view - Department of Reproduction, Obstetrics and Herd Health

Milk production (kg)
CHAPTER 4.1
was only lowered in MD+ (P < 0.0001). Lactations of H cows show a faster rise in
production (lower ramp) and faster decline (lower persistence, higher decay, P < 0.0001)
in comparison with lactation curves of cows with one (MD) or multiple (MD+) metabolic
problems. The scale of production is only diminished in MD+ cows compared to H and
MD. The significant interaction term for both ramp and scale between MD and parity
revealed a more severe impact of MD on the ramp in older cows (Parity >2) next to a
remarkably decreased scale in MD+ second parity cows compared to H. The lactation
curves corresponding to the parameter values in Table 3 are separately shown for parity
1 (Figure 2), parity 2 (Figure 3) and parity 2+ (Figure 4). As a result of the change in the
lactation curve, the TPEAK increased (P < 0.0001) between H, MD and MD+ while both
the MPEAK (P < 0.0001) and M60 (P < 0.0001) were only decreased when cows
encountered a complicated MD+ especially in >1 parity cows. The overall M305 was
equal in H and MD cows but was lowered in MD+ (P = 0.029) especially in second-parity
cows (P = 0.037 for the interaction term).
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0
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DIM
Figure 2. The effect of metabolic problems on lactation curve shape in first
lactation cows: cows that encountered no metabolic problem during the transition
period (green line), cows that encountered 1 metabolic problem during the
transition period (orange line) and cows that encountered more than 1 metabolic
problem during the transition period (red line).
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