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Estimation of genetic parameters for fertility traits and the effect of milk production on reproduction performance in South African Holstein cowsPotgieter, Johannes Phillipus 03 1900 (has links)
Thesis (MScAgric)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Profitable milk production and genetic improvement in dairy herds are largely dependant on fertile
cows capable of calving down on an annual basis. Several studies indicate declines in the
reproductive performance of Holstein cows over the last 30 years. Calving interval (CI) and services
per conception (SPC) are being used by dairy farmers as indicators of the reproductive performance
of dairy cows. However, using these traits as cow fertility indicators is problematic as CI is dependent
on subsequent calving dates while SPC is strongly linked to inseminator proficiency. The aim of the
study is therefore, firstly, to describe alternative fertility traits derived from insemination and calving
dates and pregnancy check results. The effects of some non-genetic factors on these traits are
discussed. Means±sd for interval traits from calving to first insemination (CFS) and the interval from
calving to conception (DO) were respectively 77±30 and 134±74 days while the number of services
per conception (SPC) averaged 2.55±1.79. The percentage of first servics occurring within 80 days
post-partum (FS80d) and the proportion of cows being confirmed pregnant within 100 (PD100d) and
200 days post-partum (PD200d) were 0.64±0.48, 0.36±0.48 and 0.71±0.45, respectively. Although
fertility traits were affected significantly by lactation number, calving year and month, herds
(managers) had the largest effect.
Fertility is a complex trait, however, the challenge is finding traits that best describe this trait. Genetic
parameters for these traits could give an indication of the response to selection in dairy herds. In the
second part of this study, genetic parameters and correlations between fertility traits, sourced from
standard reproduction management data bases, are analysed for Holstein cows using bivariate linearlinear
and linear-threshold animal models. Insemination events (n = 69 181) from 26 645 lactations of
9 046 Holstein cows from 14 herds, calving down during the period from 1991 to 2007, were
available. The outcome of each AI event was known. Insemination records were linked to the calving
date of each cow, lactation number as well as dam and sire identification. Fertility traits indicating the
ability of cows to show heat early in the breeding period, and to become pregnant, were derived. Data were analysed using bivariate linear-linear and linear-threshold animal models with fixed effects being
herd (14 levels), year (17 levels), season (4 levels) and lactation number (6 levels). The model
included the random effects of animal and animal permanent environment (PE). Heritability estimates
ranged from 0.04±0.01 to 0.10±0.02 for FS80d, from 0.07±0.01 to 0.08±0.02 for PD100d and from
0.06±0.04 to 0.08±0.02 for PD200d depending on the two-trait combination. Although heritability
estimates of most fertility traits were below 0.10, they were in close agreement with results published
by other researchers using linear models. Genetic correlations between different fertility parameters
analyzed in this study indicated that it is unlikely that a single characteristic would serve well for
selection purposes; instead, combining different traits could be used in selection programmes to
improve fertility. Further research in constructing an optimal fertility index is warranted.
In the third part of this study, genetic parameters for South African Holstein cows for fertility and
production traits were estimated from 2415 lactation records. Two-trait analysis of fertility and milk
yield was investigated as a method to estimate fertility breeding values when culling, or selection
based on milk yield in early lactation, determines presence or absence of fertility observations in later
lactations. Fertility traits were days from calving to first service (CFS), days from calving to conception
(DO), percentage cows inseminated within 80d post-partum (FS80d), number of service per
conception (SPC), and the binary traits percentage of cows pregnant within 100d and 200d postpartum
(PD100d, Pd200d). Milk production traits were 300 day milk, fat and protein yield. For fertility
traits, range of estimates of heritability (h2) was 0.006 to 0.08 for linear traits and 0.05 to 0.12 for
binary traits. The range for permanent environmental variance (c2) was 0.016 to 0.032. In this study
genetic correlations of fertility with milk production traits were unfavourable ranging between −0.93 to 0.76. / AFRIKAANSE OPSOMMING: Winsgewende melkproduksie en genetiese verbetering in melkkuddes hang grootliks af van vrugbare
koeie wat op ‘n jaarlikse basis kalf. Verskeie studies toon dat die reproduksievermoë van
Holsteinkoeie oor die afgelope 30 jaar afgeneem het. Melkboere gebruik tussenkalfperiode (TKP) en
aantal inseminasies per konsepsie (KIPK) as aanduidings van die reproduksievermoë van melkkoeie.
Dit is egter moeilik om hierdie eienskappe as vrugbaarheidseienskappe vir melkkoeie te gebruik
omdat TKP afhanklik is van opeenvolgende kalfdatums terwyl KIPK baie sterk gekoppel is aan die
inseminasievermoë van die insemineerders. In die eerste gedeelte van die studie word alternatiewe
vrugbaarheidseienskappe, wat afgelei is van inseminasie- en kalfdatums en die uitslag van
dragtigheidsondersoeke, beskryf. Die invloed van ‘n aantal nie-genetiese faktore op dié eienskappe
word ook bespreek. Gemiddeldes±standaard afwykings vir die periode vanaf kalwing tot eerste
inseminasie (CFS), die periode van kalwing tot konsepsie (DO) was 77±30 en 134±74 dae
onderskeidelik, terwyl die aantal inseminasies per konsepsie (SPC) 2.55±1.79 was. Die persentasie
eerste inseminasies wat binne 80 dae na kalwing (FS80d), en die persentasie koeie wat dragtig
bevestig is binne 100 (PD100d) en 200 dae na kalwing (PD200d) was 0.64±0.48, 0.36±0.48 en
0.71±0.45, onderskeidelik. Hoewel vrugbaarheidseienskappe betekenisvol beïnvloed is deur
laktasienommer, jaar en seisoen van kalwing, het kuddes (bestuurders) die grootste effek op
eienskappe gehad.
Vrugbaarheid is ‘n ingewikkelde eienskap en die uitdaging is om eienskappe te vind wat dit die beste
beskryf. Genetiese parameters vir eienskappe wat oorweeg word sal ‘n aanduiding gee van die
seleksieresponse in melkkuddes. In die tweede gedeelte van die studie is genetiese parameters van
vrugbaarheidseienskappe en korrelasies tussen dié eienskappe beraam. Eienskappe is bekom vanaf
reproduksiebestuursprogramme wat in melkkuddes gebruik word. Al die inseminasierekords (n =
69 181) van 26 645 laktasies van 9 046 Holsteinkoeie van 14 melkkuddes wat tussen 1991 en 2007 gekalf het, was beskikbaar. Die uitslag van elke inseminasie was bekend. Inseminasierekords is met
die kalfdatum, laktasienommer, identifkasienommers van die moeder en vader van elke koei,
gekoppel. Vrugbaarheidseienskappe wat die vermoë van koeie aandui om vroeg na kalwing op hitte
te kom en beset te raak, is verkry. Die data is ontleed deur gebruik te maak van twee-eienskap liniêreliniêr-
en liniêr-drempel-diere modelle met vaste effekte kudde (14 vlakke), jaar (17 vlakke), siesoen (4
vlakke) en laktasienommer (6 vlakke). Die modelle het die ewekansige effekte van dier- en dierpermananente
omgewingseffkte (PE) ingesluit. Genetiese, diere PE en residuele korrelasies is
vervolgens beraam. Oorerflikhede varieer vanaf 0.04±0.01 tot 0.10±0.02 vir FS80d, vanaf 0.07±0.01
tot 0.08±0.02 vir PD100d en vanaf 0.06±0.04 tot 0.08±0.02 vir PD200d, afhangende van die tweeeienskap
kombinasie. Ten spyte daarvan dat die oorerflikhede van die meeste vrugbaarseienskappe
laer as 0.10 is, is die resultate in ooreenstemming met ander navorsers wat liniëre modelle gebruik
het. Genetiese korrelasies tussen verskillende vrugbaarheidseienskappe toon dat daar nie enkel
beste eienskap is wat vir seleksiedoeleindes gebruik kan word nie. Dit sou waarskynlik beter wees om
verskillende eienskappe te kombineer om die vrugbaarheid in melkkoeie te verbeter. Verdere
navorsing is nodig om ‘n optimale vrugbaarheidseienskap te ontwikkel.
