1 Fers., 1898.] QUEENSLAND AGRICULTURAL JOURNAL. 97 
ON CROSS-BREEDING. 
By P. R. GORDON, 
Chief Inspector of Stock. 
SEVERAL meanings have been attached to the term ‘“cross-breeding.”’ It hag 
been used in connection with the mating together of different types or 
varieties of the same great family, such, for instance, as the American with the 
Australian merino. In this sense it is used in contra-distinction to “ breeding 
in the line” or consanguinity, and this form of breeding together of two types 
of the same breed is known among practical breeders as breeding for an 
“ outcross.’ The meaning, however, generally attached to the term is the 
coupling of the male of one distinct breed with the female of another distinct 
breed, or vice versd, as, for instance, a Shorthorn with a Hereford, or an English 
coarse-woolled sheep with a merino, a thoroughbred with a draught horse, &c.; 
and it is in this latter sense that the term is here used. Cross-breeding has 
been practised with two distinct objects in view. First, for the production of 
a superior class of beef or mutton; and, second, with the intended object of 
establishing a new permanent variety midway, or at some point, between two 
breeds. The former requires very little skill on the part of the breeder beyond 
care in the selection of the animals to be crossed. It is the case that the first 
cross between two distinct breeds, particularly in cattle, results in the pro- 
duction of a superior beast for the butcher. There are breeds that can be 
crossed with greater certainty of success than others; as, for instance, the 
Shorthorn on the Aberdeen-Angus or (talloway, the reason being obvious— 
namely, the preponderance of fat in the Shorthorn and the compactness of 
flesh of the two latter breeds; but as a general rule the qualities of each 
breed blend pretty equally in a first cross between any two different, old- 
established breeds of cattle. To proceed beyond a first cross is to court a 
certain amount of risk and uncertainty as to the character of the progeny, for 
‘here the prepotency of the line of one or other of the parents will dominate, 
and the best and most experienced of breeders cannot forecast the result with 
even an approach to certainty; but when a second cross, or “ grade” as the 
Americans term it, has been decided upon, only a pure sire should be used, 
and, if the sire is of the same breed as the sire previously used, the produce is 
termed in bush phraseology a ‘come back.’’ There are many. instances in 
which the use of a pure sire of a breed with a female of very mixed 
ancestry has resulted in excellent butchers’ beasts; but in such cases the 
many instances of failure frequently overbalance the successes. Those who 
undertake the formation of a new breed by the blending together of two 
distinct varieties, such as the merino and cross-woolled sheep, or say the 
Shorthorn and Hereford breed of cattle, must not look for success until after 
long years of patient observation and the careful weeding-out of all inferior 
animals from the flock or herd. In order to understand the difficulties they 
will have to contend with, it will be convenient to represent the breeds to be 
blended by figures. Taking a maximum of 100 to a minimum of 0 to 
represent the hereditary strength of the parents, and using for the first 
three crossings a pure sire, say Hereford, on Shorthorn cow, the male will 
be found in all his hereditary strength, while heredity or constancy will 
after the first cross be weakened and ultimately destroyed in the female. The 
case would stand thus : am = 50 for the first cross ; that is, the progeny would 
represent equal parts of each breed. The second cross—pure Hereford sire 
\=4 
ey = 75 of the male and 25 of the 
female. The third cross would be represented by WD 87:5, or seven- 
2 
eighths Hereford to one-eighth Shorthorn. Having arrived at this grade, we 
on first cross dam—would represent 
