Relationship between body condition scores and ultrasound measurements of subcutaneous fat and m. longissimus dorsi in dairy cows differing in size and type
R. Schwager-suter et al., Relationship between body condition scores and ultrasound measurements of subcutaneous fat and m. longissimus dorsi in dairy cows differing in size and type, ANIM SCI, 71, 2000, pp. 465-470
In the present study body condition scores (BCS), ultrasound fat thickness
and ultrasound m. longissimus dorsi thickness as well as body measurements
and management factors were recorded repeatedly during lactation in 71 Hols
tein-Friesians, 71 Jerseys and 71 Holstein-Jersey F1-crosses (first to nint
h lactation) on four feeding regimens. BCS were analysed with ultrasound me
asurements as explanatory variables by mixed models. A compound symmetry st
ructure for the variance components was applied. The models were also teste
d for an autoregressive error structure [AR(1)]. Ultrasound fat thickness a
nd ultrasound m. longissimus dorsi thickness explained most of the variabil
ity in BCS. Coefficients of determination were between 0.84 and 0.85. Manag
ement factors such as feeding group and stage of lactation (week of taking
measurements) and the breed type X lactation interaction were, although sig
nificant, not relevant for the fit. Holsteins tended to have lower scores t
han F1-crosses and Jerseys and younger cows tended to have higher scores th
an older cows. Despite small differences between breeds, Edmonson's BCS pro
ved to be consistent within each breed type; thus BCS can be applied to var
ious dairy breeds.