WEANERS
Once the little pigs have been weaned from their sow, they can be left in the follow-on pens or transferred to a weaner pool, depending on the system used in the piggery. A weaner pool has the advantage that litters are mixed together and have time to settle down before being moved into the fattening pens. In addition, the pens can be filled with pigs of equal size and if required, the same sex. It is always a good idea to fill a fattening pen with pigs of the same size so that there are no smaller pigs to be bullied and knocked back. Pigs should be treated for worms and, if necessary, sprayed for mange before being moved into their fattening quarters.
BOUGHT IN WEANERS
Producers buying in weaners need to take special care, because the move to a new farm imposes special stress connected with transport, sometimes over long distances, fighting and a change of environment and feed. Lastly, and perhaps most important, these pigs are exposed to new strains of disease organisms such as E.coli and certain viruses.
It is not often realised what a tremendous impact can result from this change in bacterial environment. Every pig herd has its own germ population. Piglets are born without the circulating antibodies that protect them from disease, but they obtain them from the sow’s colostrum and when 2 – 3 weeks old are capable of producing their own.
This immunity, however, only applies to the diseased environment on the farm where the pigs are reared, and does not protect them against the new strains of bacteria, and viruses they encounter when moved to other farms or when mixed with pigs from other farms. The effect is particularly severe when new organisms are encountered at the same time as stress, so it is not surprising that bought in weaners present a special problem. Nevertheless, there are some special rules of feeding and management which, if properly carried out, will ensure the pigs suffer no unnecessary setbacks. They apply to any pigs bought in at ages between 7 and 12 weeks.
If possible, buy weaners from one source only. They should already have been weaned two and preferably three weeks before the move.
Warm, clean and well bedded housing is important. If possible, house the newly arrived pigs well away from older fattening pigs already on the farm.
Feeding should be restricted, to start with. No food should be given on the first day; follow this by 700 gm. per pig per day for the first week. Then step up the feed to the full ration by the end of the second week.
If possible, arrange with the weaner producer for him to feed the same feed while the pigs are still on his own farm as they will receive at the new premises.
Medicated feed can often prevent troubles during the first 2 – 3 weeks. A mixture of drugs such as tylan and tetracycline is usually best, but always consult a veterinary surgeon first.
Mange can flare up in bought in weaners, so spray the pigs with a suitable dressing when they arrive. Similarly, routine worming is worth carrying out about 10 – 14 days after arrival.
2. PORKERS
Figure 2: Feeding and Growth Pattern for Pigs
Four fifths of the food used in a pig unit is consumed by the growing and fattening pigs, i.e. those between 8 weeks of age and slaughter. Clearly, food cost per pig is the first important factor affecting profits during this stage of production. The second factor is carcass grading which depends on thickness of fat. A pig having a K measurement of 25 mm is worth $10 more than one having a fat thickness of 32 mm, and the latter would have been produced at a loss. A third factor to be considered is growth rate, but unlike the other two its value is not so easy to quantify, but is clearly most important on farms where fattening space is at a premium.
Basically, there are two ways of feeding a bacon or pork pig. It can be given as much food as it will eat – usually from an ad lib hopper – or it can be fed a limited and smaller amount of food per day. Many comparisons of the two feeding systems have been made, and the results of a trial carried out in U.K. (see graph above) show the type of results that would be expected on a commercial farm.
| TABLE 1 – COMPARISON OF AD LIB AND RESTRICTED FEEDING (MAX. 2.3KG/DAY) | ||
| Ad lib | Restricted | |
| Total food/pig (kg) | 230 | 215 |
| Days in fattening house | 104 | 122 |
| Carcass weight for 90 kg pig | 151.8 | 150.0 |
| Fat thickness: Shoulder (mm) | 46.0 | 41.0 |
| Rump (mm) | 25.0 | 21.0 |
| % in top grade | 42.0 | 88.0 |
These figures clearly show that ad lib feeding leads to a higher food cost per pig, a faster growth rate, a higher carcass weight, inferior carcass grading. Thus a pig producer turning from restricted to ad lib feeding is likely to find that his food cost/pig would have risen and that his average carcass return would be reduced.
