Practical Techniques and Methods for Raising Pigs on Forage Grass
Using high-quality forage grass to raise pigs can not only reduce feed costs, but also increase the lean meat percentage of pork, greatly improving the economic benefits of pig farming. The main high-quality forage grasses suitable for pig raising include: grain amaranth, Russian fodder kale, bitter lettuce, winter grazing 70 ryegrass, chicory, alfalfa, white clover, and others.
The Economic Value of Growing Grass to Raise Pigs
1. Nutritional advantages: The forage grasses grown contain diverse and abundant vitamins and trace elements, with relatively high protein content, which is beneficial for livestock and poultry to absorb and utilize.
2. Yield advantages: High-yielding forage grass can produce 10,000-15,000 kg of fresh grass per mu per year; calculated at 14% dry matter conversion, the annual dry matter yield can reach 1,400-2,000 kg, higher than that of crops.
3. Palatability advantages: When feeding sows, adding forage grass allows the use of some feed ingredients that have poor palatability but low prices in the daily ration, which can reduce feed costs without affecting sow intake; feeding sows an appropriate amount of green fodder during pregnancy can increase the number of live piglets born and the number surviving to weaning.
4. Digestion and excretion advantages: The crude fiber in forage grass can reduce abnormal behaviors in pigs, effectively prevent the occurrence of gastric ulcers, edema disease, and diarrhea, increase the weight of the digestive tract and internal organs, and protect pig health. Combining forage grass with pig feed can promote gastrointestinal peristalsis in pigs and acts as a cleanser for fecal excretion.
5. Ecological advantages: Growing grass to raise pigs can both ease the difficulty of manure treatment and provide high-quality green fodder for pig raising.
6. Cooling and heat-stress prevention advantages: Feeding forage grass in summer can reduce pigs' stress from extreme heat; planting forage grass in open areas of the pig farm can reduce the impact of high temperatures on pig growth and development, and lower the production costs increased by cooling measures such as electric fans.
Feasibility of Growing Grass to Raise Pigs
Pigs are omnivorous animals with a relatively strong ability to consume and utilize forage grass, especially the fine local pig breeds in China, which have a particularly outstanding ability to utilize forage grass. The nutrients in forage grass can be fully digested and absorbed by pigs, with relatively high nutritional value. Experiments and production practice show that feeding pigs green fodder year-round can achieve the effect of "supplementing concentrated feed with green feed, reducing costs and increasing efficiency." Feeding sows high-quality forage grass can meet their nutritional needs and increase litter size, while feeding fattening pigs can improve meat quality.
From the perspective of the "pig-forage grass" food chain composition, growing grass to raise pigs is feasible. According to pigs' nutritional needs and their ability to utilize forage grass, without affecting normal pig growth, fattening pigs can be fed 5-8 kg fresh weight of forage grass per day in combination with feed, and sows can be fed 10-12 kg. Generally, the fresh grass yield per mu of forage grass is about 10,000-15,000 kg, and the fresh grass harvested from growing 1 mu of forage grass can meet the supplementary feeding amount for 20 fattening pigs or 10 sows.
From the perspective of returns, growing grass to raise pigs is feasible. Under current production and technical conditions, the feed conversion ratio for raising fattening pigs is generally 3:1. Raising one 100 kg fattening pig requires about 300 kg of concentrated feed, which at current feed prices costs about 780 yuan. After feeding forage grass to replace part of the concentrated feed, 20-30 kg of concentrated feed can be saved, reducing feed costs by 50-80 yuan. If forage grass is used to feed sows, the usage ratio is even higher, more concentrated feed can be saved, and the reduction in production costs is even greater.
In places where the supply of concentrated feed ingredients is tight or concentrated feed is insufficient, growing grass to raise pigs is a relatively good method. In addition to using cultivated land to grow grass for pig raising, farmers can also make full use of idle land such as field edges and abandoned land to grow high-quality forage grass for pig production.
Utilization Methods of Forage Grass in Grass-Based Pig Raising
In growing grass to raise pigs, suitable forage grass varieties must be selected, and the method of using forage grass for pig raising must be determined according to the season. In summer and autumn, the main utilization method is feeding fresh grass directly; in winter and spring, high-quality grass meal or pulped silage forage grass is used as a mixed feed ingredient.
1. Fresh forage feeding method: Choose spring and summer for planting, grow succulent forage grasses such as grain amaranth, comfrey, and chicory, with fresh grass added at 15%-30% of the daily ration, and 1 mu of forage grass for every 10 pigs.
2. Utilization method of processing forage grass into grass meal and adding it to concentrated feed: The planted varieties are alfalfa, Mexican corn, sorghum-Sudan grass, etc. Fresh grass can be used in summer and autumn, and in winter and spring it is added to the daily ration in the form of grass meal. The amount of grass meal accounts for 8%-15% of the daily ration, and 0.5 mu of alfalfa is planted for every 10 pigs.
3. Utilization method of pulping or chopping forage grass to make silage and feeding it together with concentrated feed: As long as there is surplus forage grass for direct use in the season, it can be pulped or chopped to make silage and fed together with concentrated feed in other seasons when green fodder is lacking. The specific amount added to the daily ration can be determined according to the pig breed, growth stage, and physiological condition.
Forage Grass Varieties Suitable for Pig Raising
Forage grasses such as European chicory, cup plant, bitter lettuce, American grain amaranth, Rumex k-1, alfalfa, Mexican corn, sorghum-Sudan grass, and sainfoin have relatively comprehensive nutritional components. Calculated on a dry matter basis, their crude protein content is relatively high, generally above 12%, with the highest reaching 30%, and they have a complete range of amino acids with high utilization rates, which can make up for the shortcomings of cereal feed in having an incomplete range of proteins and amino acids. They also contain relatively rich vitamins and inorganic salts, have low crude fiber content, are easy to digest, have good palatability, high yield per unit area of land, low production cost, and wide sources.
