Two experiments were conducted to determine the response in performance, including uniformity and mortality, of two broiler strains to dietary protein content. In Experiment 1, 480 Cobb 500 and 480 Ross 788 day-old sexed broiler chickens were housed in cages…
The objectives of the study were to estimate genetic parameters for stayability in the South African Angus cattle and to compare the sire and animal threshold models. Data and pedigree information were obtained from the Integrated Registration and Genetic Information…
A method is presented for predicting the genetic superiority of rainbow trout (Salmo gairdneri) selected by multistage selection for body mass at ten months of age. Trout selections are currently based on successive gradings for body width at 2, 4…
Growth-related parameters, such as feed intake, growth rate and feed efficiency were investigated in ewe lambs of two genetically related synthetic lines and the Dorper. Ten ewe lambs in each of the three groups were individually fed in metabolism cages…
Data of Dormer (n = 290) and SA Mutton Merino (n = 306) lambs, born by ewes which were observed continuously during lambing in 1989-1991, formed the basis of this investigation. Progeny of SA Mutton Merino ewes were heavier at…
Italian ryegrass was evaluated over four seasons at stocking rates (SR) of 20, 24, 28, 32 and 36 ewes with lambs/ha. During each of three seasons, between 19 and 24 ewes per SR were milked for 10 weeks, from three…
Data of the Elsenburg Dormer sheep stud which was kept closed since its inception, were collected over a period of 50 years (1941-1990). These data were analysed to monitor the increase in actual level of inbreeding and to investigate the…
Data from the Elsenburg Dormer sheep stud were used to estimate genetic and environmental change in early growth traits from 1943 to 1990. Best linear unbiased predictions (BLUP) of breeding values were obtained by Restricted Maximum Likelihood (REML) procedures fitting…
In an investigation of the subjective categorization of pelt traits in Karakul lambs it was demonstrated that the common practice of treating the categories of a trait as equally spaced intervals is invalid.
Genetic trends owing to selection for an increase in pattern and hair quality and a decrease in hair length and curl development in the Karakul were estimated with the Animal Model in four selection lines and in a control flock…
For two weeks prior to the start of the breeding season, the suckling behaviour of beef calves, separated from their dams for 12 h out of 24, was investigated. Fifty-six per cent of the 44 cows which were separated from…
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…
An investigation was conducted into the effects of two phenolic amines, N -methyl-β-phenethylamine (NMP) and tyramine (T) on corpus luteum function and reproductive performance of Angora goats. Both compounds are widely distributed through the plant kingdom and, because of their…
Genes were introduced from the prolific Finnish Landrace sheep breed by crossbreeding with indigenous breeds to produce several composites. In this study, two of these composites were compared to the Dorper in terms of reproductive characteristics and growth. Mean ovulation…
This study was undertaken to investigate the genetic stability of an unselected Control Group of South African Merino sheep and genetic change in a flock selected for increased clean fleece mass (Selection Group) under the same environmental conditions. Data regarding…
African Mutton Merino ewes as supplementary feed during late pregnancy and lactation, while grazing wheat stubble at 2 ewes/ha during 1986 and 1987. Blood glucose, urea, calcium, magnesium and zinc levels of the ewes were monitored in 1986 only. Ewes…
Data from 267 individuals were used to. investigate factors influencing 13 linear type traits (scored on a 1-50 point scale) in progeny of a Merino flock subjected to 20 years of selection for increased clean fleece mass (Selection Group, 116…
Heritability estimates were obtained by using a unitrait derivative-free animal model REML programme. Estimates of heritability for curl type (h 2 = 0.46) and pattern score (h 2 = 0.27) followed expectations as derived from literature. The estimate for hair…