Such disadvantages far outweigh the advantages of better growth rate and better killing out % and labour saving, and thus ad lib feeding cannot be recommended for feeding pigs up to slaughter. There may be some farms that have strains of pigs that will grade well on ad lib feeding, but these will be the exception.
PART AD LIB FEEDING
Has ad lib feeding any place at all in bacon or pork production? In other words, how economical is an ad lib/restricted feeding regime. Creep feed should always be ad lib fed, and there is often an advantage in continuing the pigs on the self feeders for a week or two afterwards to keep them growing quickly. The optimum period of ad lib feeding will vary from farm to farm. Trials showed clearly that ad lib feeding to 50 kg was too long, because grading was adversely affected. The trials found that ad lib feeding until 10 weeks followed by restricted feeding was best. On other farms, this may not be so, and it is up to each producer to test himself which ad lib/restricted feeding regime suits his own circumstances. However, it is unlikely that there will be any benefit on any farm in ad lib feeding to pigs heavier than 35 kg. In fact, on many farms it pays to start restricting feed when pigs are 10 weeks old, as overfeeding beyond this stage can lead to poorer grades later on.
3. BACONERS
All bacon pigs kept for high quality bacon production must be restricted in their feed before going for slaughter. The type of feeding programme used will be reflected directly in the grades obtained for the finished pigs, and the aim must be to achieve at least 80% of Grade 1 baconers. Too much food will produce overfat pigs and poor grades. A good producer with a selected strain of lean pigs can afford to use the following system:
Up to pork weight: Ad lib feeding.
Pork to bacon weight: 2 kg/pig/day.
If the farmer decides to restrict the amount of food from 8 – 12 weeks onwards, various feeding scales can be used, and the farmer must experiment until he finds the feeding scale that suits his strain of pigs – measured by the percentage of Grade 1 pigs obtained and the number of days to bacon weight. One method is to restrict the pigs to what they will eat in two daily feeds of 20 minutes each, but this requires careful observation of the pigs during the time they are feeding.
Provided that the pigs are being weighed regularly e.g. once a week, feeding scales can be based on the average weights of the pigs in a pen.
| TABLE 2: WEIGHT TO FEED RATIOS | |||
Live-mass | Meal kg/day | ||
| Weaning to | 20kg | Ad lib | Weaner Meal |
| 20-25kg | 1.00 | Porker Meal | |
| 25-30kg | 1.20 | Porker Meal | |
| 30-35kg | 1.45 | Porker Meal | |
| 35-40kg | 1.65 | Porker Meal | |
| 40-45kg | 1.85 | Porker Meal | |
| 45-50kg | 2.00 | Porker Meal | |
| 50-90kg | 2.00 | Baconer Meal |
The maximum amount of meal fed per pig can be increased to 2,3kg a day in the winter, particularly if the pigs are housed in open pens subject to temperature changes. The extra meal will be used to generate body heat and will not affect the final grade.
An alternative method of feeding is to ration the pigs according to their age, and this can be used where regular weighing is not carried out.
| TABLE 3: RATIONS TO WEIGHT OR AGE RATIOS | |||
Age | Meal kg/day | ||
| Weaning to | 10 weeks | Ad lib | |
| 10-11 weeks | 1.3 | Weaner Meal | |
| 12 onwards | Increase by 0.11kg of meal per pig per week up to a maximum of 2.0kg in summer and 2.3kg in winter. |
The meals fed can be purchased weaner, porker and baconer meal, or they can be mixed on the farm from home grown maize and the appropriate concentrate.
FEEDING FREQUENCY
One is often asked “should pigs be fed once, twice, or several times daily”. With older pigs, there seems to be no advantage in feeding more than twice daily, but with 8 – 12 week old pigs it is sometimes worthwhile feeding three times daily.
