a pedigree file consisting of 5860 individuals, 167 sires and 1582 dams collected at makooei sheep breeding station (msbs) during a period of 24 years (1990 to 2013) was used to calculate the inbreeding coefficients to reveal any probable effects of inbreeding (f) on the studied traits. the studied traits were classified to the five main groups including body weight, kleiber ratio, body measure...

Background: Interactions between inbreeding and maternal effects have received little attention, and the effect of maternal age on inbreeding depression in offspring has been almost entirely neglected. Maternal age affects allocation of resources and other materials to offspring, which can affect the fitness consequences of inbreeding. An interaction between inbreeding and maternal age thus has...

Records of five inbred lines at the Livestock and Range Research Laboratory were used to evaluate effects of inbreeding and heterozygosity on preweaning traits. Members of each line were descendants of a single founder Hereford bull. A total of 8,065 records of birth weight and 7,380 records of preweaning daily gain and weaning weight were analyzed by derivative-free REML using a model that inc...

A maternal effect is a causal influence of the maternal phenotype on the offspring phenotype over and above any direct effects of genes. There is abundant evidence that maternal effects can have a major impact on offspring fitness. Yet, no previous study has investigated the potential role of maternal effects in influencing the severity of inbreeding depression in the offspring. Inbreeding depr...

Records of five inbred lines at the Livestock and Range Research Laboratory were used to evaluate effects of inbreeding and heterozygosity on preweaning traits. Members of each line were descendants of a single founder Hereford bull. A total of 8,065 records of birth weight and 7,380 records of preweaning daily gain and weaning weight were analyzed by derivative-free REML using a model that inc...

There is ample evidence for inbreeding depression manifested as a reduction in fitness or fitness-related traits in the focal individual. In many organisms, fitness is not only affected by genes carried by the individual, but also by genes carried by their parents, for example if receiving parental care. While maternal effects have been described in many systems, the extent to which inbreeding ...

The present study was performed to study the effect of inbreeding on the pre-weaning growth traits including the birth weight (BW), weaning weight (WW), average daily gain (ADG), Kleiber ratio (KR) and lamb survival from birth to weaning (SUR) in Baluchi, Iran-Black and Zandi sheep. Significant positive inbreeding trends were found only for Baluchi and Iran-Black breeds as 0.038 and 0.278, resp...

Inbreeding depression refers to the reduction of fitness that results from matings between relatives. Evidence for reduced fitness in inbred individuals is widespread, but the strength of inbreeding depression varies widely both within and among taxa. Environmental conditions can mediate this variation in the strength of inbreeding depression, with environmental stress exacerbating the negative...

Effects of inbreeding and heterosis and the difference between them were estimated by comparing linecross (L), topcross (T), inbred (I) and control line (C) Hereford females for reproductive and preweaning growth traits of their progeny. Inbred females (average inbreeding coefficient = 26.5%) originated from four single-sire inbred lines. Control females (average inbreeding coefficient = 6.9%) ...

Inbreeding coefficients of 30,794 registered Ayrshire cows were calculated from relationships between sire and maternal male ancestors. Average inbreeding coefficient of all cows was less than 1% and of the 5,202 inbred cows was 5.4%. Fewer than 2% of inbred cows had coefficients greater than 15%. Percent of inbred cows increased from 23% of cows born in 1972 to 43% in 1980. Over the same perio...