Comparision of Estradiol-17.., Progesterone and Litter Size among Primiparous Sow Breeds Weaned after Lactation for 7 or 21 Days.
2003
Kim J.S | Kim H.K. | Yang C.B. | Son D.S. | Lee S.H. | Yi Y.J. | Park C.S
This study was carried out to find out the changes on serum concentration of estradiol-17.., progesterone in primiparous Duroc, Landrace and Yorkshire sows weaned at 7 or 21 days. Also, we compared the litter size at birth and weaning among the breeds weaned after lactation for 7 to 21 days. The estradiol-17.. concentrations among the breeds were 6.9~8.8 pg/ml and 6.4~8.8 pg/ml after lactation for 7 or 21 days, respectively. The progesterone concentrations ranged from 0.3ng/ml to 1.6 ng/ml. Duroc sow showed higher progesterone concentration compared with Landrace and Yorkshire sows weaned after lactation for 7 or 21 days . Also, we found out that litter size at birth and weaning , respectively, did not show any differences between day 7 and day 21 of lactation. From the facts menitoned above, it was suggested that very early weaning systems could work with no apparent adverse effect on prolificacy.
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