Many farms today feed separate lactating and dry sow rations. The latter with digestible energy ranging from 13 to 13.6MJ DE/kg and protein levels of 13 to 14%. It is beneficial from 3-21 days post mating to optimise feed intake relative to the sows demand since this will satisfy the nutritional requirements for the development of the placenta. This is pertinent where farms have variable weights and quality of piglets at birth. The development of the placenta in the first 12 to 25 days post mating helps to determine the quality of the piglet at the end of the pregnancy. A small placenta will contribute towards a small pig. The availability and intake of feed in this respect is important, for example where sows are fed in groups. If there is a shortage of trough space, nutritional insufficiencies can occur in the under-privileged females. During the pregnancy period the sow should be fed to body condition but also to satisfy the environmental needs. Thus it is difficult to lay down specific levels of feed intake per day, they must be determined by the stockperson. The body condition of the sow can be assessed on a numerical rating of 1 to 5 and to do this the flat of the hand should be placed over the back bone just forward of the root of the tail and rolled laterally side to side. The condition of the sow can then be scored Fig.14-16.

As a guideline sows approaching the point of weaning should score around 3. This should rise to 3 1/2 or possibly 4 in older sows by the time of the next farrowing. Sows scoring 2 1/2 or less are moving into a problem area. If more than 5% of sows at any one time score 2 1/2 or less then feeding levels are wrong. If sows are allowed to farrow with a score of less than 3 there will be insufficient fat reserves to maintain lactation and they will use muscle as a source of energy. Such sows are then in danger of developing the thin sow syndrome, being unable to maintain body condition with the demands of lactation.

In outdoor herds it is important that all sows should score over 3 before the onset of winter. It is difficult to improve body condition in cold weather. Feed levels should be higher during winter than in spring or summer.

Key points to maintaining longevity in the breeding female

• Use the correct female, that is, one expressing maximum hybrid vigour.
• Select or purchase females with sound strong legs, good teats and not too heavy hams.
• Avoid gilts showing any signs of leg weakness e.g., standing on their toes, the back legs tucked under, the front legs bent or the pasterns dropped.
• Do not breed from a female that is too lean. Maintain at least 17mm of fat at the P2 measurement by point of mating, particularly in the gilt.
• Do not serve the gilt at less then 210 days of age. Gilts served too early will still be maturing into their second pregnancy. Equally do not serve too late (240 days) otherwise body size will increase.
• Do not allow excessive body weight to develop during the first pregnancy.
• Provide the pregnant gilt with exercise during the first half of the pregnancy if possible.
• Avoid mouldy feeds.
• Do not cull a sow if her first two litters have been poor. Review management procedures.
• Feed the sow from three days post farrowing, during lactation, and to point of mating to appetite.
• Do not serve maiden gilts or first litter gilts with heavy boars. This can precipitate leg problems.
• Identify sick or lame sows early and remove to a well bedded hospital pen. Many will simply recover in a better environment.
• Good nutrition is vital.