Common feeds for pigs-energy feeds-(1) grain seeds

The commonly used feed for pigs are energy feed, protein feed, silage, roughage, mineral feed and feed additives.

Energy feed refers to the feed with crude fiber content less than 18% and crude protein content less than 20%. Its nutritional characteristics are rich in easily digestible starch and are the main source of energy for pigs. However, the contents of protein, minerals and vitamins in this kind of feed are low, including cereal seeds and their processing by-products, starchy root tubers and so on.

Cereal seeds refer to mature seeds of Gramineae plants, including corn, sorghum, barley, oats, rice, millet and so on. This type of feed is characterized by rich nitrogen-free extracts, accounting for 70%-80% of dry matter, mainly starch, accounting for 80%-90%. Its digestibility is very high, and most of the digestible energy is more than 13 megajoules / kg. The disadvantage is that the protein content is low, which is 8.5% to 12%. The use of this kind of feed alone can not meet the protein needs of pigs; the content of lysine and methionine is also low; lack of calcium, phosphorus, calcium-phosphorus ratio is not suitable, lack of vitamin A (except yellow corn) and vitamin D.

1. Corn is the most commonly used energy feed in production, which has good palatability and digestibility. Among all energy feed, corn has the highest digestible energy content. The content of crude fiber is low, only about 2%, while it contains about 70% of nitrogen-free extracts, mainly starch, and its digestibility can reach about 90%. The fat content of corn is 3.5%-4.5%, which is twice that of wheat or barley. The linoleic acid content of corn can reach 2%, which is the highest of all cereal feeds. Linoleic acid is an octadecadiene fatty acid, it can not be synthesized in animals, can only be provided by feed, is an essential fatty acid. However, the protein content of corn is low, about 8.6%, which is less than that of wheat and barley, but close to that of sorghum, brown rice, chopped rice and so on. The amino acid composition of corn is poor, and lysine, methionine and tryptophan are insufficient. Therefore, when feeding corn to pigs, it must be combined with animal and plant protein feed such as soybean meal (cake) and silkworm pupa to supplement the deficiency of protein and amino acids in order to obtain good feeding effect. Due to the lack of tryptophan in corn, in order to make good use of tryptophan, the amount of nicotinic acid or nicotinamide should be increased in the additive premix. The content of riboflavin and pantothenic acid in corn is low, and nicotinic acid is also in a bound state, which need to be solved when preparing feed.

2. The metabolic energy level of sorghum seeds varies with varieties. The metabolic energy level of sorghum seeds with less shell is not much lower than that of corn, so it is a good energy feed. The quality of sorghum produced in northeast China is good. However, the hybrid sorghum popularized in North China for more than 20 years has a low flour yield, too much tannin, poor palatability, feeding alone and animals refusing to eat, so it can only be used in a limited amount in the diet, generally no more than 20% of the diet. The good quality sorghum seeds contain 13.81 megajoules / kg of metabolic energy, while those of poor quality are less than 12.55 megajoules / kg.

Sorghum has a low crude fat content (2.8%-3.3%) and low linoleic acid content, about 1.13%. The protein content is also low, and its content is similar to that of corn. The amino acid composition is the same as that of corn, which is also deficient in lysine, methionine, tryptophan and threonine. The protein digestibility of the varieties with more tannins decreased significantly.

3. There are two kinds of barley seeds, those with shell are called "grass barley" and those without shell are called "naked barley". The metabolic energy level of shelled barley, commonly known as barley, is about 11.51 megajoules / kg. It has good palatability and contains about 5% crude fiber, which can promote the peristalsis of animal intestines and make the digestive function normal. Barley is a favorite feed for pigs.

The protein content of barley is higher, about 11%, and the contents of lysine, tryptophan and isoleucine are higher than those of corn seeds, but they are still insufficient in terms of animal requirements. The content of crude fat is about 2%, and more than half of the fatty acids are linoleic acid.

Barley is not suitable for piglets, but if naked barley or after shelling, pressing and steam treatment, it can replace part of the corn to feed piglets. The daily gain of fattening pigs fed with barley was equal to that of corn, but the feed conversion rate was lower than that of corn. No more than 25% should be used in pig drinks. Because of its low fat content and high protein content, barley is an ideal feed in the later fattening stage, which can obtain pork with white fat, high hardness, thin backfat and lean meat. The famous "Jinhua ham" producing area in China used barley as one of the essential ingredients for raising pigs in history.

Wheat is the staple food of our people, and it is seldom used as feed. But in some areas, the price of wheat is lower than that of corn, and some use wheat as feed. The energy feed in northern European countries is mainly wheat, in which the amount of wheat is larger.

The crude fiber content of wheat in China is similar to that of corn, and the crude fat content of wheat is lower than that of corn, but the protein content of wheat is higher than that of corn, which is about 14%. The energy value of wheat is also higher, 14.36 megajoules / kg, second only to corn. However, the content of essential amino acids is low, especially the content of lysine. Like corn, wheat has less calcium and more phosphorus, and phosphorus is mainly phytate phosphorus (about 1.8%), and the contents of trace elements iron, copper, manganese and zinc are less. Wheat contains more group B and vitamin E, but very few vitamins A, D, C.

The palatability of pigs to wheat is better than that of corn, whole grains and crushed ones are better, but the details are not good. When fattening pigs are fed with the same amount of corn instead of corn, the utilization rate of feed may be reduced because the energy value is lower than that of corn, but part of protein feed can be saved, carcass quality can be improved and backfat thickening can be prevented.