Adopt the form of growing broadleaf forage grasses combined with utilizing agricultural by-products such as sweet potato vines and carrots to grow grass and raise pigs.
Pigs are monogastric animals with a relatively low ability to utilize crude fiber. For grass-based pig raising, broadleaf forage grass varieties such as chicory, cup plant, Russian fodder kale, and bitter lettuce should be selected. The first three are perennial forage grasses, with a fresh grass utilization period from March to November. Bitter lettuce is an annual forage grass, with a fresh grass utilization period from March to August. To make up for the shortage of green fodder in winter and rationally utilize agricultural by-products, sweet potato, large-root vegetables, carrots, green vegetables, etc. are planted in combination. The following two models are mostly used for crop rotation arrangement:
1. Intercropping of perennial forage grass with green vegetables
For green vegetables, choose the Qianfotou variety, which has strong individual growth potential. In March, raise seedlings and transplant chicory, with a row spacing of 60 cm and a plant spacing of 25 cm. In early November, after chicory is mowed, transplant green vegetables in the empty rows with a plant spacing of 15 cm. From January to March of the following year, harvest leaves by stripping them to feed pigs. In early April, harvest all the green vegetables and let the chicory grow alone. Using cup plant or Russian fodder kale instead of chicory for intercropping with green vegetables follows a similar method, only requiring reasonable configuration of plant and row spacing and corresponding management measures according to the characteristics of these two forage grasses.
2. Rotation of bitter lettuce, sweet potato, and green vegetables
In March, prepare the land and broadcast sow bitter lettuce. After bitter lettuce is cleared at the end of June, form ridges and plant sweet potato seedlings. After sweet potatoes are harvested in November, transplant green vegetables. After green vegetables are harvested at the end of March of the following year, plant bitter lettuce again. When feeding, use as many kinds of green fodder in combination as possible. The total amount of green fodder accounts for about 30% of the daily ration. Pigs of 15-30 kg are fed 3-5 kg of green fodder per day, and pigs over 30 kg are fed 6-10 kg of green fodder per day.
Feeding of Meat Pigs
Small pig (7 kg-20 kg) stage: Fully supply some high-quality, nutritionally complete compound feed for small pigs, with the principle of feeding to satiety. The protein content in the feed should reach above 18%, and the Ca content should reach 0.8%-0.99%. At the same time, appropriately feed a small amount of tender fresh forage grass stems and leaves. Remember not to feed too much; the daily feeding amount should be 1 kg-2 kg, and at most not exceed 3 kg. Generally, feed fresh grass half an hour before feeding feed.
Medium pig (20 kg-60 kg) stage: This stage is the most critical period for increasing lean meat percentage, and also an important period for saving concentrated feed and reducing pig-raising costs through high-quality forage grass. At this time, feed less concentrated feed with high protein content, and supplement the shortage of protein and calcium in concentrated feed by adding high-quality forage grass, as well as supplement vitamins and minerals. Generally, the daily feeding amount is 4 kg-6 kg fresh grass or high-quality grass meal accounting for 15% of the concentrated feed. (Concentrated feed formula: 70% corn, 20% wheat bran, 10% concentrated feed or soybean cake.) The daily feeding amount of concentrated feed is 1 kg-1.25 kg. Generally, feed fresh grass half an hour before feeding concentrated feed, twice a day.
Large pigs have enhanced ability to digest and utilize crude fiber, greatly improved stress resistance and adaptability, and fast weight gain. At this time, the concentrated feed should consist of 80% corn and 20% wheat bran, without adding any concentrated supplement. Feed about 6 kg-8 kg fresh forage grass per day or grass meal accounting for 20% of the concentrated feed, with a daily concentrated feed amount of 1.5 kg-2 kg. Feed fresh grass half an hour before concentrated feed, twice a day. In the half month before slaughter, feed 2 kg-3 kg fresh grass per day, along with about 2.8 kg of a mixture of 90% corn and 10% wheat bran.
Feeding of Sows
Open (non-pregnant) stage: If the sow is too thin, more concentrated feed should be supplemented. Under normal circumstances, feed the sow 0.5 kg-1 kg concentrated feed per day, and 8 kg-10 kg fresh grass, or a mixture of 20%-30% corn + 10% wheat bran and 60%-70% forage grass hay meal.
During the first 80 days after a sow becomes pregnant, the utilization rate of various nutrients in the feed is relatively high, and because embryonic growth and development are slow at this time, it is the best period to save concentrated feed. The feeding method is the same as the open stage.
From 80 days after a sow becomes pregnant to farrowing, about 35 days, energy and protein should be appropriately increased in the feed, and calcium should be supplemented. Add 20 g bone meal or 50 g fish meal per day, and at the same time increase the concentrated feed from 0.5 kg-1 kg/day to 1 kg-1.5 kg/day, and adjust high-quality forage grass to 5 kg-6 kg/day. During the lactation stage, increase the feeding amount of concentrated feed and appropriately supplement calcium. Under normal circumstances, use 60% corn + 30% wheat bran + 10% sow concentrated feed, or 50% corn + 30% wheat bran + 18% soybean cake + 2% bone meal for feeding. The concentrated feed amount is 2.5 kg-3 kg/day, plus 8 kg-10 kg fresh grass.
Forage grass fed to pigs generally does not need to be chopped or pulped and can be fed directly. However, some forage grasses have poor palatability, such as cup plant and sweet clover, and can be chopped or pulped and mixed into concentrated feed for feeding.