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DETERMINATION OF SOME BLOOD PARAMETERS IN THE AFRICAN LION (PANTHERA LEO)Erasmus, Heidi Louise 06 September 2010 (has links)
The goal of this study was to generate a database of laboratory results for African
lion (Panthera leo) blood to obtain reliable reference ranges to augment what is
currently available in literature. Also to investigate the possibility of age and sex
having an influence on these reference ranges.
The specific objectives of this study were:
o to determine reference values for haematological and biochemical
blood variables for lions bred in captivity, as a function of age and sex;
o to evaluate the Beckman Coulter Acâ¢T 5diff Haematology Analyzer for
lion differential white blood cell analyses;
o to determine morphometric measurements and establish reference
growth curves (and range reference values) for lions bred and reared in
captivity as a function of age and sex; o to determine reference values for some practical and meaningful body
measurements and their correlations.
This study was conducted on three lion ranches in the Free State province and at the
Bloemfontein Zoological Gardens (Bloemfontein Zoo) with captive lions (Panthera
leo) of both sexes and ages ranging from three months to nine years. Lions were
divided into four age groups according to published literature.
Animals were chemically immobilized (darted) with Zoletil® 100 at 4 to 5mg/kg in
their holding camps and moved to a shaded place as soon as the drug had taken its
full effect. Blood was collected into three different types of blood collection tubes
and body measurements were taken. This was all done as fast as possible before
the effect of the immobilizing drug could wear off. In some cases it was necessary to
give an animal a top-up dose to prevent it from waking up too quickly. Animals were
moved back to their holding camps to fully recover from the immobilization.
Blood analyses done with the Acâ¢T 5diff Haematology Analyzer from Beckman
Coulter® for haematological parameters was conducted within 30 minutes after blood
collection. Blood for biochemistry parameters was centrifuged, serum collected and
cryo preserved at -20°C until it could be taken to the laboratory for analyses. Blood
smears were made on the lion ranches and Bloemfontein zoo immediately after the
analysis with the Acâ¢T 5diff Haematology Analyzer, fixed and packed for transport to
the laboratory.
At the laboratory the serum was used for biochemistry analyses, using standard
laboratory techniques. Blood smears were stained and examined under a light
microscope for the differential white blood cell count by means of the manual-visual
method.
Results were statistically analyzed to determine reference ranges and the influence
of age and sex on these reference range values for the different parameters, were
considered. Body measurement were also statistically analyzed to determine correlations
between body weight and different other measurements. These correlations were
then used to determine if it will be possible in a field situation to use the age and sex
of an animal together with a certain body measurement to estimate body weight
accurately, if actual weighing was not possible.
From these analyses it was concluded that age and sex do have an influence on
blood analysis and blood reference ranges for the African lion (Panthera leo).
Unfortunately, it differs between parameters and there is not one rule to apply. The
conclusion could also be made that body weight could be determined by measuring
the head length of an animal. More research is warranted to obtain more data set
and establish range reference values that can be validated and used with a high
degree of confidence in the lion breeding industry.
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PRODUCTION PARAMETERS FOR BOER GOATS IN SOUTH AFRICAKing, Felix Joao Manuel 06 September 2010 (has links)
In the first study performance data from 465 Boer goat rams tested in a central performance test
in the Northern Cape Veld-Ram Club from 1989 to 2007 were analysed to determine the
relationship between performance and sale price. Rams were subjected to extensive management
conditions on natural pastures for 160 days and finished-off in a feedlot for 50 days. Upon the
conclusion of the entire test period, the rams were auctioned. Performance information was
available for buyers for decision making. Traits analysed included final weight (FW), final
weight index (FWI), average daily gain (ADG), average daily gain index (ADGI), growth per
day of age index (ADOI), Kleiber ratio (KR), auction weight (AW), scrotal circumference (SC),
selection index (SI) and sale price (SP). Stepwise regression analyses, using proc GLM of SAS
were performed to identify variables that significantly influenced sale prices. Final weight was
significant in eight out of eighteen years, auction weight was significant in six of the seven
years measured and selection index influenced prices in seven out of ten years. Scrotal
circumference, average daily gain, final weight index, average daily gain index and Kleiber
ratio had little influence on sale price. Growth per day of age index did not show any influence
on sale price.
