Publications by authors named "Jan A Van Wyk"

Due to their value as a food source, fiber, and other products globally, there has been a growing focus on the wellbeing and health of small ruminants, particularly in relation to anemia induced by blood-feeding gastrointestinal parasites like . The objective of this study was to assess the packed cell volume (PCV) levels in blood samples from small ruminants, specifically goats, and create an efficient biosensor for more convenient, yet accurate detection of anemia for on-farm use in agricultural environments for animal production optimization. The study encompassed 75 adult male Spanish goats, which underwent PCV testing to ascertain their PCV ranges and their association with anemic conditions.

View Article and Find Full Text PDF

Smallholder goat production plays a major role in rural livelihoods and food security in Malawi, but suffers from drastic and unpredictable production losses. While goat production is closely linked to small-scale local markets for slaughter and butchering, the perspectives of butchers and their potential as a source of animal health information are largely untapped. Butchers can provide insights into goat health status at slaughter as well as issues that go unseen before slaughter, such as the presence of indigestible foreign bodies (IFBs).

View Article and Find Full Text PDF

Refugia-based strategies are intended to help slow the development of anthelmintic resistance by providing a population of parasites that are not exposed to the treatment. Evidence from field studies is lacking. There is no single way to incorporate refugia into a parasite control program.

View Article and Find Full Text PDF

An elicitation exercise was conducted to collect and identify pressing questions concerning the study of helminths in livestock, to help guide research priorities. Questions were invited from the research community in an inclusive way. Of 385 questions submitted, 100 were chosen by online vote, with priority given to open questions in important areas that are specific enough to permit investigation within a focused project or programme of research.

View Article and Find Full Text PDF

Transmission of parasites between host species affects host population dynamics, interspecific competition, and ecosystem structure and function. In areas where wild and domestic herbivores share grazing land, management of parasites in livestock may affect or be affected by sympatric wildlife due to cross-species transmission.We develop a novel method for simulating transmission potential based on both biotic and abiotic factors in a semi-arid system in Botswana.

View Article and Find Full Text PDF

Infection with the abomasal nematode Haemonchus contortus is responsible for considerable production loss in small ruminants globally, and especially in warm, summer-rainfall regions. Previous attempts to predict infection levels have followed the traditional framework for macroparasite models, i.e.

View Article and Find Full Text PDF

Due to the threat of anthelmintic resistance, livestock farmers worldwide are encouraged to selectively apply treatments against gastrointestinal nematodes (GINs). Targeted selective treatment (TST) of individual animals would be especially useful for smallholder farmers in low-income economies, where cost-effective and sustainable intervention strategies will improve livestock productivity and food security. Supporting research has focused mainly on refining technical indicators for treatment, and much less on factors influencing uptake and effectiveness.

View Article and Find Full Text PDF

The liver fluke Fasciola hepatica causes considerable damage to the health, welfare and productivity of ruminants in temperate areas, and its control is challenged by anthelmintic resistance. Targeted selective treatment (TST) is an increasingly established strategy for preserving anthelmintic efficacy in grazing livestock, yet no practical indicators are available to target individuals for treatment against fluke infection. This paper evaluates the FAMACHA(©) system, a colour chart for the non-invasive detection of anaemia in small ruminants, for this purpose.

View Article and Find Full Text PDF

The FAMACHA(©) system is a method for selective anthelmintic treatment comprising early detection of haemonchosis in sheep and goats. In order to evaluate the hands-on training methodology and the learning level of the participants, we analyzed data from 30 training events involving 47 training classes conducted in the State of Paraná, Brazil, from July/2009 to May/2011, during which period a total of 1004 participants did 20,080 FAMACHA(©) classifications. In the practical training sessions, each participant individually evaluated 20 animals with known haematocrit values.

View Article and Find Full Text PDF

In 2004, a new concept was introduced for simplifying identification of larvae of the common nematodes of cattle, sheep and goats that comprises estimates of the lengths of the sheath tail extensions of infective third-stage larvae (L3) of each genus and/or species to that of Trichostrongylus spp., instead of having to be dependent only on measurements in micrometre. For example, if the mean length of the sheath tail extension (the extension of the sheath caudad, beyond the caudal tip of the larva) of Trichostrongylus colubriformis and Trichostrongylus axei is assumed to be 'X', then that of Haemonchus contortus is 2.

View Article and Find Full Text PDF

Sheep and goats are the species of farm animal with the highest growth rate in Paraná State. The main problems facing Paraná State flocks are gastrointestinal parasites and anthelmintic resistance. One of the newest resources used to slow down the development of anthelmintic resistance is the FAMACHA(©) system, a selective method useful for controlling gastrointestinal verminosis in small ruminants.

View Article and Find Full Text PDF

Background: Hookworms are blood-feeding nematodes that parasitize the small intestines of many mammals, including humans and cattle. These nematodes are of major socioeconomic importance and cause disease, mainly as a consequence of anaemia (particularly in children or young animals), resulting in impaired development and sometimes deaths. Studying genetic variability within and among hookworm populations is central to addressing epidemiological and ecological questions, thus assisting in the control of hookworm disease.

View Article and Find Full Text PDF

A series of new iron(III) and copper(II) complexes of bovine serum transferrin (BTf), with carbonate and/or oxalate as the synergistic anion, are presented. The complexes [Fe(2)(CO(3))(2)BTf], [Fe(2)(C(2)O(4))(2)BTf], [Cu(2)(CO(3))(2)BTf] and [Cu(C(2)O(4))BTf] were prepared by standard titrimetric techniques. The oxalate derivatives were also obtained from the corresponding carbonate complexes by anion-displacement.

View Article and Find Full Text PDF

Escalating anthelmintic resistance has made it essential to develop alternative ways of worm management for reducing selection for worm resistance, and one of the most promising approaches is to treat only those animals unable to cope with worm challenge, thus favouring unselected worms originating from untreated animals. Only clinical evaluation of anaemia (FAMACHA system) and the body condition score are regarded as being of practical value or having potential, respectively, for repeatedly examining flocks or herds and identifying individuals for treatment. Only the FAMACHA system has been tested well enough for use under practical farming conditions.

View Article and Find Full Text PDF