Table 7.

ABMs for prolonged hunger in individual pens in dairy farms

ABM	Comments
Body condition score (BCS)	Definition: Poor body condition (protruding bones, sharp ribs etc.). For estimation of BCS categories, the following criteria are taken into account (adapted from the Welfare Quality® protocol for veal calves (2009)): – Calves should be assessed on the basis of the quantity of muscle, the estimated weight and physical appearance characteristics including: (i) visibility of the ribs, (ii) the extent to which the backbone protrudes, and (iii) the size of the belly. – Calves are compared with the mean level of the batch. Severe lower condition: the calf is 30% below the average weight or condition of the batch. Sensitivity: Low. The calf will only show low body condition if group stress occurs over a long period of time and the animal is prevented from accessing feed sources over this period. Specificity: Low. The specificity of this indicator decreases in cases of disease (chronically ill animals may also have low BCS).
Non‐nutritive sucking	Definition: Sucking equipment, e.g. a teat bucket, a dry teat, or pen fixtures (Herskin et al., 2010), or sucking the head or neck of a neighbouring calf (Mounier et al., 2006). Sensitivity: Low, because not all animals experiencing prolonged hunger will show non‐nutritive sucking. Specificity: Low. This ABM can also be present in cases of inability to perform sucking behaviour.
Number of vocalisations	Definition: Every single open mouthed ‘muh’ vocalisation with inhalation between two occurrences (Johnsen et al., 2015). Sensitivity: High. Specificity: Low. It can also occur in situations of for example separation stress and handling stress.
Restlessness, i.e. increased activity and decreased lying	Definition: Expression of behaviours like stepping, kicking, foot‐lifting (Gygax et al., 2008), leg stomping, weight shifting, repositioning, head swinging (Cooper et al., 2007). Sensitivity: High. Specificity: Low. Can also occur, e.g. in situations of acute hunger.