Thesis (MScAgric)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: Regardless of the extensive game eradication during most of the previous century, the
game farming industry in South Africa has shown dynamic growth over the past few
decades. Currently the approximately 8 000 game farms have a total income of more
than R850 million per annum. Although there are various game species included in
these farming enterprises, three of the most important species for commercial farming
and meat marketing are springbok iAntidorcas marsupialisï, blesbok (Damaliscus
dorcas phillipsiï and impala (Aepyceros melampus).
Since nutrition is a key factor in the productivity of animals, any information on this
subject is essential for the successful management of a game farm. However, apart
from the general lack in applied research on game animals (due to the different
approaches by biologists and agricultural researchers), there is also only limited
information available on the nutritional requirements of game species or any of the
aspects affected by nutrition.
In order to address the above shortcomings in game animal nutrition, two separate
studies were conducted. The purpose of the first study was to determine the physical
body component and nitrogen (N) distribution in the springbok, blesbok and impala.
The chemical composition of the three-rib cut was also compared with that of the carcass. Amino acid requirements for growth of the three game species were
investigated in the second study according to the ideal protein concept. The essential
amino acid (EAA) profile of the whole empty body of the three game species was
compared with the EAA profile of the duodenal digesta in order to detect any
imbalances for optimal growth.
The same animals were used in both studies, namely eight of each of the three game
species. Characterization of the physical body composition revealed that the dressing
percentages (% of body weight; % of empty body weight) for the three game species
were: springbok (57.1 ± 2.4 %; 64.0 ± 2.5 %), blesbok (50.2 ± 2.1 %; 62.8 ± 1.4 %)
and impala (57.4 ± 2.2 %; 65.6 ± 2.0 %). The proportional distribution ofN between
the carcass, external offal and internal offal was also determined. The mean carcass N
concentration of the impala was higher (P<0.05) than that of the springbok and
blesbok on a dry matter basis. According to the carcass chemical composition, the
three game species seem to have a better potential for lean meat production (fat
content of carcass 4.7-5.2 %) than domestic sheep (17-25 % fat). Male animals had a
lower (P<0.05) fat and higher (P<0.05) moisture percentage in the carcass and threerib
cut than the females. The fat correlation between the three-rib cut and the carcass
on both an as-is and dry matter basis was significant across species and sexes. The
protein content of the same cuts did, however, not yield a significant correlation on an
as-is basis, and only the protein content of the springbok three-rib cut related (P<0.05)
to that in the carcass on a dry matter basis.
The second study concentrated on the nutritional requirements of springbok, blesbok
and impala, and more specifically the EAA requirements. Differences (P<0.05) were
found between the whole empty body EAA composition of the three game species.
These differences were present whether protein quantity was included in the
calculations (g AA/100 g crude protein) or not (expressed as % of lysine). The
chemical scores indicated that the four most limiting amino acids (three for impala) in
the duodenal digesta for whole empty body growth were: arginine, histidine,
threonine and methionine (springbok); methionine, arginine, histidine and lysine
(blesbok); and methionine, histidine and arginine (impala). Further disproportion of
the amino acids in the duodenal digesta was present in excess levels of isoleucine
(blesbok) and lysine, valine, leucine, threonine, isoleucine and phenylalanine (impala). The EAA:Lysine ratios of the whole empty body indicated a similar trend
for the three game species. / AFRIKAANSE OPSOMMING: Die essensiële aminosuurbenodighede van springbok,
blesbok en rooibok vir optimale groei: Ten spyte van die feit dat wild grootskaals uitgedun is gedurende die vorige eeu, het
die wildboerdery-bedryf in Suid-Afrika oor die laaste paar dekades dinamiese groei
getoon. Die totale inkomste van die ongeveer 8000 wildsplase beloop tans meer as
R850 miljoen per jaar. Alhoewel daar verskeie wildspesies is wat by hierdie tipe
boerdery ingesluit word, is die springbok (Antidorcas marsupialis), blesbok
(Damaliscus dorcas phillipsi) en rooibok (Aepyceros melampus) van die belangrikste
spesies vir kommersiële boerdery en vleisbemarking.
