Ovum production: action of various gonadotrophins in sheep and goats

Following progesterone pre-treatment a total of 45 anoestrous ewes consisting of equal numbers of Merino, Angora, and Boergoat ewes was treated with gonadotrophin according to three different schedules. Detailed observations were made on behavioural response and, at laparotomy, on ovarian morphology and ovum recovery. Merino ewes showed the highest overall ovulation rate (7·1) followed by Boergoat (4·8) and Angora ewes (3·0). Pregnant mare serum (PMS) was highly variable in sheep and resulted in poor responses in goats. A horse anterior pituitary gonadotrophin (HAP) resulted in variable but marked follicular growth in all breeds; however, in goats the majority of follicles failed to ovulate. PMS combined with simultaneous human chorionic gonadotrophin (PMS/HCG) suppressed ovulation to some extent in sheep but markedly potentiated follicular growth and ovulation in goats and was the most predictable of the three gonadotrophins. A small but significant difference of total follicular growth in favour of the right ovary was found. Large persistent follicles were encountered in most animals and increased proportionally with the number of ovulations. These follicles persisted up to 70 hours after oestrous onset, where after regression was rapid. Excessive follicles were accompanied by an increased incidence of unfertilized ova. Recovery of cleaved ova was also seriously hampered by accelerated tubal transport in Merino ewes, but no such phenomenon was encountered in goat ewes, which in fact exhibited evidence of retarded tubal transport of ova in relation to oestrous onset. Oestrus commenced in 84 per cent of all animals on the second or third day following gonadotrophin treatment and was longer than usual with PMS and considerably shortened by PMS/ HCG. Excessive persistent follicles hastened the onset of oestrus but the numbers of follicles and ovulations had no effect on oestrous duration. Indirect evidence that the endogenous luteinizing hormone contribution is optimal in sheep, marginal in Boergoats and deficient in Angora goats is discussed and a relationship to the high incidence of gestational failure in Angora ewes suggested.The articles have been scanned in colour with a HP scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to final presentation PDF-Format

Reproductive physiology and endocrinology of normal and habitually aborting Angora goats

Recurrent abortion of non-infectious or non-organic origin is exceedingly prevalent in many species including man, yet virtually no information on possible metabolic and endocrine causes was available. In order to study the pathogenesis of this form of gestational failure, an experimental flock was constituted which consisted of normal and habitually aborting Angora goats, a species in which the high incidence of abortion constitutes a significant economic problem. The investigation was initially complicated by the fact that at the time of its inception there were no acceptable theories regarding the cause of the initiation of normal parturition. For this reason experimental work on relevant fundamental aspects was included in the study. Comparative studies on normal and aborting goats entailed: (i) Investigations of sexual behavioural patterns and of breeding performance in mature animals, followed by physiological, clinical and pathological observations on mature does, foetuses and kids. (ii) Development of suitable methods for the precise chemical assay of steroid hormone metabolism in goats. The methods used facilitated detailed studies on luteal function, cortisol metabolism and the excretion of oestrogens. (iii) Investigation of the mohair growth rate as well as its fibre characteristics in relation to reproductive capabilities. (iv) Experimental reproduction in normal animals of the aberrations found and the investigation of the significance of such aberrations in causing gestation termination. Gestational failure was more prevalent in the heavier, older type of goats which were found to have enlarged pituitaries and which occasionally exhibited clinical signs of disturbed adrenal function. Animals that had aborted exhibited abnormally short oestrous cycles which appeared to be responsible for a lowered conception rate. Their ovaries contained cystic corpora lutea and displayed excessive follicular growth; experimental studies indicated that these changes were secondary to adrenal hyperplasia. Abortions were most frequent during the early part of the fourth month of gestation, a time which coincided with the most rapid increase in the rate of foetal growth and also with the cessation of placental growth. The condition of the foetus destined to be aborted suggested placental insufficiency; growth was retarded, anaemia was usually present and the concentration of some elements in the liver was abnormally low. Changes noted prior to abortion included excessive or deficient urinary oestrogen excretion, excessive ovarian follicular growth, the sudden onset of maternal adrenal atrophy, accumulation of excessive foetal fluids and degeneration of the placentomes. Control of gestation maintenance by the corpus luteum was confirmed; removal of the corpus luteum from Angora goats at any stage of pregnancy resulted in abortion 40 to 60 hours later. Variations in the level of luteal function during gestation are postulated to be due to a placental lactogen-type hormone secreted by the growing placenta. Peripheral plasma levels of progesterone tended to be higher than usual in pregnant aborters, but were depressed shortly prior to abortion in only some individuals. Studies on ovarian secretion rates suggested that this reduction was partly due to a lowered adrenal contribution, which may be expected in view of an observed concurrent adrenal atrophy. Signs of impending abortion were, however, evident while luteal function was still quite normal. The markedly aberrant oestrogen excretion rate of aborters could only be ascribed to an abnormal supply of steroid precursors resulting from altered metabolism in the maternal adrenal glands. Newborn kids destined to perpetuate the abortion defect tended to be heavier than normal and had finer birthcoats. The quantity of mohair produced by the young animal born from aborter stock was exceptional and the young males produced 30 per cent more than usual. Adrenal function in young high-producing aborter stock was lower than usual. However, established regular aborters had enlarged adrenal cortices and produced smaller quantities of finer mohair. Such findings are consistent with experimental results obtained with other species, the results demonstrating that corticosteroids inhibit the rate of hair growth and the fibre diameter. Evidence is presented which suggests that the adrenal enlargement found in aborters is an adaptive response favouring the foetus at the expense of hair production characteristics; aborter does which could maintain a higher level of adrenal function throughout gestation carried their foetuses successfully to term. Experimental administration of small doses of corticosteroids to goats during pregnancy prolonged gestation by several days, a situation which resembled successfully adapted aborter does. Dose-related prolongation of gestation was also obtained when small amounts of corticosteroid were administered to the sheep or goat foetus, but slightly higher dosages lead to rapid expulsion of the foetus. When administered maternally to sheep, these steroids caused a moderate reduction of placental progesterone synthesis. However, the same dosage rate given to the foetus caused a more drastic progesterone block, rapidly followed by expulsion of the foetus. Adrenalectomy of the foetus caused indefinite prolongation of gestation in sheep, but not in goats. The investigations have contributed to the concept that normal birth is initiated by the foetal hypothalamus-pituitary-adrenal axis; when the hypothalamus is adequately sensitive to ensure viability of the foetus, it responds to the usual prenatal deterioration of the foetal nutritional environment by stimulating the foetal adrenal glands and the elevated steroid secretions have effects on the foetoplacental unit, resulting in the initiation of parturition, possibly by means of blocking both the production and the action of progesterone. The cause of abortion in Angora goats appears to be intimately related to a high metabolic priority for hair growth, artificially induced by intensive selection and inbreeding. An abnormally low level of adrenal function, coupled with some qualitative changes in adrenal steroid biosynthesis seems to be the responsible mechanism. Physiological adaptation involves adrenal hyperplasia in order to assist the transfer of maternal nutrients to the foetus. Abortion is a consequence of the failure of this mechanism.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

