Date of Award

5-2016

Document Type

Master Thesis

Degree Name

Masters of Science (Research)

Department

Biological & Pharmaceutical Sciences

First Advisor

Dr Joanna B. Tierney

Second Advisor

Dr Geraldine Twamley-Stein

Abstract

Diseases such as parasitic gastroenteritis are very common in cattle and can have detrimental economic consequences on agricultural productivity. This study was conducted to establish the prevalence and distribution of gastrointestinal nematode parasites associated with Dexter cattle under an organic lowland grazing regime and an extensive upland system. A secondary aim to the study was to investigate dung beetle assemblages in upland and lowland sites and their interactions with gastrointestinal nematode parasites as they offer an alternative method of natural control to organic farming systems in particular.

Cattle weights were recorded and faecal samples were collected at the beginning and end of the study. Faecal egg counts (FEC) were performed using the McMaster method and pasture infectivity was monitored by transect twice monthly. Standardised artificial dung pats were used to monitor dung beetle assemblages, larval migration and nematode–beetle interactions. Dung samples were analysed for Nitrogen and Carbon across the grazing season and more exhaustive subsampling was performed across the month of August.

The level of parasite burden was low in both in the upland and lowland cohorts. Younger animals had higher FEC compared to adults which is characteristic of herd infections. Mean FEC were below subclinical levels indicating that cattle were healthy with minimum risk of production loss. Pasture larval levels were low on all sites with a typical peak observed in late summer. The predominant species of nematode larvae in both sites were Ostertagia ostertagi and Cooperia oncophora. Cattle weights increased in the lowlands but were sustained in the uplands. Dung analysis showed higher levels of nitrogen and lower dry matter in the lowland dung. Major differences between populations were the dominance of Cercyon genus in the lowlands. Aphodius rufipes and A. fimetarius were found in similar numbers in both sites and A. fasciatus was found exclusively in the uplands. Dung beetle numbers were higher in the lowlands compared to the uplands, 1,660 and 301 respectively, with species richness similar in both sites. However, species diversity and evenness was greater in the upland site.

This study has found that there was a minimum risk to animal health by nematode parasites in the upland grazing regime suggesting that upland pastures can be utilised in the summer months to alleviate lowland grazing pressure by removing non-fattening stock. Low levels of gastrointestinal parasites in the organic lowland site were achieved by good management practices. A novel finding of this study points to the Hydrophilidae beetle family as potential nematode control agents. Grazing management strategies and biological control methods should form an integral part of any grazing management plan.

Access Level

info:eu-repo/semantics/openAccess

Coverage

July 2024

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