“…This is an indicator of prolonged lack of food (Horton et al, 1996;Knowles et al, 1996), or indeed starvation, in which functional body tissue is being utilised (Broom and Fraser, 2007). Knowles et al (1993Knowles et al ( , 1995Knowles et al ( , 1998 transported lambs for 9, 14 and 24 h and ewes for 24 h and found that after each journey there was an increase in the plasma concentration of β-hydroxybutyrate.…”