Effect Of Different Birth Order On Sow Reproductive Performance And Economic Benefits

Sow reproductive performance was affected by variety, feed, feeding and management, age and birth order. As the development of the swine industry, influence of birth order on sow reproductive performance was more and more pay attention. This thesis is dealt a pig farm of Zhejiang province, analysis statistically effects of different birth order on sow reproductive performance.The results showed that:(1)The litter weight at birth express low in the1st birth, gradually increase in the2nd to5th birth, and reduced after6th birth.(2)The litter size and litter alive size increase with the birth order from the1st to the6th birth, peak in the4th to6th birth, then decrease after the7th birth.(3)The number of abnormal piglets in the1st birth is significantly higher, compared to the2nd to7th birth, and no significantly different between the others birth order.(4)The conception rate in the1st and9th birth is significantly different to the2nd to7th birth.(5)The delivery rate in the1st,9th and above9th birth is significantly different to the2nd to6th birth. The abortion rate in different birth order is not significantly different.(6)The interval from weaning to mating express the longest in the1st birth, which is significantly different to the others birth order, decrease from the2nd to6th birth, fluctuate after the7th birth.(7) The incidence rate of sow metritis, non-estrus or post-estrus after weaning, non-pregnant after mating, death or sick birth piglet, mastitis and limb hoof is increased with the increased birth order.(8)The difficult birth is always happened in the1st birth or the older sows.Summarization above results:There is a certain effect of birth order on in the different varieties of swine. Generally, the reproductive performance is expressed lowest in the1st birth, and raised from2nd birth, then peaked highest in the4th and6th birth, finally decreased in later birth. Therefore according to the effect of the different birth order in reproductive performance, the sow age and parity structure should be timely adjusted in the scale pig farms. The peak reproductive period should be used to maximize the reproductive performance of sows, and to improve the farming economic benefits. The birth order with the3rd to7th birth should reasonably obtain60%of age structure in the intensive pig farms, the1st and2nd birth shouldn’t exceed30%, the7th birth shouldn’t exceed10%. The production sows after the7th birth should be gradually eliminated, the high quality sows should be replenished into sows group in order to maintain a reasonable gestational age structure.