MANAGEMENT OF THE PREGNANT SOW
The gestation period, and the period between service and giving birth, for a sow is 114 – 116 days, or 3 months, 3 weeks and 3 days. During this period, the feeding and management of the sow is important to ensure that the maximum number of piglets develop and grow inside her, so that she farrows down with a good, vigorous and healthy litter.
It is impossible to lay down absolute rules concerning feed rates during pregnancy as conditions on farms vary. Also it is important that the pregnancy stage alone is not considered, as the entire pregnancy/lactation stage must be considered as a whole. Generally speaking, it is better, from many points of view, to feed sows well during lactation. This will ensure a good supply of milk to the litter whilst also ensuring the sow does not lose too much bodyweight. In addition, as mentioned above, flushing during weaning to service period will also help to correct the loss of bodyweight that was occurring towards the end of lactation. As a guide, it is often quoted that a sow should gain 10 to 15 kg between each litter, at least for the first 3 – 4 litters.
|Weaning: to remove a young animal from the milk source of its mother.|
Quite a lot of work has been done on the relative feed levels during both pregnancy and lactation. The conclusions of this work seem to be that the ideal is to feed on a low plane during pregnancy and a high plane during lactation. This system will reduce the bodyweight loss of the sow and will even out the fluctuations in bodyweight over the entire pregnancy/lactation period. It will also mean that the sow will not be too fat and heavy at farrowing. This means that problems over farrowing are less likely to occur.
The quantities of meal fed during the pregnancy period are:
|Weaning||No feed for 24 hours and restricted water to dry off the milk.|
|Weaning to Service||3.7 kg of meal to ‘flush’ the sow so that she produces the maximum number of eggs at ovulation.|
|First 12 weeks of pregnancy||1.8 – 2.7 kg of meal per day depending on the size and condition of the sow.|
|Last 3 weeks of pregnancy||Increase meal to 2.3 – 3.2 kg per day.|
During the gestation period the sow should be fed properly and, unless she is housed in a sow stall, she should have plenty of exercise. Dry sows can be run together in yards or run outside in paddocks that are well fenced and supplied with water. It is important to avoid any physical damage to the sow, caused by fighting, trailing through deep mud or jumping or squeezing through fences. Other factors to consider are:
- Sows that are running outside should be brought in for their extra feeding 3 weeks before they are due to farrow. Sows in yards should, in any case, have individual feeders so that they all get their fair share of food.
- One week before a sow is due to farrow, she should be brought in to her farrowing quarters, and if crates are used she should be put into the farrowing crates. At this stage it is good practice to wash the sow with clean water and rinse her with a proprietary solution to kill any lice, fleas and other parasites. De-worm against internal parasites. This means that the sow is clean when she goes into the farrowing house and will not introduce parasites into the house.
- 24 Hours before farrowing give the pen a good clean and litter with chopped straw or wood-shavings; never use long straw or hay for litter because this will prevent the little pigs from moving about in the pen. Switch on the infra-red lamps so that the sow gets accustomed to the light.
Figure 1: A Farrowing Pen
Signs of the sow being about to farrow are:
- The vulva becomes red and swollen;
- The sow becomes restless and will attempt to build a nest; and
- Milk appears in the udder and drips or runs from the teats.
During the farrowing of the sow, the pig farmer should watch out for the following points:
|Farrowing: the act of giving birth to piglets.|
- Make sure that the sow is not constipated at the time of farrowing. If she is, feed a wet bran mash;
- Watch the sow during farrowing, but do so quietly and from some spot out of her sight;
- Do not interfere with the sow unless she appears to be in trouble. Occasionally a piglet will become stuck in the birth canal and has to be removed by hand, but this calls for experience on the part of the pig farmer. If in any doubt, send for the veterinary surgeon;
- As the little pigs are born, they will go to a teat and suckle. Once each pig has had a drink, it should be removed and placed in the nest under the infra-red lamp. Do this quietly and try to stop the little pig from squealing as this will upset the sow;
- Watch for the sow’s cleansing and remove this before the sow can eat it. The appearance of the cleansing is the end of farrowing and no more piglets will be born;
- Once the farrowing is over and the little pigs are fed and settled in their nest under the lamp, it is a good idea to give the sow 10 – 15 minutes of exercise. A short walk is all she needs and she will not stay away for long from her little pigs;
- Make sure that each pig has a teat e.g. a sow with 14 teats and 16 little pigs means that 2 piglets cannot suckle. The pig farmer should make sure that the extra piglets get a drink of colostrum for at least two days and then either mother them on to another sow or rear them by hand;
- Watch the litter for teat biting and fighting at feeding times; and
- The average weight of a piglet at 24 hours old is 1,5kg.
