Well, some of this increase maybe due to the mild weather experienced over good portion of the country, we are encouraged that the improving trend we saw over the back half of 2011 continues into 2012, even if the growth rates do not sustain at the levels experienced in the first quarter. In contrast to the improving U.S. environment, in Europe we saw the organic growth rate for our Companion Animal businesses decreased to 5% as compared to 8% growth experienced in the fourth quarter last year.
Performance varies widely in the region with countries such as Germany and France showing strong performance and performance in countries such as Italy and Spain, reflecting the impact of their challenging fiscal situation. On balance we continue to believe that our businesses will benefit modestly from an improvement in the macro environment over the course of 2012 with 1% to 2% volume growth attributable to a more robust economy.
Now for some further detail on first quarter revenue performance of some of our businesses. VetLab Instrument and Consumable revenue of a $102 million, grew 9% organically. Sales of instruments were $20.5 million, also 9% organic growth. Our worldwide chemistry placements were up 20%, with solid performance by both Catalyst and VetTest.
This quarter’s growth is aided by the relatively easy compare we had versus the placements in the first quarter of 2011, prior to the launch of our protocol based rebate programs in the U.S., in the third quarter of 2011. As you recall, we saw an acceleration in the rate of placements in the U.S. in the back half of the year, due to the success of this marketing program.We also saw strong performance in our hematology placements with a combined placement growth of 25%. ProCyte remains an attractive choice for our larger customers and sales of new and recertified LaserCytes are continuing to do well in accounts with lower volumes.