Available information on the selenium (Se) status of grazing herbivores in South Africa is reviewed and collated in the form of a geographical distribution map. Marginal to acute Se deficiencies have been reported to occur in the Midlands region and…
Estimation of 300-day lactation yields of milk, fat, protein and lactose from combined morning and afternoon milk samples collected at five-weekly intervals is time-consuming, and proportional bulking of morning and evening samples is not always done correctly by farmers. This…
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…
Imbrasia belina is utilised as a food item by certain ethnic groups of southern Africa, but little is known of the genetic structure of this resource. The aims of this study were to determine whether the limited flight ability of…
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 aim of this experiment was to determine the site and extent of digestion of nutrients in sheep fed broiler litter alone (100% litter treatment), broiler litter plus 7.5% sugarcane molasses (92.5% litter treatment) and broiler litter plus 15% molasses…
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…
Twenty Holstein-Friesian cows, two to four months postpartum, were randomly assigned to two groups. The control group received no monensin, whereas the treatment group received 300 mg monensin per cow per day. Cows grazed kikuyu pasture and received maize-based concentrates…
Concentrations of eight essential elements (Ca, Co, Cr, Cu, Fe, Mn, Ni and Zn) and three toxic metals (Al, Pb and Sr) were measured in various tissue samples from African whitebacked (Pseudogyps africanus), Cape griffon (Gyps coprotheres) and Lappetfaced (Torgos…
The Texas A&M University (TAMU) Beef Cattle Production model was expanded to include basic concepts of quantitative genetics. The traits simulated were birth weight, yearling weight, mature weight and milk production. The progeny inherited attributes from both the sire and…
The aim of this study was to evaluate the livestock production potential of Panicum maximum cv. Gatton cultivated under dry-land conditions and grazed at various stocking rates after various periods of re-growth. Treatments included a high stocking rate, fast rotation…
The aim of the study was to evaluate the nutritional value of Panicum maximum cv. Gatton for sheep production in three different seasons and at three different stages of maturity. More mature pasture, compared to younger pasture, resulted in lower…
The aim of this study was to quantify the partial digestion of organic matter (OM), nitrogen (N) and neutral detergent fibre (NDF) in sheep grazing Panicum maximum cv. Gatton pastures at three stages of pasture maturity during summer, autumn or…
Milk production and milk composition responses to supplementation of Holstein-Friesian cows grazing kikuyu pasture in summer and a combination of annual ryegrass and maize silage in winter with 64 mg/d flavophospholipol were determined. There was no difference in the average…
A simulation study was carried out to investigate the effect of selection on the estimation of genetic parameters for butterfat production in dairy cattle. It was found that selection leads to a substantial overestimation of fixed effects and variance components…
This study was conducted to evaluate direct and correlated selection responses to selection for total weight of lamb weaned per ewe joined (TWW), number of lambs born (NLB), number of lambs weaned (NLW) and weaning weight (WW). Data from the…
(Co)variance estimates for birth weight, pre-weaning lamb survival and weaning weight were obtained for Merino lambs derived from 16 bloodlines. Between bloodline variance ratios (± s.e.) amounted to 0.10 ± 0.04 for lamb birth weight, 0.053 ± 0.036 for lamb…
The purpose of this review is to define possible breeding objectives for Southern African beef cattle farmers and to review different means of expressing genetic reproductive merit. The breeding objective considered was to maximize the number of calves born or…
Italian ryegrass (Lolium multiflorum cv. Midmar) is often fertilized with high levels of nitrogen (N) in order to ensure maximum dry matter (DM) yields. This practice also increases the N content of herbage. This study was conducted to determine whether…
This study was conducted to assess the effect of greenleaf desmodium (Desmodium intortum) and sweet potato vine (Ipomoea batatus) supplementation of napier grass on dry matter intake, degradation and rumen fermentation in Friesian steers. Four fistulated steers were offered napier…
