Which ingredients to use?
Energy sources - Maize, wheat, and sorghum constitute the major energy sources of most nursery diets around the world. Barley and oat groats are also frequently used, whereas rye and triticale are not very popular because they are rich in anti-nutritional factors. Tapioca is also an excellent energy source. Rice, especially broken rice, is used mainly in Asia, but cooked rice is used worldwide in high quality diets. Cereal by-products, such as those from the production of wheat flour or corn wet-milling are also used in diets for young pigs but not in diets immediately following weaning, and always in limited quantities because they tend to increase bulkiness and thus depress feed intake. Oils are generally favoured over animal fats for young pigs because they are more digestible. Thus, oils extracted from soybeans, maize, and sunflower are most frequently used during the first two weeks post-weaning, whereas animal fats, such as lard, white grease, and tallow, are favoured in the later phases of the nursery period.
Protein sources - Fish meal is an excellent source of protein for young pigs, yet price and availability frequently limit its use. Other major animalderived protein sources include dairy proteins, poultry meal, meat meal, and blood products (where permitted). Blood plasma protein is an established ingredient in nursery diets because its high content in immunoglobulins leads to improved growth performance. Today, plasma has been replaced by the less expensive egg-derived immunoglobulins, that also pose no risk of transmitting BSE and other diseases. Common plant proteins include soybean meal, soybean protein (in early diets), wheat gluten, potato protein, peas, lupines, sunflower meal, faba beans, and lentils, depending on price and local availability.
Soybeans and most other plant protein sources are rich in anti-nutritional factors and thus, heat treatment is needed to make these ingredients suitable for young pigs. Unrefined plant proteins are frequently restricted in the first two weeks post-weaning to avoid inflammatory reactions to antigenic proteins that are usually found in these ingredients. But, past the initial postweaning phase, plant protein sources supply the majority of amino acids in practical diets for young pigs.
Growth-promoting minerals – Copper sulphate and zinc oxide are wellestablished mineral salts that enhance growth performance and reduce symptoms of diarrhea in postweaned pigs.
Up to 3000 ppm zinc from zinc oxide, or less from new forms of potentiated zinc oxide, are frequently added in diets during the first couple weeks post-weaning to enhance growth performance and reduce symptoms of diarrhoea. Also, up to 250 ppm copper from copper sulfate is recommended for the remainder nursery period, but this usually drops to 125 ppm due to local regulations. The effect of these mineral salts are not additive, but their action is additive to that of antimicrobial agents, including organic acids.
How feed should be manufactured?
Feed preparation continues post-formulation when the feed must be actually manufactured. Here, certain processes can increase the nutritive value of piglet feeds and make them more acceptable as nourishment.
Grinding - The degree of fineness of ingredients in diets for young pigs has received considerable attention in scientific literature but not as much in commercial practice. It is generally accepted that a finer particle size increases the surface available for enzymatic digestion resulting, thus, in better nutrient digestibility. In general, 1.3% improvement in feed efficiency should be expected for each 100-micron reduction in particle size. An accepted particle size for maize is about 600 microns. For soybean meal, a range of 600 to 900 microns is considered sufficient.
Pellet quality - Pelleting improves growth rate and feed efficiency by about 10% in nursery pigs due to improved nutrient ingestion (pellets are less bulky than meal) and improved digestibility.
Pellet quality is traditionally associated with (index >90%) durability. A durable pellet should not necessarily be a hard pellet because performance can be depressed by as much as 10%-15% when pigs have trouble chewing their feed. Another aspect of pellet quality is size, and more precisely diameter. Research has indicated that piglets as young as 14-21 days old can easily cope with any pellet size ranging from 1 to 12 mm. Since wastage may be excessive in pellets larger than 3-4 mm, most commercial piglet diets have an average pellet diameter of 2 mm.
Conclusion
Piglet nutrition is definitely a fascinating subject, covering aspects of digestive physiology, feed formulation, ingredient selection, feed manufacturing and feed management. We have to be aware that a quality post-weaning diet is essential in alleviating the shock and consequences of early weaning. But, a top diet should be coupled with top on-farm feed management procedures to ensure the quality diet indeed reaches the gut of those piglets. After all, they are still babies.