What are the technical key points of the straight-line fattening method?

First, for fattening, piglets should be selected from normal-growing two-way or three-way crossbred pigs, transferred to the group at 60 to 70 days of age with a body weight of 15 to 20 kg or more, healthy and disease-free. Second, 7 to 10 days before the start of fattening, separate them into pens according to breed, body weight, and strength, and carry out castration, deworming, and epidemic prevention. Third, the formal fattening period is 3 to 4 months, requiring a daily weight gain of about 1.3 kg. Fourth, for the nutritional level of the daily ration, the early stage (20 to 60 kg) requires the diet to contain 17% crude protein and 3.1 Mcal digestible energy; the later stage (61 to 100 kg) requires 13 to 14% crude protein and 3 to 3.1 Mcal digestible energy. At the same time, pay attention to a variety of feed combinations as well as amino acids, minerals, and vitamins. Fifth, feed 2 to 3 meals a day with free access to feed; in the early stage, feed 1.2 to 2 kg per day, and in the later stage, 2.1 to 3 kg. Concentrate feed should be fed dry or wet, green feed should be fed raw, drinking water should be freely available, and the pig pens should be kept dry, clean, quiet, and at a suitable temperature.