Sheep at dusk in field

RESEARCH AND DEVELOPMENT

Cape Wools NPC is the representative Industry Organization responsible for the consideration and evaluation of research projects within the woollen sheep environment. A research advisory committee, under the chairmanship of Dr George de Kock, and constituted from various representative Industry experts and scientists, is responsible to advise the Board of Directors of Cape Wools on all research applications. Each project is carefully evaluated by the committee and qualifying projects  recommended for approval to the Board. A short summary of current research projects funded by Cape Wools are provided below for interested readers. For more information contact capewool@capewools.co.za

Lucerne-cropping systems

Background

For sustainable wool production to continue in the semi-intensive winter rainfall cropping areas, increased fodder production per ha. per mm. rainfall is needed.

Objectives of the study

  • Feasibility of overseeding dryland lucerne in terms of seasonal fodder production.
  • Decision making on crop specie/s most suitable for overseeding dryland lucerne.
  • Evaluating the quality of fodder produced by the oversown pasture.

Rangeland Biodiversity

Background

For sustainable wool production in the arid extensive regions, it is important to determine the effect various grazing strategies has on the species composition and general condition of natural veld.

Aim of the project

The purpose of the Monitoring Program is to serve as a comprehensive and integrated framework for rangeland monitoring and management within various eco-regions within the Northern and Eastern Cape Provinces.

OJD Studies

Background

There is a need to demonstrate that the Gudair vaccine is an effective means of preventing the spread of Johne’s Disease. 

Goals of the study:

a) To determine the frequency of OJD in two South African resource flocks by ELISA, faecal culture and postmortem methods.

b) To determine the impact of vaccination for OJD on the status of resource flock animals derived from ELISA, faecal culture and postmortem methods.

c) To study the genetics and genomics of susceptibility to OJD.

Temperature Analysis

A final report was submitted on 7 May 2018 and a poster of the work was showcased at the 89th NWGA congress on 13/14 June 2018. A publication is being prepared to be submitted to the Australian Veterinary Journal.

Short Duration Grazing

Background

There is a need to demonstrate that the effect of High Density, Short term Grazing on farmer profitability as well as veld composition.

 It has been claimed that Holistic Management (HM) and specifically, Holistic Planned Grazing (HPG, hereafter holistic grazing), can reduce desertification and reverse climate change by using livestock as a tool. At the same time, high animal densities and stocking rates associated with holistic grazing are claimed to result in improved plant and animal production but with little evidence or suggested mechanisms for these changes. The project addressed these gaps in knowledge via a three-year trial and corral studies, fence-line contrasts of existing and long-term practitioners of holistic grazing in the grassland biome, and remote sensing over sub-Saharan Africa.

Useful applications of holistic grazing based on our data are:

  • Holistic grazing may be useful as a tool for specific purposes such reduction of heterogeneity of plant standing biomass; alternatively, managers who wish to enhance vegetation heterogeneity and possibly initiate the formation of grazing lawns might consider adopting season-long grazing which, in combination with fire, commonly used in FCG, may enhance biodiversity;
  • Degraded rangeland may be restored to higher levels of basal cover and forage palatability by matching the soil resource status to the appropriate grazing management approach, i.e. managers adopting more intensive rotational grazing might try maximizing grazing frequency on nutrient-rich soils, and grazing recovery on nutrient-poor soils;
  • Holistic grazing may be used to reduce tick loads;
  • High-density grazing practices do not increase plant or animal production and due to increased infrastructure and labour costs are thus less profitable than conventional season-long grazing or the four-camp approach;
  • Corrals at animal densities over 400 LSU ha-1 may be a useful disturbance regime for restoration
  • of bare ground and increasing phosphorus concentrations for cropping but only on already disturbed ground. 

Model for Lamb Production

Background

Raising lambs intensively in feedlots is becoming common in SA. As margins in intensive feeding systems are low, accurate growth curve data is important. 

 Aim of the project

The aim of this project is to develop a prediction model that can be applied to the growth and feedlot production characteristics of various South African sheep breeds.

Objectives of the project

  • To collect growth data and determine the growth curves of each breed and then to model the curves with nonlinear regressions.
  • To develop feed intake curves for each breed with the change in live weight.
  • To develop curves for the increase in backfat thickness, which is measured using ultrasound technology.
  • To develop curves to describe wool growth of the growing lambs of various wool breeds.
  • To determine the ideal slaughter weight of lambs from different breeds.
  • To assess the product quality of the wool, leather and meat obtained from the various breeds.
  • To develop curves to predict growth, intake, fat deposition and slaughter weight of crossbred lambs.

Evaluation of Tail Docking

Background

It is becoming increasingly important for wool growers to justify the need for husbandry practices that may cause temporary discomfort to sheep or lambs. 

Aim of the project

  • To determine whether tail docking has an influence on the prevalence of breech strike.
  • To determine whether tail docking has an influence on weight gain.
  • To determine whether long tails has an influence on reproduction.
  • To determine whether tail docking facilitates ease of shearing.

General

This study assessed the impact of tail docking in fine wool Merino lambs at Tygerhoek Research farm.  The tails of lambs in the control group were left intact while the tails of lambs in the docked group (treatment group) were docked with a hot iron at the third palpable joint at roughly 3 weeks of age.  Lambs were randomly allocated to either treatment within sexes (lambing seasons 2016 & 2017).

Milestones against set goals

a) To determine whether tail docking has an influence on the prevalence of breech strike.

