Thesis (PhD)--Stellenbosch University, 2008. / ENGLISH ABSTRACT: Although small, the South African ostrich industry contributes 60% to the total world production of slaughter ostriches. Ostrich leather contributes more than 50% of the R2.1 billion turnover of this industry. This study is the first structured investigation into the characteristics of ostrich leather focussing on factors such as age, nutrition, slaughter weight, and genetics, and the influence thereof on intrinsic leather traits. Large variation in terms of skin quality was found between producers, month of the year and production years. The effect of age suggested that leather thickness and tensile strength increased with age while the number of nodules declined by 2.8 for every month increase in slaughter age. Slit tear strength and tensile strength increased with heavier slaughter weights. Older ostriches had higher values for slit tear strength and skin thickness. Nodule diameter increased at a rate of 0.08mm per month increase in age. Nodules with an average diameter of more than 4.0mm were only obtained in the combination of old heavy birds, while nodule diameter of the other age-weight combinations ranged between 3.3mm and 3.5mm. Subjective assessment of nodule traits by participants with or without prior knowledge of age suggested that slaughter age accounted for 46% of the variation in estimated slaughter age. Nodule acceptability scores generally increased with an increase in slaughter age. Moderately acceptable scores were found in skins from birds 11 months and older. The effect of energy and protein concentrations of ostrich diets suggested that raw skin areas were 19.4% and 21.8% larger at slaughter for birds receiving a diet containing 10.5 MJ/ME and 12.0 MJ ME/kg DM respectively, compared to that of birds receiving a 9.0 MJ ME/kg DM diet. Leather thickness taken parallel to the spine was increased by 13% when birds were fed the higher energy diet. Dietary protein concentrations failed to influence skin weight, skin area or any physical leather properties. The genetic variation in nodule size measured at different sampling sites on the skin suggested that nodule size increased chronologically with age at the neck, back, upper leg, and flank and butt areas. Estimates of h² for nodule size ranged from 0.09 ± 0.07 on the flank region to 0.24 ± 0.10 on the upper leg region. Preliminary results seem to suggest that nodule size on different locations of the skin is not necessarily the same genetic trait. It was concluded that measurements at any specific site is unlikely to predict measurements at other sites with a high degree of accuracy due to the large variation that exists between measurement sites. This dissertation provides an insight into the complexity of ostrich leather quality, and the interaction of leather traits, such as nodule size and shape, leather thickness and tensile strength, that determine ostrich leather quality. / AFRIKAANSE OPSOMMING: Alhoewel klein, produseer die Suid-Afrikaanse volstruisbedryf 60% van die totale wêreldproduksie van slagvolstruise. Volstruisleer is verantwoordelik vir meer as 50% van die R 2.1 biljoen omset van die bedryf. Hierdie studie is die eerste gestruktureerde ondersoek na die intrinsieke eienskappe van volstruisleer en die invloed van ouderdom, voeding, slagmassa en genetika op hierdie eienskappe. Groot variasie t.o.v. leerkwaliteit is waargeneem tussen produsente, maande van die jaar en produksiejare. Die effek van ouderdom toon dat leerdikte en treksterkte verhoog het met toename in ouderdom, terwyl die aantal knoppies afneem met 2.8 vir elke maand toename in slagouderdom. Skeur- en treksterkte het verhoog met ʼn swaarder slagmassa (64kg vs. 99kg). Hoër waardes vir skeursterkte en veldikte is vir ouer voëls (384 dae vs. 234 dae ouderdom) verkry. Knoppie deursnit het teen ʼn tempo van 0.08mm per maand toename in ouderdom verhoog. Knoppies met ʼn gemiddelde deursit van groter as 4.0mm is slegs waargeneem in swaar-ou voëls, terwyl die knoppie deursnit van die ander massa-ouderdom kombinasies tussen 3.3mm en 3.5mm gewissel het. Die subjektiewe waarneming van 28 respondente, ingelig of oningelig oor die betrokke slagouderdom, dui daarop dat die werklike slagouderdom verantwoordelik is vir 46% van die variasie in geskatte slagouderdom. Die puntetoekenning vir knoppie-aanvaarbaarheid het verhoog met ‘n toename in slagouderdom. Aanvaarbare puntetoekenning vir knoppie-ontwikkeling is verkry vir voëls vanaf 11 maande en ouer. Die effek van energie- en proteïenkonsentrasies in volstruisdiëte toon dat die rouveloppervlakte onderskeidelik 19.4% en 21.8 % groter was met slagting vir voëls wat onderskeidelik ‘n 10.5 MJ/ME en 12.0 MJ ME/kg DM diëte gevoer is, in vergelyking met voëls wat ‘n 9.0 MJ ME/kg DM dieet ontvang het. Leerdikte, geneem parallel met die ruggraat, het met 13% toegeneem wanneer die hoër energie dieet gevoer is. Dieetproteïen konsentrasies het geen invloed op velmassa, veloppervlakte of enige fisiese leerkwaliteitseienskappe gehad nie. Die genetiese variasie in knoppiegrootte geneem op verskillende lokaliteite op die vel toon ʼn chronologiese toename met ouderdom in die nek-, rug-, boud-, sy- en stuitjie gebiede. Beraamde h² vir knoppiegrootte wissel vanaf 0.09±0.07 op die sye tot 0.24±0.10 op die boudgedeelte. Voorlopige resultate dui aan dat knoppiegrootte op verskillende lokaliteite nie noodwendig dieselfde genetiese basis het nie. Die gebruik van een lokaliteit vir die voorspelling van die eienskappe van ʼn ander, blyk nie sinvol te wees nie a.g.v. die groot variasie wat tussen verskillende lokaliteite bestaan. Hierdie studie verskaf insig oor die kompleksiteit van volstruisleerkwaliteit en die interaksie van leereienskappe soos knoppiegrootte en –deursnit, veldikte en treksterkte, in die bepaling van leerkwaliteit.

