CLYDE J. STORMONT 
509 
Table I. — The approximate number of blood factors, recommended typing procedures, and the phenotypic systems 
of blood groups identified in cattle, dogs, horses, pigs and sheep 
Species 
Approximate 
no. of 
blood factors 
Typing procedures 
in order of 
preference 
Recognized phenotypic systems of blood groups; 
minimum no. of alleles shown within parentheses 
References 
Cattle 
80 
Hemolysis only 
12 systems 
A (10),** B (500+). C (70+), F-V (5), 
J or J-Oc (4 + ), L (2), M (3), N (2), 
S or S-U (8), Z (3), R'-S' (3),** and T' (2) 
14, 16, 30, 31, 
32, 33, 34, 35, 
JO en CI CO 
48, 50, 51, 00. 
Dogs 
9 
Agglutination 
Hemolysis 
(Ai only) 
The 9 canine blood factors (Ai, A2, B, C, D, E, 
F, G, and Tr) are yet to be classified with 
respect to phenotypic systems. 
5, 6, 36. 
Horses 
20 
Hemolysis 
Agglutination 
8 systems 
A (5), C (2), D (6), K (2), P (3), Q (6),** 
T (2), and U (2) 
37, 38, 39, 
40, 41, 48. 
Pigs 
60 
Agglutination* 
Hemolysis 
15 systems 
A-0 (A locus 2; S locus 2), B (2),** C (2), 
D (2),** E (13),** F (3),** G (2),** H (6), 
I (2),** J (3), K (5), L (6),** M (9). 
N (3),** and O (2).** 
42, 43, 44, 
48, 52. 
Sheep 
50 
Hemolysis 
Agglutination 
(D only) 
7 systems 
A (2), B (60 + ), C (3), D (2), M (4),** 
R-O (R locus 2; I locus 2) and X-Z (2).** 
10, 17, 18, 23, 
25, 26, 27, 45, 
46, 47, 48, 54. 
* Some of the agglutinins act as so-called incomplete agglutinins and require the use of anti-globulin to bring about agglutination. Some of 
the others produce agglutination when the red cells are suspended in dextran solutions. The majority, however, act as saline agglutinins. 
** Closed systems. That is, there is no phenotype which is non-reactive with all of the reagents used in typing the particular system. All 
others are open systems. That is, there is one phenotype in the particular system which is characterized by the absence of reactions with all 
reagents used in typing that system. 
Generally, fresh rabbit serum, now commer- 
cially available (Pel Freez Biologicals, Rogers, 
Arkansas), is the complement of choice for cat- 
tle blood typing. It is also the complement of 
choice in cytotoxicity tests (e.g., the human leu- 
kocyte A system). There are, however, certain 
cattle reagents which produce better hemolysis 
with guinea pig complement but such reagents 
are exceptional. 
Fresh rabbit serum has one major disadvan- 
tage when employed in tests on the red cells of 
Forssman-positive species (dogs, goats, horses, 
pigs and sheep) . The reason for this is that rab- 
bits, being Forssman-negative, develop, natu- 
rally, Forssman antibodies which, in conjunc- 
tion with rabbit complement, will lyse the red 
cells of such species as dogs, horses, pigs and 
sheep. But such antibodies, and all other inter- 
ferring natural antibodies, can be absorbed 
from fresh serum without affecting the comple- 
ment if the absorptions are performed at 0-4 °C 
using red cells of the species under study, a 
methodology described by Ehrlich and Morgen- 
roth"<^ in 1899. 
With few exceptions, as already noted, each 
of the numerous blood factors is inherited as a 
dominant in contrast with its absence. But not 
all blood factors are inherited independently of 
one another as already indicated for blood fac- 
tors which belong to inclusion groups. All blood 
factors fall naturally into one or another pheno- 
typic system of blood groups (Table I) and 
much of the effort in blood typing studies is de- 
voted to the analysis of such systems. 
Perhaps the simplest systems of all are the 
two-allele, closed systems, and there are numer- 
ous systems of that order, particularly in pigs 
(Table I). They do, however, on further study, 
have a tendency to expand into multiple allelic 
systems, a notable example being the F-V sys- 
tem of cattle.^" As a model of two-allele, closed 
systems, consider the X-Z system of sheep with 
two alleles, X and X^, and three phenotypes X 
XZ and Z, conveniently written as X/X, X/Z 
and Z/Z to indicate the contribution of each 
parent to the phenotypes of their offspring. 
Such systems are referred to as "closed" sys- 
tems because each phenotype is represented by 
at least one blood factor. This is in contrast to 
the two-allele, open systems which involve only 
a single blood factor, one phenotype being rep- 
resented by the presence of the particular blood 
factor and the other by its absence. There are 
numerous examples of such systems. 
At the opposite extreme are the multi-allelic 
systems like A, B, C and S of cattle. A, D and Q 
of horses, E, H and M of pigs, and B of sheep. 
Some of these multi-allelic systems are open 
