Dtsch Tierarztl Wochenschr. 1991 Sep;98(9):352-4.

[The problems of spotted breeds of rabbits. 1. Fattening and body condition at slaughter, organ parameters].

[Article in German]

Wieberneit D, Mahdi N, Zacharias K, Wegner W.

Source

Institut für Tierzucht und Vererbungsforschung, Tierärztlichen Hochschule Hannover.

Abstract

Rabbits of the Giant German Spot Breed and of the English Spot Breed were bred, reared, fattened and evaluated under standardized conditions. 

A total of 50 animals (31 German spot = DRS; 19 English spot = ES; both derived from mating of heterozygotes) was tested, belonging to the three possible genotypes: 

Homozygous black (kk), heterozygous spotted (Kk, "standard animals") and homozygous spotted (KK, so-called "Chaplins").
As expected, breed differences consisted of better daily gains and higher carcass weights in DRS, but higher dressing percentages in ES. 

With respect to colour genotypes, only in DRS-KK depressions of daily gains and carcass weight were observed; food conversion efficiency however was even better in these animals (of both breeds), primarily because of lower feed uptake.
Very distinct differences in some important organ traits could be demonstrated for those genotypes: 

A significantly augmented intestine (abs. and rel.) in KK-animals, specially with reference to the gross intestine--indicating a tendency to motility disturbances and/or chronic obstipation. 

This predisposition was underlined by the premature loss of three KK-rabbits suffering from severe corresponding symptoms. 

Seemingly analogous syndromes (Megacolon) in man and other species are cited, though further investigations are needed to clarify the etiology in spot rabbits. 

Significance of lower heart weights was stated in DRS-KK-animals, probably induced by minor activities observed in this genotype. 

Thus the K-gene can be classified as a subvital one when homozygous though manifestations of the symptoms obviously vary with the genetic background (breed, line) and perhaps with the environment.

(ABSTRACT TRUNCATED AT 250 WORDS)