Bibliography: leaves 172-214. Interleukin-12 (IL-12) is a heterodimeric cytokine composed of two disulphide-linked subunits, p35 and p40, which form biologically active p70. IL-12 is able to induce IFN-y production from T and NK cells, and promote the proliferation of mitogen-activated T cells. It is thought that IL-12 may be an important cytokine in the initiation and progression of allograft destruction. This thesis describes the characterisation of ovine IL-12.

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Doctor of Philosophy(PhD) / This study was conducted to provide accurate information about the impact of OJD on sheep mortality and financial status on infected farms in Australia. Industry considered this research to be important because little credible information was available regarding the magnitude of the OJD problem and the responses required to control and manage OJD in southern Australia. This 3-year study, conducted on 12 OJD-infected farms in southern NSW, commenced with a 12-month observational study in 2002. During this year OJD mortality estimates were derived from farm records (livestock inventories) and quarterly farm visits (necropsy inspections). Questionnaires, climatic records and pasture samples enabled a detailed description of each farm to be made and a single collection of blood and faecal samples provided OJD prevalence information for specific age cohorts of sheep in each flock. The financial impact of OJD was established using two approaches, a gross margin analysis and the provision of a financial value on the mortalities inspected during the necropsy inspection periods. For a further 2 years, inventory and management information was collected from each of the twelve farms to provide 2003 and 2004 estimates for OJD mortality and financial loss due to OJD based on gross margin analyses. A more detailed gross margin model was developed that has the capacity to compare three disease status scenarios (uninfected, infected and vaccinated) for a number of different sheep production enterprises. These enterprises include fine, medium and strong wool Merino ewes and wethers as well as 1st and 2nd cross lamb production. From the four 5-day necropsy inspections conducted in 2002, a most likely cause of death was determined for 362 necropsied sheep on the basis of findings related to the environment, clinical signs, gross pathology and histopathology. Of these, OJD was most likely to have contributed to the death of 250 sheep, OJD was unlikely to have contributed to the death of 1 sheep and OJD did not contribute to death of 111 sheep. During 2002, across the 12 farms, there were a total of 52,718 wethers and 47,374 ewes at-risk of becoming infected with OJD. The distribution of mortalities in each sex group translates to an OJD mortality rate of 4.3% among wethers and 4.9% among ewes. Distribution across inspection periods showed a trend among OJD-related necropsies and total necropsies with the majority occurring in winter (31%) and spring (35%) and fewer in autumn (18%) and summer (16%). Across the 12 farms, the annual OJD mortality rate ranged from 1.8% to 17.5% during the 3-year study with mean annual figures of 6.2% in 2002, 7.8% in 2003 and 6.4% in 2004. Of concern is the fact that these mean OJD mortality figures were all above the accepted annual mortality rate from all causes for adult sheep of 4-6% (McGregor et al., 2003) for Australian flocks. Gross margins were calculated for each of the 12 farms assuming each farm was free of OJD and then these were compared with the actual farm gross margin. The mean percentage decrease in gross margin due to a farm being infected with OJD was 6.4% in 2002, 8.5% in 2003 and 7.4% in 2004. This equates to a mean reduction in annual income of $15,000 per farm in 2002, $12,154 in 2003 and $13,991 in 2004. Using the necropsy inspection information the mean estimated cost of OJD losses on the 12 farms over 2002 was $60,500 (range $10,978 to $150,836). The estimated cost of OJD losses accounted on average for 69.4% (range 19.4% to 100%) of the estimated total loss related to sheep deaths over the 12-month period. The OJD prevalence in 2-year old sheep in 2002 based on pooled faecal culture (PFC) ranged from 0.7% to > 23% on the 12 farms and was found to be associated with OJD mortality rate (P = 0.02). In contrast, no significant relationship was found between faecal excretion rate of MAP in two-year old sheep based on PFC and OJD mortality rate, or between age-related OJD seroprevalence and OJD mortality rate. The association between various environment, management and disease factors and quarterly OJD mortality rate was analysed and several factors (including flock size, stocking