Price was positively correlated (P<0.05) with many of the performance traits. All significant
correlations were moderate to high and ranged from 0.37 to 0.80. The amount of variation in
sale price accounted for by the performance traits ranged from 15% in year 1991 to 65% in 1998.
The most important traits influencing sale price (SP) were final weight, auction weight, and
selection index. The results indicated that buyers of stud rams put more emphasis on production traits such as body weight and that they recognize the importance of performance data as shown
by their preference for animals with high selection indices.
In the second study data consisting of 3855 records and collected from 1998 to 2008 were
analysed to estimate genetic parameters for economic traits in two Boer goat flocks. The traits
investigated were weaning weight and post-weaning weight. Least square analysis was used for
estimation of environmental effects. Genetic parameters were estimated from single and bivariate
trait analyses using ASREML software fitting animal models. By ignoring or including maternal
additive genetic effects and their covariance and maternal permanent environmental effects
seven different models were fitted for each trait. The fixed effects of sex, type of birth, age of
dam, year of birth, herd, season and age of lamb, were all significant (P<0.05) for both traits. The
direct heritability estimates varied from 0.24 for weaning weight to 0.31 for post-weaning
weight. The corresponding maternal permanent environment due to the dam was 0.10 and 0.44
respectively. The maternal heritability (0.03) for weaning weight was lower than its
corresponding direct heritability. Estimates of genetic parameters in this study confirmed that
selection for weaning weight would result in genetic improvement of Boer goats.
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THE EFFECT OF CORYNE BACTERIUM CUTIS LYSATE TO CONTROL SOMATIC CELL COUNTS IN DAIRY COWSPretorius, Christa 20 September 2010 (has links)
The main aim of this study was to evaluate the effectiveness of repeated inoculations
of a Corynebacterium cutis lysate (Ultra-Corn®) - a non-specific immune-stimulant,
to reduce the milk SCC in commercial dairy cows. An additional aim was to evaluate
if these inoculations had any detrimental effects on milk quality.
This study was performed in two separate trials, using Holstein cows with SCCâs
over 250 000 cells/ml of milk at different stages of lactation from two commercial
dairy farms in the Free State Province. On each farm, cows were paired according
days in milk and SCC, in order to obtain two homogeneous groups of experimental
animals. The two groups of cows in each farm were randomly allocated to a
treatment or a control group. Both groups in the same farm were managed under
the same conditions for the entire trial periods. The only difference was that cows
from the treatment group received 3 weekly inoculations of Corynebacterium cutis
lysate(Ultra-Corn® ), while those from the control group received distilled water for
injection (the same volume as the cows in the treatment group). Two similar trials were conducted, using the same basic experimental design.
Differences were only in the dose of the Corynebacterium cutis lysate inoculated per
cow treated, number of experimental animals and duration of the observation
periods. In Trial 1, cows from the treated group received 3 weekly vaccinations of
Ultra-Corn® (4 ml per cow, thus 80mg of Corynebacterium cutis lysate per cow)
injected subcutaneously (sc), while those from the control group received 3 weekly
sc injections of 4 ml distilled water. This was followed by 8 weeks of observation of
the effect of treatment on milk SCC and composition. In Trial 2, the three doses of
Corynebacterium cutis lysate administered weekly per cow for the treated group was
2ml/100kg, thus 40mg Corynebacterium cutis lysate/100 kg per cow. This was
followed by 8 weeks of observation of the effect of treatment on milk SCC and
composition.
Individual quarter milk samples were collected weekly from all cows and analysed for
SCC and a combined milk sample (from the measuring bottle in the milk parlour)
from each cow was also taken for butterfat, protein, lactose and urea content. The
results were compared between the two groups per farm, using ANOVA procedures
for repeated measures analysis, using the 95% confidence level (SAS, 2004).
The two farms were evaluated separately, due to the possible differences between
general management conditions, which could introduce serious confounding factors
if the results from the two farms were combined. However, it can be considered that
both dairy farms used an acceptable level of commercial dairy management
practices and produced an acceptable yield per cow under South African commercial
conditions.
In general no significant differences were recorded between the treated and control
groups of cows in both farms in both trials in terms of milk SCC, butterfat, protein,
lactose and urea content of the milk. In this study, the immuno-stimulant effect of
Ultra-Corn®, a Corynebacterium cutis lysate could not be confirmed in lactating
cows. Although this inoculant does not seem to have any detrimental effects on the main solids of the milk, its use cannot be justified as it did not significantly reduce
somatic cell counts in lactating cows.