Dit is belangrik dat die verband tussen reproduksie en melkproduksie vir melkkoeie bepaal word. In
die derde gedeelte van die studie is genetiese parameters vir vrugbaarheid- en melkproduksieeienskappe
vir Suid Afrikaanse Holsteinkoeie beraam. ‘n Totaal van 2415 laktasierekords was
beskikbaar. Vrugbaarheid en melkproduksie is volgens ‘n twee-eienskap analise ontleed as ‘n metode
om teelwaardes vir vrugbaarheid te bepaal in gevalle waar die uitskot of seleksie gebaseer op
melkproduksie in vroeglaktasie die teenwoordigheid of afwesigheid van vrugbaarheidseienskappe in
latere laktasies bepaal. Vrugbaarheidseienskappe was die periode (aantal dae) tussen kalfdatum en
eerste inseminasie (CFS), die aantal dae van kalf tot konsepsie (DO), die persentasie koeie wat by 80
dae na kalf vir die eerste keer geïnsemineer was (FS80d), die aantal inseminasies per konsepsie
(SPC), en binêre eienskappe van die persentasie koeie wat by 100 dae en 200 dae na kalf beset was
(PD100d en PD200d). Melkproduksie-eienskappe was 300-dae melk., vet- en proteïnproduksie. Vir
vrugbaarheidseienskappe het die oorerflikheidswaardes (h2) vanaf 0.006 tot 0.08 vir liniêre
eienskappe gevarieer en tussen 0.05 tot 0.12 vir binêre eienskappe. Die permanente
omgewingsvariansie (c2) het tussen 0.016 tot 0.032 gevarieer. In hierdie studie was die genetiese
korrelasies tussen vrugbaarheidseienskappe en melkproduksie-eienskappe ongunstig en het dit
tussen −0.93 tot 0.76 gevarieer.
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The effects of a multiple-enzyme combination in maize-soya diets for broiler chickensFourie, Juan-Louis 03 1900 (has links)
Thesis (MscAgric (Animal Sciences))--University of Stellenbosch, 2007. / The effect of a multiple-enzyme combination in mash and pelleted vegetarian maize-soya
diets for broilers was evaluated in terms of apparent excreta- and ileal nitrogen- and amino
acid digestibility and production performance. Two separate digestibility trials and one
performance trial were conducted. For Trial 1, the apparent nitrogen (N) - and amino acid
(AA) digestibility was determined by the collection of the excreta (total collection method)
and in Trial 2 from digesta collected at the terminal ileum (ileal digestibility method).
Production performance was also recorded in Trial 1. In Trial 3, the effect of the multipleenzyme
combination in potentially improving performance of broilers in commercial
conditions was evaluated. Broilers were fed a balanced- and low apparent energy (AME)
vegetarian maize-soya diet with the addition of the multiple-enzyme combination. The
addition of enzymes improved the apparent excreta- and ileal N digestibility of the mash diets
during the period 14-21 d, and the ileal N-digestibility of the pelleted diets at 28 and 35 d of
age. Conflicting results with regard to apparent excreta- and ileal AA digestibility were found.
By both methods the digestibilities of threonine (Thr), methionine (Met) and phenylalanine
(Phe) (14-21 d) and Cys (22-28 d and 29-35 d) were improved by the addition of the enzyme
combination to the mash diets. Over the entire experimental period (14-35 d) the ileal
digestibilities of histidine (His), Cys and leucine (Leu)of the mash diets were improved by 0.2
%, 0.2 % and 1.9 % respectively, following enzyme addition. By both methods the
digestibilities of Thr, arginine (Arg), Met, Cys, Phe and Leu (14-21 d), serine (Ser), Arg,
glutamic acid (Glu), Val, His, aspartic acid (Asp), lysine (Lys), proline (Pro), Met, tyrosine
(Tyr), Phe and Leu (22-28 d), and Pro (29-35 d) were improved by the combination of
enzymes and pelleting. For the entire experimental period (21-35 d), the ileal digestibilities of
Ser, His, Lys, Met, Tyr, Cys, Phe and Leu was improved by the combination of enzymes and
pelleting, indicating enzymatic activity was not destroyed by cold pelleting at 60 - 80º. The
improvements in apparent nitrogen- and AA digestibilities were, in most cases, not reflected
in production performance, although the combination of enzymes and pelleting resulted in
improved body weight gain (BWG) for the first two weeks of chicks life and significantly
improved the feed conversion ratio (FCR) during the second week of the chicks’ life. The
effect of the multiple-enzyme combination on the production performance of broilers on a low
AME- and commercial diet was mostly non-significant except for a significantly lower feed
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intake of the balanced diet for the fourth and fifth week of chick’s life following enzyme
addition. A financial calculation showed, however, that the enzyme combination might
increase profitability of a nutritionally balanced vegetarian maize-soya diet for broilers.
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A nutritional and financial evaluation of breeding African Grey parrots (Psittacus erithacus)Dennison, D. T. 12 1900 (has links)
Thesis (MPhil (Animal Sciences))--University of Stellenbosch, 2004. / African Grey Parrots are now being bred on a commercial scale in South Africa, mainly for the export market. In order to produce the best breeding results it is necessary to formulate balanced diets but no research has been done on the feeding value for African Grey parrots of ingredients used in formulating diets. Once the apparent metabolisable energy (AME) of extruded maize for African Greys has been established it will be possible to calculate the AME of other ingredients such as full fat soya, soya oil cake or sunflower oil cake. By feeding an extruded mix containing a known amount of maize mixed with a known amount of soya oil cake and establishing experimentally the AME of the mix, the AME of soya oil cake for African Greys can be calculated by difference. This information will make it possible to decide whether AME results obtained for poultry can be used in formulating diets for African Grey parrots.
The study consisted of two parts where the determination of the apparent metabolisable energy (AME) of extruded maize and the practical application thereof in formulating parrot diets, and the economic viability of a commercial African Grey parrot breeding operation was investigated. A reference procedure adopted by several European laboratories for the in vivo determination of metabolisable energy (ME) was used to determine the apparent metabolisable energy (AME) of extruded whole maize for African Grey parrots. The long term goal is to make a well balanced, extruded diet for these birds. Extruded maize is the form in which maize is generally included in commercial parrot diets and was therefore chosen as the experimental feed. Maize can be conveniently extruded with other single ingredients such as full fat soyabean meal, soyabean oil cake meal or sunflower oil cake meal to determine, by difference, the AME of those ingredients. For the first part of the study, ten, 3-year-old African Grey parrots were individually housed and fed in cages designed to facilitate collection of the faeces. Cage design varied between a tall type (n=6) and a low type (n=4). The parrots were acclimatized to their new environment before the trial commenced to ensure normal feeding behaviour.
The average AME value established for the ten African Grey Parrots was 16.8 MJ/kg. In the trial it became apparent that it is very difficult to get consistent results with the cages used and a modified cage design is proposed for the future. The second part of the study investigated the economic viability of breeding African Grey parrots commercially, with extruded maize as part of their diet. It was generally concluded that the breeding of African Grey parrots for the pet market can be considered as an economical venture.
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Die gebruik van Mamalvite en Flavomisien in die grootmaak van suiwelkalwersVermaak, Maizie Maria 03 1900 (has links)
Thesis (MPhil (Animal Sciences))--University of Stellenbosch, 2006. / South Africa produces only 0,50 % of the world’s milk. Although the number of milk producers is decreasing in South Africa, the milk production per se is increasing. The total number of small producers is decreasing while the number of big producers is increasing.
The cost to raise replacement heifers is very high. Replacement heifers are the cows of tomorrow and should be seen as a valuable investment for the longterm survival and profitability of the dairy farm. A successful heifer rearing program is one in which:
• Heifers are economically raised to be of adequate size and body condition to calve at a reasonable age.
• Heifers produce high levels of milk during the first lactation.
In the current study, the effect of Flavomycin and Mamalvite supplementation to young calves was investigated. According to manufacturer’s claims, Flavomycin would result in improved gains, improved conception rates, shorter calving intervals, increased milk production and improved weaning weights. Mamalvite, according to the manufacturer, should reduce risk of infections, increase feed utilization, increase feed intake and production, and also increase rumen microbial efficiency.
Thirty two Holstein calves, four days of age, were randomly divided into four groups of eight. All calves received 4 kg whole milk daily and had free access to calf starter pellets. Treatments were: 30 ml Mamalvite daily supplemented in the milk and 5 g Flavomycin daily per os (Treatment 1), 30 ml Mamalvite daily supplemented in the milk (Treatment 2), 5 g Flavomycin daily per os (Treatment 3) and a control group that received milk only (Treatment 4). All the calves were weighed weekly.
According to the results obtained in the current study, neither Flavomycin, nor Mamalvite, nor a combination of the two resulted in an improvement in calf weight gains. It was concluded that it does not appear to be an economically viable option to supplement Mamalvite or Flavomycin to calves that are reared in a well managed environment.
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Determination of the nutrient requirements of breeding ostrichesOlivier, Theodore Riel 03 1900 (has links)
Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The nutrient requirements for breeding ostriches are currently not well-defined. Quantification of the nutrient
requirements will improve the financial wellbeing of the industry. A study of the growth of the reproductive organs
and liver, together with various production studies, were therefore undertaken in order to gain knowledge about
the nutrition of breeding ostriches, thereby quantifying the nutrient requirements of breeding ostriches.
Various studies were conducted to determine the influence of dietary protein, amino acids and energy on
production levels of breeding ostriches.
