Reproduction of Pig

 

Selection of boars for breeding purposes
  • They must be offspring of better producing gilts and sows.
  • They must belong to a litter with size and weight of not less than 8 and 72 kg respectively at weaning.
  • Boars satisfying above stipulations are subjected to preliminary selection at 5 months of age provided they have a body weight of at least 60 kg.
  • Final selection of boars should be undertaken at 7 months provided it has attained a body weight of at least 90 kg.
  • Must be free from physical defects.
  • Breeding males and females should be selected from different litters and boars should be changed periodically preferably once in two years for avoiding inbreeding.
Management of boars
  • Although boars reach sexual maturity at 7 months of age, it is generally recommended that they must be at least 10-12 months (100 kg body weight) before being put to regular use.
  • Boars should be fed after service rather than before.
  • Boar: sow ratio may be 1:25.
  • Outdoor exercise is good for keeping the boar thrifty and virile. He should neither be over fat nor run down. The boar may be handled firmly but gently, keeping in mind that he can be dangerous.
  • Each boar should be housed separately.
  • Number of services for boars: 2 - 4 per week depending on the age of boar.
  • Boars should be tested for brucellosis and leptospirosis periodically.
Breeding Females
  • Gilts: Breeding pigs are selected from mother pigs having good mothering ability as shown by large litter size and weight at weaning. Gilts should have 12-14 evenly spaced sound teats, good growth rate and feminity.
  • Weaned sows: Sows are usually weaned at 8 weeks after farrowing. The weaned sows come into heat in 3-10 days after weaning. They may be bred on the first post-weaning heat itself since this period is most fertile. She may respond to nutritious diet and pick up fast if the condition is poor.
  • Pregnant sows and gilts: In addition to having proper nutrition, the pregnant animals should be provided with regular exercise. Forced exercise may be brought about by feeding some distance away from the house or inducing the animal for moderate walk. Sows of the same size and condition can be run together. The bred and gilts may be housed separately. Do not house boars along with pregnant stock. Avoid overcrowding, mixing of new and old stock, slippery ground and overexciting of pregnant pigs.

Breeding chart for pigs
Item Male Female
Mean Range Mean Range
1. Age at puberty (months) 7 6 8 6  5 - 7
2. Age at which the pigs can be bred (months) Approximate body weight (kg) 11
-
10 12
80 110 kg
9
-
8 10
80 100 kg
3. Oestrous cycle     21 days 18 24 days
4. Oestrous period (days)     2 days 2 3 days
5. Signs of heat Restlessness, grunting, champing of jaws, swollen vulva, mounting on other pigs, standing still when mounted or pressed on the back.
6. Apt time for mating 24 hours after the onset of heat symptoms. Second mating is advised 8-12 hours after the first mating
7. Gestation period   114 days 111 117 days
8. Farrowing time   3 hours 2 12 hours
9. Litter size at birth   8 no. 6 12 no.
10. Birth weight   1.3 kg 1 2.5 kg
11. Suckling period   56 days -
12. Post-weaning heat in sows   5 days 3 10 days
 
References Kerala Agricultural University. 2001. Package of Practices- Recommendations: Veterinary and Animal Husbandry, Kerala Agricultural University, Trichur. .