Digital monitoring of parasites – how should we think about this in the future?
Can animals' individual movement patterns reveal parasitic infections? In a new study, SustAinimal researcher Oleksiy Guzhva has investigated how animal activity is linked to possible gastrointestinal parasitic infections.
Infections with gastrointestinal worms are among the most common and most production-limiting diseases in grazing animals. In temperate climates, such as Sweden, the medium-sized rumen worm, Ostertagia ostertagi, together with the small intestine worm, Cooperia oncophora, are the main causes of subclinical production losses in cattle. Infections with grazing parasites can largely be prevented through good grazing practices, but sometimes it is still necessary to deworm grazing animals.
What deworming practices have we used so far?
Traditionally, deworming has been done at the group level. To reduce the risk of resistance to deworming agents, it is now recommended to minimize the use of deworming agents by treating only those animals with a high degree of infection, while individuals with less parasite infection are not treated. However, such targeted selective treatment needs to be based on some indicator, such as egg excretion in feces or weight loss.
We know that grazing animals' behavior changes when they become infected with gastrointestinal parasites. Continuous automatic recording of behavior could therefore be a way of detecting possible parasite infection at an early stage. With the help of sensor-based threshold values, it would also be possible to identify and thus selectively treat super spreaders.
How do animals move on pasture?
The study investigated how grazing cattle activity is related to their individual contribution to parasite infection on pasture. Fifty-eight dairy heifers were included in the experiment, which lasted ten weeks in early summer 2022. The heifers were fitted with a sensor (IceQube) on one hind leg. The sensor recorded the animal's activity, i.e., lying and standing time, number of lying periods, number of steps, and movement index (a measure of total activity). The animals were weighed regularly and fecal samples were taken for parasite testing. All groups were kept on natural pastures that had been grazed by cattle the previous year and were therefore naturally contaminated with gastrointestinal worms.
The results show how important it is to understand how different factors, such as the breed of animal, affect their behavior and susceptibility to disease, and how this can influence the individual contribution to pasture infection. Understanding this allows for the development of more targeted and sustainable strategies for managing parasitic infections in grazing animals.