Stage of Breeding Affected | |||
---|---|---|---|
____________________________________________________________ | |||
Proven or Suspected Factors | Puberty | After Weaning | After Service |
Insufficient male stimulation | +a | + | −b |
Housing and social environment | + | + | + |
High ambient temperature | + | + | + |
Season of year (summer/fall) | + | + | + |
Photoperiod | + | ?c | − |
Genotype | + | + | − |
Nutrition | + | + | + |
Short lactation | − | + | − |
Large litter reared | − | + | − |
Adapted, with permission, from Meredith MJ, Pig News and Information 5, 1984, published by CAB International, Wallingford, Oxon, UK. | |||
a Effect has been demonstrated | |||
b No evidence for effect | |||
c Effect uncertain |