Selection for production and reproduction in South African Merino sheep is always combined with selection based on visual appraisal and will, in all probability, remain so for many years to come. Heritabilities for acceptability were estimated using a threshold model…
The object of this study was to estimate heritabilities and sire breeding values for stayability and reproductive traits in a composite multibreed beef cattle herd using a threshold model. A GFCAT set of programmes was used to analyse reproductive data…
The object of this study was to estimate heritabilities and genetic correlations for reproductive traits in a composite multibreed beef cattle herd using multitrait analysis. A REML procedure fitting a multitrait animal model was used to analyse data. Heritabilities and…
Genetic parameter estimates for scrotal circumference (SC), testis diameter (TD) and two-tooth liveweight (LW) were obtained for 1380 two-tooth Merino rams born from 1986 to 1998 on the Tygerhoek Experimental Farm. The effect of SC of service sires (n =…
Pedigree and race run data from Thoroughbreds racing in Southern Africa, covering the period 1986-2002 (63 146 horses in pedigree data-set and 778 532 race runs), were analysed in order to study genetic and environmental factors affecting the incidence of…
Data of 3272 lambing records collected on 818 ewes born from 689 dams and sired by 371 rams were used in the evaluation of ewe lifetime productivity (total number born, number weaned and total weight weaned). These records were collected…
Data obtained from the Friesian Horse Studbook of Southern Africa and Friesian Horse Breeders’ Society of South Africa were analyzed to describe and evaluate the population regarding inbreeding and morphological body measurements. Eight different body measurements (height at withers, height…
Nodule size is an important indicator of leather quality in the ostrich leather trade. The present study investigated genetic variation in nodule size at five sites on the skin, namely the neck, back, upper leg, flank and butt. Nodule size…
Yearling live weight and fleece trait data were obtained from between 2214 and 2270 yearling SA Mutton Merino progeny of the Elsenburg flock during a 20-year period from 1983 to 2002. Information of (co)variances for these traits in SA Mutton…
The study investigated genetic parameters for egg and chick production recorded over an 8-month breeding season, as well as average egg and chick weight for pair-bred ostrich females. Estimates of h² were moderate for reproduction traits and very high for…
The objective of this research was to validate the maternal breeding value for preweaning gain as a predictor of genetic differences in milk production. Phenotypic variation in preweaning gain and in milk production measured by the weigh-suckle-weigh method was partitioned…
Sheep from a Merino selection experiment at the Tygerhoek research farm in the Southern Cape provided material for this study. The selection lines involved included a line selected for clean fleece weight, a "Wet and Dry" line, a fine wool…
Preliminary genetic parameters for nodule traits of ostrich skins were estimated to examine whether genetic improvement of skin quality is feasible. Average nodule size and density per dm² were determined on five localities on each of 439 ostrich skins. An…
Genetic parameters for growth traits in the South African Brahman breed were estimated using ASREML from data records of birth weight (BWT) = 41 509, weaning weight (WWT) = 37 705, yearling weight (YWT) = 22 682 and final weight…
(Co)variance components for linear type traits of South African Jerseys and Holsteins were estimated. Heritability estimates are mostly in agreement with other studies although some estimates for the Jersey population are lower. Genetic trends for conformation traits of the South…
An objective was defined for a breeding program in South Africa to improve the female fertility of the national herd. The aim of the study was to change the approach of defining a trait based on female fertility and to…
Records of the Elsenburg stud where the Dormer sheep breed originated in 1941, were analysed from 1941 to 1990 to investigate non-genetic factors contributing to early growth traits. The fixed effects, identified as having a significant (P < 0.01) effect…
The objectives of this study were to determine the effects of season, year of calving and parity on lactation period, calving interval, number of days open and dry period in Egyptian buffalo, and to estimate genetic and phenotypic parameters for…
A total of 3696 Test Day Milk Yield (TDMY) records of Brown Swiss cows raised at Konuklar State Farm in the Konya Province of Turkey were used for estimating phenotypic and genetic parameters for TDMY. The phenotypic and genetic parameters…
Heritability estimates for Kleiber ratios associated with growth were obtained for a Hereford stud, subjected to selection for growth over an 11-year-period. Heritability estimates obtained indicate that growth efficiency in terms of the Kleiber ratio is moderately heritable.
