There is strong evidence to show that weaning (artificially removing foals from their mothers) causes foals considerable stress. A variety of factors can affect just how stressful weaning is for foals, including their age and management factors (e.g., feeding, social grouping, handling, housing).
A recent study by Italian researchers aimed to investigate stress in foals exposed to two different weaning protocols. It was published in the Journal of Veterinary Behaviour under the title: ‘Behavioral and hormonal effects of two weaning situations in trotter foals.’
- Foals in situation 1 (S1) (n=10) were weaned at five months old, two at a time and handled regularly.
- Foals in situation 2 (S2) (n=12) were weaned at seven months old, all on the same day with little handling.
Stress was evaluated by watching video recordings of foal behaviour and measuring stress hormones (cortisol) in saliva and hair samples. Behaviours included interactions between foals, exploring, resting, eating, drinking, urinating and defaecating.
On the day of weaning, all the foals displayed behavioural changes consistent with stress, such as increased vocalisations and decreased time eating. The decrease in time spent eating was also present on day seven for S1 foals, but not for S2 foals.
One week after weaning, foals in S1 had higher cortisol in hair samples compared to foals in S2.
However, because the foals in each of the situation varied in treatment and age, the study could not determine what aspects of S1 may have been more stressful to foals compared to S2, with the authors recommending further research to investigate influencing factors.
The study by Normando S, Giaretta E, Schiavon I et al (2021) titled ‘Behavioral and hormonal effects of two weaning situations in trotter foals’ is published in the Journal of Veterinary Behavior. The abstract is available here.
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