1995 ^. Volume 18, Number 4

In general, pigs are thought to consume enough feed to meet their energy needs and that the energy requirement actually dictates intake. Consequently, if fat is incorporated into a diet the animal will decrease it's consumption of the higher energy feed, while maintaining approximately the same metabolizable energy intake. Thus, energy intake is not generally a problem in animals that are self or full-fed, but sows are not always fed to appetite while in the farrowing house. This often means that they are fed enough feed so that they will have cleaned up the previous feedings allotment by the next feeding. This is often a major problem in warm environments where sows will not consume a great deal of feed during the hottest portion of the day, and will end up being restricted in their evening feeding. However, the sow should consume the greatest amount of feed during the cool night, but intake can be restricted if the portion is not alotted properly. Considerable emphasis should be placed on developing feeding programs around temperature changes and increasing the energy density during summer months. Also, consider offering greater quantities of feed at night than in morning or midday feedings. Documenting actual feed consumption will help the nutritionist better meet the nutrient needs of the sow.

Another problem when considering energy consumption is knowing what the sow is actually consuming, versus what someone predicts she is eating. It is known that daily feed intake as predicted by the NRC (1988) is not an accurate representation of pigs in North Carolina. This stems from the fact that requirements were determined on animals nursing smaller litters with a generally lower lean growth potential. Thus, not only is the requirements different for milk production of the current sow base, but so are the intake and maintenance estimates. The differences in nutrient requirements are documented for amino acid nutrition , but little is known about genetic differences for energy requirements. Also, lactating gilts have a very different intake pattern than a multiparous sow. Therefore, we will focus specifically on differences in intake patterns and learn how to compensate for potential deficiencies.

Example:

We are feeding gilts and the average body weight will be around 300 to 350 lb., with a daily feed intake of about 9.5 to 10.5 lbs. We estimate the daily metabolizable energy (ME) intake need at 14 Mcal/d (approximated from NRC, 1988). If the gilts consume 10 lb./d the ME content of the diet only needs to be 1400 kcal/lb. But if the gilt consumes 9 lb./d the diet must contain 1555 kcal/lb. The later is more likely to be correct. Another correction must be made for milking ability. Obviously, more energy is required for larger litters, and may increase the ME requirement to 14.5 Mcal/d. If this is the case, then for the gilt consuming 9 lb./d the diet must contain around 1600 kcal/lb. Typically, a range between 1525 to 1575 kcal/lb. is needed for gilts in lactation during the summer months, when intake is low. A more complete example is provided in Table 1.

Another consideration to feeding gilts during lactation is the level of feed intake during gestation. All to often producers over-feed gilts in gestation in order to put "condition" (almost always fat) on the animal prior to farrowing. It is a fact that fat animals do not perform well in lactation and there is an inverse relationship between gestation intake and lactation intake. Thus, if gilts are overfed during gestation they will most likely have difficulty farrowing, poor feed intake, and poor subsequent reproductive performance. Every producer should work on developing a body condition scoring system and a complementary feeding plan to alleviate potential fitness problems. All producers should work with their nutritionist, reproductive specialist, and Extension or feed industry professional to develop such a system.

Jeffrey A. Hansen

Number of acesses since May 16, 1996:
Last modified August 7, 2000.