Abstract

Lactoferrin (Lf) is a high value, low concentration protein found in milk. Lf concentrations are found to increase during mastitis. This study was instigated to investigate if the effect of inducing sterile inflammation of the mammary gland, using lipopolysaccharide (LPS), a component of bacterial cell walls, would be a useful physiological model to study the production of Lf. Ten multiparous Friesian-Jersey cross-bred (FxJ) cows (approximately 200 days in milk) with no recent history of mastitis were utilised. All cows were milked on an individual quarter basis, and milk samples were collected one week prior to the treatment date to provide covariate data. Eight cows were infused via the teat canal with 10 ml saline and 10 μg LPS in 10 ml saline into 2 random quarters on each cow. The other two quarters on each cow were not treated. Two cows were untreated controls. All cows were milked twice daily with milk samples collected individually from all 4 quarters for 7 days with additional samples collected at 14 and 21 days. All milk samples were analysed for gross composition (fat, protein, lactose), somatic cell count (SCC), conductivity and Lf concentration. At the first milking after treatment, LPS treatment showed a significant effect on all milk components measured. By the 4th milking after treatment Lf concentrations were approximately 3.5 fold higher in LPS treated quarters compared with saline infused quarters, and remained elevated until 7 days after treatment. SCC remained elevated (P < 0.01) in the LPS treated quarters until day 7 also. These results show that LPS can be used to induce the production of Lf in lactating cows and therefore provides a model with which to further investigate the mechanisms that control Lf production. KEYWORDS: lactoferrin; lipopolysaccharide; endotoxin; somatic cell count; conductivity; milk composition.

S-A, Turner, and NA Thomson

Proceedings of the New Zealand Society of Animal Production, Volume 65, Christchurch, 290-296, 2005