Effects of glandular bacterial infection and stage of lactation on milk clotting parameters: Comparison among cows, goats and sheep

Effects of glandular bacterial infection and stage of lactation on milk quality were compared among cows, goats and sheep. These parameters affected milk quality in all three species: sheep were most affected by bacterial infection and goats by stage (particularly end) of lactation. The study highlighted the effectiveness of lactose level as a predictor of milk quality; in all three species, the correlation between lactose level and curd firmness (CF) was higher than those between casein as a percentage of total protein and CF, or between somatic cell count and CF. In all three species, lactose concentrations ≤4% were associated with non-clotting milk. A model that describes the simultaneous and close association between reductions in lactose concentration and milk yield, on the one hand, and reductions in lactose concentration and milk quality on the other hand, is presented.