Of the total of 161 tail intact lambs (control group) born across birth years, 12 suffered from breech strike (7.5%). A total of 14 docked lambs (treatment group) out of 164 present across years were struck (8.5%). When these frequencies were compared in a Chi²-test, it was evident that no treatment effect was present. 

b) To determine whether tail docking has an influence on weight gain

Weaning weight therefore wasn’t influenced by treatment. 

c) To determine whether long tails has an influence on reproduction

Second lambing season was from end of March to May 2019- data still to be analyzed.

d) To determine whether tail docking facilitates ease of shearing

At present there is no clear indication that tail docking has a beneficial effect on the shearing process, either in terms of time spent per sheep, or on the welfare of the sheep during the shearing process. Further studies on lifetime reproduction and breech strike susceptibility is being conducted.

Assessment of Ovine Meat Traits

Background

As the profitability of wool sheep farming is greatly influenced by the mutton price and as consumers become more discerning, finding ways to determine the heritability of meat quality of merino crossbred lambs is considered important.      

Milestones against set goals

a) To determine whether meat traits in the South African ovine genetic resource is affected by breed selection line and environmental effects in South African sheep

This study details slaughter and meat quality traits of lambs and yearlings from Merinos that were divergently selected for reproduction, Dormers and SA Mutton Merinos. It was found that there is a difference in carcass quality between the two most popular breeds used as terminal sires on merino ewe flocks. It appears as if selection for lean growth is required to improve the quality of mutton. 

b) To determine whether meat traits in the South African ovine genetic resource is affected by additive and non-additive genetic effects in South African sheep

The previous genetic and crossbreeding parameters will be updated in the coming year to improve on the estimates reported in the 2018 executive summary. With the bigger dataset described under the previous heading it will be possible to obtain more accurate genetic parameters with smaller standard errors. 

c) To determine whether access to genomic information using the Ovine SNP50K bead chip will add to breeding value predictions based on pedigree information alone

It was concluded that the continued generation of genomic data to allow for more    fundamental analyses on this and other resource flocks should be prioritized. 

d) Determining the accuracy of imputation from 12K to 50K using an Australian reference population

Following imputation from a 15k to 50k    density, mean accuracy levels of below the required 90% was observed but the observed results suggest that across country imputation could remain useful. Imputation from reference panels genotyped at densities higher than 50k as well as research into across country prediction is recommended.

e) Prediction of genomic breeding values using combinations of South African and Australian genotypic information

The project team will continue collaboration with the Australian group in order to make progress with this objective.

Disease-free Wool

Background

The presence of highly dangerous and contagious micro-organisms and pathogens e.g. viruses, viral Increased animal disease threats prompted the study to look at ways to sterilize wool in the case of an emergency disease outbreak.

The project concluded that without further work, the commercial sterilization of greasy wool by gamma-radiation cannot be recommended due to the associated changes in colour and area bisulphate and alkali solubilities. The results of the study are being written up in the form of a PhD thesis which is due to be submitted for examination during this year, and a paper will be prepared for submission to a peer reviewed journal. 

Critical Wool

Background

After a thorough study of the comfort properties of wool garments, as in comparison to garments made of synthetic fibers, found no evidence of wool being more comfortable, the need was expressed to examine the methodology of instrument-based comfort measurements.

 Since the start of the project on 1 July 2018, a comprehensive electronic and paper-based literature search, covering the past 70 years, or so, of all scientific publications dealing in any way with the comfort of textile fibers, fabrics and clothing has been undertaken and completed.

Copies of relevant publications will be acquired and critically examined and evaluated, in terms of the nature, soundness and validity of the experimental conditions and instrumentation employed, as well as of the results, interpretation of results, findings and conclusions drawn, with specific focus on any limitations and/or weaknesses which could possibly explain the anomalies and often contradictory results. The outcome of the above process will be integrated and summarized in the form of a table, which sets out, in a concise format, the cogent details of the various studies and any associated weaknesses or limitations.  A final report as well as a publication will be prepared. It is planned to complete the project by June 2020.

Heat Stress

Background

Climate change and global warming is placing a responsibility on the wool industry to find ways to select for traits in Merino sheep that will reduce the possible stress caused by high ambient temperatures.

Milestones against set goals

a) To assess breed differences in heat indicator traits in Dormer and SA Mutton Merino lambs born in autumn

Dormer and SA Mutton Merino lambs born at Elsenburg were monitored and measured for traits indicative of heat stress in the first 24 hours after birth. It appeared as if SAMM lambs showed more signs of stress. Lamb survival rate was not breed influenced. 

b) To assess the influence of natural tree shade on heat stress in Dormer and SA Mutton Merino lambs born in autumn

Lambs were able to regulate their own body temperature within the thermo-neutral range without negatively affecting lamb growth or production. Therefore, with the data collected so far, the provision of shade did not affect production traits of economic importance.   However, it is clear that the provision of shade enhanced animal welfare by alleviating heat stress resulting from high ambient temperatures prevailing at hot days. The dataset collected so far is still too small for the project team to be able to derive accurate heritability estimates for heat stress indicator traits in the resource flocks. Such parameters will be updated as more results become available. 

c) To study the breed differences in heat stress indicator traits in a wide range of breeds from the South African ovine genetic resource and to determine if these traits are repeatable and heritable

The homeothermic response of seven sheep breeds, namely the Dohne, Dormer, Dorper, Meatmaster, Merino, South African Mutton Merino (SAMM) and White Dorper, were studied The observed variation in heat stress indicators between breeds can be regarded as an indication of heritable genetic variation for the traits that are associated with heat stress.

Further research is required to determine how temperature and the adaptive responses of animals influence the welfare and productivity of sheep. An easily recorded indicator trait such as respiration rate should be assessed as a tool to improve within-breed heat tolerance by selection.

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