The decrease in productivity caused by fescue toxicosis has been estimated to cost the United States livestock industry more than $1 billion per year due to reduced growth and diminished reproductive efficiency. This goal of the research presented in this dissertation is to enhance the knowledge base concerning the underlying physiological changes that occur during fescue toxicosis that lead to reduced intake and weight gain in cattle. As one of the factors associated with fescue toxicosis is a reduction in feed intake, achieving a consistent and adequate intake of toxins can be a complication. Results from experiment 1demonstrate that ruminal dosing of ground seed and a seed extract are able to mimic the classic symptoms of fescue toxicosis in cattle. This model whereby seed or extract is directly dosed into the rumen eliminates the possibility of reduced alkaloid intake due to refusal of feed by the animal. This model allows for more precise and repeatable dosing of alkaloids in fescue research. Experiment 2 results indicate that ingestion of endophyte-infected tall fescue leads to decreased fasting heat production in cattle. This is indicative of a reduction in maintenance energy requirements and may be related to a decrease in liver size or other metabolic activity in animals grazing endophyte-infected pastures. In addition, a reduction in basal metabolic rate may cause the compensatory gain often observed in cattle entering the feedlot after grazing endophyte-infected pastures. Data from experiment 3 provides evidence that whole body nitrogen and energy metabolism are not altered by fescue alkaloid ingestion. Experiment 3 also addresses the rate of feed degradation and ruminal passage rates in cattle ingesting endophyte infected fescue. While ruminal VFA profile is altered, this is likely due to reduced absorption, not increased production. The data from this experiment indicate that the reduction in weight gain and productivity seen during fescue toxicosis is primarily a function of reduced intake and not secondary effects of alkaloid ingestion.

Approximately half of all reported laminitis cases are the result of “grass founder” (laminitis associated with long-term over consumption of lush, early spring pastures). Elevated body weights (BW), body condition scores (BCS), and blood glucose concentrations have all been associated with the onset of grass founder. Plasma fructosamine concentrations (PFC) have recently been used as an indicator of long-term (14–21 d), mean blood glucose concentrations in horses and numerous authors have reported that elevated PFC were observed in laminitic horses (Murphy et al., 1997; Keen et al., 2004; Knowles et al., 2012). This study was conducted to evaluate the long-term effects of transitioning from an ad-libitum tall fescue hay diet in late winter to an adlibitum tall fescue pasture diet in early spring on parameters associated with grass founder in horses. Five mature stock horse mares were given free choice access to good quality tall fescue hay for 18 weeks before initiation of data collection. Each horse acted as their own control. PFC were determined on day 1, day 128, and then monitored at 14 d intervals for the following 84 d (February 26th through May 21st). Three trained lab technicians evaluated BW and BCS on day 1, 128, 170 and 212 of the trial. The horses were placed in a 20 acre field where their diets consisted of free choice access to hay only for 156 days (DTP1) followed by free choice access to tall fescue hay with minimal access to some early emerging tall fescue pasture for 14 days (DTP2), and finally to free choice access to lush spring tall fescue pasture only for the final 42 days (DTP 3) when the animals refused to eat offered hay. Mean PFC were highest (P < 0.01) for DTP1 and decreased with each successive transition to DTP2 and DTP3. This may have been due to increased insulin secretion associated with the pasture only diet. Mean BCS at the beginning of the trial was 5.7 and increased throughout the trial (P < 0.001) to a value of 7.8. BCS associated with the pasture only diet were higher (P < 0.001) than those associated with the free choice hay and hay plus pasture diets. Mean BW increased (P < 0.05) from 1199 lbs. to 1268.3 lbs. during the 12-week trial. Mean weight gain was 113 lbs. with an average daily gain of 1.35 lbs./day. No incidence of laminitis was observed.

