Körpermaße und BCS im Laufe der Laktation und ihre Beziehungen zu Lebendmasse und Energiebilanz.

This paper characterizes changes and relationships of energy balance, live weight, body measurements and BCS during lactation. Furthermore equations for predicting live weight are developed. Data were derived from Simmental (FV100), Holstein (HF100) and crossbred dairy cows of LFZ Raumberg-Gumpenstein. Parameters were measured during 11 experimental periods (63 cows each) during a whole year. Ration was forage-based with concentrate supplementation to meet individual requirements. Breed had no influence on energy balance and its development during lactation. Live weight and BCS decreased significantly with increasing genetic potential for milk performance from FV100 (730 kg, 3.57 points) to HF100 (613 kg, 2.76 points). FV100 differed significantly from all HF groups. A gene proportion of only 12.5% Simmental in Holstein cows caused a significantly higher live weight and tendentially more BCS compared to HF100. In the dry period correlation coefficients between live weight and most body measurements were higher, especially the relationship to BCS. The two models for live weight prediction with three body measurements as covariates (belly girth, heart girth, BCS or chest depth) had smallest Root Mean Square Error (17.0 and 18.7 kg). Regression coefficients changed during lactation. In conclusion breeds differ especially in BCS and live weight, depending on genetic proportion and their genetic potential for milk production. During the dry period bigger belly girth, heart girth, body width and chest depth depend more on fatness than on actual size of bones compared to lactation. Furthermore the physiological stage seems to change the influence of body measurements on live weight during lactation. [ABSTRACT FROM AUTHOR]