Relationships Among Severity and Duration of Clinical Mastitis and Sire Transmitting Abilities for Somatic Cell Score, Udder Type Traits, Productive Life, and Protein Yield

摘要: The objective of this study was to determine the relationships among severity and duration clinical mastitis during first second lactation sire transmitting abilities for somatic cell score, udder type traits, productive life, protein yield. Recording episodes began at parturition 1704 Holstein cows (in six Pennsylvania herds one Nebraska herd) continued into 1055 these cows. A total 456 (sired by 168 bulls) had least episode lactation, 230 100 lactation. code from 1 (normal milk) 5 (acute systemic mastitis) assigned daily (for up 30 d after detection) all quarters that mastitis. Only codes occur are considered here. initial maximum codes, as well natural logarithms both sum were above normal (> 1) days regressed on herd (a classification variable), age calving, in milk detection, taken a time. Linear nonlinear effects estimated abilities. Separate analyses conducted dependent variables from: organisms, coagulase-negative staphylococci, coliform species, streptococci other than Streptococcus agalactiae, most common environmental organisms (coliform species agalactiae). Daughters sires transmit lowest score severe shortest Selection lower may reduce