| dc.description.abstract | A total of 91 goat milk samples from individual udders of Alpine does during early, middle and late lactations were used to investigate the impact of subclinical mastitis induced SCC increase on changes in chemical composition and plasmin (PL) activity in milk. Samples were collected and analyzed for fat, protein, lactose, solids non-fat (SNF) and total solids (TS), SCC and PL activity. Within three stages of lactation, all milk samples were sorted into three groups based on levels of SCC (low < 2.5 10^6, middle = 2.5 - 5.0 10^6, high > 5.0 10^6) and statistically analyzed in a 3 3 factorial ANOVA. There were no interactions of level of SCC and stage of lactation on variables measured (P > 0.05). Log10 (SCC) and percentage lactose in milk were negatively correlated (r = -0.34, P = 0.001). Fat, protein, SNF, TS and PL were altered by stage of lactation (P < 0.05). Fat content was lower in mid-lactation, whereas protein and SNF increased between early and late lactation. TS content was greater in late lactation and PL activity was greatest in early lactation. In conclusion, in high SCC milk, lactose content may be more indicative of SCC level than milk fat, protein, SNF, TS and PL activity during lactation. Stage of lactation is an important factor affecting milk composition and PL activity in goats with infection, thus is a necessary parameter in optimizing goat milk quality in conditions of subclinical mastitis. | |