In a first study, five diets, varying in crude protein (CP) but with a constant energy content of 9.2 MJ ME/kg feed,
were provided at a feed intake level of 2.5 kg/bird/day. The dietary CP levels were 7.5%, 9.1%, 10.8%, 12.3%
and 14.0%. No differences (P>0.05) between treatments (total eggs per female per season) were found for
number of unfertilized eggs (eggs per female per season; 8.9±0.8), dead-in-shell chicks (8.0±0.5), number of
chicks hatched (19.1±1.1) and change in mass of females (-16.2±1.6kg). A tendency was observed for a
difference in total egg production (mean and standard error; 39.1±3.6; P=0.08). The 12.3% CP diet caused the
lowest (P<0.05) change in live mass (-3.8±2kg) for male birds. No interaction (P>0.05) occurred between the
genotype of the bird and the dietary protein concentration for both egg and chick production.
In a second study, six diets varying in ME (MJ ME/kg feed), were provided at an average feed intake level of 3.4
kg/bird/day. The levels were 7.5, 8.0, 8.5, 9.0, 9.5 and 10.0 MJ ME/kg feed respectively. No differences (P>0.05)
were observed for total eggs produced per female per season (44.8±7.8), number of chicks hatched (15.4±4.1), number of infertile eggs (11.5±3.8), number of dead-in-shell eggs (12.1±3.2) and change in mass of females
(10.7±3.6kg). Males increased linearly (y=2.4x + 2.45; R2=0.09; P<0.05) in live mass as the dietary energy
content increased. Two eggs per diet per month were analyzed for crude protein, crude fat and trace elements,
and one egg per diet per month was analyzed for fatty acid composition. Eggs from the first and last month of
the season were subjected to amino acid analysis. Analysis of variance showed no difference in crude protein
and fat (P>0.05) content of eggs between the experimental diets, as well as for the calcium content of eggshells.
The proline content differed (P<0.05) between the diets. The C18:3n-3 (linoleic acid) content of the eggs
increased (P<0.05) amongst the dietary treatments. Crude protein, fat and C18:3n-3 content in eggs increased
(P<0.05) for the number of the egg in the laying cycle.
In a third study, the feed intake of breeding ostriches, as affected by dietary energy content was investigated.
Average feed intake (kg feed/bird/day) was not affected (P>0.05) at any dietary energy level when levels of 8.0,
8.7, 9.4, 10.1, 10.8 and 11.5 MJ ME/kg feed were provided. The mean and standard error was 3.7±0.2kg.
The production of breeding female ostriches was not influenced by dietary ME and protein at these feed intake
levels. Ostrich birds do not have the ability to regulate their feed intake at any dietary energy level as used in this
study. The amount of nutrients deposited in the eggs had no influence on the reproductive efficiency of the
breeding female ostrich. The experiments also revealed that female breeding ostriches were independent of
dietary energy and protein as used in this study for the mean frequency of egg laying at various dietary protein
and energy levels (P>0.05).
In a fourth study, the growth and development of the reproductive organs of female birds at the onset of the
breeding season were investigated. The amount of nutrients needs to be determined in order to support the
growth of the reproductive organs during the breeding season, due to the fact that these organs are linked to
egg production. It was thus necessary to investigate whether the reproductive organs grew and developed
during a season. The first slaughter interval was conducted at the start of the breeding season. The ovary,
oviduct and liver were collected, weighed after each slaughter and analyzed. Ovary and oviduct were analyzed
for crude protein and fat. No differences (P>0.05) were observed between the different slaughter intervals for the
mass, crude protein and fat content of both organs. No trend (P>0.05) in the weight of the oviduct could be
observed over the 49-day period, this weight being highly correlated with body weight; whereas the ovary weight
tended to be correlated with the time after the onset of the breeding period, although the variation in weights,
both within and between weighings, was very high. The variation in the weight of the ovary probably reflects
differences in the laying pattern of individuals. The number of follicles were not affected (P>0.05) by the number
of days after mating. Livers were assessed for crude protein and fat, but no difference (P>0.05) was detected
between the intervals, but the weight difference amongst the slaughter intervals was significant (P<0.05),
suggesting that the ostriches used liver reserves to supplement nutrients that obtained from the diet for the
development of the reproductive organs. This data will be used in an optimising model (Brand & Gous, 2006) to predict the nutrient requirements of female breeding ostriches. This study suggests that the female breeding
ostrich might need additional protein during the first 7 weeks of the breeding season.
Results from Chapter 4 and previous studies were used to calculate the energy, protein and amino acid
requirements for the egg production and maintenance of the breeding female ostrich. Two methods were used to
determine the energy requirement for egg production. The Metabolisable Energy requirement for egg production
(MEe) and efficiency of ME utilization for energy deposition in the egg (ko) was calculated as 12.2 MJ (for an
average size egg of 1.4kg) and 0.8 respectively. The Effective Energy requirement for egg production (EEe) and
maintenance (EEm) was calculated as 15.9 MJ/day and 17.1 MJ/day respectively. Average total daily protein
requirement (TPt) was calculated as 175g day. The amino acid requirements for maintenance and egg
production is also provided, which is lower than previous studies. This study also provides evidence that the nutrient requirements are different for every month of the breeding season. / AFRIKAANSE OPSOMMING: Tans heers daar onsekerheid oor die voedingsbehoeftes van volstruis broeivolstruise. Kwantifisering van die
voedingsbehoeftes sal ‘n finansiële hupstoot aan die industrie gee. ‘n Groeistudie van die reproduksie-organe en
lewer, tesame met ‘n aantal produksie-studies, is uitgevoer om inligting oor die voedingsbehoeftes van volstruis
broeivoëls te versamel. Daarby is die voedingsbehoeftes teoreties bereken.
‘n Aantal studies was uitgevoer om die invloed van dieët proteïen en aminosure en energie op produksie-data te
bepaal.
Eerstens is vyf diëte, wisselend in ru-proteïen (RP) en beperk tot ‘n inname van 2.5 kg/voël/dag, aan
broeivolstruise gevoer. Die RP van elke dieët was 7.5%, 9.1%, 10.8%, 12.3% en 14.0%. Die energiewaarde van
die voer is konstant by 9.2 MJ ME/kg voer gehou. Geen verskille (P>0.05) was tussen die behandelings
waargeneem vir aantal geil eiers (totale eiers geproduseer per voël per seisoen; 8.9±0.8), aantal dood-in-dop
(8.0±0.5), aantal kuikens (19.1±1.1) en verandering in massa van wyfies (-16.2±1.6kg) nie. ‘n Neiging (P=0.08)
is wel waargeneem vir totale aantal eiers geproduseer. Die gemiddelde en standaard fout was 39.1±3.6. Die
12.3% dieët het tot die laagste verandering (P<0.05) in lewendige massa (-3.8±2kg) vir die mannetjies gelei.
Geen interaksie (P>0.05) was tussen die genotipe en dieët proteïen konsentrasie vir beide eier- en kuikenproduksie
opgemerk nie.
In ‘n tweede studie is ses diëte, variërend in ME (MJ ME/kg voer), by ‘n gemiddelde tempo van 3.4 kg/voël/dag
gevoer. Die verskillende ME-vlakke was 7.5, 8.0, 8.5, 9.0, 9.5 en 10.0 MJ ME/kg voer. Geen betekenisvolle
verskille (P>0.05) is vir totale eiers geproduseer per voël per seisoen (44.8±7.8), aantal kuikens uitgebroei
(15.4±4.1), aantal geil eiers (11.5±3.8), aantal dood-in-dop eiers (12.1±3.2) en massa verandering van wyfies (10.7±3.6kg) opgemerk nie. Die mannetjies het toegeneem in liggaamsmassa (P<0.05) soos daar ‘n toename
was in die energievlak van die dieët. Twee eiers per dieët per maand is vir ru-proteïen, vet en spoorelemente, en
een eier per diet per maand vir vetsure ontleed. Eiers van die eerste en laaste maand van die seisoen is ontleed
vir aminosure. Analise van variansie het aangetoon dat daar geen verskille (P>0.05) bestaan vir die ru-proteïen
en vetinhoud van die eiers by die verskillende eksperimentele diëte, asook die kalsiuminhoud van die eierdoppe.
Prolien vlakke het tussen die diëte verskil (P<0.05). Die C18:3n-3 (linoleïensuur) inhoud van die eiers het verskil
(P<0.05) tussen die dieët behandelilngs. Vir die hoeveelste eier in die lê siklus het die ru-proteïen-, vet- en
C18:3n-3 inhoud van die eiers verhoog (P<0.05).
In ‘n derde studie is ondersoek ingestel na die voerinname van die broeivolstruise soos moontlik beïnvloed deur
die energievlak van die dieët. Gemiddelde voerinname (kg voer/voël/dag) is nie (P>0.05) deur die verskillende
dieët energie vlakke van 8.0, 8.7, 9.4, 10.1, 10.8 en 11.5 MJ ME/kg voer beïnvloed nie. Die gemiddelde en
standaardfout was 3.7±0.2kg.