As early as 1850 many reports of observations of the blind cave animals were made by both scientific and popular writers. Tellkempf, Agassiz, Forbes and Silliman were some of the earlier scientists who studied the eyes of cave animals. Eigenmann made a histological study of the cave vertebrates of America. In a study of Forbesichthys papilliferus, a semi-blind cave fish, Jennie Miller Orr found important structural modifications in the eyes of this species. Since no comparative histological studies of the eyes of cave animals seem to have been made, it was decided to make such a study with a view to determining whether these structural differences are similar in different cave animals. The animals chosen for this study are: Hadenoecus subterraneous, the so-called cave cricket; Cambarus pellucidus, the blind cave crayfish; Forbesichthys papilliferus, the semi-blind cave fish and Typhlichthys subterraneous, a blind cave fish. Eigenmann states that degeneration of eye tissue occurs in certain forms in the absence of light. A comparative histological study of the eyes of cave species and of those having normal eyes should reveal the nature of this degeneration.

The small mammal population of a restricted study area was live-trapped on the University farm at Western Kentucky University from November 1984 through November 1985. A total of 1800 trap-nights yielded 81 different individuals representing five species. Members of the genera Peromyscus and Microtus were the dominant individuals representing over 90% of the total. Also caught were Mus musculus and Blarina brevicauda. The members of the two major genera were examined for population size and dynamics. In addition, a statistical analysis was carried out on the randomness of the location of the home ranges. This analysis gave evidence that the Peromyseus population was centered primarily in the ecotone between field and forest while Microtus was centered exclusively in the field habitat. In addition, the absence or near absence of Microtus for part of the year allowed the Peromyscus population to expand into the field for a short time. Finally, the year long study revealed a characteristic population cycle for each major species due to a combination of reproductive rates, feeding habits and decimation by predation.

Multispecies grazing research was conducted using meat-type goats (Capra hircus L.) and Jersey heifers (Bos taurus L.) to determine the relationships between multiple grazing treatments and pasture utilization. The study was conducted for 60 days on the Western Kentucky University Farm in Bowling Green, KY. Cattle and goats have shown to differ in grazing preferences and to be economically important to the area. Grazing treatments included goats and cattle grazing simultaneously, sequentially, and goats grazing alone. A typical established Kentucky pasture was utilized with no weed management practices employed. Predominant forage species included tall fescue (Festuca arundinacea Schreb.), orchardgrass (Dactylis glomerata L.), Kentucky bluegrass (Poa pratensis L.), and white clover (Trifolium repens L.). Exclosures were utilized as controls. Data included forage quality, composition, availability, height, visual weed cover and live ground cover, and thistle consumption, collected every 15 days. Results indicated a significant difference in sample dry weights between grazing treatments and ungrazed controls in every treatment except when goats followed cattle. At day 60, grazed areas had significantly lower forage heights than the control when goats grazed with and before cattle. Instances where goats followed cattle resulted in significantly higher NDF compared to the control. All treatments containing goats had significantly lower leaf numbers per thistle plant (Carduus nutans L.) than cattle only treatment. Based on this study, sequential and simultaneous grazing of cattle and goats may be an effective nodding thistle control strategy, but future experimentation is needed for determination of forage utilization and quality relationships.

