Roelof Johannes Coertze

University of Pretoria | UP · Department of Animal and Wildlife Sciences

The high moisture content of wet distillers’ grains with solubles (WDGS) has limited its feeding value despite the relatively high nutritive value. The co–ensiling with whole–plant maize, as a complementary feed, was evaluated for growing lambs by formulating diets whose contents were: whole plant maize silage (WPMS) + sunflower oilcake meal (SOM)...

The objectives were to investigate the ß-carotene status of dairy cows under various production systems, and to determine the effect of pre-partum ß-carotene supplementation on their post-partum ß-carotene status. Ten farms were selected from each of the three production systems, namely pasture-based, hay-based total mixed ration (TMR) and silage-b...

Context Reducing emissions of greenhouse gases from livestock production systems is a global research priority. Forages that contain condensed tannins, such as the perennial legume Lespedeza cuneata, may help to reduce ruminant methane (CH4) emissions. Aims The objective of this study was to investigate the effect of feeding different levels of L....

The aim of the present study was to determine whether sunflower meal (SFM), a highly rumen degradable protein (RDP) source, can be substituted with non-protein nitrogen (NPN, urea) without impacting negatively on intake, digestibility, rumen fermentation and microbial nitrogen (N) synthesis (MNS) in wethers consuming low quality Eragrostis curvula...

The aim of the present study was to determine whether sunflower meal (SFM), a highly rumen degradable protein (RDP) source, can be substituted with non-protein nitrogen (NPN, urea) without impacting negatively on intake, digestibility, rumen fermentation and microbial nitrogen (N) synthesis (MNS) in wethers consuming low quality Eragrostis curvula...

Wet distillers grains with soluble (WDGS) were blended with whole maize plants on an as-fed basis at 0%, 20%, 30%, and 40% and ensiled in 3 L bottles to evaluate the silage fermentation characteristics and ensiling quality in a complete randomized design. Each treatment was ensiled in 15 mini-silos and three bottles were opened on days 7, 21, 42 an...

This study investigated the effects of replacing rapid-release nitrogen (N) from urea with a graded level of slow-release N (Optigen® II) source on intake, digestibility, rumen fermentation and microbial protein synthesis, when sheep were fed a poor-quality roughage diet. Five rumen cannulated wethers were used in a 5 x 5 Latin square experimental...

Four Venda indigenous scavenging (VIS) chickens (one young male and one young female of 10–16 weeks of age, a mature cockerel and a mature hen) were randomly purchased from each of six adjacent rural villages during three different seasons (autumn, winter and spring) to determine the meat yield and carcass chemical composition. A total of 72 chicke...

Rumen protected amino acids (RPAA) are increasingly being used in dairy cattle diet formulation to obtain the required concentrations of lysine and methionine in metabolisable protein for optimal milk and milk protein production. The objective of this study was to evaluate the relative bioavailability of a liquid rumen protected lysine prototype us...

The first limiting nutrient for sheep at maintenance receiving poor quality hay is rumen degradable protein (RDP), and addition of urea can substitute part of the RDP (Köster et al., 1997). However, urea is highly soluble and can cause rapid increases in rumen ammonia (NH3-N) concentrations. The aim of this study was to determine whether a slow rel...

________________________________________________________________________________ Abstract Sixty high-producing multiparous Holstein cows were used in a randomized complete block design experiment to determine the effect of a direct-fed microbial (DFM), Megasphaera elsdenii NCIMB 41125 (Me), on dairy cattle productivity and health. The cows received...

The selenium (Se) status of lambs grazing kikuyu (Pennisetum clandestinum) or ryegrass (Lolium multiflorum) in the KwaZulu-Natal Midlands was determined during four trials and their growth response to Se supplementation was measured. Two methods of Se supplementation were evaluated using a 2 × 2 factorial experimental design per season: a control,...

This study examined intraspecific variation in mineral composition and rumen degradability of Atriplex nummularia plants and the influence on selection preferences of sheep. Individual plants were categorised into high, medium and least preference groups by assessing the order in which they were selected by sheep. Nine plants were selected from eac...