rate, area of improved pasture and weaning age) were identified as being important for further investigation. Definite conclusions based on statistical analysis could not be made due to the small number of farms and use of whole flock data. However, the results provide strong support for an additional study, involving a large number of farms and focusing on a specific sheep cohort, to identify the major risk factors for OJD. The necropsy study in 2002 established 31% of deaths were due to causes other than OJD and could have been prevented in most cases. More than half (63%) of the non-OJD deaths were attributed to malnutrition, with 57% of these deaths occurring on one farm where pregnancy toxaemia resulted from sheep receiving inadequate nutrition in late pregnancy. Many of these deaths could have been prevented with earlier feeding. The occurrence of grain poisoning on some farms reinforces the need for improved strategies when supplementary feeding. Under more favourable seasonal conditions these nutritional syndromes are unlikely to occur. Sporadic drought conditions throughout the 3-year study period, for each of the four study regions, were likely to have a minimal effect on measuring the impact of OJD on the 12 farms. At the end of 2002, following the realisation the drought would likely persist into 2003, the 12 farms on average selectively reduced flock numbers by 25%. However, this reduction is unlikely to have had an adverse effect on establishing the proportion of OJD mortalities as stock reductions occurred mainly towards the end of 2002 and the sheep most likely to be sampled at each necropsy inspection period were unlikely to be sold, as they displayed low body condition score and showed signs of weakness. A gross margin model was developed to provide an estimate of the on-farm cost of OJD. Non-infected, infected (status quo) and infected (vaccination) disease scenario examples were run for 1000 head Merino ewe and wether enterprises as well as first and second cross prime lamb enterprises. The total cost of OJD (relative to an uninfected status) and an avoidable cost of OJD (using GudairTM vaccination) were reported at four investment horizons to illustrate the cost of an OJD infection on a flock as well as the potential cost saving if a control strategy involving vaccination is implemented. Although vaccination reduces OJD mortalities, there is still an unavoidable cost incurred by the producer when compared to an uninfected flock. Results are presented as cumulative gross margin per dry sheep equivalent expressed in net present value terms (GM (NPV)/DSE) at 5, 10, 15 and 20-year intervals to enable a comparison between enterprises. The model suggests a vaccination breakeven point is achieved in two to three years for breeding enterprises if the level of OJD is high. If the level of OJD is low a vaccination breakeven point is achieved in three years for either a 1st cross or 2nd cross enterprise and seven years for a Merino ewe enterprise. The Merino ewe enterprises take the longest time to reach a vaccination breakeven point as more young sheep are retained annually for breeding in addition to the cost involved with vaccinating lambs, which is borne by all three breeding enterprises. The returns to vaccination are greatest for the 1st and 2nd cross lamb enterprises due to the value and number of lambs sold annually. With Merino wethers a vaccination breakeven point is reached in year one for all disease categories due to vaccinated replacement hoggets being introduced to provide an immediate response in reducing OJD mortalities, however as no breeding occurs the ability to increase income is limited. In the absence of OJD mortalities with the at-risk disease category, a vaccination breakeven point is not reached within the model’s 20-year time frame for any of the enterprises. This study provided the first objective data on the true impact of OJD on 12 farms, and the findings are generally applicable to sheep flocks in southern Australia. Industry groups claiming that OJD does not present a threat on-farm can now be provided with accurate figures on direct losses attributable to OJD within the endemic area of NSW. There was a wide range of impacts, with some very high mortality rates. The data can be used to justify vaccination programs, other control options and the general concept of disease control and prevention. The challenge now for industry is the design and implementation of an education and extension package that can incorporate these findings and the gross margin model along with other recent research findings to address issues of misinformation about OJD and inform producer decisions regarding on-farm disease control.

