How can the feeding efficiency of growing-finishing pigs be improved? Laying a solid foundation is key

Pig production is a competitive industry in China's agriculture. Pork accounts for about 67% of total meat production and is an indispensable source of nutrition for people; pig manure and urine will play an even greater role in increasing agricultural output and developing organic agriculture.@#@227@#@It is conducive to rural economic development and increasing farmers' income. The comprehensive utilization of pigs has great development potential and awaits further development, and the international and domestic markets for pig products still need further expansion. Therefore, great attention should be paid to the genetic foundation, material foundation and survival foundation of pig production, promoting pig production toward the goals of high yield, high quality and high efficiency.

1 Pay attention to pig nutrition and feed formulation

Feed is the material foundation of pig raising, and the nutrients needed by pigs to maintain normal life activities and production all come from feed. In production practice, it can be seen that some pigs lose weight day by day. The reasons are many, but it is closely related to insufficient feed quantity and poor quality. The nutrients a pig obtains from feed cannot meet the needs of maintaining normal life activities. In order to survive, it must consume its body reserves, causing weight loss. The nutrients a pig obtains from feed each day are first used to meet the needs of maintaining normal life activities, and then used for body weight gain and other purposes. If the nutrients in the feed are comprehensive and sufficient, the pig will gain weight quickly and feeding efficiency will improve. For example, for a growing-finishing pig weighing 50-60 kg, with an expected daily gain of 550 g, the daily digestible energy requirement is about 22 MJ. According to calculations, the energy consumed for maintenance accounts for about 35% of total energy; the energy consumed for transport and metabolism accounts for about 25% of total energy; and the energy consumed for body tissue growth accounts for about 40% of total energy. If the supply is insufficient, the most important effect is reduced body tissue growth and a prolonged fattening period, which inevitably causes feed waste.

After feed is consumed by pigs, it undergoes a series of complex transformation processes in the pig's body, including digestion, absorption and metabolism. Digestion refers to the process in which large-molecule nutrients in feed are broken down into small-molecule nutrients that can be easily absorbed by the pig's body; absorption refers to the process in which digested nutrients enter the blood or lymphatic system, are distributed to the body's tissues and cells, and are utilized in metabolism; metabolism refers to a series of chemical and physical actions carried out by nutrients after digestion and absorption. Nutrient metabolism (carbohydrate metabolism, fat metabolism, protein metabolism, mineral metabolism, vitamin metabolism and water metabolism) is first used for the maintenance metabolic needs of the pig's body. Reproduction, lactation, growth and fattening all take material metabolism as a prerequisite.

The nutrients required by pigs exist in natural feeds, but no matter which feed it is, its nutrient composition cannot fully meet the nutritional needs of pigs. Therefore, it is usually necessary to use a variety of feeds to formulate pig diets, and to balance nutrition it is also necessary to add amino acids, vitamins, mineral elements, etc. The feeding value of feed depends not only on the content of nutrients, but also on the proportions among these substances. The interrelationships among nutrients are extremely complex. When formulating pig diets, attention should be paid to the "energy-protein ratio," that is, coordinating energy and protein to the range required by the pig's physiology and production, so as to improve feed utilization efficiency and production levels. If the ratio is inappropriate, it will not only affect the utilization efficiency of nutrients and cause feed waste, but also cause nutritional imbalance, affect pig health, and further reduce production levels. Some amino acids can be interconverted in the body, while antagonism exists among some amino acids. Excessive supply of one amino acid will reduce the biological value of another amino acid; deficiency of certain vitamins can reduce the conversion and utilization efficiency of some organic nutrients; mineral elements (including macroelements and microelements) also have coordinating, inhibiting or antagonistic effects among themselves and with other nutrients. For example, if the calcium content in the diet is too high, it will reduce the absorption of magnesium and manganese and easily cause or aggravate selenium deficiency.

All types of pig herds should be fed dry feed (or wet mixed feed) raw, and the hygiene of drinking water should be ensured. To meet the pigs' drinking water needs, free access to water is best. No matter how good the feed quality is, insufficient drinking water will affect pig health and feed utilization efficiency. Keepers should carefully observe the pig herd and carry out the "three observations" every day, namely observing spirit during normal times, observing appetite during feeding, and observing manure during cleaning. If abnormalities are found, measures should be taken immediately. The pigs in each pen should remain relatively stable and should not be frequently regrouped or merged into different pens, otherwise it will cause stress. Within 2-3 d after grouping, frequent biting and fighting will occur, affecting the pigs' feed intake and rest.

It can be seen that in actual pig feeding, it is not only necessary to supply the required nutrients according to nutritional needs, but also to coordinate the proportional relationships among various nutrients. On the basis of understanding the roles of various nutrients, it is also necessary to understand the interrelationships of various nutrients in the processes of digestion and metabolism in the body. Only then is it possible to formulate nutritionally balanced complete feed, utilize feed most effectively, and obtain the best feeding results.

2 Select breeding pigs with good performance

Improving the feeding efficiency of growing-finishing pig production is closely related to the quality of breeding pigs. Attention should be paid to the genetic foundation and the role of breeding pigs should be brought into play.

2.1 Strengthen selection and tap the genetic potential of pigs

Breeding pigs are one of the important factors affecting the overall situation of pig production. Among pig breeds (or strains), within breeds (or strains), or among different crossbreeding combinations, under similar nutritional levels, feeding, environment, management and other conditions, their performance (such as growth rate, feed utilization efficiency, etc.) differs, and this is related to the genetic foundation. The selection and retention of breeding pigs must follow scientific selection procedures and, through a series of measurements, select individuals with outstanding performance. Some breeding pig farms assign grades based on test results; the best are graded as special grade, the next best as first grade; the better ones as second grade (sows can be evaluated down to third grade), and the rest cannot be sold as breeding pigs. Neglecting the genetic foundation and focusing only on postnatal rearing, or neglecting postnatal rearing and focusing only on the genetic foundation, will make it difficult to achieve the expected results.

It is very difficult for some grassroots pig farms to achieve high profits by keeping investment in breeding pigs low. Breeding pigs are the "mother machines" for producing products, and their quality is related to the level of production, product quality and economic benefits. Whether a grassroots pig farm can select and retain breeding pigs from the offspring bred on its own farm mainly depends on the quality of the pig herd on the farm. On the premise of good quality, reserve sows can be selected and retained from the offspring; boars are best introduced from breeding pig farms for replacement. When introducing breeding pigs, careful investigation and research should be carried out. Introduce breeding pigs from farms with reliable immunization, good reputation for supplying breeding pigs, and no specific infectious diseases, and select from healthy herds, choosing the best among the good. When selecting pigs, first look at the records to understand the basic situation of the parental and grandparental pigs; then look at the individual itself and judge purity from body shape and appearance according to breed requirements; also look at constitution, structure, limbs and hooves, gait, external genitalia, teats, etc. The constitution should be sturdy, the structure well proportioned, the body long, the limbs and hooves normal, the four limbs tall, thick and strong and set wide apart, and the number of functional teats high (those with inverted teats or blind teats cannot be used for breeding). Boars should have well-developed and symmetrical testicles (those with hereditary defects cannot be used for breeding); sows should have normally developed external genitalia, and the individual's birth weight, weaning weight and weight at 70 days of age should be higher than the average of the whole litter, etc.