At farrowing the sow produces colostrum which is rich in:
|Antibody: a protein which is produced in the body in response to foreign substances such as bacteria or viruses.|
The protein of colostrum is also rich in the amino acids lysine, valine and threonine. These are essential amino acids for pigs and they are also important constituents of the immune proteins or antibodies which help to guard the little pigs against infection, particularly scours.
Colostrum lasts for about 5 days and then changes into normal sow’s milk made up of:
Total Solids 20.0%
The peak milk yield of a good sow is 4,5 litres a day at 3 weeks after farrowing. After this peak the milk production begins to decline slowly.
One very important point about sow’s milk is that it is deficient in the mineral iron, and little pigs have a very small storage capacity for iron. A lack of iron will cause the piglets to become anaemic because of a shortage of red blood cells which require iron for their manufacture. This is why it is essential to inject or dose little pigs with proprietary solutions of iron 3 days after birth. If this is not done, many of the litter will die from anaemia before weaning.
The aim of a good pig farmer should be to achieve:
- A high birth weight of the little pigs by good feeding and management during the sow’s pregnancy.
- A good number of little pigs born.
- A good milk yield from the sow so that the little pigs have a high weaning weight.
- Provide a good quality creep feed for the little pigs.
FEEDING THE SOW
At the first feeding time after farrowing, the sow should be given only water and then the feed should be increased each day up to a maximum ration. The sow must be fed very carefully for the first two weeks after farrowing as she is likely to have a poor appetite and go off her food.
Systems of Feeding
|Feed 1 – 2 kg of meal a day for the sow plus 0.45 kg of meal for each of her little pigs.|
|Sow + up to 8 pigs – 1.5 + 0.45 x 8 = 1.5 + 3.6 = 5.1 kg |
Sow + up to 10 pigs – 1.5 + 0.45 x 10 = 1.5 + 4.5 = 6.0 kg
Sow + up to 12 pigs – 1.0 + 0.45 x 12 = 1.0 + 5.4 = 6.4 kg per day
|Meal plus some green food|
|Sow + up to 8 pigs – 3.5 kg meal Sow + up to 10 pigs – 4.5 kg meal Sow + up to 12 pigs – 5.5 kg meal||Plus 2 – 2.5 kg of green food or 1 hour of grazing good pasture.|
|Meal plus full grazing on good pasture|
|Sow + up to 8 pigs – 1.5 kg meal Sow + up to 10 pigs – 2.5 kg meal Sow + up to 12 pigs – 3.5 kg meal Over 12 pigs||Plus full grazing on good pasture, giving the sow about 12 kg of grass a day.|
|Meal plus boiled potatoes|
|Sow + 10 pigs – 2.75 kg meal plus 12 kg of boiled potatoes a day.|
High daily energy intakes and good quality protein can give up to 20% increase in milk yield at the peak stage of the yield.
This is the feeding of high protein meal or pellets to young pigs during the time they are suckling the sow, and for a short time after they have been weaned. The creep feed should be fed in a corner of the pen out of reach of the sow. The feed should be highly palatable with a crude protein of 20%, and can be in the form of meal or pellets. Creep feed meal or pellets can be obtained from a food merchant, or the farmer can buy a pig creep feed concentrate and mix this with equal parts of ground maize by weight. The creep feed should be introduced to the young pigs when they are 1 week old by scattering some meal or pellets on the floor of the pen. Once the little pigs get the taste of the meal, they can be fed from a trough. Feeding should be ad lib, and fresh meal put into the trough twice a day; any old meal should be removed and the trough cleaned out to avoid the meal going sour. Once the piglets are 5 weeks old, the creep feed meal can be gradually changed over to growers meal so that by 8 weeks old the pigs are eating growers meal only. It is important that the little pigs have access to clean drinking water from an early age, available in a shallow trough or drinking bowl so that they do not fall into the water and drown.
