Effect of association of fresh cassava root with corn silage in replacement for cactus cladodes on dairy cow performance.

The aim of this study was to investigate the replacement effect of cactus cladodes with cassava root and corn silage (CRCS) (0, 25, 50, 75, and 100%, dry matter basis) in diets of lactating dairy cows on nutrients intake and digestibility, microbial protein synthesis, nitrogen balance, and milk yield. Ten Holstein cows with an average milk yield of 16 kg/day, an initial body weight (BW) of 670 ± 35 kg, and an average of 17 weeks in milking were assigned to an experiment using a double 5 × 5 Latin square design. The ratio of forage/concentrate was 82:18, and the ingredients used were cactus cladodes, cassava root, corn silage, soybean meal, wheat meal, urea, and mineral premix. The intake of dry matter, organic matter, and total digestible nutrients were not influenced by the replacement levels. On the other hand, the intake of crude protein and neutral detergent fiber increased while the intake of non-fiber carbohydrates decreased with addition of CRCS. The digestibility of the nutrients was not changed as the milk yield as fat-corrected milk production and milk content of fat, protein, lactose, and total solids. The microbial protein synthesis, microbial protein efficiency, nitrogen balance, and efficiency of N in milk were not changed. Therefore, we recommend the complete replacement of cactus cladodes by cassava root and corn silage in the diets of lactating cows with an average milk yield of 16 kg/day.

Replacement of wheat bran with spineless cactus (Opuntia ficus indica Mill cv Gigante) and urea in the diets of Holstein x Gyr heifers.

The aim of this study was to evaluate the replacement effect of wheat bran with spineless cactus and urea in heifers. Twenty-four heifers with an average initial weight of 185 ± 13 kg were used in this experiment. Four levels of spineless cactus corrected with urea and ammonium sulfate (9:1) were studied: 0, 33, 66, and 100 % replacement with wheat bran. Samples of feed, orts, and feces were analyzed to estimate the intake and digestibility of dry matter (DM) and nutrients. Indigestible neutral detergent fiber was used as an internal marker. The experiment was conducted in a completely randomized design. Dry matter, neutral detergent fiber, and total digestible nutrient intake demonstrated a quadratic effect (P < 0.05). Rumen degradable protein intake increased linearly (P < 0.05). The maximum DM digestibility was estimated to be 0.67 with a 43 % replacement. Crude protein and NDF digestibility increased linearly (P < 0.05). The total body weight gain and average daily gain decreased linearly with the replacement. Thus, it is practical to replace wheat bran with spineless cactus containing urea and ammonium sulfate up to 66 % in sugar cane-based diets.