Detailed Explanation of the Growth and Development Patterns of Growing-Finishing Pigs
On the basis of understanding the physiological characteristics of finishing pigs, it is very important to grasp the changes in growth and deposition of body tissues during the growth and development of finishing pigs. On the one hand, the corresponding feed nutrition can be determined according to the changes in tissues such as muscle, fat, skin and bone of pigs at different stages; on the other hand, the suitable slaughter weight of pigs can be determined.
The picture shows: a sow pig
(1) Composition of various body tissues
The muscle tissue of growing-finishing pigs is composed of skeletal muscle, cardiac muscle and smooth muscle, among which skeletal muscle accounts for the vast majority. Adipose tissue is mainly composed of a large amount of fatty acids, and morphologically it is divided into leaf fat, caul fat and subcutaneous fat. Pig bone is formed by the accumulation of minerals, and bone contains a large amount of calcium and phosphorus; pig skin is composed of many connective tissues and collagen. Pig bone and skin account for a relatively small proportion of the pig's body tissues.
The proportional relationships among the various tissues of growing-finishing pigs are affected by many factors. For example, different breeds, different feeding methods and environments, and the influence of certain external factors will all lead to certain changes in the proportional relationships. Even if the breed and feeding method are the same, different growth stages will still lead to certain changes in the proportional relationships of pig tissues.
(2) Changes in tissue growth and deposition
In the first stage, the growth of bone is dominant in growing-finishing pigs, followed by muscle, while the growth of fat is the slowest. In the second stage, adipose tissue grows with a relatively greater advantage, while bone and muscle show a downward trend. With the growth of various tissues and the increase in body weight, the proportions of muscle, fat, skin and bone tissues in the body of finishing pigs will undergo certain changes. When the proportion of fat, skin and bone gradually decreases, that is exactly when the proportion of muscle rises by a relatively large margin, and when the proportion of fat, skin and bone rises, the proportion of muscle shows a downward trend. When body weight continues to increase, the three curves gradually tend to stabilize. According to the situation shown in the tissue growth intensity chart, for the current lean pig production in our country, for a commercial pig with a reasonable ratio of muscle to fat and relatively high economic benefits, its suitable market weight should be 90-100 kg, but the suitable slaughter weight differs slightly among different breeds and different cross combinations.