Effect of Mummified Fetuses on the Prolificacy of Holsteins

Abstract

Summary Over a 30-year period in a closely observed breeding herd, 29 of 2,607 cows produced 32 mummified fetuses. This represented 1.1% of the cows and 0.43% of the parturitions. The range in gestation was 131 to 342 days (mean = 215 days). Cows having mummified fetus were considerably above herd average in number of reproductive periods and in average age at disposal. Heritability on an additively genetic basis was estimated at 16% when service sire was assumed not to be a factor. Matings of bulls postulated as heterozygous to daughters of other heterozygous bulls (1,008 cases) terminated in mummification in 0.60% of the cases. These data show that mummified fetus is not transmitted as a single lethal recessive in a simple Mendelian manner.