Grazing behaviour of Miranda donkeys in a natural mountain pasture and parasitic level changes

We assess feeding behaviour, diet selection and parasite level in grazing donkeys.Donkeys showed a preference for herbaceous vegetation.Despite this, donkeys can incorporate up to 30% of shrubs in their diet.A relation between feeding behaviour and a natural parasite control is proposed.Parasite level increase was delayed in relation with existing information.

The Miranda donkey (Equus asinus) has an important role in the maintenance of rural landscape and traditions in inland of Portugal. Breeding and keeping of these animals rely on mountain pasture areas, known for their characteristic botanical diversity. However, their grazing behaviour in these areas has not been described and this knowledge is important to set the best management practices that promote an efficient use of these particular feed resources that could be related with parasitic level of these animals. In this way, this study aimed to assess feeding behaviour, diet selection, and relate the total phenolic and tannin content of ingested plants with the parasite load in a group of Miranda donkeys under free ranging system in natural mountain pastures. For this purpose, eight adult non-pregnant Jennies from the Miranda donkey breed were managed under continuous grazing on a 1.6 ha natural mountain pasture from late May to late July. Body condition score (BCS) and grazing behaviour of the Jennies was assessed in two different occasions. Additionally, the level of gastrointestinal nematode infections of the herd was assessed throughout the study. Results showed that animals spent 75.6% of total observation time in search/prehension activities corresponding to an average of 16 h/day. Jennies showed a preference for herbaceous species, although they were able to incorporate in their diet up to 30% of shrubs, suggesting that they can be used as biological tool for controlling and reducing shrub encroachment in these mountain areas. Parasite level increased from 0% positive samples in June to a maximum of 25% in July. The increase of EPG may be related with the observed decrease in the shrub consumption throughout the observation period. Having in account the presence of phenolic and condensed tannins in shrubs, their potential as natural anti-parasitic compounds and the possibility of taking part in donkey diet, these preliminary results can be of the utmost importance regarding an integrated approach of Miranda donkey parasite control.