Question:  query regarding  artificial insemination of pig 
Answer:  artificial insemination  can be perform in pig , but there are some restriction , since sow is prolific [to obtain  high litter size ] , natural mating is mostly preferred with selective boar / the numbers of ova arelase at a time in case of sow , a large volume is required to fertilize the ova , so 2 nd mating is done in case of sow to get large litter size , drawback is that all ova are not release at a time & they do not  reach the ampullary region within specific time , so 2 nd mating is necessary , artificial insemination is sow can also be practise in sow  with  sofisticated technique , where large volume of sperm will required, with large straw & extender [  probably sofisticated  a.i will required in a sow in different time within two days of oestrous , already a. i is introduce in some state & in near future a.i can be performed  here also by following specific technique& method , research is going on in this field