The effect polyethylene intramammary devices on the somatic cell count and milk production of dairy cows

Polyethylene intramammary devices (IMD) were inserted into all 4 quarters of 15 multiparous dairy cows. Fifteen cows, matched for parity and production, were controls. The insertion of IMD's was easily achieved and produced no adverse effects. Throughout the 150-day test period, the mean somatic cell count of cows with IMD's in situ was 216,000 cells per ml, compared with 119,000 cells per ml in controls (P less than 0.01). Total production of milk, butterfat and protein was not significantly different between the 2 groups. The new infection rate was too low to allow assessment of the value of the IMD for mastitis prevention.