Atriplex species/cultivars [Atriplex nummularia, A. canescens (Santa Rita) and A. canescens (Field Reserve 1)] were compared in terms of chemical composition and in vitro digestibility. The plant material was sampled at different seasons (autumn and winter) and from different sites (Hatfield in the Gauteng Province and Mier and Lovedale, both in th...

An experiment examined the benefit of feeding fishmeal to high-producing Jersey cows receiving a maize-based supplement (6 kg/d), while grazing kikuyu pasture in late summer. Three groups of 14 cows received no additional supplement (control), a low fishmeal or a high fishmeal supplement (4 or 8% fishmeal replacing some of the maize). All supplemen...

This study was conducted to determine the effects of monensin or virginiamycin, or both on the performance of and some energy balance parameters in Holstein cows. Forty multiparous Holstein cows were used in a randomized complete block design experiment. The basal diet was a total mixed ration based on lucerne hay (38% of DM) and ground maize (34%...

________________________________________________________________________________ Abstract This trial was conducted to test the hypothesis that early lactation cows grazing ryegrass pasture and receiving maize and mineral supplementation could respond to additional supplementation with a protein source such as fish meal. Multiparous Jersey cows in e...

This study was undertaken to determine the infl uence of 3 grazing pressures [20 (HGP), 33 (MGP) and 50(LGP) g DM/kg LW/d] using South African Mutton Merino wether lambs, on qualitative and quantitative intake of Triticum × Secale cv. Pan266 (triticale) and Lolium multi-fl orum cv. Midmar (ryegrass) pastures as well as animal performance. Oesophage...

_______________________________________________________________________________ Abstract Growth and carcass characteristics of three Ethiopian goat breeds, the Afar, Central Highland (CHG) and Long-eared Somali (LES) were evaluated using three grainless diets varying in concentrate:roughage ratios (diet 1 was 50:50, diet 2, 65:35 and diet 3, 80:20)...

This study was undertaken to determine the influence of three grazing pressures [high (HGP), medium (MGP) and low (LGP), corresponding to 30, 50 and 75 g available DM/kg BW/day, respectively] on the quality of herbage consumed by lambs grazing Lolium perenne and Dactylis glomerata pastures in spring. Feed samples collected via oesophageal fistulae...

This study was undertaken to determine the influence of three grazing pressures [high (HGP), medium (MGP) and low (LGP), corresponding to 30, 50 and 75 g available DM/kg BW/day, respectively] on the performance of lambs grazing Lolium perenne and Dactylis glomerata pastures in spring. Feed intakes and average daily live weight gains (ADG in g/day)...

Silages made from directly cut or wilted Digitaria eriantha treated with or without molasses were evaluated to determine fermentative characteristics. The grass was harvested at the boot stage of growth and the material was ensiled in 1 kg mini-silos. Treatments were arranged in a factorial design of two moisture levels (directly cut or wilted) and...

Silages made from directly cut or wilted Digitaria eriantha treated with or without molasses were evaluated to determine fermentative characteristics. The grass was harvested at the boot stage of growth and the material was ensiled in 1 kg mini-silos. Treatments were arranged in a factorial design of two moisture levels (directly cut or wilted) and...

________________________________________________________________________________ Abstract A study was conducted to test whether supplementation of trace elements would have any beneficial effect on year-old ewes receiving a submaintenance level of nutrition. The ewes were fed a poor quality hay. The control group received no supplementation (Treatm...

The effect of the heat processing on the bioavailability of selenium (Se) in soybean seed containing 324μgSe/kgdry matter (DM), was investigated by measuring the accumulation of Se in rumen bacteria, bodily tissues and whole blood of sheep fed diets containing differently heat processed soybean. Ground soybean seed was subjected to three heat proce...

The aim of this study was to investigate the effect of two carbohydrate sources, barley and maize, on the ruminal fermentation of Atriplex nummularia cv. De Kock fed to sheep. Barley was used as a source of rapid fermentable carbohydrates while maize was used as a moderately fermentable source. Ten rumen cannulated Merino wethers were fed different...

This study was undertaken to determine the degradation characteristics and in vitro gas production kinetics of drought tolerant shrubs (Cassia sturtii, Atriplex nummularia and three Atriplex canescens cultivars, viz. Santa Rita, Field Reserve 1 and Rincon) growing under South African conditions (Hatfield in the Gauteng Province and Mier and Lovedal...