Bibliography: leaves 206-263. / xviii, 313, [5] leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The aim of this project was to develop tools to assist in the construction of the ovine genome map so economic trait loci in sheep can be identified. (abstract) / Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Science, 2001

Objectives of this study were to examine effects of age, castration and gestation on actvities of calpains and calpastatin in skeletal muscle. Also, the regulation of calpains and calpastatin at the molecular level was investigated. Two experiments were designed. Experiment 1 was designed to evaluate effects of age and castration on calpains and calpastatin in sheep skeletal muscle. Experiment 2 was designed to examine the effects of age and gestation on calpains, calpastatin and their molecular regulation in rabbit skeletal muscle. In Experiment 1, ten newborn male lambs, six weaned wethers (92 days), six weaned rams (92 days), six market weight wethers (89 days post-weaning) and six market weight rams (89 days post-weaning) were slaughtered and gluteobiceps femoris was taken for assay of calpain I, calpain II and calpastatin. Body weights were not different between wethers and rams in weaned animals; however, post-weaning, body weight gain of rams was greater (p < .05) than that of wethers. Ram gluteobiceps femoris weight at market weight was greater than that of wethers (p < .05). Activities of muscle calpain I, calpain II and calpastatin in newborn lambs were higher than those of weaned and market weight lambs. The age-dependent reduction of calpain and calpastatin activities was complete at weaning and may be associated with or cause age-dependent attenuation of muscle protein degradation. Although muscle weights were greater in rams compared to wethers, no differences in activities of muscle calpains and calpastatin were detected between these two groups at weaning and at market weight. Hence, castration does not influence lamb muscle growth by changing muscle total calpain or calpastatin activities. In Experiment 2, biceps femoris muscle was collected from newborn, weaned (1 month), market weight (2 months), non-gestational adults (5 months) and gestational (20 day) adult rabbits and for assay of calpains, calpastatin activities, muscle NI-- methylhistidine (NMH) and mRNA encoding calpains and calpastatin. Muscle protein content (mg/g tissue) increased as animals aged indicating proliferation of myofibrillar protein. Total RNA content and ribosomal capacity (mg/g protein) declined (p < .05) as the rabbits aged; however, no differences in protein content and ribosomal capacity were detected in muscles taken from gestational versus non-gestational adult rabbits. Concentration of muscle NMH decreased as animal aged; however, no differences were detected in 20-day gestational muscle versus non-gestational muscle. Activities of calpains and calpastatin declined (p < .05) as animal aged. Most of the loss of activity occurred before 4 weeks of age (weaning). No differences in calpain and calpastatin activities were detected in gestational versus non-gestational animals. Reductions in activities of calpains and calpastatin were associated with reduced RNA concentration (ribosomal capacity) and reduced concentrations of muscle calpains and calpastatin mRNA (expressed as densitometry units per g tissue protein). The reduction of mRNA appeared to be associated with an overall loss of RNA from skeletal muscle because mRNA/g protein was greatly reduced whereas mRNA/total RNA for both calpains and calpastatin did not change greatly; however, mRNA/total RNA in adult rabbits compared to newborn, weaned and market weight animal declined significantly. In addition, from the Northern blot assay, it was determinated that newborn and weaned rabbits only expressed an intermediate length calpastatin mRNA isoform (II). However, the longest calpastatin mRNA isoform (I) was expressed in market weight and adult rabbits. The reason why muscle cells express different forms of calpastatin mRNA at different ages remains unknown. In pregnant rabbits, neither calpains nor calpastatin changed significantly. Also, muscle NMH concentration did not change. However, at the mRNA level, the steadystate concentration of mRNA encoding calpain II increased and calpastatin band II mRNA decreased in pregnant rabbits. This implies that in late catabolic stage of gestation, increased calpain II activity and decreased calpastatin activity may facilitate proteolysis. / Graduation date: 1991

The main themes of the present thesis was the regulation of ovarian antral follicle growth, the manipulation of follicular dynamics and ovulation rate, as well as the characterization of the ovine corpus luteum (CL). Two treatments with ovine follicle stimulating hormone (oFSH) were used to assess the responsiveness of small antral follicles during different times in a follicular wave. Follicular dynamics were monitored by transrectal ultrasonography and serum FSH concentrations were measured. Two experiments were performed on anestrous Western White Face (WWF) ewes to independently examine whether or not the ovulations during treatment with a medroxyprogesterone acetate (MAP)-containing sponge and prostaglandin F2á (PGF2á), were due to the direct effects of PGF2á on the ovary or the effects of a rapid decline in progesterone at PGF2á-induced luteolysis. Non prolific Suffolk ewes were used to assess the effectiveness of treatment with medroxyprogesterone acetate (MAP)-containing sponge and prostaglandin F2á (PGF2á) to increase lambing rate. Re-introduction of rams to pre-isolated, mid-anestrous, WWF ewes was used to look at the effect of increased pulsatile secretion of LH on ovarian antral follicular dynamics at different stages of follicular wave development. We also used ovarian transrectal ultrasonography and computer assisted image analysis as non-invasive techniques to investigate whether or not there were correlations between ultrasound image attributes of the ovine CL and changing progesterone concentrations over time, in prolific and non prolific ewes. The results of the present studies showed that, in the ewe, small antral follicles can respond to the injection of FSH to yield a follicular wave more frequently than seen in a normal cycle and in the presence of a large growing antral follicle. Non induced waves can emerge during the growth phase of a wave induced by injection of oFSH. These results bring into question the presence of functional follicular dominance in the ewe. Ovulations occurred after PGF2á injection but during continuous treatment with MAP, but those ewes experiencing a decline in serum progesterone concentrations in the presence of MAP did not ovulate any follicles. We concluded that ovulations occurring after PGF2á injection, in the presence of a MAP sponge could be due to a direct effect of PGF2á at the ovarian level rather than a sudden decline in circulating progesterone concentrations. Treatment of Suffolk ewes with MAP-containing sponges and injection of PGF2á did not increase lambing rate, perhaps due to asynchrony of ovulations. Re-introduction of rams to previously isolated ewes resulted in a subtle increase in LH pulse frequency on the day of ram introduction in ewes in the static phase of a follicular wave. However, there were no consistent changes in follicular dynamics or estradiol secretion in response to this increase in LH pulse frequency. We concluded that changes in LH pulse frequency do not dramatically change ovarian antral follicular dynamics in the anestrous ewe. Both total luteal area and mean spot pixel values for the CL were correlated with the pattern of serum concentrations of progesterone from day 3 to day 15 after ovulation in WWF ewes and from day 3 to day 14 in Finn ewes. There were no significant correlations between progesterone concentrations and spot pixel heterogeneity for either WWF or Finn ewes. We concluded that pixel heterogeneity is a poor indicator of progesterone secretory ability of the CL when compared to mean pixel values. However, luteal area and mean spot pixel values are better but not strong indicators of the functional status of the CL in cyclic ewes.

