Grazed barley for dairy cows in small-scale systems in the highlands of Mexico

Abstract

Small-grain cereals with characteristics of hardiness of, such as barley have been evaluated as conserved forage for cows in small-scale dairy systems (SSDSs); but barley may also be grazed due to its regrowth capability after defoliation. The objective was to assess grazing of barley at 59 (B59), 66 (B66) and 73 (B73) days after seeding with milking cows in SSDSs. Twelve Holstein cows were grouped in a randomised 3 × 3 Latin Square design, replicated four times, with 14-day experimental periods. Measurements of animal variables and collection of feed and milk samples took place over the 4 final days of each period. A partial cost analysis was performed including only feeding expenses. The mean net forage accumulation during the experiment was 97.1 kg DM d−1. The botanical composition was affected by secondary vegetation (Mexican aster and wild radish, among others), where barley content was higher in B73 than in B66 and B59 pastures. The contents of dry matter (189–414 g·kg), neutral detergent fibre (NDF; 456–585 g·kg/DM), acid detergent fibre (ADF; 181–265 g·kg/DM) and crude protein (CP; 86–158 g·kg/DM) showed significant (p < 0.05) interactions among periods and pastures. Milk yield (MY) was 6.5% higher for treatment B66 (18.7 kg) in relation to B59 (17.5 kg), with intermediate values for B73 (18.1 kg). Feeding cost per kg milk was significantly lower in treatments B66 than B59 (p < .05), increasing the profit margins. It is concluded that grazed barley is a viable forage option for SSDSs. Initiating grazing of barley at 66 days post-sowing had a better cow performance than grazing at 59 d, with higher margins over feeding costs. The three treatments proved economically viable, with income/feeding costs ratios above 3.00. Highlights Feeding strategies with small grain cereals (barley) represent a feeding alternative for small-scale dairy farmers. The implementation of barley grazing in small-scale milk production systems is an option given the low rainfall. Barley, as a short cycle crop, allows dairy farmers to obtain good quality forage to feed their cows.