Whole-crop triticale silage for dairy cows grazing perennial ryegrass (Lolium perenne) or tall fescue (Lolium arundinaceum) pastures in small-scale dairy systems during the dry season in the highlands of Mexico

摘要

The dry season in central Mexico is a difficult time for small-scale dairy systems to meet feed requirements for their herds as pasture growth is limited. Conserved forage options are needed to complement pastures. The objective was to assess on-farm the production of dairy cows complemented with triticale silage (X. Triticosecale Witt. (TSL)) at two levels of inclusion (5.0 and 7.5 kg DM/d), grazing pastures of two grass species during the dry season: perennial ryegrass (PRG;Lolium perenne) or tall fescue (TFC;Lolium arundinaceum) (TFC) with white clover (Trifolium repens), and 4.65 kg DM/d concentrate. Experimental design was a 2 x 2 factorial in repeated 4 x 4 Latin squares. Chemical composition of TSL was 96 g CP/kg DM, 667 g NDF/kg DM, 713 g in vitro enzymatic digestibility of OM (IVEDOM)/kg DM, and pH of 4.6. There were differences (P < 0.05) in net herbage accumulation (NHA) and sward height between pastures, with higher NHA in TFC than that in PRG, although the chemical composition of PRG was higher (P < 0.05) in PC, IVEDOM, and estimated ME. There were no differences (P > 0.05) in milk yield (12.3 +/- 2.63 kg/cow/day), milk compositions (33.1 +/- 0.45 g milkfat/kg, 41 33.3 +/- 0.21 g milk protein/kg, 47.9 +/- 0.36 g lactose/kg, and 10.47 +/- 2.25 mg MUN/dL), body condition score (2.4 +/- 0.22), or live weight (490 +/- 72.8 kg). At a higher inclusion of TSL, there was lower intake of pasture. Inclusion of 5.0 kg DM/cow/day of triticale silage better complements grazing and sustains moderate milk yields when pasture growth and intake are limited.