70±0.127. There was a negative correlation between BC and FS (r = – 0.9937) and this was highly significant (P<0.0001).When animals with FS 4 & 5 were considered anemic, sensitivity of the FAMACHA^© system was found to be 84.2% while specificity was 79.7%. Sensitivity increased to 100% but specificity decreased to 42.6% when animals with FS 3, 4, and 5 were considered anemic. Serum levels for total protein, albumin, urea and cholesterol were all within the normal range for the breed. It was therefore concluded that the FAMACHA^© system could serve as a useful on – the – farm tool for the diagnosis of clinical haemonchosis in the red Sokoto goat, and give a guide on goats that need to be treated with an anthelmintic.

 

CHAPTER ONE

INTRODUCTION

1.1 Importance of Goats in the Society

Nigeria has about 56.599 million small ruminants made up of 22.104 million sheep and 34.495 million goats (Bourn et al., 1994).Goats are important to the subsistence, economic and social livelihoods of many resource-poor farmers in developing countries (Kosgey, 2004). They produce about 17 and 12% of tropical Africa’s meat and milk, respectively (Lebbie, 2004), which are likely to be underestimates, since most of the utilization of goats goes unrecorded. Communal goats fulfill multiple roles that include provision of meat, manure, milk and cash from sales of the goats and their by-products (Thornton et al., 2002). Goats also play a major role in traditional ceremonies (Ayalew et al., 2001).Goats in communal areas are less susceptible to droughts than cattle and have lower feed and capital requirements than larger ruminants (Iniguez, 2004). They are better able to utilize a variety of feedstuffs, including fibrous crop residues (Holst, 1999).

 

In addition, goats have shorter generation intervals, reaching puberty at five to nine months of age (Saico and Abul, 2007) and have a higher prolificacy in comparison with the larger ruminants. Goats are renowned for controlling bush encroachment (Mahanjana and Cronje, 2000).Despite their value to society, goat research and development has been neglected relative to sheep (Devendera, 2002; Lebbie, 2004).

 

Goat production is mainly in the hands of subsistence farmers who keep them for their meat and socio-economic reasons. These animals are either herded all year round, left on free range throughout the year or during the non-cropping season, or tethering throughout the year or during the cropping season. However, due to limitation on grazing land and financial resources, majority of farmers keep only small numbers ranging from one to ten, and are mostly raised intensively or semi-intensively and fed grains, concentrates, food left-overs, et cetera (Ndamukong et al., 1987).

In Nigeria, the Red Sokoto (RS) goat is the most widespread and well known breed constituting about 70% of the total goat population in the country (RIM, 1992). However, the production of these animals is limited by livestock diseases. Notably, diseases caused by endo-and ecto-parasites are a major setback to profitable animal production in Nigeria (SchilhornVanVeen, 1973).

The impact of diseases and parasites may be through high morbidity, mortalities, abortions, or subclinical effects manifested as weight loss or reduced gains. The negative impact of diseases and parasites may also be through the financial implications involved in controlling or overcoming the effects of disease and mortality (Mahusson et al., 2004; Sissay et al., 2006). Diseases and parasites have a heavy impact on kids because of the poor immunity status of these young animals leading to an increased susceptibility (Sebei et al., 2004). High kid mortality diminishes the benefits of the high reproductive performance of does. Pre-weaning mortality of up to 30% has been recorded with kids in Malawi (Ficarelli, 1995). Diseases also cause abortions and stillbirths (Aitken, 2007).

 

Incidences of diarrhea are high at the beginning of the rainy season, especially in kids. The problem of parasitism is compounded by the fact that, under the communal system, livestock are usually reared extensively (Bayer et al., 2001). This increases infestation and makes control measures difficult to implement. Helminthes are associated with production losses and have profound depressive impacts upon long-term animal productivity. Helminth infestations contribute immensely to anemia (Vatta et al., 2001; van Wyk et al., 2006). Parasites also reduce voluntary feed intake, efficiency of feed utilization and increase the endogenous loss of protein in the gastrointestinal tract (Alexander and Mandonnet, 2005).

