New Zealand Journal of Agricultural Research abstracts

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Genetics of susceptibility to facial eczema in Friesian and Jersey cattle

C. A. MORRIS¹
L. J. BURTON²
N. R. TOWERS¹
N. G. CULLEN¹
J. M. RENDEL²
D. L. JOHNSON²

¹AgResearch
Ruakura Agricultural Research Centre
Private Bag 3123
Hamilton, New Zealand

²Livestock Improvement Corporation
New Zealand Dairy Board
Private Bag 3016
Hamilton, New Zealand

Abstract  A total of 528 calves from 3 calf crops, sired by 34 Friesian and 28 Jersey bulls, were challenged with sporidesmin, the toxin causing facial eczema (FE), in order to determine the genetic variation in susceptibility to FE. The challenge was either by grazing toxic pasture or by oral dosing, and the response was monitored by blood sampling to measure the elevations of serum gamma-glutamyltransferase (GGT), glutamate dehydrogenase (GDH), and other possible indicators (enzymes or metabolites: bilirubin, aspartate transaminase, ferroxidase, bile acids, and 5'nucleotidase). The last calf crop was sired, in part, by bulls phenotypically selected from the second calf crop using GGT records. Data were analysed using the repeated records option of a restricted maximum likelihood programme. A sire model was used, with sires and maternal grandsires included to determine pedigree. The uni-variate heritability estimates for logeGGT were 0.29 +/- 0.15 in Friesians and 0.77 +/- 0.13 in Jerseys, and for logeGDH they were 0.20 +/- 0.12 and 0.64 +/- 0.13, respectively. Corresponding repeatabilities were 0.86 +/- 0.01 and 0.84 +/- 0.02 for logeGGT, and 0.66 +/- 0.03 and 0.69 +/- 0.03 for logeGDH. The genetic correlations between the two enzymes were 0.99 for Friesians and 0.95 for Jerseys. Genetic correlations between the five other enzymes or metabolites and logeGGT were generally high (0.79 to 0.99), with the exception of ferroxidase which was not correlated with logeGGT. The next best indicators of FE susceptibility after GGT and GDH were aspartate transaminase and 5'nucleotidase, which were phenotypically correlated with GGT, were heritable (in Jerseys) and repeatable, and showed elevation in response to challenge. The "High" and "Low" GGT-selected sire groups in the last calf crop had significantly different progeny mean GGT levels in both breeds. It was concluded that selection against high GGT concentrations following FE challenge should reduce the susceptibility to FE in subsequent generations.

Keywords  facial eczema; cattle; heritability; susceptibility; genetic correlation

New Zealand Journal of Agricultural Research, 1998, Vol. 41: 347-357

0028-8233/98/4103-0347 $7.00/0 (c) The Royal Society of New Zealand 1998

PDF file of entire paper: medium quality (607K); (scanned from paper original: notes about this process)

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