Factors affecting litter size

1. Hormonal stimulation
2. Gilt selection
3. Boar stimulat
4. Flush-feeding

   Nota:

   • Flush feeding is over feeding about 10 days before mating and then limiting food.
5. Body condition
6. Nutrition

1. Semen quality
2. mating technique
3. Stockmanship

1. feeding post mating
   1. 3.5 body condition score
2. Vitamins and minerals
3. Stress

Nota:

• There are usually 9-12 piglets born, with a mean of 11.5. The range is 3-22+ Does nature play a role in still borns as litter sizes are often 15, 16 but there are only 14 teats.

1. Stillborns
2. body condition

   Nota:

   • Piglets have no brown adipose tissue so they struggle to thermoregulate when born.  By utilising body glucose for heat production the piglets are susceptible to hypoglycaemia and hypothermia. 
   • At birth,  Protein = 16% of body content Glucose = 3-3.8% Fat = 2%
3. housing
4. nutrition

1. pre-wean mortality
   1. 10-30% (mean 15%)
2. milk yield
3. nutrition
4. apetite
5. health status
6. supplementary piglet nutrition
7. spacing and size of teats

1. wean-mating period
2. empty days

   Nota:

   • Bottom 1/3 = 53 days Average = 37 days Top 1/3 = 26 days Top 10% = 13 days 
3. nutrition
4. boar effect

   Nota:

   • Exposing the gilt/sow to a boar can be used to resync the estrus cycle. Can also mate with a vasectomised male to increase litter size. Aborting the gilt - back in cycle in 96 hours. 
5. stress
6. body condition
7. parity
8. herd management