Wheat or maize silage in feeding strategies for cows in small- scale dairy systems during the dry season

The conservation of forage as silage allows its application during the dry season in dairy cattle feeding. The most commonly used forage for this purpose is maize (Zea mays L.), but due to the possible effects of climate change, the diversification of crops with shorter agronomic cycles as wheat (Triticum aestivum L.) should be considered. Therefore, the objective was to evaluate the chemical composition of silages, the productive response of dairy cows fed wheat and maize silage, as well as their feeding costs. Three treatments were evaluated with 9.8 kg DM cow-1 d-1 silage plus 4.6 kg DM cow-1 d-1 commercial concentrate each. Treatments were 100% wheat silage (WS), 50% wheat silage-50% maize silage (WMS), and 100% maize silage (MS). Six Holstein cows were used in groups of three randomly assigned to treatment sequence in a 3x3 Latin square design repeated twice. There were significant differences (P < 0.05) between treatments in silage chemical composition, except in NDF and ADF (P > 0.05). There were nonsignificant differences in animal variables (P > 0.05) with mean milk yield of 15.4 kg cow-1 d-1, 33.7 g kg-1 milkfat, 30.5 g kg-1 milk protein, 481.2 kg live weight and 2.1 body condition score. There were significant differences (P < 0.05) in silage and total DM intake in the third experimental period (three periods, 14 d each one) with 8.1 and 12.7 kg DM cow-1 d-1, respectively. Although cost for wheat silage were higher than maize silage, all three treatments showed positive margins on feeding costs.