WESTBROOK — Idexx Laboratories Inc., which makes diagnostic products for veterinarians and tests for livestock and poultry, said first-quarter earnings rose 12 percent, but its results fell short of expectations and it cut its full-year growth outlook.

First-quarter earnings totaled 81 cents a share, up from 72 cents a share compared with the same period a year ago. Revenues rose 3 percent to $332.1 million.

The company said revenues in its pet group rose to $276.9 million from $268.1 million. Idexx attributed the growth to higher sales of consumable products used with its Catalyst Dx chemistry instrument and an increase in prices in its reference laboratories. This growth was partly offset by lower revenues from its capital equipment segment.

Revenues from its water-testing products totaled $20.7 million, up from $19.6 million, driven by higher sales volume of Colilert in Europe and Latin America. Colilert detects coliforms and E. coli in water in 24 hours.

Livestock and poultry diagnostics revenues fell to $28 million from $29.1 million a year ago. Idexx attributed the drop to lower sales of its Dairy SNAP tests used for the detection of contaminant and antibiotic residues in milk.

For all of 2013, the company cut its growth outlook. It now expects revenues to be in the range of $1.38 billion to $1.39 billion. It cited currency fluctuations, as well as an expected reduction in capital equipment sales. Earnings are expected to be in the range of $3.40 a share to $3.46 a share, compared with previous guidance of $3.47 a share to $3.57 percent.

Shares of Idexx fell $3.35, or about 3.7 percent, to $86.65 in trading Tuesday.