Idexx Laboratories Inc., which produces diagnostic tests for livestock and poultry, and tests for water and milk safety, has posted higher-than-expected first-quarter earnings and revenues. It also raised its outlook for revenue growth for the year.

The Westbrook-based company said first-quarter net income totaled $46.6 million, 89 cents a share, compared with $44.9 million, 81 cents a share, in the first quarter of last year. The earnings per share exceeded Wall Street’s expectations of 87 cents.

Revenues increased 10 percent, to $360.2 million, up from $332.1 million a year ago. The company said its revenue growth was driven by gains in its pet group. Idexx also said it had strong double-digit growth in Europe and Asia Pacific, and 8 percent growth in its North American business.

Revenues for the pet group totaled $301.6 million, compared with $276.9 million for the first quarter of 2013. Water product revenues rose to $21.4 million, from $20.7 million, while revenues for livestock and poultry diagnostics increased to $31.4 million, from $28 million a year ago.

For the full year, Idexx raised its revenue outlook slightly. It now expects revenues to be in the range of $1.495 billion to $1.51 billion, compared with its previous forecast of $1.48 billion to $1.50 billion. Its outlook for earnings remained unchanged from earlier forecasts, which called for earnings in the range of $3.76 to $3.86 a share.