SHORT-COMMUNICATION Evaluation of perfused bovine udder for gene expression studies in dairy cows.

Intramammary infections are one of the main causes of productivity loss in dairy cows. To better understand the immune system response and to avoid the use of live animals, we validated the use of isolated bovine udder as an ex situ model. Six mammary glands were collected from cows ready for culling. Three udders were perfused with Tyrode's solution and three were not-perfused. During six hours, we collected perfusate samples for biochemical analysis. We also collected alveolar and teat canal tissue to evaluate gene expression. The biochemical parameters indicated that the perfused udders remained viable for the entire period of the experiment. A real-time polymerase chain reaction showed an increase in 18S rRNA gene expression in the alveolar tissue at 3 and 4 h after perfusion. There was also an increase in the Ubiquitin gene in the teat canal from not-perfused udders at 1, 3, and 4 h after slaughter. In general, gene expression was stable during the experiment. Our results indicated that the isolated perfused bovine udder model is appropriate for genetic studies, opening a new perspective in animal experimentation methods.