Effects of anthelmintic treatment and feed supplementation on parasite infections and morbidity parameters in Cambodian cattle

Highlights

• The Cambodian humid tropical climate is conducive for helminth infections in cattle.

• Helminthiasis causes high morbidity especially in cattle under nutritional stress.

• Village cattle may benefit from anthelmintic treatment and/or protein supplementation.

• A short term effect of anthelmintic treatment on parasitological parameters was observed.

• The added value of protein supplementation was unclear from the current study.

Abstract

Helminth infections are the cause of morbidity in Cambodian cattle but other factors such as nutritional deficiencies and concurrent diseases may enhance the effects of parasites. The present study aimed to investigate the impact of anthelmintic treatment, feed supplementation, or both on gastrointestinal strongyle (GIS) and trematode infections as well as on morbidity parameters in Cambodian village cattle. At the beginning of the dry season, cattle populations in six villages were randomly assigned to a group: (A) receiving anthelmintic treatment (ivermectin + clorsulon) at week 0; (P) feed pellet supplementation during week 0–13 or both (AP). On five visits (week 0–29), faecal and blood samples were obtained for parasitological examination and haematocrit determination, respectively. Body condition (BCS), hind quarter fouling (HQFS), diarrhoea (DS), and conjunctiva colour (FAMACHA^©) were scored and heart girth circumference was determined. To investigate the impact of treatment over time (week 0–29), a mixed model was used with treatment, time, and their interaction as fixed effects, and animal and village as random factors. At baseline, the proportion of GIS positive animals was high (67.9%), whereas trematode infections were low (Paramphistomum: 8.8%; Fasciola: 2.6%). Very thin to emaciated cattle (BCS 1–2) were more prevalent (11.4%) and FAMACHA^© scores of ≤3 or below (65.8%) less prevalent than in an earlier study in the region. A Time ⨯ Treatment interaction was present for faecal egg counts (FEC) of GIS, GIS prevalence (both p < 0.0001), PCV (p = 0.0034), DS (p = 0.0086) and HQFS (p = 0.0241). For GIS FEC, treatment groups differed at a specific time point, with levels of treatment group P being higher than in A at week 6 (p = 0.0054). For Paramphistomum prevalence as well as FAMACHA^© scoring, heart girth and BCS, the interaction between treatment and time was not significant, yet, time in itself had a significant impact on all (p < 0.0001). The beneficial effects of protein supplementation were unclear from the current study.

Introduction

Infections with gastrointestinal nematodes and trematodes are detrimental for cattle health and production (Loyacano et al., 2002 Vercruysse and Claerebout, 2001). Infected animals most commonly suffer from anorexia (Coop and Holmes, 1996), concomitant ill-thrift (Loyacano et al., 2002 Vercruysse and Claerebout, 2001) and diarrhoea (Jones et al., 2009), whilst others also suffer from anaemia (Díaz et al., 2006, Lotfollahzadeh et al., 2002, Van Aken et al., 1997), These symptoms obviously affect farmers’ profits and have an economic impact (Magaya et al., 2000). Therefore, the early yet cost-effective treatment and thus identification of animals potentially benefitting from this treatment is paramount. In most cases, traditional parasitological analyses are used as decision-tools for treatment. However, some studies have advocated the use of morbidity parameters related to these infections (e.g., body condition and faecal consistency scoring) as quick and easy methods to detect infected animals (Vercruysse and Claerebout, 2001).

In Cambodia, as in many tropical countries, cattle production is low due to poor nutrition and management as well as the presence of endemic diseases. Important diseases for cattle in the country are foot-and-mouth-disease, haemorrhagic septicaemia and blackleg (Clostridium chauvoei) in addition to both external and internal parasites (Young et al., 2014). Climatic conditions favour year-round development and transmission of infective parasite stages (Tum et al., 2007). Not surprisingly, infections with gastrointestinal nematodes and trematodes are thus highly prevalent in the country (Dorny et al., 2015, Dorny et al., 2011, Sothoeun et al., 2006). An abattoir study in Kandal province revealed 35.9% to 42.9% of livers being damaged because of immature liver flukes during the dry season (Sothoeun et al., 2006), whereas Tum et al. (2007) found Fasciola infections to range between 0 and 85% in 11 provinces in the country. In a large scale study on bovine helminth infections in the Pursat and Kampong Speu provinces, Dorny et al. (2011) reported 37–52% of sampled cattle being positive for gastrointestinal nematodes, most commonly for Cooperia spp. Infections with Fasciola and Paramphistomum were detected in 5–20% and 45–95% of cattle, respectively (Dorny et al., 2011). In the same study, a lower BCS was found to be associated with the presence of gastrointestinal nematodes and Fasciola whereas a soft faecal consistency was associated with Paramphistomum infections (Dorny et al., 2011).

Next to helminth infections, nutritional stress and extensive farm practices also affect the general condition of animals and morbidity parameters. In a survey conducted in several agro-ecological zones in Cambodia, lack of good quality feed resources was mentioned as one of the major constraints among cattle owners (Samkol et al., 2015). Banana stem, rice straw and bran were commonly used as supplementary feeds but contained low levels of protein (5.6%, 8.3% and 4.0%, respectively) (Samkol et al., 2015). Nematode infected ruminants have higher protein requirements, caused by anorexia, the predominant effect of helminth infections (Coop and Holmes, 1996) and by increased endogenous losses in the gastrointestinal tract. In sheep protein supplementation does not influence the establishment rate of nematode infections, however, it enhances immunity acquisition, and reduces the pathophysiological consequences of the infection (Coop and Holmes, 1996).

Few studies have investigated the potential benefits of protein supplementation and anthelmintic treatments in cattle in a tropical environment. In a study in Zimbabwe, protein supplementation and anthelmintic treatment in cattle resulted in higher weight gains than in cattle receiving an anthelmintic treatment only. Between those groups, no significant differences could be observed in faecal worm egg counts and haematocrit (Magaya et al., 2000).

The aim of this study was to compare the long-term effects of anthelmintic treatment and protein supplementation on infection levels of gastrointestinal nematodes and trematodes as well as on morbidity parameters under practical circumstances: namely in traditionally reared cattle in six villages in Cambodia.