Die produksie van broeivolstruise nie deur verskillende dieëtvlakke van proteïen en energie by vlakke soos
gevoer in hierdie studie geraak nie. Broeivolstruise in hierdie studie het nie die vermoë gehad om hul
voerinname te beheer by enige dieët energievlak soos gebruik nie. Die aantal nutriënte wat in die eiers neergelê
is, het geen bydrae tot die reproduksievermoë van die wyfie gehad nie. Die studie het verder bewys dat die
gemiddelde frekwensie van eier-lê by wyfies onafhanklik was by dieët-energie en -proteïenvlakke (P>0.05) soos
in hierdie studie gebruik.
In ‘n vierde studie is die groei en ontwikkeling van die reproduksie-organe van die wyfies bestudeer tydens die
aanvang van die broeiseisoen. Die hoeveelheid of konsentrasie van voedingstowwe moes bepaal word om die
groei van die reproduksie-organe te ondersteun tydens die broeiseisoen, omdat hierdie organe aan
eierproduksie gekoppel is. ‘n Studie is derhalwe uitgevoer om te bepaal tot watter mate die reproduksie organe
groei en ontwikkel tydens die broeiseisoen. Die eerste slagting is uitgevoer op die dag van afkamp. Die ovaria,
ovidukt en lewer is versamel, geweeg en ontleed. Die ovaria en ovidukt is ontleed vir ru-proteïen en vet. Geen
verskille (P>0.05) is tussen die verskillende slagtings vir die gewig, ru-proteïen en vetinhoud vir beide organe
opgemerk nie. Geen betekenisvolle tendens in die gewig van die ovidukt is waargeneem oor die 49-dae periode
nie, maar die gewig was hoogs gekorreleerd met liggaamsmassa. Ovaria-gewig het geneig om gekorreleerd te
wees met die aantal dae na afkamp. Variasie binne en buite die gewigte was baie hoog. Die aantal follikels
teenwoordig is nie beïnvloed (P>0.05) deur die aantal dae na paring. Die lewers is ontleed vir ruproteïen en vet,
maar geen verskille (P>0.05) is tussen die intervalle opgemerk nie, maar die gewigte van dag 0 en 49 na paring
het verskil (P<0.05). Dit kan aangevoer word dat die voëls moontlik lewer reserwes gebruik het om die
voedingstowwe van die dieët te supplementeer vir die ontwikkeling van die reproduksie-organe. Data uit hierdie
studie kan gebruik word in ‘n optimiseringsmodel (Brand & Gous, 2006) om die voedingsbehoeftes van broeivolstruise te bepaal. Hierdie studie beveel aan dat die broeiwyfie moontlik addisionele proteïen tydens die
eerste sewe weke van die broeiseisoen benodig.
Resultate van Hoofstuk 4 en vorige studies is gebruik om die energie- proteïen- en aminosuurbehoefte vir
eierproduksie en onderhoud van broeivolstruise te bereken. Twee metodes is gebruik om die energiebehoefte
vir eierproduksie te bereken. Metaboliseerbare Energie behoefte vir eierproduksie (MEe) en effektiwiteit van ME
benutting vir energie deponering in eier (ko) is onderskeidelik as 12.2 MJ (vir ‘n eier wat gemiddeld 1.4kg weeg)
en 0.8 bereken. Effektiewe Energie behoefte vir eierproduksie (EEe) en onderhoud (EEm) was onderskeidelik as
15.9 MJ/dag en 17.1 MJ/dag bereken. Die gemiddelde daaglikse proteïenbehoefte (TPt) is as 175g proteïen/dag
bereken. ‘n Aanduiding van die aminosuur behoefte vir onderhoud en eierproduksie word ook gegee, wat laer is as vorige studies.
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Genetic analyses of growth traits for the Simbra composite breedSmith, Algina Maria Johanna 03 1900 (has links)
Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The aim of this study was to evaluate the Simbra breed of cattle for certain non-genetic as well as
genetic parameters influencing live weight traits in the breed. Live weight traits included birth weight
(BW), weaning weight at 200 days of age (WW), yearling weight at 400 days of age (YW) and 600
day weight. The Simmental and Simbra Breeders’ Society of Southern Africa availed 148751 records
for analysis from the year 1987 till 2009. Due to deficiencies of various kinds in the data and the
restrictions imposed for the purposes of the analysis, 56.44% of the records were discarded for BW,
76.55% for WW, 91.54% for YW and 96.32% for 600-day weight.
Non-genetic parameters affecting BW, WW, YW and 600-day weight were analysed using the
General Linear Models procedure of the Statistical Analysis System (SAS, 2004) software. During
this procedure sex of calf, breed composition of calf, breeder of calf, month of birth, year of birth and
dam age were fitted in the models. BW, WW, YW and Mature Cow Weight (MCW) were fitted as
covariates where possible. It was determined that the fixed effects of sex, dam age, breeder, year
and month had a significant (P < 0.05) effect of BW and WW while dam age was not significant (P >
0.05) for YW or 600-day weight. Breed was found non significant for YW. Breeder of the calf
accounted for the most variation in BW, WW, YW as well as 600-day weight with a contribution of
17.55%, 25.77%, 18.35% and 10.71% respectively. Tukey’s multiple range tests were performed for
testing differences between least square means. Results indicated male calves to be significantly
heavier than females for all four traits measured. Breed composition differences were found
significant until WW. Calves with higher Brahman percentage weighted more at birth while calves with
higher Simmental percentage weighed more at weaning. Middle-aged dams were found to account
for heavier calves at both BW and WW while very young dams and very old dams produced lighter
calves for the two live weight traits. A number of years showed a significant difference from each
other for all the traits measured as well as month of birth.
(Co) variance components and the resulting genetic parameters were estimated using single-traits
and three-traits analysis by means of Restricted Maximum Likelihood procedures (Gilmour et al., 2002). Appropriate models were selected by means of Log likelihood ratios tests and implemented to
estimate genetic parameters for each of the traits studied. Direct additive heritabilities for BW, WW,
YW and 600-day weight in the Simbra were respectively 0.56 ± 0.08, 0.67 ± 0.09, 0.70 ± 0.11 and
0.10 ± 0.03 when the most suitable animal model was fitted in single-trait analyses for each trait.
Single traits analysis also included maternal additive as well as the correlation between direct additive
and maternal additive for BW, WW and YW. Maternal additive heritability estimates of 0.24 ± 0.07,
0.33 ± 0.06 and 0.38 ± 0.07 was obtained for BW, WW and YW. Correlation estimates between direct
additive and maternal additive were -0.75 ± 0.07, -0.93 ± 0.07 and -0.85 ± 0.08 for BW, WW and YW
respectively. Furthermore, dam permanent environment was included as an additional random effect
that increased the log likelihood value significantly. A value of 0.04 ± 0.05 was obtained for dam
permanent environment estimate for WW. When a three traits analysis was done for the same traits,
but using a significantly smaller data set, direct additive heritabilities of 0.24 ± 0.07 for BW, 0.33 ±
0.06 for WW and 0.38 ± 0.07 for YW were obtained. Genetic and environmental correlation estimates
of 0.18 ± 0.16 and 0.09 ± 0.06 between BW and WW; 0.27 ± 0.16 and 0.07 ± 0.06 between BW and
YW; as well as 0.52 ± 0.10 and 0.45 ± 0.05 between WW and YW were obtained during the three-trait
analysis. The magnitude of the heritabilities obtained in this study indicates that the opportunity exists to make genetic progress through proper selection objectives. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die Simbra bees ras te evalueer op grond van sekere niegenetiese
so wel as genetiese parameters wat lewende gewig beïnvloed. Gereelde en akkurate
opnames van lewende gewig, is ‘n goeie indikasie van groei potensiaal en is ‘n minimim vereiste vir
meeste beesras telings genootskappe. Lewende gewigs eienskappe sluit in geboorte gewig (BW),
speen gewig gemeet op 200 dae (WW), jaaroue gewig gemeet op 400 dae (YW) en finale gewig
gemeet op 600-dag gewig. Die Simmentaler en Simbra genootskap van Suid Afrika het 148751
rekords beskikbaar gestel vir evaluasie vanaf die jaar 1987 tot 2009. Daar was egter groot tekort
komings aan die gewewe data en dus is daar 56.44% van die rekords vir BW nie gebruik nie, 76.55%
vir WW, 91.54% vir YW en 96.32% vir 600-dag gewig.
Nie-genetiese parameters wat die onderskeie lewende gewigte beïnvloed het, is geanaliseer deur
Algemene Lineêre Modelle met behulp van die Statistiese Analitiese Sisteem (SAS, 2004) sagteware.