Graduation date: 1990

The main themes of the present thesis was the regulation of ovarian antral follicle growth, the manipulation of follicular dynamics and ovulation rate, as well as the characterization of the ovine corpus luteum (CL). Two treatments with ovine follicle stimulating hormone (oFSH) were used to assess the responsiveness of small antral follicles during different times in a follicular wave. Follicular dynamics were monitored by transrectal ultrasonography and serum FSH concentrations were measured. Two experiments were performed on anestrous Western White Face (WWF) ewes to independently examine whether or not the ovulations during treatment with a medroxyprogesterone acetate (MAP)-containing sponge and prostaglandin F2á (PGF2á), were due to the direct effects of PGF2á on the ovary or the effects of a rapid decline in progesterone at PGF2á-induced luteolysis. Non prolific Suffolk ewes were used to assess the effectiveness of treatment with medroxyprogesterone acetate (MAP)-containing sponge and prostaglandin F2á (PGF2á) to increase lambing rate. Re-introduction of rams to pre-isolated, mid-anestrous, WWF ewes was used to look at the effect of increased pulsatile secretion of LH on ovarian antral follicular dynamics at different stages of follicular wave development. We also used ovarian transrectal ultrasonography and computer assisted image analysis as non-invasive techniques to investigate whether or not there were correlations between ultrasound image attributes of the ovine CL and changing progesterone concentrations over time, in prolific and non prolific ewes. The results of the present studies showed that, in the ewe, small antral follicles can respond to the injection of FSH to yield a follicular wave more frequently than seen in a normal cycle and in the presence of a large growing antral follicle. Non induced waves can emerge during the growth phase of a wave induced by injection of oFSH. These results bring into question the presence of functional follicular dominance in the ewe. Ovulations occurred after PGF2á injection but during continuous treatment with MAP, but those ewes experiencing a decline in serum progesterone concentrations in the presence of MAP did not ovulate any follicles. We concluded that ovulations occurring after PGF2á injection, in the presence of a MAP sponge could be due to a direct effect of PGF2á at the ovarian level rather than a sudden decline in circulating progesterone concentrations. Treatment of Suffolk ewes with MAP-containing sponges and injection of PGF2á did not increase lambing rate, perhaps due to asynchrony of ovulations. Re-introduction of rams to previously isolated ewes resulted in a subtle increase in LH pulse frequency on the day of ram introduction in ewes in the static phase of a follicular wave. However, there were no consistent changes in follicular dynamics or estradiol secretion in response to this increase in LH pulse frequency. We concluded that changes in LH pulse frequency do not dramatically change ovarian antral follicular dynamics in the anestrous ewe. Both total luteal area and mean spot pixel values for the CL were correlated with the pattern of serum concentrations of progesterone from day 3 to day 15 after ovulation in WWF ewes and from day 3 to day 14 in Finn ewes. There were no significant correlations between progesterone concentrations and spot pixel heterogeneity for either WWF or Finn ewes. We concluded that pixel heterogeneity is a poor indicator of progesterone secretory ability of the CL when compared to mean pixel values. However, luteal area and mean spot pixel values are better but not strong indicators of the functional status of the CL in cyclic ewes.

The blue sheep (Pseudious nayaur) is the major large-size herbivores in Helanshan. During studying, the blue sheep mean group size were 4.2¡ã7.1, with smaller group size than in other ranges. Mixed groups were usually bigger than male and female groups. Sex ratio the most close was 1:1.08 (¡ð:¡ñ) in winter, and other samples still favored males except for fall. The highest ratio of adult female to young was 1:0.78 in summer. In daily activity cycle, blue sheep usually moved and fed in morning and evening, but rested during noon. In summer, animals started active earlier and ended latter than in winter, but had more short active time. From summer to fall, the blue sheep mostly used the edge of forest and used forest least in altitude 2200m. But in altitude 1700m, blue sheep used grassland more than frequently bush and fountain.

Thesis (MSc (Veterinary Sciences))--University of Pretoria, 2001. / Includes bibliographical references.