Objective assessment of cow condition during early lactation
B.A. Clark, L.M. Chagas, P.J. Gore, B. Dow and G.A. Verkerk
Dairying Research Corporation, Private Bag 3123, Hamilton, New Zealand.
Proceedings of the New Zealand Society of Animal Production.
2000 60: 15-18
Changes in a range of metabolites and body condition parameters
in lactating cows were measured during early lactation to determine if
any key indicators or combination of key indicators could be used as a
predictor of length of post-partum anovulatory interval (PPAI).
Fifty-three cows in a range of body condition scores were involved in
the trial which ran from calving to 10 weeks post-calving. Plasma
non-esterified fatty acids (NEFA) and serum cholesterol, glucose,
betahyroxybutyrate (BOH) and urea content were measured in weekly
samples. Live weight and body condition score (BCS) were measured
weekly. Cows were categorised into four groups. Three groups were based
on the post-partum anovulatory interval (PPAI). PPAI was defined as the
interval between calving and the first evidence of oestrus behaviour.
The fourth group contained all the two-year-old cows only. There was a
calving interval of 31 days from the first to the last cow to calve. The
nadir for live weight for all groups occurred one week after calving.
Animals with a shorter PPAI had higher live weights on all occasions,
with live weight at week 5 having the strongest association with length
of PPAI (P<0.001). Mean BCS was higher for animals with a PPAI<60 days.
Plasma urea concentrations were associated with PPAI at weeks 3 and 4
(P<0.01). NEFA and glucose were correlated with PPAI at weeks 3 and 4
only, respectively. There was no association between cholesterol or BOH
with PPAI. These results demonstrate that the selected variables do not
contribute greatly to prediction of PPAI. Those measures which give the
closest association with PPAI are live weight, BCS and age.
Keywords: NZSAPAB;
dairy cows; post-partum anovulatory; calving; metabolite; live weight.
Last Updated 12-07-2000