Gedurende die analise is geslag van die kalf, ras samestelling, teler van die kalf, maand van
geboorte, jaar van geboorte asook moeder ouderdom gepas in die modelle vir die onderskeie
gewigte. Geboorte gewig, speen gewig, jaaroue gewig asook volwasse koei gewig is gepas in elk
van die modelle as ko-variate. Volgens die resutate is daar vasgestel dat geslag van die kalf, moeder
ouderdom, teler, jaar, maand en volwasse koei gewig almal ‘n betekenisvolle (P < 0.05) invloed
gehad het op BW en WW. Die moederouderdom was nie betekenisvol (P > 0.05) vir YW of 600-dag
gewig nie. Die ras samestelling was ook nie betekenisvol gevind vir YW. Teler van die kalf was
verantwoordelik vir die meeste variasie in BW, WW, YW asook 600-dag gewig met ‘n bydrae van
17.55%, 25.77%, 18.35% en 10.71% onderskeidelik. Tukey se veelvuldige vergelykings toets is
gebruik om onderskeid te tref tussen “least square means”. Resultate het aangedui dat manlike diere
swaarder weeg as vroulike diere tot en met finale gewig. Ras samestelling vir BW en WW was
betekenisvol verskillend vir die diere. Kalwers met ‘n hoër Brahmaan persentasie het swaarder BW
opgelewer as dié met ‘n hoër Simmentaler persentasie, terwyl kalwers met ‘n hoër Simmentaler
persentasie swaarder geweeg het met speen en dus ideal is vir speen kalwer produksie stelsels.
Middel-jarige moeders het swaarder kalwers geproduseer met geboorte en speen as baie jong en -
ou moeders. Sommige jare waarin van die kalwers gebore is, het ook betekenisvol van mekaar
verskil asook die maand waarin die kalf gebore is. Ko) variansie faktore en opeenvolgende genetiese parameters is bepaal met behulp van enkeleienskap
analises asook meervuldige-eienskap analises deur middel van die “Restricted Maximum
Likelihood” prosedure (Gilmour et al., 2002). Modelle is opgestel vir elk van die gewigte deur die
geskikte genetiese terme toe te voeg en te toets met behulp van “Log likelihood tests” om sodoende
die onderskeie genetiese parameters te bepaal. Direkte genetiese oorerflikhede bepaal deur enkeleienskap
analises vir die Simbra ras was as volg, 0.56 ± 0.08 vir BW, 0.67 ± 0.09 vir WW, 0.70 ± 0.11
vir YW en 0.10 ± 0.03 vir 600-dag gewig. Die direkte maternale genetiese oorerflikhede tydens
dieselfde enkel-eienskap analise vir die onderkeie gewigte was 0.24 ± 0.07 vir BW, 0.33 ± 0.06 vir
WW en 0.38 ± 0.07 vir YW. Korrelasies tussen direkt genetiese en direk maternale eienskappe was
sterk negatief. ‘n Waarde van -0.75 ± 0.07 is bepaal vir BW, -0.93 ± 0.07 vir WW en -0.85 ± 0.08 vir
YW. ‘n Adisionele faktor was ook ingelsuit vir WW, naamlik die permanente omgewing van die
moeder, wat ‘n waarde opgelewer het van 0.04 ± 0.05. Tydens die veelvuldige-eienskap analise het
die oorerflikhede merkwaardig verminder vir die betrokke gewigte en kan ook waargeneem word as
die meer korrekte genetiese weergawe. Direkte genetiese oorerflikhede van 0.24 ± 0.07 vir BW, 0.33
± 0.06 vir WW en 0.38 ± 0.07 vir YW was bepaal. Hierdie matig tot hoë parameters dui op genetiese
vordering deur middel van korrekte seleksie prosedures. Genetiese- en omgewing korrelasies is ook
bepaal tydens die analise en het positiewe waardes opgelewer. ‘n Genetiese korrelasie waarde van
0.18 ± 0.16 tussen BW en WW is bepaal asook ‘n waarde van 0.27 ± 0.16 tussen BW en YW en ‘n
waarde van 0.52 ± 0.10 tussen WW en YW. Hierdie korrelasies dui daarop dat na-speengewigte
vermeerder kan word deur te selekteer vir verhoogde WW sonder om BW dramties te vermeerder.
Omgewings korrelasie waardes van 0.09 ± 0.06 tussen BW en WW, 0.07 ± 0.06 tussen BW en YW
asook ‘n waarde van 0.45 ± 0.05 tussen WW en YW is gevind. Genetiese neigings is bepaal vir die
onderskeie gewigte deur die gemiddelde voorspelde teelwaardes aan te teken teenoor elke jaar wat
bereken was tydens die enkel-eienskap analises vir die onderskeie gewigte. Groot variasie asook
negatiewe tendense vir WW en YW is ondervind van jaar tot jaar en dui daarop dat die seleksie
doelwitte vir lewendige gewig nie in plek gestel is nie en is dit nodig om te her evalueer.
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The effect of electrical input during beef processing on resultant meat qualityLombard, Anthonie Christoffel 03 1900 (has links)
Thesis (MScAgric) -- Stellenbosch University, 2009. / ENGLISH ABSTRACT: The two main determinants of post-slaughter processing outcomes are rates of pH and temperature decline.
Muscle pH and temperature interact continuously during rigor development to affect both the muscle
contracture and proteolytic enzyme activity. The pH, however, can be manipulated independently of
temperature by electrical inputs applied to the carcass. Electrical inputs that should be considered range
from electrical stunning to the various forms of electrical immobilisation (EI) and stimulation (ES) that occur
during and after the dressing procedures. EI is used to suppress convulsions that occur after electrical
stunning to ensure operator safety to maintain high throughputs speeds while ES is used to induce rapid
tenderisation, although having other biochemical and biophysical effects on meat.
The objective of the study was to supply information on the effect of different EI and ES treatments,
frequencies and pulse widths on the meat quality of beef. There are very little data on the effect of EI when it
is combined with ES on meat quality. This study used two different EI frequencies (high – 800 Hz; HFI and
low – 15 Hz; LFI) combined with either high (1040 V; HVS) or medium (300 V; MVS) voltage ES to study the
effect of these treatments on meat quality. In the following experiment the EI waveform and ES was
standardised using HFI with MVS with the frequency being changed to either 5, 15 or 50 Hz. Then the pulse
width of the waveform was changed to 0.1, 0.5, 1 and 10 ms to optimise the ES system.
Meat quality measurements were made from the Longisimmus dorsi (LD) and Semimembranosus (SM) after
1, 5 and 9 days of chilled storage at 0 C. The LD (shear force = 94.3±2.2; cooking loss = 26.85±0.29; retail
drip = 0.996±0.037; storage drip = 2.78±0.155; WBC (water binding capacity) = 45.4±0.36) had significantly
lower shear force and higher water binding capacity than the SM (shear force = 103.7±2.5; cooking loss =
34.63±0.25; retail drip = 2.12±0.103; storage drip = 3.63±0.245; WBC = 59.3±0.57). Day of assessment (Day
1 = 122.7±2.9; Day 5 = 87.7±2.2; Day 9 = 81.0±2.4) had a significant effect on tenderness of the LD as shear
force declined with an increase of day of assessment. The LFI HVS (storage drip = 3.30±0.223; shear force
= 102.9±4.5) produced significantly greater drip during storage and shear force values when compared to the
HFI followed by either HVS (storage drip = 2.45±0.261; shear force = 85.2±4.0) or MVS (storage drip =
2.60±0.178; shear force = 94.2±4.2) in the LD, probably attributable to different rates of pH decline post
mortem. LFI HVS (a* = 20.79±0.31; chroma = 22.92) and LFI MVS (a* = 20.24±0.27; chroma = 22.23±0.30)
had a redder and more vivid bloomed colour than HFI HVS (a* = 19.71±0.33; chroma = 21.49±0.37) and HFI
MVS (a* = 20.00±0.27; chroma = 21.98±0.31), while LFI HVS (a* = 15.27±0.40) and HFI MVS (a* = 14.64±0.29) had a redder colour compared to HFI HVS (13.85±0.35) at day 9 for the LD. The oxygen
consumption rate (MTT assay) correlated inversely linear (r = -0.63 and -0.73) with the a* values 24 hrs post
mortem allowing for 3 hrs of bloom.
Stimulation with 15 Hz (0.47±0.040) and 5 Hz (0.41±0.045) had a higher pH decline (ΔpH) during stimulation
than 50 Hz (0.29±0.027). Shear force measurements and cooking loss percentage were obtained from the
LD after 24 hrs of chilled storage at 0 C. There were no difference between the stimulation treatments for
shear force (15 Hz = 121.3±3.3; 5 Hz = 123.8±7.6; 50 Hz =114.8±7.94), while cooking loss was higher in 15
Hz (28.8±0.47) than 50 Hz (25.9±0.71) which correlated (r = 0.43; p = 0.01) with ΔpH.
