Herbage intake, grazing behaviour and body-weight recovery in winter- and spring-calving Sarda suckler cows under Mediterranean silvopastoral conditions

This field study compared herbage intake, daytime behaviour and body-weight dynamics of Sarda suckler cows calving in winter (Group W; n = 5) or spring (Group S; n = 5) under the same Mediterranean silvopastoral conditions. Group S cows were at an earlier stage of lactation and nursing younger calves than Group W cows. We hypothesised that their greater expected nutritional demands would be associated with greater herbage intake, longer grazing time and lower body-weight recovery rate (RR). Herbage dry matter intake (HDMI) was estimated using the n-alkane technique, daytime behaviour was assessed on three occasions between 08:00 and 21:00, and body weight (BW) was recorded repeatedly. Group S had greater HDMI relative to BW than Group W (3.6 vs 2.8 kg DM 100 kg−1 BW d−1; p = 0.03) and showed lower RR (0.08 vs 0.59 kg d−1; p < 0.001). However, Group S did not devote a greater proportion of the observed daytime to grazing. Instead, the temporal distribution of grazing activity differed between groups (p < 0.001), indicating differences in the organisation rather than the overall duration of observed grazing. Thus, Group S cows showed greater relative HDMI and lower RR, but not longer observed grazing duration. Greater HDMI may therefore involve other components of the grazing process, such as bite rate, bite mass or diet selection, which were not measured. Given the limited number of animals and daytime observation windows, these results should be interpreted cautiously and confirmed in larger, independently replicated studies.