New Zealand Journal of Agricultural Research abstracts
Sire effects on antibodies to nematode parasites in grazing dairy cows
C. A. Morris
N. G. Cullen
S. M. Hickey
AgResearch
Ruakura Research Centre
Private Bag 3123
Hamilton, New Zealand
R. S. Green
AgResearch
Wallaceville Animal Research Centre
P.O. Box 40 063
Upper Hutt, New Zealand
Abstract A study was carried out on New Zealand dairy
cows at pasture, to test for evidence of genetic differences in immunological
response to nematode parasites. Nine widely used Holstein-Friesian artificial
insemination bulls, with daughters in many herds, were evaluated for nematode
antibodies by sampling milk of their daughters in mid lactation in each of
20 North Island herds. One milk sample was taken from each cow (ranging from
4 to 11 years of age), during a routine herd test in the period from mid
November 2000 to early February 2001. Assays were undertaken subsequently
on pooled samples of skim milk (0.2 ml per cow; up to 20 cows per sire ´
herd) to assess antibodies to both the infective third larval (L3) and adult
parasitic stages of Cooperia oncophora and Ostertagia ostertagi.
Sire effects were significant for all four antibody types (P < 0.001).
For O. ostertagi L3, there was a 1.20-fold range in the mean antibody
levels of the sire groups; corresponding proportional ranges for the other
three antibody types were from 1.22 to 1.23. The correlations of sire means
among the four antibody types were high, averaging 0.81 (range 0.65-0.99).
These results show that significant sire effects on anti-parasite antibody
levels were present in mature lactating dairy cows at pasture in New Zealand,
with repeatabilities of sire means across herds of 0.29-0.39, and that sire
effects on antibody levels to two different nematode parasite species were
highly correlated (for antibodies to either the L3 or the adult stages).
Keywords antibody; nematode; genetics; cattle
A01032 Received 5 October 2001; accepted 12 April 2002; published 30
September 2002
New Zealand Journal of Agricultural Research, 2002, Vol. 45: 179-185
0028-8233/02/4503-0179 $7.00/0 © The Royal Society of New Zealand
2002
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