Voeding IS 'n sleutelfaktor in die produktiwitieit van diere en daarom is emge
inligting oor hierdie onderwerp noodsaaklik vir die suksesvolle bestuur van 'n
wildsplaas. Afgesien van die algemene tekort aan toegepaste navorsing op wilde diere
(as gevolg van die verskillende benaderings van bioloë en landboukundige navorsers),
is daar ook slegs beperkte inligting beskikbaar oor die voedingsbehoeftes van wilde
dierspesies of enige van die faktore wat deur voeding beïnvloed word.
In 'n poging om bogenoemde tekortkominge in die voeding van wilde diere aan te
spreek, is daar twee aparte studies uitgevoer. Die doel van die eerste studie was om
die fisiese liggaamsamestelling en die stikstof (N) verspreiding in die springbok,
blesbok en rooibok te bepaal. Die chemiese samestelling van die drie-ribsnit is ook met die van die karkas vergelyk. In die tweede studie is ondersoek ingestel na die
aminosuurbehoeftes van die drie wildspesies deur van die ideale proteïen konsep
gebruik te maak. Die bepaling van die essensiële aminosuurprofiel van die totale leë
liggaam van die onderskeie drie wildspesies is bepaal en met die essensiële
aminosuurprofiel van die duodenale-inhoud vergelyk, ten einde enige wanbalans vir
optimale groei vas te stel.
Dieselfde diere is in beide studies gebruik, naamlik ag springbokke, blesbokke en
rooibokke. 'n Beskrywing van die fisiese liggaamsamestelling het aangetoon dat die
uitslagpersentasies (% van liggaamsmassa; % van leë liggaamsmassa) van die drie
wildspesies as volg was: springbok (57.1 ± 2.4 %; 64.0 ± 2.5 %), blesbok (50.2 ± 2.1
%; 62.8 ± 1.4 %) en rooibok (57.4 ± 2.2 %; 65.6 ± 2.0 %). Die proporsionele
verspreiding van N in die karkas, uitwendige afval en inwendige afval is ook bepaal.
Die gemiddelde N konsentrasie in die karkas van die rooibok was hoër (P<0.05) as
die van die springbok en blesbok op 'n droë materiaal basis. Dit blyk vanaf die
chemiese samestelling van die karkas dat die drie wildspesies 'n groter potensiaal het
vir die produksie van maer vleis (vet-inhoud van karkas 4.7-5.2 %) as skape (17-25 %
vet). Manlike diere het 'n laer (P<0.05) vetpersentasie en 'n hoër (P<0.05)
vogpersentasie in beide die karkas en die drie-ribsnit teenoor die vroulike diere gehad.
'n Betekenisvolle korrelasie is tussen die persentasie vet in die drie-ribsnit en die
karkas van al drie wildspesies en vir beide geslagte gevind, op beide 'n nat en droë
materiaal basis. Die proteïeninhoud van dieselfde snitte was egter nie op 'n nat basis
betekenisvol gekorreleerd nie, en slegs die proteïen-inhoud van die springbok se drieribsnit
het verband gehou (P<0.05) met die in die karkas op 'n droë materiaal basis.
Die klem van die tweede studie was op die voedingsbehoeftes van springbok, blesbok
en rooibok, en meer spesifiek die essensiële aminosuurbenodighede. Daar is verskille
(P<0.05) tussen die totale leë liggaam essensiële aminosuursamestelling van die drie
wildspesies gevind. Hierdie verskille was aanwesig afgesien daarvan of die
hoeveelheid proteïen in berekening gebring is (g aminosure /100 g ruproteïen) of nie
(uitgedruk as % van lisien). Volgens die chemiese tellings was die vier mees
beperkende aminosure (drie vir rooibok) in die duodenale-inhoud vir totale leë
liggaamsgroei as volg: arginien, histidien, treonien en metionien (springbok);
metionien, arginien, histidien en lisien (blesbok); en metionien, histidien en arginien (rooibok). Verdere wanbalanse in die armnosure van die duodenale-inhoud was
aanwesig in die oormaat isoleusien (blesbok) en lisien, valien, leusien, treonien,
isoleusien en fenielalanien (rooibok). Die verhouding van die essensiële aminosure tot
lisien van die totale leë liggaam het by al drie wildspesies dieselfde tendens getoon.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/52524 |
| Date | 12 1900 |
| Creators | Van Zyl, Liana |
| Contributors | Ferreira, A. V., Stellenbosch University. Faculty of AgriSciences. Dept. of Animal Sciences. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 86 p. |
| Rights | Stellenbosch University |
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