The following should be carried out during the suckling period:
|7 days old||Introduce creep feed.|
|9 days old||Move the sow and litter from the farrowing house into a follow-on pen. A good idea is to have 2 pens next to each other with a small hole through which the little pigs can move between the two pens. The sow sleeps and eats in one pen and the little pigs in the other pen, but they have access to the sow for suckling.|
|see image below table|
|21 days old||a) Weigh each piglet and record its weight. b) Count and record the number of teats on each piglet. c) Ear notch all piglets with numbers so that their performance can be followed through to slaughter. d) Castrate all male pigs, using a scalpel or razor blade.|
|4 weeks old||Introduce growers meal into the ration.|
|5 weeks old||Weigh each piglet. If they are mainly over 9 kg each, the litter can be weaned. Remove the sow from the pen and leave the piglets behind in their pen for at least 2 weeks to reduce weaning stress.|
The 2 – 3 week period immediately after weaning is one of the most critical in the pig’s life and to understand the problems involved, consider the habits of wild pigs. In the natural state a wild sow will find a quiet corner to make her nest and to farrow on her own. She will rejoin the herd a week or two after farrowing and the litter by then would have learnt how to root for its food. The piglets, however, will continue to get their mother’s milk until they are, perhaps, four months old and the sow is pregnant again.
In other words, in the natural state, weaning is a gradual process and is not fully complete until the pigs are relatively old. As pigs have become domesticated, man has imposed many changes on their natural habits. Perhaps the most critical is to wean earlier and more suddenly.
|Bowel oedema: a bacterial infection of pigs associated with sudden changes of diet and management. Pigs may throw fits, stagger and become paralysed.|
Weaning always results in some stress on the piglets, regardless of what age it is carried out. This stress results in bacterial changes in the gut of the pig. Coliform numbers rise sharply and this in turn is often associated with problems such as gastro enteritis, bowel oedema, growth checks and sometimes death. Proper attention to detail and following a few fundamental rules will reduce this stress and have a marked effect on the health of the weaner and its subsequent progress in the fattening house.
WHEN TO WEAN
Traditionally, pig farmers have weaned their pigs at about 8 weeks of age, when the digestive systems of the pigs are mature enough to digest a new sow and weaner type of ration. With our modern knowledge of nutrition, however, creep feeds can be formulated which are digestible and palatable enough for pigs to be weaned earlier, and weaning at 5 – 6 weeks is now common. The degree of management skill needed is about the same as 8 week weaning. The sow needs a little less food because she is suckling for 2 – 3 weeks less and the fact that she is mated earlier means that she should produce two litters per year. Thus, under normal farm conditions 5 – 6 week weaning is recommended with backward litters being left to 6 weeks rather than weaned at 5.
Pigs should be handled and disturbed as little as possible before weaning. Castration, ear marking, iron injections all impose stress and it is a good rule to get these over and done with well before weaning time – certainly two weeks before and preferably earlier.
To reduce the stress of weaning, ideally it should be done gradually and some farmers remove the piglets from the sow for progressively longer periods during the last week or so. In most cases, however, this is impractical from the labour point of view and weaning is a sudden process. The shock, however, is much less if the piglets are eating their creep feed well at weaning time.
Whenever possible, wean by removing the sow and leave the litter in the pen they were reared in for at least two weeks. If for some reason, the litter must be moved on weaning day, make sure that it goes into a warm, well bedded pen and do not mix the litter with others for at least two weeks.
As described above, creep feed should always be given to a litter from 1 week of age. The type of creep feed required depends on age at weaning. For 5 – 6 week weaning, a specialist 20% protein feed is needed, and this is given ad lib over weaning. During the 8th week, gradually introduce the 16/17% grower ration so that by 8 weeks of age the little pigs will be entirely on this feed.
With 7 – 8 week weaning, it usually pays to use a specialist creep feed, but this can be changed to the grower ration before weaning, as long as the change is gradual and has been completed for about a week before weaning. Alternatively, the grower ration can be used as a creep feed from the beginning, but the litter will not be as heavy at 8 weeks as if the specialist creep had been used.
As mentioned earlier, newly weaned litters should not be grouped together until two weeks after weaning. Limit the group to three litters at most, and keep a careful watch for the after effects of the move and the mixing. Do not overfeed and allow plenty of clean water. Cut down the feed for a day or two if scouring starts, and make sure the pen is warm and use bedding if available.