There were no differences between 10 ms (0.46±0.020), 1 ms (0.43±0.020) and 0.5 ms (0.44±0.019) pulse
widths on the ΔpH while 0.1 ms (0.33±0.020) had a lower decline. Stimulation with a 1 ms (94.6±5.6) pulse
width had the lowest shear force that varied from 10 (111.3±3.8) and 0.1 ms (111.3±5.8). While cooking loss
(0.1 = 25.3±0.48; 0.5 = 26.9±0.67; 1 = 25.9±0.63; 10 = 25.5±0.66) and water-holding capacity (0.1 = 36.1±1.60; 0.5 = 37.3±1.42; 1 = 37.5±1.15; 10 = 36.9±1.45) was not affected in the LD after 24 hrs of chilled
storage at 0 C. Colour measurements on the SM indicated that a 0.1(a* = 19.38±0.50; chroma =
22.70±0.51), 0.5 (a* = 20.89±0.49; chroma = 24.34±0.56) and 10 ms (a* = 19.69±0.46; chroma =
22.98±0.58) pulse width had a deeper red and a more vivid colour than 1 ms (a* = 16.66±0.37; chroma =
19.99±0.32) at day nine of retail display.
In conclusion, HFI improves meat quality when combined with either HVS or MVS and that MVS either
improves (colour stability) or has no adverse effects on meat quality (tenderness and WBC) in relation to
HVS when combined HFI. In addition, it shows that there are alternative electrical parameters to voltage that
can be used to change the pH decline and by changing frequency and pulse width, subtle changes can be
made to an ES system. Since every abattoir is different due to layout, chiller space and cooling regime these
electrical parameters can be modulated to optimise an electrical stimulation system without expensive
modification to the whole system. / AFRIKAANSE OPSOMMING: Die tempo van pH en temperatuur daling is die twee hoof bepalings van na-slag prosseserings uitkomste.
Spier pH en temperatuur het ’n gedurige interaksie tydens rigor ontwikkeling en beïvloed die spier
sametrekking en proteolitiese ensiem aktiwiteit. Die spier pH kan onafhanklik van temperatuur gemanipuleer
word, deur elektriese golfvorms deur die karkas te stuur. Die elektriese golfvorms wat in ag geneem moet
word varieer van elektriese impulse tydens bedwelming tot die verskeie golfvorms van elektriese
immobilisasie (EI) en stimulasie (ES) wat gebruik kan word gedurende en na die slagproses. EI word gebruik
om konvulsies te beheer wat onstaan na elektriese bedwelming om werker veiligheid en hoë deurvloei
tempos te verseker, terwyl ES die verouderings proses versnel, alhoewel dit ander biochemiese en biofisiese
uitwerkings het op vleis.
Die studie het verneem om inligting te verskaf oor die effek van verskillende EI en ES kombinasies,
frekwensie en puls wydtes op die kwaliteit van beesvleis. Daar is baie min inligting van EI in kombinasie met
ES se effek op vleis kwaliteit. Die studie het gebruik gemaak van twee verskillende (EI) frekwensies (hoog –
800 Hz; HFI and laag – 15 Hz; LFI) wat gekombineer is met of hoë (1040 V; HVS) of medium (300 V; MVS)
spanning ES se effek op vleis kwaliteit. In die volgende eksperiment was die EI golfvorm en die ES
gestandardiseer en HFI met MVS was gebruik met die frekwensie wat verander is tussen 5, 15 en 50 Hz.
Daarna was die pulse wydte van die golfvorm verander tussen 0.1, 0.5, 1en 10 ms om die ES sisteem te
optimiseer.
Vleis kwaliteit van die Longisimmus dorsi (LD) en Semimembranosus (SM) spiere was bepaal na 1, 5 en 9
dae van verkoelde storing teen 0°C. Die LD (skeurkrag = 94.3±2.2; kookverlies = 26.85±0.29; kleinhandel
drup verlies = 0.996±0.037; storing drip verlies = 2.78±0.155; WBV (water bindings vermoë) = 45.4±0.36) het
‘n betekenisvolle laer skeurkrag waardes en hoër water bindings vermoë gehad in vergelyking met die SM
(skeurkrag = 103.7±2.5; kookverlies = 34.63±0.25; kleinhandel drupverlies = 2.12±0.103; bergings
drupverlies = 3.63±0.245; WBV = 59.3±0.57). Die dag van assesering (Dag 1 = 122.7±2.9; Dag 5 = 87.7±2.2;
Dag 9 = 81.0±2.4) het ’n betekenisvolle effek gehad op die skeur krag waardes en het afgeneem met ’n
toename in die dag van assesering. LFI HVS (storing drupverlies = 3.30±0.223; skeurkrag = 102.9±4.5) het
betekenisvolle hoër vog verliese gehad tydens verkoelde storing en skeur krag wanneer dit vergelyk word
met HFI gevolg deur of HVS (storing drupverlies = 2.45±0.261; skeurkrag = 85.2±4.0) of MVS (storing
drupverlies = 2.60±0.178; skeurkrag = 94.2±4.2). LFI HVS (a* = 20.79±0.31; chroma = 22.92) en LFI MVS
(a* = 20.24±0.27; chroma = 22.23±0.30) het ‘n helder en dieper rooi kleur gehad in vergelyking met HFI HVS (a* = 19.71±0.33; chroma = 21.49±0.37) en HFI MVS (a* = 20.00±0.27; chroma = 21.98±0.31), terwyl LFI
HVS (a* = 15.27±0.40) en HFI MVS (a* = 14.64±0.29) ’n rooier en helderer kleur as HFI HVS (13.85±0.35)
gehad het in die LD. Die suurstof verbruik tempo (MTT analise) korreleer omgekeerd (r = -0.63 en -0.73) met
die a* waardes 24 hr post mortem na 3 hr van blootstelling van lug.
Stimulasie met 15 (0.47±0.040) en 5 Hz (0.41±0.045) het ’n hoër pH daling (ΔpH) tydens stimulasie as 50 Hz
(0.29±0.027). Skeurkrag waardes en kookverliese is verkry vanaf die LD na 1 dag van verkoelde storing teen
0 C. Daar was geen verskil tussen stimulasie frekwensie se effek of skeurkrag (15 Hz = 121.3±3.3; 5 Hz =
123.8±7.6; 50 Hz =114.8±7.94) nie, terwyl die kookverliese hoër was in die 15 Hz (28.8±0.47) as 50 Hz
(25.9±0.71) behandeling wat gekorreleer (r = 0.43; p = 0.01) het met ΔpH. Daar was geen verskill tussen 10 (0.46±0.020), 1 (0.43±0.020) en 0.5 ms (0.44±0.019) puls wydtes se effek
op ΔpH nie, terwyl 0.1 (0.33±0.020) ms ‘n kleiner afname tot gevolg gehad het. Stimulasie met ‘n 1 ms
(94.6±5.6) puls wydte het die laagste skeurkrag gehad wat verskil het van die 10 (111.3±3.8) and 0.1 ms
(111.3±5.8) puls wydtes, terwyl kookverliese (0.1 = 25.3±0.48; 0.5 = 26.9±0.67; 1 = 25.9±0.63; 10 =
25.5±0.66) en waterbindingsvermoë (0.1 = 36.1±1.60; 0.5 = 37.3±1.42; 1 = 37.5±1.15; 10 = 36.9±1.45) nie
beïvloed was nie. Kleur metings van die SM het getoon dat ‘n 0.1 (a* = 19.38±0.50; chroma = 22.70±0.51),
0.5 (a* = 20.89±0.49; chroma = 24.34±0.56) en 10 ms (a* = 19.69±0.46; chroma = 22.98±0.58 puls wydtes
die helder en dieper rooi kleur gehad het as 1 ms (a* = 16.66±0.37; chroma = 19.99±0.32) teen dag 9 van
kleinhandel vertoning.
Ter opsomming, lei HFI tot beter vleis kwaliteit wanneer dit gekombineer word met of HVS of MVS. Verder
lei MVS tot of ’n verbetering (kleur stabiliteit) of geen nadelige effek op vleis kwaliteit (sagtheid en WBV) in
vergelyking met HVS wanneer dit gekombineer word met HFI. Die studie bewys ook dat daar ander
elektriese parameters bestaan as spanning, wat verander kan word om die pH daling te beïvloed. Deur die
frekwensie en pulswydte te verander, kan klein veranderinge aangebring word aan ’n ES sisteem. Elke
abattoir is verskillend as gevolg van uitleg, koelkamer spasie en verkoelings tempo en hierdie elektriese
parameters kan verander word om ’n ES sisteem te optimiseer sonder enige duur veranderinge aan die hele
sisteem.
