BLOOD GROUPING SYSTEMS IN DOGS, CATTLE AND SHEEP 
E. B. Black and J. M. Stengle' 
During the past thirty years complexes of antigens 
have been discovered on the erythrocytes of dogs, cat- 
tle, and sheep which have led to the development of 
blood grouping systems for each species comparable to, 
although in many respects more intricate than, that in 
the human. The first major blood group in cattle, blood 
group A, was discovered in 1940. Since then the num- 
ber of known bovine blood groups has been expanded 
to eleven, including the B system, which is probably the 
most complex blood group in any species and the J sys- 
tem with the intriguing relationship of "J substance" to 
bovine serum and erythrocytes. Seven major blood 
group systems are now recognized in sheep including 
the M-L system. The antigens of this system may be 
biochemical entities which play an important role in 
biological membrane function. The canine red cell anti- 
genic system contains seven major blood groups. Trans- 
fusion reactions in A negative dogs immunized with 
type Ai erythrocytes provide an interesting comparison 
with hemolytic transfusion reactions in the human. Al- 
though of little significance from a clinical veterinary 
standpoint, ovine, canine, and bovine blood group anal- 
ysis presents a major challenge to the imagination and 
technology of the immunohematologist, the geneticist, 
and biochemist, and the evolutionist. 
INTRODUCTION 
During the past thirty years complexes of an- 
tigens have been discovered on the erythrocytes 
of dogs, cattle and sheep which has led to the 
development of blood grouping systems compa- 
rable to, although in some respects more intri- 
cate than that in the human. Although of little 
significance from a clinical veterinary stand- 
point, canine, bovine, and ovine blood group 
analysis present a major challenge to the imagi- 
nation and technology of the immunohemato- 
logist, the geneticist, the biochemist, and the ev- 
olutionist. 
* National Blood Resource Piogram, National Institutes of Health, 
Bethesda, Maryland. 
SHEEP 
Seven major antigenic groups have been 
identified on the erythrocytes of sheep : R-0, 
X-Z, A, D, M-L, C, and B. The R-0 system was 
the first discovered. Our current knowledge of 
that system is founded upon the early work of 
Bialosuknia and Kaczkowski^-* in the mid- 
1920's and that of Andersen^ in the late 1930's. 
These workers demonstrated that the red cells 
of some sheep were agglutinated or lysed by 
naturally occurring isoantibodies from ovine 
serum and that the red cells of other sheep were 
not. The former group is now recognized as R 
and the latter as 0. 
In the early 1950's Stormont^ isolated natu- 
rally occurring antibodies from bovine serum 
which reacted with group 0 sheep erythrocytes. 
In tests of over 100 bloods with anti-R anti-0 
reagents, Stormont observed mutually exclusive 
R and 0 reactions indicating that 0 is truly re- 
cessive to R and is not expressed in the hetero- 
zygous condition. In 1954 RendeF et al. discov- 
ered a third phenotypic red cell in sheep which 
was lysed by neither anti-R nor anti-0. This 
phenotype is called i. At least two genetic loci 
play a part in the control of the R, 0, and i 
phenotypes. Where r° represents the gene 
which when homozygous gives rise to the 0 
phenotype, the genotype of sheep of group R is 
1/ — R/ — ; the genotype of group 0 is 1/ — 
r°r°. The recessive genotype ii is epistatic to 
both R and 0 (Figure 1). In 1958 Rasmusen 
discovered an i lamb from an 0X0 mating, 
supporting the hypothesis that ii is epistatic to 
0. Anti-R antibodies are frequently encoun- 
tered as a natural component of the serum of R 
negative sheep. Anti-R antibodies were found in 
all of 20 group 0 sheep studied by Rendel et al. ; 
however, the sera of only two out of 23 group i 
sheep were shown to contain Anti-R. Sheep 
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