Sow energy requirement summary outline

introduction

Sow breeding is one of the important links in pig production. In production practice, how to improve the performance of sows is the focus of pig production. The number of sows born, the high survival rate of piglets, and the use of extended sows have always been the goal pursued by pig farmers. In addition to genetic factors, nutrition is the most important factor in the reproductive performance of nutritional sows. Therefore, in the highly intensive and large-scale production of pigs, the nutrition of sows is put forward higher, and energy nutrition has different physiological characteristics for sows. The stage is of great significance.

1 System of energy needs representation

The energy requirements used to describe pigs and the energy concentration of feed are mainly digestive energy (DE) and metabolic energy (ME). DE is the difference between the animal's feed intake and the energy of the feed that is not digested in the form of feces; ME is the difference between the DE minus the energy of the urine and the gas of the digestive tract. Generally, energy utilization research refers to apparent DE or ME. Considering that DE is easier to measure than ME, DE is often used in daily measurement. The two can be mutually pushed by the following formula. ME=DE×[96-(0.202×crude protein%) .

2 gilt energy needs

The breeding goal of gilts is the growth and development of normal skeletal muscle tissue, ensuring the body condition of not being fat or thin, and the sexual maturity and body maturity develop in parallel, and can be bred as scheduled. The energy needs of gilts mainly include maintenance needs and growth needs. The physiological characteristics of gilts are that the body condition is not yet mature. On the one hand, energy intake should meet the needs of their own growth and development, and at the same time maintain good body condition and lay a good foundation for breeding. Unlike the sows and commercial pigs, the commercial pigs pursue the fastest growth rate and the fastest muscle deposition, while the gilts breed excellent pigs that can perform the best reproductive performance.

3 pregnant sow energy needs

The overall feeding goal of pregnant sows is to achieve the desired body condition during the delivery of the sow, and the fetus and mammary gland are well developed. The energy of the sow during gestation needs to be the sum of the need for maintenance, uterine growth, weight gain of the sow and establishment of reserves. The energy of pregnant sows varies according to the weight of the sow, the environment, the parity, the loss of the previous lactation weight and the expected net weight gain of the mother. The energy needs of the pregnant sow basically include the following five types: (1) Maintaining the generation energy = 0.0040 × BW 0.75 (kg); (2) the energy requirement of the weight gain of the maternal tissue: 13.7 × body weight gain (kg) + 46 × P2 back thickness increase (mm); (3) The energy requirement of uterus weight gain = 4.8 × fetal weight gain (kg); (4) metabolizable energy required for each hundred minutes of standing = 0.030 × BW 0.75; (5) metabolic energy required for body temperature regulation: (0.010 ~ 0.020) × BW 0.75. In addition to the effects of receptor weight and body condition, the energy needs and feed intake of pregnant sows are closely related to environmental temperature, feeding conditions and health status.

4 Lactating sow energy needs

Energy plays an important role in the reproductive performance of lactating sows, and it is the most abundant in feed. The most nutrients. The impact of energy needs on the reproductive performance of lactating sows is increasingly becoming a research hotspot. By adjusting the energy concentration in the sow feed, the utilization efficiency of feed energy and the reproductive performance of the sow can be improved. The energy needs of lactating sows are divided into: (1) maintenance needs; (2) milk production needs; (3) weight change energy needs; and (4) energy requirements for body temperature regulation.

4.1 Energy needs for primiparous lactating sows

The energy deficiency and weight loss of primiparous sows are extremely obvious. Many studies have confirmed that primiparous sows fed a low-energy diet or restricted feeding during lactation continue to be ill after weaning. In order to ensure the long-term good reproductive performance of the sow, the weight loss during lactation should be minimized or even lost.

4.2 Energy needs for lactating sows

The energy needs of lactating sows include two parts: maintenance needs and lactation. The maintenance needs to be about 0.46 MJ ME/kg, at which time the body temperature regulation and activity energy need to be negligible. In most cases, lactating sows do not meet the energy needs, and must be mobilized to cause body weight loss during lactation. The interval between weaning and mating is prolonged, even if there is no estrus or the number of sputum discharges is reduced, which seriously affects the production efficiency.