Intramammary Response to Modified Intramammary Devices1,2

Abstract

Twenty-five cows in three experiments were used to evaluate the following intramammary devices: abraded surfaces; abraded and sulfur hexafluoride-coated, abraded, sulfur hexafluoride-coated, and weighted; and smooth surfaces and weighted. The objectives of the experiments were 1) to determine whether coating the abraded intramammary devices prevented amorphous deposits and bacterial adherence on the devices, 2) to determine whether addition of weight to devices increased the concentration of somatic cells in milk, and 3) to evaluate milk production and response of mammary epithelial cells to the devices.Milk SCC and NAGase (EC 3.2.1.30) from quarters fitted with devices were increased in quarter bucket and stripping milk, but increases were similar among all devices. Macrophages were the pre-dominate cell type in quarter milk before insertion and neutrophils after insertion. Moderate to heavy deposits of amorphous material were observed on all devices, regardless of time residing in the gland. Approximately 50% of the devices were colonized after intramammary inoculation with Corynebacterium bovis. Milk production in control quarters and in quarters with devices were similar. Neither coating with sulfur hexafluoride nor addition of weight to devices reduced amorphous deposits or bacterial adherence or enhanced milk somatic cell response.