Unexpected production loss caused by helminth parasites in weaned beef calves

Abstract

shEEP farmers are generally quick to consider helminth parasitism as the cause of diarrhoea and illthrift in their lambs, because they are aware that effective helminth control using anthelmintic drugs is difficult to achieve. There is a general awareness among sheep farmers of the production-limiting disease potential of helminth parasites, the inherent difficulties in using anthelmintic drugs to suppress pasture contamination with third-stage infective larvae (L3), and the high prevalence of anthelmintic-resistant helminths. helminth control in cattle, on the other hand, is generally perceived to be more straightforward, because certain parasites such as Fasciola hepatica, while important, are inherently less pathogenic; fewer nematode genera are considered to be pathogenic; there is a greater range of both conventional and persistent acting anthelmintic products, many of which are routinely conveniently administered as pour-ons (Barton and others 2006); and the prevalence of anthelmintic resistance is considered to be low, especially in the most pathogenic nematode species, Ostertagia ostertagi. Cattle farmers are therefore generally slower than their sheep farmer counterparts to investigate the possibility of helminth parasitism as a cause of diarrhoea and illthrift in animals that have been treated with anthelmintic drugs in accordance with a prescriptive herd health plan. This short communication describes production loss caused by helminth parasites in weaned beef calves, despite adherence to a prescriptive herd health plan.approximately 350 weaned, small, springborn suckled calves were purchased annually from the west coast of scotland during October and November and then introduced to an 18-to 24-monthold finishing system on an arable farm in East Lothian. a rational herd health plan was rigidly adhered to, involving pour-on treatment with 0.5 mg/kg doramectin (Dectomax Pour-On solution for Cattle 5 mg/ml; Pfizer) and oral treatment with 12 mg/kg triclabendazole (Fasinex 10 per cent; Novartis animal health) of every calf on arrival. The calves were then kept outdoors for five to eight weeks on fields that had been grazed by yearling cattle during the previous summer, before being housed in groups of approximately 50 during December and January, depending on the weather conditions. Yearling cattle were all treated with a depot injection of 1 mg/kg moxidectin (Cydectin 10 per cent La for Cattle; Fort Dodge animal health) at turnout during May.On December 9, a group of approximately 50 eight-month-old calves that had been housed on the previous day, five weeks after arrival on the farm, was examined. The average weight of the calves was approximately 150 kg, the group was uniformly dull and ill thriven, and most had diarrhoeic faeces (Fig 1). Contrary to expectations, there was no evidence of respiratory disease; rather, the clinical findings were consistent with helminth parasitism. serum samples were collected from five calves to determine the glutamate dehydrogenase (GLDh), albumin and globulin concentra...

Fasciola hepatica demonstrates high levels of genetic diversity, a lack of population structure and high gene flow: possible implications for drug resistance

“…Thereafter, our results indicate that clonal expansion within the snail intermediate host, coupled with clumped transmission, could act to propagate these resistant genotypes within a farm and increase the likelihood of resistant genotypes mating within a host. In relation to the spread of resistance, in the UK sheep are treated with anthelmintics against F. hepatica more often than cattle and resistance to triclabendazole is more frequently reported in parasites infecting sheep (Sargison et al, 2010). However, our findings indicate that drug-resistant F. hepatica from sheep could be readily transferred to cattle.…”

Gastrointestinal nematode species diversity in Soay sheep kept in a natural environment without active parasite control

“…The use of macrocyclic lactone drugs in beef calves has effectively controlled Ostertagia ostertagi, but allowed the establishment of pathogenic burdens of Cooperia spp. and Nematodirus helvetianus (Sargison et al, 2010), for which the efficacy is lower and period of persistence of protection against reinfection is shorter. Thus, the history of no anthelmintic drug treatments having been administered to the study flock of Soay sheep might account for the high abundance of parasites such as O. venulosum and B. trigonocephalum, which have long prepatent periods, and for the relatively low abundance of T. circumcincta, which commonly survives anthelmintic drug treatment in managed flocks, as a consequence of a high level of selection for anthelmintic resistance (Sargison et al, 2007b).…”

Nematode control in suckler beef cattle over their first two grazing seasons using a targeted selective treatment approach

“…These findings are in agreement with international studies where the risk of parasitic gastroenteritis (PGE) developing in spring-born suckler beef calves in the FGS is regarded as low [ 4 – 6 ]. However, PGE may develop in weaned beef calves [ 7 ] in a similar pattern to PGE in FGS dairy calves.…”