Selenium (Se) is an important trace mineral in the diet of cattle. Our objective was to determine whether the form of supplemental Se fed to the dam would affect the expression of genes regulating steroidogenesis in the newborn testis. Twenty-four Angus-cross cows were assigned randomly (n=8) to individual ad libitum access of a mineral mix containing 35 ppm of Se supplied as sodium selenite (inorganic, ISe; Prince Se), Sel-Plex (organic, OSe; Sel-Plex, Alltech) or a 50/50 mix of ISe/OSe (MIX) 4 months prior to breeding and throughout gestation. All male calves were castrated within 2 days of birth and total testis RNA was subjected to microarray analysis using the Affymetrix Bovine 1.0 ST array. Ingenuity Pathway Analysis of differentially expressed genes, separated by one-way ANOVA (p<0.05) and a post-hoc LSD test, identified eight mRNAs associated with steroidogenesis. Specifically, mRNAs involved in the conversion of testosterone to estradiol were increased in the testis of OSe-supplemented when compared to ISe-supplemented animals, and mRNAs encoding genes regulating the conversion of androstenedione to testosterone or androstenedione to estradiol were decreased in the testis of MIX-supplemented when compared to ISe-supplemented cows.Expression in the neonate may equate to differences in fertility in the adult animal.

<p>Developing bat pups produce distinct vocalizations called isolation calls (I‐calls) that serve to attract the bat’s mother. How individual pups shift their vocalizations from I‐calls to downward frequency modulated (FM) sweeps during development remains unclear. By recording individual bat pups from the day of birth to twenty‐five days postnatal we observed behavioural and bioacoustic (temporal and spectral) changes in pup calls. Temporal characteristics examined were call duration and call rate; spectral characteristics were minimum frequency, maximum frequency, peak spectral frequency, total signal bandwidth, maximum frequency of the fundamental acoustic element and bandwidth of the fundamental. I‐calls were produced only until a certain point in development, after which pups change from emitting long‐duration, tonal I‐calls to downward FM signals and eventually short‐duration biosonar vocalizations. We discovered additional spectral changes in the harmonic structure of pup calls, with the number of harmonic elements decreasing with age. We also recorded pup vocalizations during prolonged separation from their mothers to determine if extended isolation alters the type, number or acoustic structure of emitted vocalizations. Rate of calling was influenced by prolonged separation; younger pups had higher calling rates and called longer than older pups. We also compared temporal and spectral characteristics of spontaneous and provoked calls. We found that provoked calls were more similar to vocalizations produced by younger pups. By documenting the vocal behaviour and acoustic structure of pups calling in different situations, this research provides groundwork for further studies on the ontogeny and development of FM vocalizations in bats and other mammals.</p> / Master of Science (MSc)

Thesis (MPhil (Animal Sciences. Aquaculture))--University of Stellenbosch, 2005. / This paper contains literature on tilapia culture, feeding and nutritional factors of prime consideration to survival and growth of Oreochromis mossambicus. Results are presented for a three-phase laboratory experiment on survival of O. mossambicus fry in an attempt to evaluate the use of live Spirulina platensis. The experiment was conducted on fry in a closed system in an effort to maximize the use of live Spirulina and also optimize growth and production. Fry were tested for tolerance levels of salinities, 0-35 g/lt, and showed favourable survival rates up to 15 g /lt salinity without being fed. Manipulation of input in freshwater turned high fry mortalities with increasing rates without difference for physical form of Spirulina. Growth was not significantly affected by types of input. However fry grew well at 0-40% rates with considerable survival performance. It is noted good quality of water that allow improved survival and growth of fry in a closed system may be assured with rates of input up to 5 or 10% of bodyweight. These input rates can guide use of live Spirulina in saline water tilapia culture if Spirulina proves good productivity at the consistency of fry tolerance to the salinity levels established in this paper.

