Effect of the inclusion of sunflower silage for cows in small-scale dairy systems in the highlands of Mexico

Small-scale dairy systems are an option to ameliorate rural poverty in developing countries. These systems need to enhance their productivity through improved feeding strategies. The objective was to assess in a participatory on-farm experiment the effect on dairy cow performance of the inclusion of sunflower silage (SFS) with maize silage (MSL) during the dry season in three treatments: T1= 100% MSL, T2= 50% MSL/50% SFS, and T3= 75% MSL/25% SFS. Cows grazed 8 h/day, received 6.8 kg DM/cow/day of silage treatments, and 4.6 kg DM/cow/day of commercial concentrate (as decided by the collaborating farmer). Design was a 3x3 Latin Square replicated three times with nine Holstein cows, and 14-day experimental periods. Analysed variables were milk yield and composition, live weight and body condition score; as well as chemical composition of feeds and feeding costs. There were significant differences with a higher milk yield and higher milk fat content in T2 than T1 with intermediate values for T3; but no significant differences for protein (mean 31.4 +/- 6.1 g/kg), lactose (45.1 +/- 3.4 g/kg), pH (6.5 +/- 0.16) or milk urea nitrogen (10.5 +/- 0.81mg/dL). There were highly significant differences in live weight with T3 recording a lower live weight than T1 or T2, but no differences between treatments for body condition score (mean 2.3). Feeding costs were lowest for T2 and highest for T1. The inclusion of SFS at 50% with MSL to complement grazing dairy cows of moderate milk yields is an alternative to increase milk yields and income in small-scale dairy systems.