Further research is warranted to develop and evaluate the effectiveness of vaccines
against mastitis causing organisms, in order to control SCC and mastitis in dairy
cows. However, when such studies are conducted it is advisable to use very high
number of experimental units and proper control trials should be conducted. All
efforts should be done to ensure minimum environmental changes during these
trials, which can introduce serious confounding effects in the experimental design.
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CHARACTERIZATION AND CRYOPRESERVATION OF SEMEN OF FOUR SOUTH AFRICAN CHICKEN BREEDSMosenene, Thatohatsi Madaniel Bernice 20 September 2010 (has links)
The aim of the study was to characterize and evaluate the quality of fresh semen of 4 breeds
of chicken and the susceptibility of cockerel semen to a cryopreservation protocol, assessed
microscopically for sperm motility and morphology and ultimately fertilizing ability
following AI. The differences between breeds were determined by comparing the fertilizing
ability and hatchability of fresh and frozen-thawed semen. The study was carried out at Glen
Agricultural Development Institute and at the University of the Free State. Four chicken
breeds, namely the Rhode Island Red, Potchefstroom Koekoek, New Hampshire and White Leghorn, were used. Qualitative characterization of the semen was performed in 28 cockerels
(7 per breed). Semen was collected using the massage technique twice a week in the first
trial. The eosin-nigrosin staining technique was used to microscopically evaluate the
morphology of the sperm from the different breeds. The fresh semen parameters evaluated
were ejaculate volume, semen colour, semen pH, sperm concentration, the percentage live
and dead sperm, sperm motility and the abnormalities of the sperm. The percentage live and
dead sperm, sperm motility and abnormalities were also evaluated for the frozen-thawed
cockerel semen.
During the second phase of the study, semen was collected 3 times per week from the same
cockerels. Semen was frozen using a fastâfreezing procedure on dry ice, with 10% DMSO as
the cryoprotectant. AI was performed on 4 different breeds of hens (20 hens per breed)
(Rhode Island Red, Potchefstroom Koekoek, New Hampshire and White Leghorn), using
fresh semen (control) and frozen-thawed semen. During AI of each breed, 10 hens were
inseminated with fresh and the remaining 10 hens with frozen-thawed semen.
The sperm characteristics of the semen samples of the 4 breeds recorded were ejaculate
volume, ranging from 0.3±0.1 to 0.4±0.1ml, semen pH of 7.6±0.4 to 7.7±0.3, sperm motility
(scale of 0-5) 2.8±0.8 to 3.1±0.9, estimated sperm motility 58.8±12.5 to 63.8±13.6%,
ejaculate concentration (x109 sperm/ml) of 320.4±286.5 to 748.5±475.3, percentage live
sperm 75.6±29.1 to 81.5±26.8%, and the percentage dead sperm 18.6±26.8 to 24.4±29.1%
respectively, with the percentage normal sperm ranging between 77.3±17.1 and 84.8±9.0%.
Head, mid-piece, tail and other sperm abnormalities of the fresh semen of the 4 breeds ranged
from 2.9±3.3 to 7.7±9.6%, 7.9±5.2 to 11.0±7.0%, 0.4±0.8 to 1.9±3.0% and 0.6±0.9 to
1.5±1.9%, respectively. Semen samples were frozen in pellet form on a block of dry ice, by
pipetting into the indentations on the surface of the ice. The frozen cockerel pellets were thawed following cryopreservation, by being placed into a test tube in a water bath (60°C),
and the tube shaken continuously until complete thawing of the pellet. During the time of
semen cryopreservation, a decrease in the number of live, morphologically normal sperm,
and increase in the percentage dead sperm and sperm with abnormalities were recorded. The
freeze-thawing process caused a significant (P<0.05) decrease in the percentage live sperm
and the sperm motility, ranging between 37.4±10.4 and 42.3±12.1% and 3.6±0.5 and 3.9±0.3
respectively. A consequent increase in the percentage of dead sperm (between 57.7±12.1 and
62.4±10.8%) was also recorded. The sperm abnormalities regarding sperm head
abnormalities ranged between 17.3±3.8 to 22.5±10.3%, the mid-piece abnormalities 7.9±3.8
to 10.4±2.0% and the tail abnormalities between 0.5±0.9 to 2.0±2.4% respectively for the
thawed semen. Frozen-thawed semen was thawed in a water-bath 60°C and hens were
inseminated twice per week using the frozen-thawed semen, and once a week with fresh
semen for a total period of two weeks. Data for the two trials were analyzed using the
ANOVA and the Tukeyâs Studentized Range (HSD) test for repeated measures (SAS system
General Linear Models Procedure).