 

Although several species of gastrointestinal nematodes co-infect these animals, the abomasal nematode Haemonchus contortus is particularly important and causes severe anemia and death in heavy infections and substantial production losses even at low infection levels (Allonby and Urquhart, 1975; Nwosu et al., 1996; Fakae et al., 1999).

 

Anthelmintics remain the principal means of control of gastrointestinal parasites. Over time with regular and frequent use of anthelmintics, multiple anthelmintic resistance in H.contortus and other helminthes is becoming a severe problem in the livestock industry (Kaplan et al., 2004; Jan and Gareth, 2002). In Africa, anthelmintic resistance has been reported in both the commercial and resource – poor farming sectors in at least 13 countries including Nigeria (Mbuh et al., 2008; Fashanu and Fagbemi, 2003). Resistance has developed because the typical strategy used by small ruminant producers for controlling gastrointestinal nematodes, especially H. contortus, involves the treatment of all animals at fixed frequent intervals during peak transmission periods and or treating the entire group when one or more animals demonstrate clinical signs suggestive of worm infection (Kaplan et al., 2004). Although this and other strategies may seem effective in controlling nematode parasites, they also place heavy genetic selection pressure for resistance on nematode populations. This is because all worms in all animals are exposed to the drug, and unexposed environmental refugia are therefore kept at a low level. Refugia are the proportion of a population of worms that are sensitive to a dewormer or in refuge from a dewormer (Luis, 2006). When treating all animals in a herd as is commonly practiced, only resistant worms survive, which subsequently contaminate clean pastures. However, if only animals in need are treated and they go back to contaminated pasture, the resistant worms can breed with sensitive worms and maintain a worm population that should still respond to anthelmintics (Luis, 2006). Hence, current recommendations include treatment of only animals in need (selective treatment). Untreated animals will harbor sensitive worms.

The major limitation to instituting a selective treatment approach has been the lack of an efficient and practicable means of identifying those animals requiring treatment. This problem has been solved by a system developed for identifying sheep that are anemic. The FAMACHA^© system was developed in South Africa (Malan et al., 2001; Bath et al., 2001). The conjunctiva of individual sheep and goat is matched to a simple color chart to grade anemia (a diagnostic feature of haemonchosis) to identify the worst affected animals for treatment. The chart has five color categories (scores), each corresponding to a particular degree of anemia. Score 1 represents a healthy animal (normal reddish eye conjunctivae), while score 5 represents a highly anemic animal (porcelain white conjunctivae). Trials on commercial sheep in South Africa and the United States have demonstrated the practical usefulness of the chart for aiding in the control of H. contortus in small ruminants (Bath et al., 2001; Kaplan et al., 2004). However, only limited research has been carried out to evaluate the applicability of the FAMACHA^©chart in goats under resource – poor conditions (Vatta et al., 2001) where nutritional deficiencies, and hemoparasitism may play important roles as causes of anemia. It is usually considered that the response of goats to nematode infection is less efficient than that of sheep (Hoste et al., 2005).This is attributed mainly to their browsing behavior, which limits contact with nematode L3 (infective third larval stage) in the environment, especially at soil level, which is believed to have contributed to the evolution of less effective immunoregulatory mechanisms in goats than in sheep. This makes it difficult to extrapolate results from sheep to goats. Moreover, because most published studies on the usefulness of the FAMACHA^© system have been performed in South Africa and the United States, it is important that the method be tested in other areas of the world before its use can be broadly recommended.

 

1.2 Statement of the Research Problem

Haemonchosis is a highly devastating parasitosis of small ruminants wherever they are found. It is characterized by severe anemia and anarsaca (Susan, 2009).

Great economic losses occur in goats reared in Kano and Zaria areas due to haemonchosis, especially during the rainy season. This has been estimated to be up to sixty-million naira (N60m) annually, equivalent to one-hundred and nine million ($109m) US dollars (Akerejola etal., 1979; CBN, 2006). Ebbo et al., (2003) and Useh (2005) reported a high incidence (60%) of gastrointestinal parasitism in small ruminants presented for clinical examination at the Usman Danfodio University Veterinary Teaching Hospital (VTH), Sokoto, and ABU VTH Zaria, respectively.

