A combined effort to avoid strongyle infection in horses in an oceanic climate region: rotational grazing and parasiticidal fungi

Abstract

BackgroundAn approach to preventing strongyle infection in horses was tested, comprising rotational pasturing and the administration of spores of two parasiticidal fungi, Mucor circinelloides and Duddingtonia flagrans.MethodsTwenty-two adult Spanish Sport Horses were dewormed with ivermectin (1 mg pour-on/kg body weight) and then randomly divided into three groups. G-1 was maintained with continuous grazing, and G-2 and G-3 were kept on a four-paddock rotation system. Commercial pelleted feed (2.5 kg/horse) was supplied to G-1 and G-2 twice a week; horses in G-3 received pellets containing 2 × 106 spores/kg of each fungus. Fecal samples were analyzed by the flotation method to estimate the reduction in the fecal egg counts (FECR), the percentage of horses shedding eggs (PHR), and the egg reappearance period (ERP).ResultsThird-stage larvae were identified in fecal pats as Cyathostomum (sensu lato) types A, C and D, Gyalocephalus capitatus, Triodontophorus serratus, Poteriosthomum spp., Strongylus vulgaris and S. edentatus. Two weeks after treatment, the FECR values were 100% in G-1, 96% in G-2 and 99% in G-3; the PHR values were 100% in G-1, 75% in G-2 and 88% in G-3. A strongyle ERP of 6 weeks was observed in G-1, ERP of 10 weeks was observed in G-2, and ERP of 16 weeks was observed in G-3. The counts of eggs per gram of feces (EPG) were > 300 EPG in G-1 and G-2 but remained below 250 EPG in G-3 throughout the observation period of 12 months.ConclusionsThese results suggest that horse strongyle infection could be decreased by combining rotational pasturing with feeding pellets containing the spores of parasiticidal fungi.

Sustainable Control of Equine Nematodes: A Literature Review about Control by Fungal Cultures

“…However, excluding the study of Healey et al, the effect has been demonstrated by same active researchers by same methods in same climate conditions. Climate in Brazil, in which most of these studies have been carried out and in subtropical environment of southern Louisiana (Baudena et al, 2000), and in Spain (Paz-Silva et al, 2011;Herná ndez et al, 2016Herná ndez et al, , 2018 cannot tell the utilization potential of fungal cultures in climates outside these countries. Ferná ndez et al (1997) have reported that dry climate conditions affected the transmission of infective larvae resulting in low numbers of larvae on the herbage, and during the rainy periods a significant reduction in the number of larvae recovered around fungal containing pats.…”

“…Daily treatments are previously and more recently recommended (Fernandez et al, 1997(Fernandez et al, , 1999Healey et al, 2018), but the dose administered to the animals may be adjusted according to the isolate employed (Buzatti et al, 2015). On the other hand, a single dose (Tavela et al, 2013), twice a week administration (Herná ndez et al, 2018) and longer intervals (Buzatti et al, 2015) can also be effective alternatives to the daily treatment.…”

“…The culture of Duddingtonia flagrans can be used either as a laboratory strain with a reference code ATCC 38101, as an isolate of AC001, as a Brazilian isolate of CG 768 or IAH 1297 (BioWorma®). Sometimes there is not an only D. flagrans fungi isolates in effectiveness studies, but Monacrosporium thaumasium (Tavela et al, 2013) and Mucor circinelloides (Herná ndez et al, 2016;Herná ndez et al, 2018) are also included.…”

“…Firstly, the efficiency of biological control has been studied in field by feeding experiments (Ferná ndez et al, 1997;Ferná ndez et al, 1999;Baudena, Chapman, Larsen, & Klei, 2000;Braga et al, 2009;Paz-Silva et al, 2011;Tavela et al, 2011;Almeida et al, 2012;Herná ndez et al, 2018). For these purposes horses have been placed in pastures naturally infected with parasitic larvae and fungus-treated and control group have been established.…”

“…Despite the study design of biological fungi-based control anthelmintic therapy was not totally excluded. In the study of Paz-Silva et al this information is missing, but in general, animals in trials were received an anthelmintic treatment with ivermectin, which reduced the eggs per gram (EPG) of feces count to zero for investigation purposes (Baudena et al, 2000;Braga et al, 2009;Araujo et al, 2010;Braga et al, 2010;Almeida et al, 2012;Tavela et al, 2013;Herná ndez et al, 2018). This procedure was carried out before the experiment (14 days was reported in studies of Araujo et al, Braga et al and Tavela et al).…”