Zoetis, pharmaceutical giant Pfizer's animal-health division, made a dramatic debut on Wall Street Friday as the biggest initial public offering since Facebook, AFP reports. The shares, trading under the symbol ZTS on the New York Stock Exchange, soared 19.27 percent to close at $31.01 a share. The shares had climbed 22 percent higher in morning trade. Zoetis generated heavy interest from investors after the group indicated Thursday that it had raised its initial public offering price to $26 after initially proposing a range of $22-$25. The IPO, with 86.1 million shares offered, raised $2.24 billion. It leaves Pfizer holding an 83 percent stake in the unit. An additional 12.9 million shares of Zoetis could be sold in a supplementary offering. If the additional allocation is sold, Pfizer's holding will be reduced to about 80 percent.