A total of 973 eggs, from all breeds of chicken namely the Rhode Island Red, Potchefstroom
Koekoek, New Hampshire and White Leghorn were collected following AI with fresh and
frozen semen from individually caged hens. Eggs were collected, incubated and hatched to
check if fertile and normal chicks could be produced from frozen-thawed cockerel semen.
The difference in fertility and hatchability of the hens of the different breeds were compared
and found to be highest in Rhode Island Red, White Leghorn, and Potchefstroom Koekoek
respectively and lowest in New Hampshire using fresh semen. When using frozen-thawed
semen, the sequence of fertility performance was the White Leghorn, Rhode Island Red,
Potchefstroom Koekoek and New Hampshire, respectively. The effect of the numbers of sperm per AI dose on fertility, age at embryonic death, and hatchability of fertile eggs were
also evaluated. Low numbers of sperm per AI in the hens resulted in a decrease in the total
number of chicks hatched. The lowest fertility rate recorded was in the New Hampshire
(2.7%), when using frozen-thawed semen to inseminate the hens. This may be attributed to
the low numbers of sperm inseminated per AI dose. Egg hatchability of the fertile eggs was
high in the White Leghorn (13.6%), Rhode Island Red (12.8 %), Potchefstroom Koekoek (9.7
%) and low in New Hampshire (2.7%) respectively, which could possibly be attributed to the
egg size. Medium sized eggs were preferable for setting, in order to obtain an acceptable
hatch, as they generally hatch better than the larger eggs. The results recorded for fertility and
hatchability in the control group (fresh semen), was similar to the results recorded by other
researchers, showing that the AI method used was acceptable. There still exists a necessity to
develop an ideal cryopreservation method (diluent and freezing procedure), which would
allow for acceptable long term storage of cockerel semen in liquid nitrogen (-196°C) for
future use and export with minimum loss regarding sperm viability and fertilizing capacity.
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FERMENTATION CHARACTERISTICS AND NUTRITIONAL VALUE OF OPUNTIA FICUS-INDICA VAR. FUSICAULIS CLADODE SILAGEMciteka, Hugh 09 October 2009 (has links)
A laboratory study was under taken to investigate the nutritional value of different Opuntia varieties
from chemical analysis. One year old cladodes from six different varieties of Opuntia ficus-indica
namely Castello, Chicco, Fusicaulis, Montery, Morado and Rubasta were randomly harvested in
five replicates. The highest (P<0.05) average dry matter (DM) content was observed for the Chicco
variety and was the average for all varieties generally low (9.13%). There were no significant
difference (P>0.05) in ash content. Significant (P<0.05)differences among varieties were recorded
for crude protein (CP) (3.7 to 8.1%), acid detergent fibre (ADF) (13.6 to 17.4%), neutral detergent
fibre (NDF) (19.9 to 38.5%), cellulose (2.4 to 14.8%), hemicellulose (4.5 to 12.7%), lignin (2.51 to
21.5%), non fibre carbohydrates (NFC) (33.4 to 48.6%), ether extract (EE) (1.9 to 2.4%). The
average mineral composition were as follows, phosphorus (P) 0.18%, potassium (K) 3.02%, calcium
(Ca) 2.3%, magnesium (Mg) 3.6% and sodium (Na) 0.04%. It was concluded that in general
cladodes could be classified as a high moisture energy source with an energy level between that of
roughages and concentrates with a low CP and high Mg, K and Ca content.
In a second study the influence of dry matter (7.12 to 27.6 %) and molasses (0 to 24%) content on
the fermentation characteristics of Fusicaulis cladode silage was investigated. One year old cladodes
was ensiled in three litre square plastic bottles (six replicates). A higher DM content were
characterized with a lower (P<0.05) ADF, NDF, CP and EE content. The inclusion of molasses
resulted in a lower (P<0.05) ADF, NDF and EE content. An increased (P<0.05) acetic acid (AA)
content in Fusicaulis silage was observed as the level of DM and molasses increased. A higher
silage DM content resulted in a lower (P<0.05) propionic acid (PA) and butyric acid (BA) content.
