Invasive Species Compendium

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Abstract

Events around weaning in semi-feral and stable-reared Konik polski foals: evaluation of short-term physiological and behavioural responses.

Abstract

The annual weaning, stabling and subsequent sale of semi-feral Konik polski foals born in forest reserves ensure a stable population of free-roaming Konik polski horses. However, welfare concerns regarding the maternal and herd separation of young horses, manipulation by humans, transportation and stabling of forest-reared Koniks have arisen. The aim of the present study was to examine the physiological and behavioural responses of weaned, 7-to-9-month-old forest-reared Konik polski foals (FR, N=26) relative to those of stable-reared peers (SR, N=27). Fifty-three weanlings (24 colts and 29 fillies) were studied. FR foals from five distinct herds were captured and transported and stabled together in loose-housing stables (FR weaning scheme). Three weeks later, SR foals were weaned by separating them from their dams and joining them with FR foals (SR weaning scheme). Faecal cortisol metabolites (FCM), which reflect adrenocortical activity on the day preceding weaning (WD -1) and on the day of weaning (WD), were analysed to evaluate the effect of weaning on FCM concentrations. The time budget over the 6 h following weaning on the day of weaning (WD) and one day post-weaning (WD +1) was recorded. Weaning caused a significant increase (P<0.0001) of adrenocortical activity in all horses. Sex (P=0.0064), but not rearing condition (P=0.1542) had an effect on FCM concentrations. Differences between FR and SR foals in terms of their behavioural responses to the two weaning schemes were observed, FR foals exhibiting less outward arousal (lower social and locomotor activity, less vocalisation) compared to SR foals. On WD +1, both groups tended to adapt to the post-weaning scheme. However, FR foals still stood for longer periods than their SR peers and presented less alert behaviour and lower locomotor and social activity. Increased FCM levels on weaning day were correlated with longer periods of standing (rs=0.32, P=0.0149) and shorter feeding bouts (rs=-0.42, P=0.0017). It seems that forest foals were more disturbed by all events around weaning. They presented higher apathy and more forest horses were among those showing higher FCM concentrations. However, as the FCM did not differed significantly between groups from different rearing conditions, the claim of a higher "stress" response to the weaning scheme in forest foals cannot be unequivocally supported based on behavioural and physiological measures in our study. For both groups, feeding behaviour appears to be a good indicator of post-weaning stress.