Intercropped oats (Avena sativa) - common vetch (Vicia sativa) silage in the dry season for small-scale dairy systems in the Highlands of Central Mexico

Small-scale dairy systems in the highlands of central Mexico require feeding strategies based on quality home-grown forage that may reduce high concentrate costs. Eight Holstein cows paired by parity and date of calving were used in a split-plot experiment to evaluate supplementing 6 kg DM/cow/d of oat-vetch silage (OVS) in comparison to maize silage (MS) as dry season feeding, for a more intensive use of the land through an oat-vetch catch crop. Cows had 9 h/d access to continuous grazing of perennial ryegrass – white clover pasture and 4 kg/d of commercial concentrate. The 9 week experiment, recorded weekly milk yield and composition, and body condition score and live-weight every fortnight. Milk yield was 20.1 kg/cow/d for OVS and 15.4 for MS (SEM ±2.9, P > 0.05), with no differences for fat or protein content, body condition score, or live-weight (P > 0.05). The economic analysis showed that although feeding costs were higher for OVS, margins were greater than for MS, with feeding cost per litre of $0.21 for MS and $0.16 for OVS. OVS is a viable catch crop after the MS harvest that can substitute MS in the dry season enabling a more intensive use of the land.