No significant (P>0.05) influence of molasses on PA and BA occurred. Lactic acid (LA) content and
pH of cladode silage was increased (P<0.05) by higher DM and molasses levels. It was concluded
that the content of cladode silage could have detrimental effect on intake and animal performance.
In a third study, the effect of DM (35.5 and 37.4%) and molasses (0 and 24%) content of ensiled
cladodes on dry matter intake (DMI) and apparent digestibility by sheep was investigated. Twentyfour
merino wethers were randomly divided into 4 groups of 6 each. No statistical significant (P>0.05) influence of DM and molasses levels in Fusicaulis silage on the apparent digestibility of
DM and CP as well as metabolizable energy (ME) content occurred. The inclusion of molasses
resulted in a reduction in the ADF (P=0.08) and NDF (P=0.05) digestibilities. Apparent EE
digestibility was reduced (P<0.05) by a higher DM level. DM content of cladode silage had no
influence (P=0.42) on DMI by sheep. The inclusion of molasses influenced DMI favourably
(P=0.54). In contrast with molasses, a higher DM level (37.4%) in silage resulted in a higher
(P<0.05) metabolizable energy intake (MEI). Cladode silage supplied more or less in the ME
requirements of 30 kg wether lambs. Weight losses were decreased (P=0.07) by the inclusion of 24%
molasses. It was concluded that the laxative effect of cladode silage resulted in a higher rate of
passage through the digestive tract. Accordingly the digestibility and ME content of cladode silage is
relatively low. Accompanied by a low DMI, cladode silage as a sole energy source supplied only in
the maintenance requirement of sheep, especially when molasses was included at ensiling.
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IN VITRO EMBRYO PRODUCTION AND SEMEN CRYOPRESERVATION IN SHEEPMahoete, Nts'emelo 17 October 2011 (has links)
Two trials were conducted at Agricultural Research Council (Irene â Pretoria),
between March (autumn) and October (spring), 2008. The first trial evaluated the
effect of the oocyte harvesting technique on the quantity and quality of ovine
oocytes recovered, as well as the effect of the culture media used on embryonic
development. The second trial evaluated the effect of breed and semen
cryopreservation on the embryonic development following in vitro fertilization
(IVF).
For the first trial, ovine ovaries were collected from slaughtered animals at the
Boekenhout abattoir near Pretoria. All ovaries were immediately transported to
the laboratory for further processing and use in the trials. On reaching the laboratory, ovaries were processed, and oocytes were harvested, either by
slicing (140 ovaries), or follicular aspiration (167 ovaries). The oocytes collected
were matured, fertilized with fresh ram semen and cultured in order to produce
embryos. The average total number of ovine oocytes recovered per ovary, and
the total number of oocytes collected were higher (P<0.05) when using the slicing
(5.2±0.4 oocytes/ovary and 75.3±12.9 total oocytes) technique, compared to the
aspiration technique (2.6±0.5 oocytes/ovary and total of 40.3±9.1 oocytes). The
number of acceptable quality (intact cumulus layers) oocytes was also higher
(P<0.05) following the slicing (46.7±10.3 oocytes), compared to aspiration
(10.3±2.0 oocytes) technique. However, the number of poor quality oocytes did
not differ between the 2 oocyte harvesting techniques. The acceptable oocytes
were then matured in vitro for 24h and no difference (P > 0.05) in oocyte
maturation rate between the oocytes recovered using the slicing or aspiration
technique was recorded.
A comparison of the 3 culture media (Potassium simplex optimization medium -
KSOM, Synthetic oviductal fluid - SOF and Charles Rosenkrans medium - CR1)
used for maintaining subsequent embryonic development was then evaluated.
All oocytes were further matured, using the maturation medium - TCM 199
containing FSH, LH and E2, supplemented with 10% FBS. After maturation, the
oocytes were fertilized (using fresh ram semen) and incubated for a period of
18h. At the end of 18h fertilization period, oocytes were vortexed in an Eppendorf
tube containing 100μl M199 + 10% FBS for 1.5min. The vortexing was performed
to remove the cumulus cells surrounding the zygote. A total of 1405 presumptive
zygotes were randomly allocated to the 3 different culture media (481, 461 and
463 zygotes in KSOM, SOF and CR1, respectively). The zygotes were then
cultured for a period of 7 days. No significant difference between all 3 culture
media was recorded regarding cleavage rates, showing that culture media had
no effect on the subsequent cleavage. However, the percentages of embryos
decreased with an advancement of the embryonic developmental stages.
