Relationship between litter size and other reproductive traits in the dutch kooiker dog

Abstract

A study of the relationship between litter size and other reproductive traits in Dutch Kooiker dogs born between 1956 and 1990 is described. The characteristics investigated were: litter size, homozygosity of the litter, paternal and maternal homozygosity, paternal and maternal litter size, paternal and maternal age, maternal parity, the year of birth, and interactions between these factors. A Poisson model with identity link was used. A negative effect on litter size was found for homozygosity of the litter (‐ 3.175) and for maternal age. Positive effects on litter size were found for maternal litter size (+ .09786) and maternal parity (+ .5847, parity 2; + .8756, parity 3; + 1.044, parity ≥ 4). The effects of paternal age, paternal litter size, maternal homozygosity, and expected interactions were not significant. The positive effect of paternal homozygosity (+ 2.30) may have been caused by the frequent use of a small number of related sires.