view - Department of Reproduction, Obstetrics and Herd Health

LACTATION CURVE ANALYSIS IN METABOLIC DISEASES
Affected cows had a delayed TPEAK both in KET (53-61d 95% CI) and KET+ (59-
66d 95% CI) when compared to H cows (50-51d 95% CI) as a result of a slower milk
production inclination (P < 0.0001) especially in the older cows (P < 0.0001). Scale of the
lactation was higher in H compared to KET+ cows (P = 0.014) resulting in similar
differences for MPEAK (P = 0.0027) and M60 (P < 0.0001). Older KET cows had a higher
lactation scale (P = 0.033) and concomitant increased MPEAK (P = 0.0002) and M60 (P =
0.0003) when compared to older KET+ cows. KET+ cows had a higher persistency
compared to H cows (P = 0.0003). Overall M305 was not altered by KET (P = 0.64, Table
8).
Because of the low number of LDA (N= 31), first and second parity cows were
grouped to avoid loss of information (Table 9). A slower increase in milk production (P <
0.0001) and longer persistency in LDA+ cows compared to their healthy counterparts
combined with a lower scale (P = 0.037) results in a decreased MPEAK (P = 0.0041) and
M60 (P = 0.0007) but overall equal M305 (P = 0.77). The interaction term shows that
older LDA cows (>2 parity) also have a slower milk increase compared to H (P = 0.0008).
Overall TPEAK was delayed in both LDA (49-82d 95% CI) and LDA+ (57-76d 95% CI)
cows when compared to H cows (43-45d 95% CI, P < 0.0001).
Mastitis during early lactation (