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DIE EFFEK VAN DIE VERVANGING VAN VISMEEL MET ALTERNATIEWE PROTEÃENBRONNE IN DIÃTE VAN BABER (Clarias gariepinus) LITLINGEBooysen, Rohan 23 October 2009 (has links)
Not available
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THE DEVELOPMENT OF BREEDING OBJECTIVES FOR HOLSTEIN AND JERSEY CATTLE IN SOUTH AFRICABanga, Cuthbert Baldwin 16 November 2010 (has links)
A sound breeding objective is the basis for genetic improvement in overall economic
merit of animals. Breeding objectives for Holstein and Jersey dairy cattle breeds in South
Africa were developed in the current study, using a systematic approach. First, a logical
framework with a profit focus was utilised to develop plausible selection goals for the
pasture-based and concentrate-fed dairy production systems in South Africa, leading to
an exhaustive list of objective traits influencing these goals and subsequently their
possible selection criteria. Next, economic values were calculated for those objective
traits for which there was adequate bio-economic data, viz.: milk volume, fat yield,
protein yield, live weight, longevity, calving interval and somatic cell score. A bioeconomic
model, simulating typical South African pasture-based and concentrate-fed
herds, was used to calculate economic values by determining changes in profit arising
from an independent unit increase in each trait. Alternative payment systems of four
major milk buyers in South Africa were used. Relative economic values, standardised to
the value of protein, were used to compare the relative importance of traits across breeds,
production systems and payment systems. Protein yield, fat yield and longevity
consistently had positive economic values and the converse was true for body weight and
calving interval. Economic value for volume was positive or negative, depending on
whether the payment system paid for it or did not. Economic values were reasonably
robust to fluctuations in the cost of feed and price of beef; with the exception of fat,
whose value became negative beyond the feed price of ZAR3.50. Protein was, overall,
the most important trait, although volume, live weight, longevity and somatic cell score were more important in some situations. Calving interval was the least important trait, its
value ranging from 4 to 22% compared to that of protein, probably because the model
used underestimated its value. Sire rankings on aggregate EBVs based on these
economic values did not differ much across breeds, production systems and payment
systems, most rank correlations falling in the range 0.70-0.99. A single breeding
objective may therefore be used for both the Holstein and Jersey breeds, across the
different production and payment systems. The basis for multiple-trait selection in the
major cattle breeds in South Africa has thus been developed. Considerable work,
however, needs to be done to enhance this breeding objective as well as facilitate its wide
adoption by industry.
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A PLANT BASED STUDY OF THE FEEDING ECOLOGY OF INTRODUCED HERBIVORE GAME SPECIES IN THE CENTRAL FREE STATEJanecke, Beanélri Bénene 13 March 2013 (has links)
Wag-ân-Bietjie Private Nature Reserve is situated ±30 km north of Bloemfontein in the summer
rainfall area. The northern part is 437 ha in size and represents a transition between grassland and
riparian vegetation. Vegetation types present are grassland, open thickets, dense thicket, drainage
lines of the Modder River, a wetland and disturbed area.
Phenology (seasonal leaf carriage) of plants formed the basis of this study. Percentage leaves in
each phenophase (Budding-, Immature-, Mature-, Yellow- and Dry leaves) was noted fortnightly
for specific marked trees and shrubs representing each vegetation type. The deciduous nature of
woody species influenced quality and quantity of browse available for herbivores. Consequently the
nitrogen concentration in faeces (Nf) of four game species was determined to indicate their
nutritional status through the different seasons. The rise and fall of Nf values corresponded to the
seasonal increase and decrease of leaves (phenology pattern). Nf ranged during four years from 18 â
37 gN/kgDM for giraffe, 14 â 33 g/kg for kudu, 16 â 35 g/kg for eland and 17 â 28 g/kg for impala.
Abovementioned minimum concentrations are close to, and in the case of kudu below known
critical values where animals start to lose body condition. Nitrogen is the most limiting nutrient in
the dry, cool season and is linked to protein percentage present in browse. Browse becomes a
limited resource in the winter, therefore certain game species moved seasonally to different areas
inside the private reserve in search of food. It was decided to supply feed in order to sustain animals and help them maintain body condition during the critical period that was established to be from
July/August to middle October. The duration of feeding is important and it is recommended to start
feeding from July at a low ration and then gradually increase feed towards the end of the critical
period in correspondence with the declining browse and grass resources.
