Milk production on smallholder dairy cattle farms in Southern Vietnam

摘要: Dairy production is a rather new and not traditional system in Vietnam. It mainly based on smallholder dairy farms. The general aim of the studies this thesis was to improve milk farms Southern Vietnam also create foundation that could be used advisory service or/and further research for better milking management routines. Studies were done cover specific objectives thesis. designed identify problems farms, investigate which are factors influenced somatic cell count (SCC) lactating cows, prevalence subclinical mastitis SCC study protein degradation caused by Streptococcus (Str.) agalactiae. The survey indicated majority farmers kept between 2 17 cows (mean = 12). main breed cow Holstein Friesian (HF) crosses. This HF produced about 16 kg/day/cow. Around 35% provided fresh water ad libitum while 51 % less than 30 L per day. Moreover, high (1,300,000 cells/mL milk) many studied second found limited drinking significantly increased herd SCC. Str. agalactiae predominant species infected udders. Further investigation showed (SCC > 200,000 at quarter basis 63.2% (285 out 451) 88.6% (101 114). 65% 35.6% (41 115) 21% quarters (96 458). Among 96 isolates agalactiae, 11 different strains identified. proteolysis casein higher (12-70%) compared with whey proteins (4-12%). same phylogenic group did show protein. aglactiae proteolytic activity where αS2-casein highest, up 70%, control milk. Proteolytic large variation. lowest breakdown 30% milk. Overall, present poor udder health infection udders