Genetic and environmental effects affecting the variation in birth date and birth weight of reindeer calves

Abstract

e factors causing variation in birth date and birth weight were analysed from the data from an experimental reindeer herd consisting of 1136 calves with parental information. e traits had coe cient of variation of 37 and 14%, respectively. e variation in both traits was a ected by year and sex (male calves heavier) and by management factors, such as the age distribution of females and males. Early calving results from the use of older breeding males and is most apparent in prime age females. In both traits the heritability was moderate (0.23 and 0.24) with a high proportion of maternal genetic variation (0.23) in birth weight. e North Atlantic Oscillation (NAO) indices, summarizing the major weather conditions prior to rut, explained part of the annual variation in the traits. e amount of total genetic variation in relation to trait mean, or the evolvability, was 21% in birth date and 10% in birth weight indicating that selection could successfully be used to improve herd productivity and that the traits have substantial potential for adapting to possible changing environmental conditions. e results on genetic correlations imply that selection on calf 's birth weight leads on one hand to calves being born earlier and on the other hand to dams with later parturition.

Genetic variation in meat production related traits in reindeer (Rangifer t. tarandus)

“…Heydarpour et al, 2008). Contrary to the birth weight of reindeer (Muuttoranta et al, 2013), the inclusion of the maternal e ect in the growth model did not cause reduction in the direct heritability, as also reported by Safari et al (2005) for sheep. In reindeer this is due to the strongly negative direct-maternal genetic correlation in growth (Willham, 1972; Table 2).…”

“…In addition, paternities were monitored using marking harnesses for calves born in 1987, 1988, and 1990-1993. e pedigree dataset contained 3320 animals, of which 101 were sires and 566 dams of the calves. e dataset has been described in Muuttoranta et al (2013) Calf data e calves were weighed at birth in May (few born in June) and before selection in September. e weights are in kilograms and birth date is presented as days counting from 1 st of May.…”

“…e data structure related to the calf traits has earlier been described in Muuttoranta et al (2013). e summary statistics of the studied traits are given in Table 1. e rst calf was lighter than those born in the later parities (CAW1<AW1).…”

Reversal of response to artificial selection on body size in a wild passerine

“…The heritability estimated for birth date and calf body mass were of the same order as previously recorded in reindeer (both traits, Muuttoranta et al, 2013), Feder et al, 2008), soay sheep Ovis aries (both traits, Wilson et al, 2005a) and red deer (body mass, Kruuk and Hadfield, 2007). Our sample sizes of less than 170 individuals (see Table 2) limited the quantitative genetic analyses to univariate models (Kruuk, 2004;de Villemereuil et al, 2013).…”

“…Hence, the unmeasured additive genetic covariance could have limited the additive genetic variation in each trait that was available for unconstrained phenotypic evolution (Hansen and Houle, 2008;. Indeed, a negative genetic covariance between birth mass and date has earlier been found for instance in reindeer (Muuttoranta et al, 2013), while a positive genetic covariance has been found in soay sheep (Wilson et al, 2005a). Although we were not able to estimate genetic covariances in this study, we found a negative phenotypic covariance between calf body mass and birth date, which could indicate the presence of a negative genetic covariance (see Table 2; Cheverud, 1988).…”