Average monthly leaf carriage percentages were used to calculate browsing capacity per month in
each vegetation type and in the study area as a whole. Browser units that could be sustained on
browse resources within the 0 â 2 m stratum ranged from 1 â 6.7 BU between winter and summer
due to the deciduousness of all woody plants present in the study area. This justifies in some way
the provision of feed, or else the numbers of animals would need to be reduced to 1 BU which does
not represent sustainable populations. Viable population numbers, economic value, diet and
reproduction rates were used in determining the numbers of individual animals that can be stocked.
Grazing capacity of the area differed according to annual rainfall and increased with higher rainfall.
Consequently it needs to be recalculated annually.
Habitat occupied by all 17 herbivore species was determined. Some species did not historically
occur in the province. Most of them have adapted to the central Free State conditions over time,
while others were introduced more recently. Inter-species competition for space and food resources
proved to be high in the study area. A reduction in animal numbers has been recommended to limit
competition.
There is an ever increasing number of private game ranches in the province, >343 in August 2010,
that will benefit from this research. Some general, operational guidelines have been presented that
are applicable to the management of other game ranches in the province as well. When calculating
individual animal numbers equivalent to carrying capacity values of other areas, the percentage
grass and browse that herbivores include in their diet need to be adjusted to the specific area for
accurate stocking densities.
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CRYOPRESERVATION OF SOUTH AFRICAN INDIGENOUS RAM SEMENMunyai, Pfananani Hendrick 17 May 2013 (has links)
Semen was collected from the indigenous Damara, Namaqua Afrikaner, Pedi and
Zulu rams. Hundred and twenty eight (128) ejaculates were collected throughout the
entire study, with semen being collected twice a week (every Monday and Tuesday)
from each ram, using the electro-ejaculator. Ejaculates were collected in graduated
test tubes, placed in a thermo flask at 37°C, and transported to the laboratory for
evaluation within 1h interval. The raw or fresh undiluted semen was then
microscopically evaluated for volume, concentration, pH and sperm motility. The
sperm concentration was determined with the aid of a spectrophotometer
(Spermacue®) and the semen pH using a pH meter (Microprocessor pH/mV/°C Meter
Hanna HI 931401). A Computer Assisted Sperm Analysis (CASA) system was used
to evaluate the different sperm motility characteristics. All data were analysed using
the statistical GenStat® program. The analysis of variance (ANOVA) was used to test
for significant differences between treatments.
Characterization of the South African indigenous ram sperm viability (percentage
live/dead) of the semen samples was determined, using an eosin/nigrosin stain (60μl eosin/nigrosin and 6μl semen), in a thin smear. All sperm cells were evaluated on the
same day of semen collection with the aid of a fluorescent microscope (BX 51TF),
using an oil immersion objective (X100 magnification). The live sperm fluoresced
green, while the dead cells stained red. The live sperm cells were further categorized
as morphologically normal or abnormal. The volume of the indigenous ram ejaculates
ranged between 0.4 and 0.9mL. The sperm concentration recorded in this study
ranged between 0.9 and 1.3x109 sperm/mL, which are much lower when compared to
other studies. The semen pH recorded in this study ranged between 6.5 and 7.3 and
the sperm abnormalities ranged between 5.2% and 8.2% â which is regarded as
acceptable for fertilization.
To test the effect of storage temperatures on the viability of the diluted ram semen
stored for different periods of time, the same procedure of semen collection and
semen evaluation was followed. After the initial semen evaluation, all semen samples
were pooled and diluted equally in an egg yolk citrate extender in the ratio of 1:1(v/v).
The pooled semen sample was then divided into two portions, one sample being
stored at 5ºC, and the other at 15°C, following storage periods of 3, 6, 9, and 24h
respectively. Sperm characteristics were then recorded for each interval of storage. In
general the percentage total motile sperm recorded after a 24h period of storage at
15°C was higher (61.2%), compared to that at 3h (51.4%), 6h (50.1%) and 9h
(50.6%). From the results of this study it was concluded that diluted ram semen can
be successfully stored for 24h at 15°C, retaining sperm motility for the application of
AI.