This study was undertaken to determine the influence of three grazing pressures [high (HGP), medium (MGP) and low (LGP), corresponding to 30, 50 and 75 g available DM/kg BW/day, respectively] on the quality of herbage consumed by lambs grazing Lolium perenne and Dactylis glomerata pastures in spring. Feed samples collected via oesophageal fistulae...

The scent-marking frequency of adult leopards when spraying urine and clawing trees was studied in the southern Kalahari. Between the leopard classes, males scent-marked significantly more frequently than females with and without cubs. Males spray-urinated 2.3 times as often as females without cubs and 5.9 as often as females with cubs. Moreover, i...

In prey-rich environments, leopard survival is ensured by an energy-maximizing, prey-selective strategy through which the leopard obtains the maximum amount of energy as food for the minimum amount of energy expended in hunting. In prey-poor environments, like the southern Kalahari, this is impossible. These leopards must use other strategies for s...

Leaves of three Atriplex spp. and Cassia sturtii grown in two different locations in South Africa were analysed for certain nutritive characteristics. Crude protein values ranged from 176 to 234 g/kg DM for the Atriplex spp. and for C. sturtii from 114 to 147 g/kg DM. The in vitro digestible organic matter concentrations for the Atriplex spp. varie...

The aim of this study was to evaluate the quality and quantity of cashmere produced by Boer goats in South Africa. No significant differences were found between reproductive status and qualitative and quantitative characteristics of cashmere produced by Boer goats. Both fibre production and fibre diameter did not differ between two to three year ol...

The main disadvantages of the rumen fluid in vitro technique are the cost and welfare issues of keeping cannulated animals. The purpose of the study was to find an accurate alternative in vitro technique to determine organic matter digestibility (OMD) of Atriplex nummularia supplemented with two energy sources. The in vitro faeces technique of El S...

The aim of this study was to evaluate the nutritional value of Atriplex spp. for small stock production. Selected plants were harvested and analysed for crude protein, in vitro digestibility and leaf to stem ratio. Significant differences in nutritional value were noted between leaves and stems as well as between sites for the three Atriplex spp. S...

The objective of this study was to quantify the macro and trace mineral concentrations of Atriplex canescens, A. halimus, A. nummalaria and Cassia sturtii at two different sites in South Africa. Statistically significant differences in Ca, P, Mg, Se, Zn and Mn concentrations occurred between plants and sites. Calcium, Mg, Zn and Mn were present in...

The aim of this study was to evaluate the interspecies variation in oxalic acid (OA) concentrations of leaves between Atriplex canescens, A. halimus, A. nummularia and Cassia sturtii. Significant differences in the oxalic acid concentration were noted between the three Atriplex spp. and C. sturtii at Hatfield. Cassia sturtii at Lovedale also had a...

Many arid and semi-arid areas have been degraded to bare patches and interventions are necessary to restore a productive state. Fodder shrubs, both exotic and indigenous, have been used for revegetation and reclamation. Ideally the species to be used should be adapted to arid conditions. This trial included one exotic (Cassia sturtii) and two indig...

The aim of this study was to quantify the suitability of Boscia foetida as a fodder source for goats. Samples of leaves and twigs were taken in the Northern Cape and Limpopo provinces of South Africa. The concentrations of Ca, Mg, and Mn in leaves and stems were sufficient for production, but both leaves and stems lack in P, Cu and Zn. Crude protei...

The objective of this study was to investigate the effect of level of rumen protected conjugated linoleic acid (CLA) 35 on milk yield and composition in Saanen goats. Eight multiparous goats were used in an eight animals and four periods repeated Latin square experimental design. Supplementation levels were based on 10% of the recommended level for...

Thirty Holstein cows in early lactation were used in a randomised complete block design to compare a lysine deficient diet, which was sufficient in methionine, to the same diet supplemented with a rumen protected lysine product. The lysine supplementation resulted in an optimal dietary lysine : methionine ratio in metabolisable protein of 7.2:2.4....

