ABSTRACT
Research into the chinchilla male fertility concerned mainly semen quality. Little attention has been paid to lifetime reproductive performance, essential from the economical point of view. Thus, the aim of this study was to analyze factors affecting the intensity of breeding use and lifetime performance of male chinchillas. After data transformation, the analysis of variance was performed to evaluate the effect of male birth litter size and age at the first effective mating. Additionally, the correlation coefficients for both litter sizes and litter rearing efficiency were calculated. For all traits, the linear regression on the sire's age at the first effective mating was found non-significant. Litter sizes differed slightly between seasons. The length of sire reproductive use was highly correlated (about 0.8) with the total number of litters and kits born and weaned. The total rearing efficiency was low, and in some cases negatively correlated with other traits, that is, with the total number of litters and kits born and weaned. Most sires were mated up to six dams; they were used in one polygamous set each. In total, the males sired about 60 litters each, hence the conclusion is that they could be extensively used and produce more benefits to chinchilla breeders.
Subject(s)
Breeding , Chinchilla/physiology , Farms , Fertility , Reproduction , Age Factors , Aluminum Hydroxide , Animals , Breeding/economics , Litter Size , Magnesium Hydroxide , Male , Poland , Seasons , Semen AnalysisABSTRACT
The aim of the study was to analyse inbreeding and relationship in the Polish population of Black-and-White sires. Data were pedigrees of 25,036 Black-and-White sires born from 1960 through 2000, divided into subsets of 11,447 proven and 13 589 unproven sires, and their 38,228 ancestors, altogether 63,264 animals. Average inbreeding coefficients were about 0.3% for both subsets of sires. Mean relationship coefficients ranged from 0.1% in all animals to 0.7% in the subset of proven sires. Positive time trends in inbreeding coefficients were observed when the subsets of sires were divided into 5-year intervals according to the year of birth and in terms of Holstein Friesian gene contribution.