When evaluating the effect of glycerol as a cryoprotectant, in the diluted ram semen
stored at two temperatures for different periods of time, the same procedure for semen
collection and evaluation was followed. After initial evaluation, all semen samples
were pooled and diluted equally with an egg yolk citrate extender containing 14%
glycerol in the ratio of 1:1 (v/v), resulting in a final glycerol concentration of 7%. The
pooled semen sample was then divided into two portions, one sample being stored at
5ºC and the other at 15°C, for periods of 3, 6, 9, and 24h. Sperm characteristics were
recorded at each interval of semen storage. Semen stored at 15°C recorded a 48.3%
total motile sperm after 3h of storage, but this increased to 50.4% following 24h of
storage. The percentage of total motile sperm remained relatively constant at 40% after 3h of storage and 40.8% after 24h in the semen stored at 5°C. The addition of
glycerol as a cryoprotectant demonstrated a protective effect on the sperm motility
characteristics of sperm stored at both 5°C and 15°C for up to 24h of storage. The
effect of different glycerol inclusion levels in the diluent, on the indigenous ram
semen characteristics following cryopreservation were evaluated. The same procedure
for semen collection was followed and semen was subjected to the initial evaluation
comprising sperm concentration, semen pH and sperm motility. After initial
evaluation of the ejaculates, the semen samples were diluted with an egg yolk citrate
extender (EYC) fraction A (without glycerol), in the ratio of 1:1 (v/v) and cooled over
a period of 2h to 5°C. All ram ejaculates were pooled and then divided into 4 portions
treatment (groups). The first group was diluted with EYC (fraction A), which served
as a control and the other 3 groups with EYC (fraction B) contained 7, 10 or 14%
glycerol (GLY) in the ratio of 2:1 (v/v), making final glycerol concentrations of 2.3,
3.3 or 4.7% respectively. The semen samples were equilibrated for 2h and then loaded
into 0.25mL semen straws. The straws were frozen in liquid nitrogen (LN2) vapour,
whereafter semen straws were plunged into the LN2 (-196°C). The semen straws were
thawed 7 days later, in a water bath (37°C) for 30 seconds. The sperm characteristics
(motility and velocity) were microscopically evaluated using the Sperm Class
Analyzer® (CASA) system. A 10% glycerol inclusion rate recorded a higher
percentage of total motile sperm (15.6%), compared to the 7% glycerol (12.8%) and
14% glycerol (8.5%) inclusion levels, although all these differences were not
significant. This study demonstrated that an egg yolk- citrate extender containing 10%
glycerol can be used to cryopreserve indigenous ram semen effectively, based on the
sperm motility characteristics. The low sperm motility results recorded when semen
was cryopreserved in an extender containing 14% glycerol also indicated a degree of
toxicity of glycerol at high inclusion levels in the semen extender.
Regarding the conventional slow cryopreservation (programmable freezer) of ram
semen versus semen cryopreservation in liquid nitrogen vapour, the same procedure
for semen collection and evaluation was followed. After the initial evaluation of the
raw semen samples, all ejaculates were pooled and then diluted using an egg yolk -
citrate extender (EYC) fraction A (without glycerol), in the ratio of 1:1(v/v) and
cooled over a 2h period at 5°C. After equilibration, the pooled semen sample was
further diluted with EYC fraction B, containing 14% glycerol, in a ratio of 2:1(v/v)resulting in a final glycerol concentration of 4.7%. The pooled semen sample was
then further equilibrated and loaded into 0.25mL semen straws. Half of the straws
were frozen in liquid nitrogen (LN2) vapour and then plunged into the LN2. The other
half of the semen straws were frozen with the aid of a programmable freezer. After 7
days, the semen straws were thawed in a water bath at 37°C, for 30 seconds. The
sperm characteristics (sperm motility and velocity) were microscopically evaluated
using the CASA system. From the findings in this study, it can be concluded that a
controlled rate of semen cooling gave superior sperm motility results (15.3±3.0%),
compared to semen frozen in LN2 vapour (8.8±0.9%). It should be noted that
programmable freezers are costly, when compared to the liquid nitrogen vapour
technique. Due to the fact that sperm motility differences recorded were not
significant, it is suggested that the freezing of semen on a small scale be done using
the LN2 vapour technique, without any significant decrease in sperm motility or
possible fertility.
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