The allometric-autoregressive quantification of growth and efficiency divides rat growth into 3 different physiological phases. Significant differences between families for some of these parameters existed. Consequently, heritabilities and, phenotypic and genetic correlations of the different parameters were estimated. Significant heritabilities…
Field data for the period 1976 to 1998 from South African and Namibian Afrikaner, Drakensberger, SA Angus and Simmentaler beef cattle breeds was used to investigate two fertility traits, calving rate (CR) and calving success (CS). Calving rate, a lifetime…
Data from 2801 individuals (born from 1996 to 2002) were used to obtain heritability (h2) estimates for five objectively measured and six linearly assessed type fleece traits (scored on a 1-50 point scale) from the Tygerhoek Merino flock. Correlations of…
In animal breeding, selection decisions are often made amongst animals from separate environmental groups. Production data in these groups may differ both in mean and variance. In South Africa, yearling weights of beef cattle are recorded in two different phases…
A total of 967 animal records, of subjective trait scores, obtained between 1989 and 1990, from the control flock at the Karakul Research Station near Upington were used to evaluate 20 pelt traits in Karakul sheep, applying linear and threshold…
Data consisting of records from 3 040 animals, born of 59 sires and 597 dams, were collected from 1978 to 1991 and analysed to estimate variance components for birth weight, weaning weight, average daily gain (ADG) and Kleiber ratio. Birth…
