Evaluation of the health status of mammary glands and compositional changes in udder-half milk obtained from dairy goats for milk quality management.

This study evaluated the health status of the mammary glands and milk composition of dairy goats. The California mastitis test (CMT) score, somatic cell counts (SCCs), somatic cell type, electrical conductivity (EC), N-acetyl-β-d-glucosaminidase (NAGase) activity, mastitis-causing pathogens, and milk composition in 121 udder-half milk samples from 62 crossbreed goats (1-3 years old) at 23-45 days postpartum were compared in four categories with SCCs of <200 × 10 3 , <300 × 10 3 , 301-1000 × 10 3 , and >1010 × 10 3  cells/ml. The SCC, CMT score, EC, and NAGase activity were significantly lower (p < 0.05) in udder-half milk with SCCs of <200 × 10 3 and <300 × 10 3  cells/ml than those in milk with SCCs of 301-1000 × 10 3 and >1010 × 10 3  cells/ml. The protein, lactose/ash, and solids-not-fat (SNF) in milk with an SCC of <300 × 10 3  cells/ml were similar to the previously reported values. The proportion of polymorphonuclear neutrophils was significantly higher (p < 0.05) in milk with SCCs of 301-1000 and >1010 × 10 3  cells/ml than in milk with an SCC of <300 × 10 3  cells/ml. Assessing mammary gland health and milk composition based on categorization of udder-half milk by SCC may be useful for milk quality control on goat farms.