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The effect of slaughter age on the lamb characteristics of Merino, South African Mutton Merino and Dorper lambsVan der Westhuizen, E. J. 03 1900 (has links)
Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: The aim of this study was to investigate the effect of feedlot production on the growth and carcass
characteristics, as well as the distribution of the main tissues (muscle, fat and bone) and meat quality of
Merino, South African Mutton Merino (SAMM) and Dorper lambs.
The Merino and SAMM 2008 outperformed (P<0.05) the 2007 SAMM and both Dorper production groups in
terms of average daily gain, while the Merino and both SAMM production groups achieved the best feed
conversion ratio (P<0.05). The highest percentage A2 graded carcasses was achieved after 42 days under
feedlot conditions by the Merino and both Dorper production groups, but it took only 21 days in the feedlot for
the SAMM lambs to achieve the same result.
Slaughter weight, carcass weight and dressing percentage all increased significantly with an increase in the
number of days under feedlot conditions for all three breeds, while a decrease in the percentage head,
trotters and red offal was also documented. The fatter retail cuts (thick rib, flank, prime rib and loin)
increased (P<0.05) in percentage with an increase in the number of days under feedlot conditions. A
significant decrease in the percentage leaner retail cuts (raised shoulder and hind-quarters) was found when
the amount of days under feedlot conditions increased. The highest profit is obtained by the prime rib, loin
and hind-quarters in a lamb carcass. For the Merino and Dorper lambs these three cuts, or a combination of
the three showed the highest combined percentages after 42 and 63 days under feedlot conditions,
respectively. The late maturing SAMM lambs achieved the highest percentages for these three cuts after 63
and 84 days under feedlot conditions in 2007 and 2008 respectively.
Visceral and renal fat deposition increased throughout the production period for all breeds. The Dorper
lambs attained the highest subcutaneous fat depth, and also produced the heaviest, but fattest carcasses.
For A2-graded carcasses, Dorper lambs had the highest dressing percentage and lowest subcutaneous fat
depth, followed by the SAMM and then Merino breed. A decrease in the percentage muscle and bone was
found with an increase in the number of days under feedlot conditions, whilst an increase in the percentage
fat was found under the same conditions.
Meat quality was mostly affected by the 48h post mortem pH. This pH value is affected by the cooling rate of
the carcasses, which in turn is affected by the level of carcass fatness. Carcass fatness increased with an
increase in the number of days under feedlot conditions, resulting in a low 48h post mortem pH. A low 48h
post mortem pH is accompanied by higher percentages of cooking and drip loss, as well as a high a*-colour
reading for all three breeds. / AFRIKAANSE OPSOMMING: Die doel van hierdie studie was om die effek van voerkraalproduksie op die groeivermoë, karkaseienskappe,
verspreiding van spier, been en vet, en vleiskwaliteit van Merino, Suid-Afrikaanse Vleismerino
(SAVM) en Dorperlammers te bepaal.
Die Merino en SAVM 2008 produksiegroepe het hoër (P<0.05) gemiddelde daaglikse toenames getoon as
die SAVM 2007 en beide Dorper groepe, terwyl die Merino en beide SAVM produksiegroepe die beste
voeromset verhoudings bereik het (P<0.05). Die hoogste persentasie A2 gegradeerde karkasse is na 42
dae in die voerkraal deur die Merino en beide Dorper produksiegroepe geproduseer, terwyl dit slegs 21 dae
onder dieselfde toestande vir die SAVM groepe geneem het om dieselfde resultaat te lewer.
Daar is ‘n betekenisvolle verhoging in slagmassa, karkasmassa en uitslagpersentasie vir al drie die rasse
gevind met ‘n toename in die aantal dae in die voerkraal, terwyl ‘n afname in die persentasie kop, pote en
haarslag gevind was. Die persentasie vetter groothandelsnitte (dikrib, dunrib, ribtjop en lendesnit) het
toegeneem (P<0.05) met ‘n toename in die aantal dae in die voerkraal. ‘n Betekenisvolle afname in die
persentasie van die maerder groothandelsnitte (blad en boude) is gevind met ‘n toename in die aantal
produksie dae in die voerkraal. Die hoogste inkomste van ‘n lamkarkas is afkomstige van die ribtjop, lende
snit en boude. ‘n Kombinasie van hierdie drie snitte was die hoogste vir die lammers van die Merino en
beide Dorper groepe na 42 en 63 dae in die voerkraal onderskeidelik. Die laat volwasse SAVM lammers het
die hoogste persentasie van hierdie drie snitte bereik na 63 en 84 dae in die voerkraal vir die SAVM 2007 en
SAVM 2008 onderskeidelik.
Die neerlegging van pensvet en niervet het voortdurend toegeneem deur die produksieperiode vir al drie
rasse. Die Dorperlammers het die hoogste onderhuidse vetneerlegging getoon, maar het ook die swaarste
en vetste karkasse geproduseer. Dorperlammers het die hoogste uitslagpersentasie en laagste onderhuidse
vetneerlegging vir A2 gegradeerde karkasse gehad, gevolg deur die SAVM en Merino. ‘n Afname in die
persentasie spier en been in karkasse is waargeneem namate die lammers langer in die voerkraal was,
terwyl ‘n toename in die persentasie vet onder dieselfde omstandighede waargeneem is.
Die 48h post mortem karkas pH affekteer die meeste vleiskwaliteit eienskappe. Hierdie pH waarde word
weer deur die tempo van karkasafkoeling beϊnvloed, wat op sy beurt deur die vetheidsgraad van die karkas
bepaal word. Die vetheid van karkasse het toegeneem met ‘n toename in die aantal dae in die voerkraal,
wat ‘n lae pH waarde 48h post mortem tot gevolg gehad het. ‘n Lae 48h post mortem pH waarde het gelei
tot hoër persentasies kook- en dripverliese en hoë a* kleurlesings vir al drie rasse.
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Post mortem carcass interventions to improve beef qualityDu Toit, Francois Matthys 03 1900 (has links)
Thesis (MScAgric (Animal Sciences))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: A total of 32 cattle were divided into four groups of eight each (A1-8, A9-16, A17-24, B1-B8) to be
slaughtered on different days over a period of 45 days. All the cattle in Groups A were of Bonsmara type
and those in Group B were of Charolais type. Three treatments, Tenderstretch (TS), Tendercut (TC) and
Hock suspension (HS) were randomly allocated to each of the 48 sides from group A. Only two
treatments (TC and HS) were implemented on the carcass sides in Group B alternating between the right
and left sides. Two muscles from each side namely Gluteus medius and Longissimus dorsi were
evaluated for purge, cooking loss, shear force and sarcomere length after 2, 4, 6, 10 and 14 days of
aging. Paired t-Tests were performed for each pair of treatments and each day separately, on all
variables accessed (Snedecor, 1980). The differences in purge and cooking loss between treatments
were all found to be inconclusive for each day of aging. Although purge had significant differences
between the treatments TC and TS for the GM and LD muscle after 14 days of aging (P = 0.0341 and P =
0.0348 respectively) these were found to be open to doubt as the treatment that delivers the most purge
differs between muscles and that the two treatments delivered no differences compared to its HS values.
Aging had a significant effect on purge as it doubles after 14 days of aging. Cooking loss values only
differed significantly on day 2 for the LD muscle between treatments TC and HS. The differences in
shear force were all smaller than 0.3205 kg/ 1.27cm and not consistent over all carcasses. A mean
positive improvement in tenderness was calculated from high difference in mean values from some
carcasses although some carcasses showed a decrease in tenderness when using TS and TC, which
suggests that the treatments are of no relevance towards the industry. Although the differences in shear
force become smaller as aging commences, it is not constant, a phenomenon most probably due to the
variance between animals. Aging again had the most significant effect (P<.0001) on shear force.