This is particularly so if the pigs are backward and light for their age. Many comparisons have been made between once and twice daily feeding, and the following data from the U.K. are typical.
| TABLE 4 – ONCE OR TWICE-DAILY FEEDING OF BACON PIGS | ||
Once | Meal kg/day | |
| Growth rate (kg/day) | 0.6 | 0.55 |
| Food required to slaughter (kg) | 230 | 255 |
| Length (mm) | 805 | 807 |
| Killing out % | 73.8 | 74.8 |
It is seen that there is little difference in growth efficiency and carcass quality. However, killing out percentage is usually lower with once a day feeding, and this would more than offset the labour saving achieved. Thus twice daily feeding is recommended but one afternoon feed per week, can be omitted with no adverse effects, so long as the amount withheld is distributed between the remaining feeds each week.
WET OR DRY FEEDING
Many comparisons have also been made between feeding of dry meal in a trough or on the floor and wet feeding in a trough. In the great majority of cases dry feeding has resulted in a higher usage of food and a slower growth rate. The magnitude of the difference varies from farm to farm, but adoption of wet feeding on average means a saving of about 5% in food required and a saving of 10 days in age at bacon. Trials have also compared different rations of meal and water in a wet feed, and there is little difference in performance between a 1:1 by weight ratio and 1:4 by weight ratio of meal to water. In our experience, pigs prefer a 1 part by weight of water to 1 part by weight of meal mixture (approximately 2 parts meal to 1 part of water by volume) – i.e. add sufficient water to make a damp crumble. Whatever the feeding method, under African conditions, additional water should be given ad lib from a water bowl or from a separate trough.
Please take note: when wet feeding, never mix the water with the meal more than 30 minutes before feeding times, otherwise rancidity changes can occur in the meal leading to poorer performances.
FLOOR OR TROUGH FEEDING
Nowadays, floor feeding of pigs is becoming popular as it allows extra pigs to be kept in a given pen, and also because pen shape is less critical with floor feeding than when a trough is installed. Comparison has shown that there is little difference in performance between pigs fed dry food on the floor as compared to dry food in a trough. The one exception is when scouring occurs in the pen and the food on the floor consequently becomes contaminated, and aids in the spread of disease.
PEN SIZE
It is well known that fighting occurs when different pigs are mixed together. They do this to establish their pecking order and their social status so, once this is obtained the order remains as long as they remain together. This is one of the main reasons why the weight range within 2 groups of pigs in the same pen gradually opens out, even if the range is very small to start with. The other reason why we get this uneven growth is that some pigs eat their food quicker than others. For example, it has been shown that 30 kg pigs vary from 17 to 35 minutes in the time taken to eat 1kg of cubes. With restricted feeding of pigs in a group, it does mean that some pigs eat more food than others – some get more than their share and others less. The larger the group of pigs the bigger the variation and the weight spread as time goes on. This leads to more total food intake per pig with large groups than small.
Research has found that pigs in pens of 14 – 16 take an average of 12 days longer to reach bacon than pigs penned in groups of 7 and 8 and this has also been proved in the U.S.A. Therefore, large pens should always be avoided for fattening. The ideal would be very small pens, but this is impractical and pens of 7 – 9 are the most satisfactory.
SEGREGATION OF SEXES
When mixed groups of hogs and gilts are fed on a restricted scale such as 5lb./pig/day, it is likely that on average the gilts eat 4 – 4lbs. while the hogs eat up to 5 ½lbs. Thus, the more voracious appetite of the hogs exaggerates fat thickness of their carcasses, which is, in any case, inherently greater than in gilts.
Therefore, there is a good case for penning hogs and gilts separately. It will lead to the hogs grading better because they will not eat of the gilts allowance, and will lead to the gilts growing faster because they have more food. It is impractical to separate sexes on small units, but in larger units it is well worth the extra effort at the beginning. This is one of the advantages of multi-suckling – it provides a large mixed group of weaners, from which pigs of the same sex and approximately the same weight can be drawn off into the fattening pen.
