To yreriict the apytccriat vacanabon nine for piglet with various 1es of marital ansibcdy is a very important thing for the HC vaccination wogram in Taiwan. La (1%8) indicaJ that tie piglets withnaernalanubcdylevel1s than 1:8, wIn they were vaixinaril, could get xd immunity and maintain it for about six months, while the marital antilxdy tins higher than 1:16, they could not get good immunity. La (1%9) reporti that tie surnival rar of vaaxinati piglet was 93.75% in the group with colostralannkdy titers leas than 1:16,1(0% in the grouc with leas than 1:8, and 54.2% in the soup with tins higher than 1:32. For this xtons, how long wlU 1rs than 1:16 of mananal anti&dy of piglets, it was evaluaal in this report. The serum sample of sows and pglets were collect! from the areas of Pintung Kceshiung Tainan sub jxovizas and Taiwan Sugar Caporation (TSC). lie pcojxt were carrti out in three years, the studied in the firet aid the serxni year, tie five surti colc€inim and tow without sucker! piglets of sane litter, that from tie various level anti&dier of sows te sdect! at randsam. But tie studied in the third year we collni tie samplea inaUpigleis ofsairelittthatwerebonibythett of 1:128 aid F256of sows, Inause both tins 1:128 and 1:236 had chstribusiou signifbntly high acentage kysriwn in first and serxnd year in Taiwan.
The total numker of 5,767 serum sarns from sews and piglet with various levels of neutralizing annbzdr n evaluari for thnr HC neutralization antikdies, by rrean of Exaltation of NewcastleDisease Virus method (1D method) tlexnult were surrirnarii as follows:
1.i1nmeforpig1ett1osstheumthernalann1xlylevdto1:8orlessu20to30 days for piglets withUutialmarrnalantiSzdy*rs less than 1:16;4Oto5Odays, for piglet withtiters 1:3Ltol:128;andf0to4?tthysforpigletwithnterl:256or higher.
2.The variation of HC neutralization antilxdy tiers in sews fran Pintung area is 323% atannbcdy level 1:128,32.5% at 1:64, 22.5% at 1136, 12.5% at 1:16,7.5% at 1312, 5%ateither 1:4 or 132, aid 2.5% at eit)t 1:Sorl:1,024;inthceefroin Kceshiung area is 35.4% at level 1:128,25.8% at 1:256, 16.1% at 1:512. 11% at 1:16.8% at 1:1,024 ajxl3.1%atl:32;inthcsefromTainanaxeais 22%at 1:64 18%at 1:128, 14% ateitler 132or 1:256, or 1:512, 12% at 1:16,4% at 1:8, and 2% at 1:4;in those from TSC is 25.9% at 1:128, 16.8%at 1:23613.2% at 164, 12.1% at 1156,9.6% at 1:32, 7.2%atl:8,6.61%atl:4, 6.0% at 1:16, and2.4% at 1:1,2C$. T)eavera,ge disthrtion of reutralizanon anabcdy tins in sews from the areas is 27.3% at level 1:128, 17.6%dat 1:2.56, 15.4% at 164, 12.5% at 1:512, 8.4% at 1:32,6.3% at 1:16, 4.7% at 1:8, 4.4% at 1:4, and 1.9% at 1:1,024.
3.In first and second year of this gopt, a total of 2,88) serum samt coflet from 378 piglet at ety 10 days ‘ate evaluation for their HC neutralthng antibody. The
erctx1age of serum samks with antikdy tins 1:716 is 32.8% InthCGe cdkterl at 10 day-old, 53% at ) day-old, 71.6% at 30 day-old, 89% at 40 day-old, 96.4% at SO day-old, 98.6% atE0day-old, and 99.4% at’O day-old.
4 .The sane evaluation west psefonnel In a total of 2.56) sawn samples form 240 piglet czlkti in tlt third year, lit percentage dsenim samples with tins less than 1:16is 43% inthasecdlaisiat30day-d4 7)3% at40day-old, and93.3% at 50 day-old.
5.Acccdthg to & evaluan merticstI abwe the suitakk age for aglet to incculae HCvaxing was pitkaasfoUows: a. 2Oto3Oday-oMfctpiglets fixin sews with
bgannbdylevdl:16. b.40to50day-oldforthc6efroxnsows with antibdyntr lJ2tol:128.c. 6)to70thy-ddfcrthc6efrcmsowswlth 1136a higher.
6.Urder the condition in Taiwan, it was an&aani that 612% of piglet could gocd immunity I the HC vaccination were pSonrrd at 30 days of ag 83% while vaccination west talcesi at 40 day-oW, and 952% at 50 day-old. Acurding to the result of& studies, the goiamrait vaccination ogxam that vaccination with HC vaccire at 6 wk-oki of piglet is