Thesis (MPhil (Animal Sciences. Livestock Industry Management: Pig Science))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: This mini-thesis describes the pig industry in South Africa which consists of a commercial intensive sector and an extensive sector that is also known as the small scale sector. Challenges in such as, marketing, feed, housing and genetics of small scale farmers are discussed. The objective of this study is to identify the problems experienced by the emerging/small scale pig farmers and to benchmark the production parameters of these farmers. Data was collected using questionnaires, telephone and site visits to farms/projects. The data collection was grouped into descriptions of small scale piggeries, feeding strategies, management programs, production parameters, regional constraints, marketing, comparisons between stud and commercial piggeries. The results were arranged into the following manner: general, regional constraints, description of small scale piggery facilities, feeding strategies of small scale farmers, management programs in small scale piggeries, production parameters of small scale piggeries in the Limpopo province, production parameters of stud and commercial piggeries, and the management strategy in a commercial piggery. Those piggeries having 5-30 sow units were interviewed. Results indicate that small scale farmers were found not to be sustainable in their production. The small scale farmers have no understanding of the pig industry, genetics and breeding of pigs, feeding strategies, and marketing channels for pigs. Typical problems experienced are: marketing is only done once or twice a year and not regularly as with any commercial piggery – a main problem identified here was access to the formal market. Typical production problems experienced were long farrowing intervals, small litter sizes, late weaning periods and low weaning percentages. This was attributed not only to mismanagement but also to bad infrastructure. Small scale piggeries typically have low cost sty’s that have inadequate floors, walls, roofing and very few of the piggeries has sufficient fresh water. Another problem experienced was poor growth which could be directly linked to the nutrition of the pigs. Most of the feed fed consisted of kitchen waste as balanced diets were perceived to be too expensive whilst access to suppliers, and transport (of both feed and pigs off to market) was generally lacking. Another major problem identified by the producers was insufficient scientific help from Government. Most producers also mentioned that they would welcome a mentorship program and help with the marketing and sourcing of funds. None the less, the pig owners all indicated that they wish to continue farming with pigs and that with the right help, they would be able to be successful. / AFRIKAANSE OPSOMMING: Hierdie werkstuk beskryf die vark industrie in Suid-Afrika wat bestaan uit ‘n kommersiële intensiewe en ekstensiewe sektor wat ook bekend staan as die klein-skaal sektor. Uitdagings soos bemarking, voer, behuising en genetika van klein-skaalse boere word bespreek. Die doel van die studie is om die probleme te identifiseer wat ervaar word deur die opkomende/klein-skaalse boere asook om die produksie-parameters van die boere te bepaal. Data was versamel deur middel van vraelyste, telefoonoproepe asook besoeke aan die boere/projekte. Die dataversameling was op verdeel in beskrywings van klein-skaalse vark eenhede, voerstrategieë, bestuursprogramme, produksie-parameters, distriksbeperkings, bemarking, en vergelykings tussen stoet- en kommersiële-eenhede. Die resultate was gesorteer op die volgende manier: algemeen, distriksbeperkings, beskrywing van klein-skaalse varkeenhede, produksie-parameters van klein-skaalse varkeenhede in die Limpopoprovinsie, produksieparameters van stoet- en kommersiële varkeenhede, en die bestuurstrategie in ’n kommersiële varkeenheid. Ondehoude is gevoer met dié eenhede wat tussen 5-30 soê het. Resultate wys dat klein-skaalse boere nie volhoubaar is in hul produksie nie. Die klein-skaalse boere het geen kennis van die vark bedryf, genetika en teel van varke, voerstrategieë en bemarking van varke nie. Tipiese probleme wat ervaar word is: bemarking word slegs een of twee keer per jaar gedoen en nie gereeld soos met kommersiële eenhede nie – die hoof probleem wat geïdentifiseer is die toegang tot die formele mark. Tipiese produksieprobleme wat hier geïdentifiseer is, was lang kraam intervalle, klein werpsel groottes, laat speenperiodes en lae speenpersentasies. Dit was as gevolg van nie net misbestuur nie, maar ook as gevolg van slegte infrastruktuur. Klein-skaalse vark eenhede het gewoontlik goedkoop varkhokke met onvoldoende bevloering, mure, en dakke en baie min van die eenhede het genoegsame vars water gehad. Nog ’n probleem wat ondervind is, was die slegte groei van die varke wat direk gekoppel kan word aan die voeding van die varke. Meeste van die voer het bestaan uit kombuisvullis omdat gebalanseerde rantsoene beskou was as te duur, terwyl daar oor die algemeen ’n te kort was aan toegang tot verskaffers en vervoer (van beide voer en varke na die mark). Nog ’n groot probleem wat geïdentifiseer is deur die produsente was dat daar ’n tekort is aan wetenskaplike hulp van die Regering. Meeste van die produsente het ook genoem dat hul ’n mentorskapprogram sal verwelkom asook hulp met bemarking en befondsing. Nie te min, die varkeienaars het almal aangetoon dat hul graag met die varkboerdery sou wil aangaan en dat met die regte hulp sou hul suksesvol kan wees.