The occurence of foetal dwarfism in the Angora goat

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The significance of the cytoplasmic droplet in the disintegration of semen in Guernsey bulls

The occurrence of sperm disintegration in Guernsey bulls in South Africa was investigated in thirteen animals that were either sterile or displayed low fertility. One of these was kept under observation and subjected to repeated tests and examinations for three years. In an attempt to elucidate the mechanism whereby the sperm head was detached from the tail, the sperm activity in the epididymis, and particularly the discarding of the cytoplasmic droplet, were studied in three normal bulls and two normal rams. In ten affected bulls the percentage disintegrated sperm varied from 4 to 100. In several this percentage was not as high as that reported in Britain and the animals showed some degree of fertility in the early stages, but the condition deteriorated with ageing. Two exhaustion tests were carried out on one bull. These yielded 22 and 25 ejaculates in 85 and 262 minutes totalling 74·7 and 61·7 ml semen respectively. In each test only four intact sperm were found. The tests further showed that spermatogenesis was normal as regards the number of sperm formed, while pH and the citric acid and fructose levels were also normal in the seminal plasma. A determination of fructolysis activity and pH shift showed that the metabolic rate of disintegrated sperm was similar, or only slightly below that of normal sperm. Their survival rate indicated that there was no selective absorption or phagocytosis of either heads or tails in the male genital tract. On centrifugation of semen the biggest concentration of heads was in the sediment and tails predominated in the supernatant fluid. The tails of the sperm are mainly responsible for fructolysis. In the bull available for post mortem study, an examination of sperm from different sites showed that disintegration occurred mainly in the rete testis and curvature of the caput epididymis. Examination of live sperm from different parts of the caput epididymis immediately after collection disclosed considerable activity characterized by violent lashing of the tails in all the spermatozoa with a cytoplasmic droplet. This activity ceased as soon as the droplet was discarded. Most of the droplets are unloaded from the distal end of the middle-piece and few reach the tail. The discarding of the droplets occurs mainly in the curvature of the caput epididymis. It is concluded that in those animals with an abnormally weak attachment between the sperm head and tail, caused by congenital defect or a pathological condition, separation between the two components occurs in the rete testis and caput epididymis during the severe lashing movements made by the sperm in its efforts to cast off the cytoplasmic droplet. The evidence indicates that in affected Guernsey bulls the defect is attributable to a recessive hereditary factor.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Ovarian function, follicular oestradiol-17β, and luteal progesterone and 20α-hydroxy-pregn-4-en-3-one in cycling and pregnant equines

