Growing Pig
Targets for the weaned pig
The weight of the piglet at weaning will depend on many factors, for example, age, birth weight, genetics, sow nutrition and husbandry, litter size. Beyond 20 days of age the piglet suckling a sow is capable of growing at a rate of 300 g/day if conditions are right and yet in the immediate post-weaning period growth is often minimal.
For the piglet weaned at 6 kg at 25 days one would expect a minimum growth of 150 g/day in the first week, 300 g/day in the second week and increasing to 500 g/day or more over the subsequent 2 weeks. This would give the modest achievement of 16-17 kg at 4 weeks' post weaning (53 days).
Feed conversion over this stage should not exceed 1.3 and mortality would be expected to be below 1.5 percent.
Feed availability
Prior to weaning piglets will have become established on a teat and the complex social interaction between sow and litter will stimulate and provide feed (that is, milk) for the whole litter. At weaning feed and water supply whilst available ad lib will present a major obstacle to the piglet. There is no stimulation to feed and all piglets can rarely feed together resulting in erratic intake.
This problem can be overcome with a number of 'tricks".'.
- Hand feed 3 to 6 times a day for the first week after weaning, preferably using gutter troughs.
- Provide bowled water for pigs in the first week.
- Feed gruel or porridge to weaned piglet twice daily.
- Ensure floors are comfortable to encourage pigs to get up and feed or drink.
- Address stocking rates to avoid excess competition for feed space and fighting.
Ensure diets are fresh and palatable at all times - remember that creep diets contain high levels of oils that will oxidise easily at high temperatures; at best this will reduce feed intake; at worst it will cause major gut upsets.
Energy requirements
Energy is required for both growth and maintenance. If provision falls below maintenance levels then energy will be mobilised from the body to compensate.
The greatest challenge to the weaned pig is the maintenance of body temperature, which is a balance between heat generated and ambient temperatures. The textbooks will tell us that the lower critical temperature (LCT) for a newly weaned piglet group housed on slats with ad lib feed is 30°C. However, this is frequently not achieved at pig level as a result of inadequate heat provision and insulation, draughts etc. The use of lying mats or even kennels for newly weaned pigs will reduce the LCT by at least 3°C and have the added benefit of improving comfort on fully slatted floors.
In straw penned weaning accommodation sufficient warmth can be equally difficult to achieve in the absence of an external source of heat and this should not be precluded.
To minimise the challenge of microbes to the newly weaned pigs, the following standard rules of husbandry should apply:
- Operate to high standards of hygiene within buildings.
- Operate an all in, all out policy.
- Minimise the age variation within a population. (The wider the age range, the greater will be the variance between pigs with respect to immunity, colonisation of tonsils and active replicating infection). The effective weaning age is the age of the oldest pig.
- Minimise group size within a single air space, providing adequate space for piglets and sufficient fresh air to remove restorable microbes, dust and waste gases.
