The pig farmer, no matter how good, cannot do better than the animal’s genetic potential for production. Improvements in productive parameters can thus be achieved only by selection of animals with superior genetic make-up as the parents for the next generation.
Since the primary objective of pig farming is for meat production, the farmer must learn to select those animals that can be manipulated through breeding and management in order to tap that animal’s optimum potential for meat production.
For maximum performance, a systematic crossbreeding programme should be followed. The primary advantage of cross breeding is in the use of the cross bred dam which farrows and weans more pigs. On the average, cross-bred pigs gain more weight and are more efficient than pure-breeds. It is not as if there is an optimum number of breeds that a farmer can use in a crossbreeding programme but a practical recommendation is three.
It is advisable to select breeds that are somehow dissimilar in their characteristics for such cross-breeding.
Selection of Pig Breeding Stock
Select the breeding stock when the pigs are sexually mature (i.e. about five months. of age). Select from the same age group for their fair comparison. Good reliable indicators of the pig’s performance are traits such as growth rate and efficiency of gain.
- Growth Rate: Measured by determining the difference in weight at weaning and weight at maturity divided by the number of days. A good rule of thumb is to weigh the animals at two months and then at five months. The daily gain is the difference in weight divided by 90, the number of days in three months. At five months, the live-weight of a pig should be between 65-85kg. The rate of gain should not be less than 600g/day.
- Efficiency of Gain: A measure of how much feed was consumed to put on the weight gain. It is usually measured for a group of pigs. Add the total feed consumption of the group that was fed together and divide by the total weight gain of all the group to get the feed efficiency of the group.
- Litter Size: Is important, but it is a low heritable trait. Select breeders from among large, healthy and well performing litters.
- Conformation and Sex Characteristics: Pigs selected for breeding must be physically healthy, have good strong legs, be free from any defects and must not be too fat. It is important to note that the genetic influence of the boar on the next generation is greater than that of the sow since one boar will be used to mate several sows. Boars must have two equally sized and firmly suspended testicles, exhibit sex drive and be void of bad habits. Gilts must have a good underline and udder with at least 12 well spaced, fully formed teats.
- Other Selection Criteria: For the small-scale farmer, the above four criteria are adequate but for the large scale farmer and pig breeding or testing stations, other criteria are commonly in use. These include: furrowing rate, number of still born litter, average pig birth weight, pigs weaned per litter furrowed, average weaning weight, loin muscle area, carcass length, back fat depth, fat depth, percent lean, mortality rate at weaning and in growing finishing stage.