Overview of Genomic Selection in Zimbabwe
Animal production is likely to grow in both the developed and developing
countries. To meet future needs, genetic and genomic improvement of
animals must increase. Agriculture currently contributes about 6 % to
the gross domestic product (GPD) and ranks third after mining and
tourism in the economy of Zimbabwe. Livestock are estimated to
contribute about 19% to the agricultural GDP. This is in contrast to
45% contribution in highly developed economies, clearly indicating a
production gap. About 66% of the population derives its livelihood from
agriculture, with 40% doing so from the livestock sector.Rural farmers
have an average of 1-4 beehives for subsistence, with a few commercial
producers with up to 300 beehives. Production by most smallholders is
largely for home consumption. Production is estimated at 150 tonnes
annually, leaving a 60% unmet demand, especially by pharmaceuticals
firms and supermarkets. As a result, this gap is met by imports from
Zambia, Malawi and South Africa.
Variation among individual animals is caused by genetic and
environmental differences. If one considers all the different breeds of
sheep and goats and various strains within breeds one can conclude that
there is a wide variation in performance traits for o small ruminants.
All traits provide a high selection potential. There is much greater
potential for increasing both biological and economic efficiency of lamb
and kid production through genetic improvement. Such potential depends
on the magnitude of genetic parameters for the traits of economic
importance. Selection for traits of economic importance has not been
exploited fully in small ruminants. This is well illustrated with
Matabele goat. In Matableeland South and North provinces there are
differences in the Matabele goat in terms of horns and ears. This is so
conspicuous that one can categorize them into local area strains. There
are Matabele goat strains of Gwanda (Tuli), Kezi, Plumtree Ntabazinduna,
Beitbridge and Mbembesi districts. Similarly this can also be said of
the Mashona East African type of goat and the Save sheep of Zimbabwe.
The Zimbabwe Herd Book was established by an Act of Parliament in 1980
to oversee the registration of pedigree livestock. Stud breeding
involves the controlled mating of livestock and detailed birth
notifications of progeny with parents are recorded with the Herd Book.
In addition, stud breeders record the fertility, survival and growth
performance.
Livestock production depends on three pillars: genetics, health and
husbandry. Stud Breeding - genetics - is the cornerstone of commercial
livestock production. A strong commercial industry is dependent on a
healthy and vibrant stud industry to offer stud/breeding stock that meet
requirements in a range of production environments and market scenarios.
At its annual National Sales, all animals on offer have undergone
veterinary examination and inspection so that the livestock industry is
offered a wide range of top-quality genetics. Stud breeding is a
long-term passion where breeders strive to breed the ‘best’ animal.
Breeders apply modern breeding technologies to carefully select animals
to be parents of the next generation and in so doing, improve the
genetic merit of future generations.
Breeders also select parent material from outside the country in the
form of live imports, semen and embryos. Stud breeding also requires the
meticulous recording of parentage (pedigree) as well as specific
performance data that measures reproduction, survival and growth. These
performance figures, together with the parentage information, are used
to select the best animals to be parents of the next generation. Genetic
improvement is therefore passed on from generation to generation and
from the stud herd to the commercial herd.
ZHB has recently implemented Breed Plan, the leading performance
evaluation software from Australia. The industry can now avail itself of
the latest technologies that provide both breeders and commercial
producers with accurate genetic assessment of animals that are selected
for breeding purposes. A wide range of genetic material is also
available for commercial producers who want to select the best breeds
and breed combinations to meet their particular production environments.
It is more economical to select the right breed for a particular
production environment than adapt the environment to meet the
requirements of the breed.
In Zimbabwe, Pure breeds of Tuli, Nguni, and Mashona cattle are
available but there a very few breeders registered with the Zimbabwe
Herd Book. No performance recording scheme has been developed for small
ruminants (sheep and goats) in Zimbabwe. The Zimbabwe Herd Book (ZHB)
records ancestry of all recognized livestock breed societies. Almost all
major small ruminant (sheep and goat) breeds have registered breed
societies. Breed societies were founded for the purpose of establishing
breed purity by recording ancestry and defining the standards towards
which selection should be made. Identification of sheep and goats is
done by individual farmers. They also record ancestry. There is a need
for a national performance recording scheme in small ruminants. This
should involve data collection by participating farmers or a responsible
agent and submission to a data processing centre. The data should be
analyzed at the centre to obtain estimates of breeding values of tested
animals. These estimates are returned to the farmer and form the basis
of selection within, and between herds. Farmers can have selection
programmes on their farms and also make informed decisions when buying
breeding stock; focus on traits of economic importance taking into
account the age. To have a huge impact, selection needs to be done at a
large scale hence clustering, forming cooperatives and swapping animals
can be helpful. This approach also decreases inbreeding that
characterises the small -scale sector. Records and information are
critical in breeding and selection together with some infrastructure.