Presence of Mycoplasma species and somatic cell counts in bulk-tank goat milk

Abstract

This cross-sectional study performed on dairy goat herds was designed to establish the relationship between the presence of Mycoplasma species in bulk-tank milk samples from different farms and the bulk-tank milk somatic cell count (BTMSCC) in an area where contagious agalactia (CA) is endemic. Three BTMSCC thresholds, used in payment schemes or as legal requirements for milk quality in Europe and the USA, were considered: (1) 2,000,000 cells/ml; (2) 1,500,000 cells/ml and (3) 1,000,000 cells/ml. Of the 1068 milk samples tested, 7.9% ( n = 84) showed the presence of Mycoplasma spp. ( Mycoplasma agalactiae 82% and Mycoplasma mycoides subsp. mycoides large colony 17%). Somatic cell counts for bulk-tank samples containing mycoplasmas were higher than those recorded for negative samples (1,176,000 cells/ml vs. 875,000 cells/ml; P < 0.001). Two-by-two table analyses revealed that the presence of mycoplasmas in bulk-tank milk increased the risk of surpassing all SCC thresholds considered, with the highest risk for Mycoplasma positive bulk-tank milk samples exceeding the threshold of 1500 × 10 3 cells/ml (odds ratio = 2.42 (1.49 < OR < 3.91). Our results indicate that the presence of mycoplasmas in goat milk had yet another economic consequence and a further incentive to encourage the implementation of specific programs for disease control.