MILAN — Italian yarn manufacturers have been buoyed by rising sales this year, and mills will seek to keep up the momentum at next week’s Pitti Filati yarn fair by focusing on one-of-a-kind high-quality fibers and fabrics. Natural and luxury fibers will be front and center, and mills expect mohair and merino and alpaca wool to be big sellers. They are also focused on innovation. Zegna Baruffa will introduce a yarn produced from a new breed of cashmere goat, and mills such as Luigi Botto have used technology to create cashmere yarns with enhanced performance. Here are some examples of what mills will have on display next week.