Most experimental studies on the FAMACHA^© system have been conducted in sheep. There is every need to evaluate its usefulness in the Red Sokoto goat, being a highly prolific breed and accounting for about 70% of the total population of goats in Nigeria (RIM, 1992). This method was tested in goats farmed under resource-poor conditions in South Africa (Jan and Gareth, 2002), and a test sensitivity of 76 to 85% was obtained, meaning that the system could be used to identify correctly 76-85% of those animals in need of treatment with an anthelmintic. However, the researchers recommended the need for further work in goat populations in other parts of the world.

1.3 Justification of the Study

There is still difficulty in the accurate diagnosis of haemonchosis as a specific disease entity both by veterinarians, veterinary assistants and farmers. By the time typical clinical signs such as “bottle jaw”, emaciation and weakness are noticed, the disease would have reached an advanced stage with poor prognosis. Hence, the need for a simplified and accurate system for the diagnosis of the disease entity in goat populations in Nigeria. In addition, other factors such as nutrition, ectoparasitic infections, and extant diseases may influence the anemic state of the animal. It has been recommended (Spicket, 2009) that the FAMACHA^© system be supported by other criteria such as clinical signs and body condition score. This study will take them into consideration in the evaluation of the FAMACHA^© system, as research has shown that there is an interaction between nutrition and nematode parasitism (Hoste et al.,2005) as well as changes in some blood metabolite levels. It is, therefore, important to determine the relationships, if any, between blood metabolite levels and parameters that indicate clinical haemonchosis. Little, if any information is available on relationships of concentrations of nutritionally -related blood metabolites with fecal egg counts, FAMACHA^© scores, and Packed Cell Volume in RS goats.

The use of the FAMACHA^© system would assist in the production of meat animals with minimal chemical (anthelmintic) input, thus reducing chemical residues in meat. The system would also help in identifying those animals that are genetically resistant to H.contortus (those with frequently low FAMACHA^© scores) which can be bred with susceptible ones in order to increase the herd resistance. Highly susceptible animals (those with frequently high FAMACHA^© scores) can be identified and culled.

Adequate control of haemonchosis will help in improving the production of goats in Nigeria and hence, increase the source of the much needed animal protein at a cheaper rate for the ever increasing population. This is even most desirable now as more people are discouraged or restricted from beef in preference to mutton and goat meat due to health challenges.

1.4 Aim of the Study

The primary aim of this study is to evaluate the FAMACHA^© chart system in relation to PCV, FEC and adult worm counts so as to ascertain its accuracy as a tool for detection of clinical anemia due H. contortus in RS goats.

1.5 Objectives of the Study

1. To score goats using the FAMACHA^© chart and relate the score with PCV, FEC and adult contortus counts in the goats.

 

2. To test the reliability of the FAMACHA^© scoring in identifying anemic goats, when compared to the PCV gold standard.

 

3. To study the relationship between some serum biochemical indicators of nutritional status and FAMACHA^© scores in goats.

 

4. To determine the prevalence of hemo- and ectoparasites as possible contributors to anemia in goats.

 

1.6 Research Hypothesis

 

The hypothesis to be tested is that:

There is no relationship between the FAMACHA^©  scores, fecal egg counts, PCV, some nutritionally related blood metabolites and clinical anemia in RS goats.

 

1.7 Scope and Limitation of the Study

The FAMACHA^©system was designed to be applied on animals in a farm setting and it is desired that each animal be scored at specific intervals over a period of time. Due to time and financial constraints as well as unavailability of an organized farm where the study could be carried out, the study was narrowed down to a preliminary evaluation of animals presented for slaughter. The results obtained from this study are expected to pave the way for further work on validating the use of the FAMACHA^©system in Red Sokoto goats.

 

A STUDY ON THE RELATIONSHIP BETWEEN FAMACHA SCORES AND PACKED CELL VOLUME, FECAL EGG COUNTS AND ADULT HAEMONCHUS COUNTS IN RED SOKOTO GOATS AT SLAUGHTER IN ZARIA, NIGERIA.

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