New Zealand Journal of Agricultural Research abstracts
Relationships among faecal egg counts, anti-parasite antibodies and milk
yields in an experimental Friesian herd
C. A. Morris1
R. S. Green2
S. M. Hickey1
M. J. Auldist3*
N. A. Thomson3
N. G. Cullen1
1AgResearch Ruakura Agricultural Centre
Private Bag 3123
Hamilton, New Zealand
2AgResearch
Wallaceville Animal Research Centre
P.O. Box 40 063
Upper Hutt, New Zealand
3Dexcel Ltd
Private Bag 3221
Hamilton, New Zealand
*Present address: Department of Primary Industries, RMB 2460, Hazeldean
Road, Ellinbank, Vic 3821, Australia.
Abstract Two studies were carried out to measure variation
in faecal nematode egg count (FEC) or serum anti-nematode antibody (Ab) concentration
in Friesian cattle, and correlations between these traits and subsequent milk
yield traits. In Study 1, FEC and Abs were measured in 9-month-old calves
and 21-month-old heifers (1996 and 1995 calf crops, respectively), and correlations
with the subsequent first-lactation yield traits were estimated in herds calving
in late winter (July/August). In Study 2, Abs were measured in mixed-age cows
during lactation in each of four groups (summer, autumn, winter, and spring
calving mobs), and correlations were estimated between Abs and yield in the
current lactation. In Study 1, concentrations of the six different Abs (adult
and/or third larval stages of four nematode parasite species) were moderately
correlated with each other (average correlations of 0.57 in calves and 0.65
in heifers). In Study 2 the average correlation among Abs was 0.74. In Study
1, the average FEC values were 142 and 56 eggs/g in April and June samples
collected from calves, and 14 and 28 eggs/g from heifers. Repeatability of
FEC over time was moderate in the calves (0.45), but much lower in the heifers
(0.13). Correlations between FEC and Ab were low but favourable in sign, averaging
–0.24 in calves and –0.12 in heifers, while those between FEC as
a juvenile and first-lactation milk or milk-component yields were close to zero,
averaging
–0.05 for calves and –0.02 for heifers. Correlations between Abs
to Cooperia
oncophora or OstertagiaL3 antigens and milk or milk-component
yields averaged 0.23 and 0.07, for the two age groups in Study 1, respectively,
and 0.06 in Study 2. Correlations between these Abs and liveweight averaged
0.14 for calves and 0.17 for heifers. It is concluded that, under the routine
herd management conditions applied, concentrations among all Abs studied
were consistently correlated, FEC was repeatable in calves, and those calves
with a higher Ab response to Cooperia oncophora or Ostertagia
L3 antigens tended to show slightly higher first-lactation yields.
Keywords nematode parasite; faecal egg count; antibody;
dairy cows; milk yield
A03071; Online publication date 17 August 2004 Received 8 December 2003;
accepted 17 May 2004
New Zealand Journal of Agricultural Research, 2004, Vol. 47: 267–274
0028–8233/04/4703–0267 © The Royal Society of New Zealand 2004
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