Growth and development law of fattening pigs

On the basis of understanding the physiological characteristics of finishing pigs, it is very important for    to grasp the changes of tissue growth and deposition in the process of growth and development of finishing pigs. On the one hand, the corresponding feed nutrition can be determined according to the changes of muscle, fat, skin and bone of fat pigs in different periods; on the other hand, the suitable slaughtering weight of pigs can be determined.

The picture shows: live pig

   (1) the composition of various tissues of the body

The muscle tissue of growing-finishing pigs is composed of skeletal muscle, myocardial muscle and smooth muscle, of which skeletal muscle accounts for the vast majority. Adipose tissue is mainly composed of a large number of fatty acids, which can be divided into suet, flower oil and subcutaneous fat. Pig bones are formed by the accumulation of minerals, the skeleton has a large amount of calcium and phosphorus, and pig skin is composed of many connective tissue and collagen. Hunting bones and skins account for a small proportion in the tissues of pigs.

The proportion of various tissues in    growing-finishing pigs is affected by many factors. Such as different varieties, different feeding methods and environment, the influence of some external factors will lead to certain changes in the proportion relationship. Even if the breeds and feeding methods are the same, different growth stages will still lead to some changes in the tissue proportion of pigs.

   (II) tissue growth and deposition changes

In the first stage, the growth of bone was dominant, followed by muscle, and the growth of fat was the slowest. In the second stage, adipose tissue grows with greater superiority, while bones and muscles are on a downward trend. With the growth of each tissue and the increase of body weight, the proportion of muscle, fat, skin and bone tissue in fattening pigs will change to some extent. When the ratio of fat to skin and bone gradually decreases, it is when the proportion of muscle increases greatly, while when the ratio of fat, skin and bone increases, the ratio of muscle shows a downward trend. As the weight continues to gain, the three curves tend to stabilize gradually. According to the situation shown in the tissue growth intensity map, for the current lean pig production in China, a commercial pig with reasonable proportion of muscle and fat and high economic benefit should have a suitable market weight of 90kg to 100kg. However, the suitable slaughtering weight is slightly different for different breeds and different hybrid combinations.