The aim of this study was to evaluate two techniques, Optical Fibre Diameter Analysis (OFDA) and Video Image Analysis (VIA) that were used to measure fibre diameter of cashmere and guard hair produced by South African indigenous goats. The fibre measured by the OFDA technique was less fine than that measured by the VIA technique. The findings of th...

The aim of the study was to determine the qualitative value of Cenchrus ciliaris cv. Molopo and Gayndah utilized by small ruminants as a foggage (standing hay). Molopo material had crude protein (CP) concentrations that varied from 76 to 101 g/kg DM and Gayndah CP concentrations ranging from 78 to 135 g/kg DM over a five week period. Molopo had in...

The effects of type of carbohydrate supplementation on intake and digestibility of Atriplex nummularia cv. De Kock were investigated. Ten rumen cannulated sheep were fed different increments of maize and barley supplements (0%, 15%, 30%, 45%) to a basal diet of A. nummularia cv. De Kock. Supplementation of A. nummularia cv. De Kock with an energy s...

The aim of this study was to evaluate the effect of level of nitrogen (N) fertilisation and stage of maturity on certain qualitative parameters and dry matter (DM) production of Panicum maximum cv. Gatton during autumn. Treatments included seven levels of N fertilisation (0, 25, 50, 75, 100, 125 and 150 kg N/ha) and harvesting at three stages of ma...

The aim of this study was to measure the effects of stage of maturity and level of nitrogen (N) fertilisation of Panicum maximum cv. Gatton on intake, ruminal fermentation and the partial digestibility of organic matter (OM) in sheep grazing the grass. More mature compared to younger pasture resulted in lower N, higher neutral detergent fiber (NDF)...

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 quality being selected. This was reflected in lower N values, lower digestibility and higher NDF, ADF...

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 treatment (A), a medium stocking rate, medium rotation treatment (B) and a low st...

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 winter. As pasture progressed from the young to the mature stage, OM digestibility decreased for all seas...

The investigation entailed four trials in which selenium (Se) was supplemented to lambs grazing kikuyu (Pennisetum clandestinum) pastures during two summer periods or Italian ryegrass (Lolium multiflorum) pastures during two winter periods. Two methods of supplementing the lambs were tested, via fertilizing the pasture with Se and/or injecting a lo...

Most prediction equations of feedlot performance cover average daily gains (ADG) below 1.5 kg/d. The question is whether these equations would be accurate for higher ADG. Medium-to-large-framed weanling and yearling steer calves were fed individually using a transponder-electronic gate system in three feedlot trials and fed in groups in two trials....

The influence of sire breed and breed genotype of dam on birth and weaning mass in calves of Afrikaner, Hereford, Simmentaler and Bonsmara cattle, as well as Fl> and two-and three-breed rotational crosses between Afrikaner, Hereford and Simmentaler were investigated. Afrikaner bulls sired calves with lower birth and weaning mass (P .;;; 0.05) than...

The influence of different breeds of sire and dam types on cow productivity in an arid, subtropical environment was studied. Cows with calves sired by Simmentaler, Hereford and Bonsmara bulls were more (P less than 0.05) productive than those with calves sired by Afrikaner bulls. Simmentaler sires were superior (P less than 0.05) to Bonsmara sires....

Response of Dorper sheep to treatment with FSH and PMSG and fertilisation after natural service, natural service following application of PGF2 alpha-containing gel on the posterior os cervix and surgical insemination with fresh semen were evaluated. FSH gave a significantly (P greater than 0.05) better response than PMSG. No significant differences...

Results from various straight- and crossbreeding trials conducted in South Africa were reviewed. The conclusion is drawn that in some instances, initial crossbreeding followed by inter se mating of crossbred cattle give the same if not better results than continued crossbreeding. This facilitates rangeland improvement as it limits the number of pas...

The influence of sire breed and breed genotype of dam on calving interval (CI) and cow productivity (CP) in Afrikaner, Hereford, Simmentaler and Bonsmara cattle, as well as in Fl, and two-and threebreed rotational crosses between Afrikaner, Hereford and Simmentaler were investigated. Cows bred to Afrikaner and Bonsmara bulls exhibited longer (P < 0...