Correlations between sarcomere lengths and shear force were low for all the treatments on the GM
muscle (HS = -0.453; TC = -0.401 and TS = -0.2) but in the LD muscle the TS method showed a higher correlation (TS = -0.665) than the other treatments (HS = 0.059 and TC = 0.059). / AFRIKAANSE OPSOMMING: `n Totaal van 32 beeste was opgedeel in vier groepe van agt elk (A1-8, A9-16, A17-24, B1-B8)
wat geslag is op verskillende dae oor n periode van 45 dae. Beeste van die A groep was almal Bonsmara
tipe en die van die B groep charolais tipe. Drie behandelings naamlik Tenderstretch (TS), Tendercut (TC)
en Hak suspensie (HS) was ewekansig tot die 48 sye van die karkasse van groep A toegedeel. Groep B
se 16 sye is net met TC en HS ewekansig tot die linker en regter sy toegedeel. Twee spiere naamlik
Gluteus medius en Longissimus dorsi was geevalueer vir drup verlies, kook verlies, sarkomeer lengte en
taaihied na 2, 4, 6, 10 en 14 dae se veroudering. Gepaarde t – toetse is gedoen vir elke paar
behandelings vir elke dag van veroudering op al die veranderlikes genoem. Die verskil in drup verlies en
kook verlies tussen behandelings was as nie betekeinisvol bestempel. Behalwe vir die feit dat drup verlies
betekenisvolle verskille getoon het tussen die behandelings TC en TS vir die GM (P = 0.0341) en die LD
(P = 0.0348) spiere na 14 dae se veroudering was dit bevind as nie betekenisvol juis oor dat die twee
behandelings teenoor hul HS waardes geen verskille getoon het nie. Veroudering van die vleis het wel
die grootste betekenisvolle verskil in drupverlies gemaak waar dit amper verdubbel soos die vleis
verouder vir 14 dae. Kookverlies het net op dag twee n betekenisvolle verskil getoon in die LD spier vir
die HS – TC kombinasie. Die verskil in taaiheid was almal kleiner as 0.3205 kg/ 1.27cm en nie kostant vir
alle karkasse nie. n’ Positiewe gemiddelde verbetering in sagtheid is verkry deur die kalkulasie van hoë
positiewe waardes en lae negatiewe waardes vir sommmige karkasse wat n laer sagtheid getoon het
wanneer TS en TC gebruik is. Hierdie onkonsekwente verbeterings in sagtheid maak dat hierdie
behandelings van min praktiese nut vir die bedryf is. Alhoewel hierdie verskille tussen behandelings
kleiner raak tydens veroudering, is dit nie konstant nie, wat as gevolg van die variasies tussen diere kan
wees. Veroudering het weereens die mees betekenisvolle effek op die vleis getoon (P< 0.001). Die
korrelasie tussen sarkomeer lengte en WBSF taaiheid was laag vir alle behandelings in die GM spier (HS
= -0.453; TC = -0.401 en TS = -0.2) behalwe vir die LD spier waar die TS behandeling n hoer korrelasie
van TS = -0.665 as die ander twee behandelings (HS = 0.059 en TC = 0.059) opgelewer het.
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The evaluation of larvae of Musca domestica (common house fly) as protein source for broiler productionPretorius, Q. 03 1900 (has links)
Thesis (MScAgric)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: The objective of this study was to evaluate the use of Musca domestica (common house fly) larvae meal, as
protein source, for broiler production. This was done by investigating the nutritive value of house fly larvae meal
together with its total tract digestibility, potential toxicity and carcass characteristics of the broilers supplemented
with house fly larvae meal. The proximate analysis of house fly larvae meal show that it contained, on a dry
matter basis, a gross energy value of 20.10 MJ/kg, 60.38% crude protein, 14.08% crude fat and 10.68% ash and
that the house fly pupae contained a gross energy of 20.42 MJ/kg, 76.23% crude protein, 14.39% crude fat and
7.73% ash. House fly pupae meal had the closest match of amino acid profile when compared with the ideal
amino acid profile required by broilers and it has arginine relative to the lysine content closer to the ideal amino
acid profile than the house fly larvae meal. The essential fatty acid, linoleic acid, was found at levels of 26.25
and 36.27% of the total fats for the house fly larvae and pupae meal respectively. House fly larvae meal
supplementation did not induce gizzard erosion or showed toxicity (regarding the gastro intestinal tract, immune
system and organ stress) in broilers.
Results revealed that house fly pupae meal had higher total tract digestibilities for most nutrients than of the
house fly larvae meal. House fly larvae meal had a crude protein total tract digestibility of 69% and that of pupae
meal was 79%. Both larvae and pupae meal had high amino acid total tract digestibilities of all the amino acids
analysed. The house fly larvae and pupae meal had an apparent metabolizable energy (AME) value of
14.23MJ/kg and 15.15MJ/kg respectively. The larvae meal total tract crude fat and crude fibre digestibilities
were 94% and 62% respectively. The pupae meal total tract crude fat and crude fibre digestibilities were 98%
and 58% respectively.
House fly larvae meal supplementation in a three phase feeding system significantly increased average broiler
live weights at slaughter, total feed intake, cumulative feed intake as well as average daily gain (ADG) when
compared to commercial maize: soya oil cake meal diet. In direct comparison of larvae inclusion levels with
fishmeal in isonitrogenous and isoenergetic diet, no significant differences were observed between a 10% house
fly larvae and a 10% fish meal diets regarding performance characteristic. The 25% house fly larvae meal diet
yielded significantly better average broiler live weights at slaughter, total feed intake, cumulative feed intake
(from the second week until slaughter) as well as average daily gain when compared to the 25% fish meal diet in
the growth phases.
Carcass characteristics of the 10% larvae, 10% fishmeal and commercial diets were compared. Chicks that
received either the 10% house fly larvae meal or 10% fish meal supplementation produced significantly heavier carcasses and breast muscle portions than the chicks that received the commercial maize: soya oil cake meal.
No treatment differences were found regarding breast and thigh muscle colour or pH.
This study showed that house fly larvae meal can be regarded as a safe protein source that can be used to
replace other protein sources and that has the ability to promote broiler performance without having any
detrimental effects on carcass characteristics. / AFRIKAANSE OPSOMMING: Die evaluasie van Musca domestica (gewone huisvlieg) larwe meel as ‘n proteien bron
vir braaikuiken produksie
Die doel van die studie was om die effek van Musca domestica (gewone huisvlieg) larwe meel, as ‘n protein
bron, in braaikuikens te evalueer. Dit was gedoen deur die nutrient waarde van huisvlieg larwe meel saam met
die totale spysvertering verteerbaarheid, moontlike toksiesiteit en karkas-eienskappe van braai kuikens te
evalueer. Laboratoruim analiese toon dat huisvlieg larwe meel 20.10 MJ/kg bruto energie, 60.38% ru- protein,
14.08% ru- vet en 10.68% as bevat en huisvlieg papie meel 20.42 MJ/kg bruto energie, 76.23% ru- protein,
14.39% ru- vet en 7.73% as bevat. Huisvlieg papie meel stem die meeste ooreen met die idiale amino suur
profiel soos wat benodig word deur braaikuikens en dit het ‘n arginien tot lisien verhouding wat die meeste
ooreenstem met die idiale amino suur profiel in vergelyking met huis vlieg larwe meel. Die essensiele vet suur,
linolien suur, was geanaliseer teen vlakke van 26.25- en 36.27% van die totale vette onderskeidelik vir huisvlieg
larwe- en papie meel. Huisvlieg larwe meel vervanging het nie spiermaag erosie of enige ander toksiese effekte
te veroorsaak nie.
Resultate het getoon dat huisvlieg papie meel, in vergelyking met larwe meel, het ‘n hoër totale spysvertering
verteerbaarheid vir meeste van die nutrient. Die huisvlieg larwe meel het ‘n totale ru- protein spysvertering
verteerbaarheid van 69% en die van papie meel van 79%. Beide larwe en papie meel het hoë amino suur
spysvertering verteerbaarheid. Larwe meel en papie meel het skynbare metaboliseerbare energie waardes van
14.23MJ/kg en 15.15%MJ/kg onderskeidelik. Die larwe meel het ‘n ru-vet en ru- vesel spysvertering
verteerbaarheid van 94% en 62% onderskeidelik, waar die papies ‘n ru-vet en ru- vesel spysvertering
verteerbaarheid van onderskeidelik 98% en 58% het.
Huisvlieg larwe meel vervanging in ‘n drie fase voer stelsel het getoon om die gemiddelde braaikuiken lewende
gewigte by slag, totale voer iname, sowel as die gemiddelde daaglikse toename te verhoog waneer dit vergelyk
word met ‘n kommersiele mielie- soya olie koek dieet. Geen mekwaardige verskille was waargeneem toe die
10% larwe meel dieet direk met die 10% vismeel diet vergelyk was rakende enige produksie einskappe gemeet
nie. Die 25% larwe meel dieet het merkwaardig beter gemiddelde braaikuiken lewende gewigte by slag, totale
voer iname, sowel as die gemiddelde daaglikse toename getoon wanneer vergelyk word met die 25% vismeel
dieet gedurende die verskeie groei fases.
Karkas eienskappe van die 10% larwe meel, 10% vismeel en die kommersiele diete was gevergelyk. Kuikens
wat 10% larwe meel en 10% vismeel in die diete ontvang het, het swaarder karkasse gelewer met swaarder
borsie massas wanneer vergelyk word met die kommersiele mielie- soya olie koek dieet. Geen behandelings
verskille was gevind rakende die borsie- en dy spier kleure of pH nie.
Die studie toon dat huisvlieg larwe meel as ‘n veillige protein bron kan beskou word, wat gebruik kan word om
ander protein bronne te vervang. Huisvlieg larwe meel het ook die vermoë om braaikuiken produksie te verhoog
sonder om enige negitiewe effekte rakende die karkas eienskappe te toon nie.
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