Reproductive patterns were studied in the majority of 46 mares before obtaining the ovaries for examination at slaughter. Steroids identified and determined were progesterone and 20∝-hydroxypregn-4-en-3-one in the corpora lutea and oestradiol- 17 β in the follicular fluid. A study of ovarian morphology revealed no significant cyclical variations of the ovarian weight and number of follicles, but the total volume of follicular fluid increased in the latter half of the cycle. Consistent and marked follicular growth was present at about the 25th day of gestation. Mares 16 to 28 days pregnant had significantly more follicles than cycling mares, and the ovarian weight and volume of follicular fluid were also increased at this time. Peak total oestradiol values at 25 days and maximal progesterone concentrations at 27 days preceded implantation on the 28th day. Oestradiol was present before puberty and the amount in anoestrous animals seems to increase gradually as the breeding season approaches. In cycling mares, total follicular fluid oestradiol values are variable for up to five days after ovulation, but oestradiol is virtually absent during the mid-luteal period. From the 12th day there is a rapid increase to maximal values immediately prior to oestrus. Limited evidence suggests that ovarian oestradiol decreases from the commencement of oestrus. Pregnant animals exhibit an indistinguishable pro-oestrual rise, but drop suddenly when oestrus would be expected on the 17th day. When more than one corpus luteum was present and after two months gestation, no oestradiol was detected. Waves of follicular growth and oestradiol synthesis commence at 2, 12, 22 and 32 days after ovulation, suggesting a cyclical release of pituitary gonadotrophin every 10 days, irrespective of whether an active corpus luteum is present or not. Maximal follicular growth during pregnancy was encountered at 25 days, before the appearance of PMSG. Actual ovulation was only encountered soon after the– expected appearance of PMSG, suggesting a synergistic effect between PMSG and pituitary gonadotrophin. When steroidal inhibition of pituitary gonadotrophin increased and PMSG levels were maximal, the ovaries were relatively quiescent. Many active luteinized follicles were encountered as PMSG levels waned. Luteal progesterone concentrations rose linearly for 14 days; in cycling mares, regression took place on the 14th or 15th day. In pregnant animals the concentration continued to rise, reaching a peak at 27 days. Secondary corpora lutea, resulting from ovulations during the second month of gestation, had an initial concentration resembling cycling animals, but marked increases were found during the third month of gestation. The primary corpus luteum does not regress with the occurrence of secondary ovulations as is generally believed, but remains active for at least three months. 20∝-Hydroxypregn-4- en- 3- one was always present in the corpora lutea of cycling animals and increases were associated with luteal regression. This steroid was never detected in animals more than 18 days pregnant, including fresh secondary corpora lutea. The ovaries of mules contained similar amounts of steroids as found in horses. However, the occurrence of ovulation in the presence of functional corpora lutea suggests failure of the luteal regression mechanism, or alternatively an inability of the hypothalamus to regulate gonadotrophin secretion in the usual manner. The theoretical implications of these findings on sterility work are discussed.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Alteration of reproductive function in the rat by cortisol acetate

The effects of cortisol acetate were studied on immature gonadotrophin treated rats, mature intact and hysterectomized cycling females, gestating and pseudopregnant subjects with pituitary implants, and mature males. Observations included growth, organ morphology, histological, follicular and corpora lutea counts and measurements, vaginal smears and ovarian progesterone assays. The diameters of larger follicles were potentiated and the incidence of follicles exhibiting histological atresia increased. Luteinization occurred more rapidly but many corpora lutea were cystic in treated immature rats. The cycles of mature rats exhibited dose-related prolongation of the dioestrous period which was unaffected by hysterectomy. Ovulation, conception, and nidation were unchanged by chronic treatment, but embryonic mortality was increased. The combined uterine-decidual tissue weight was inhibited to a greater extent than the various conceptus elements. Uterine growth was unaffected in pseudopregnant immature and mature rats, but under conditions of oestrogen predomination inhibition was marked. Ovarian progesterone concentration was reduced by treatment only in pregnant rats, and the significance of this finding is discussed. No evidence of alterations in the endogenous gonadotrophic secretions was found in any of these experiments. It is concluded that the administration of excess cortisol acetate exerted no true inhibitory influences on gonadal activity, unlike the potent inhibitory effects of adrenocorticotrophin.The journals have been scanned in colour with a HP 5590 scanner; 600 dpi. Adobe Acrobat v.11 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Imperial Cold Storage and Supply Lt

The urinary excretion of 5β-pregnane-3α : 20α-diol and gestational failure in Angora goats

The urinary excretion of pregnanediol has been studied over the full period of gestation in a group of twenty Angora ewes. A comparison is drawn between animals in which conception presumably did not occur, those which kidded normally producing strong healthy kids, and those which produced weak undersized young, stillborn kids or aborted before term. Evidence is presented suggesting that abortion, prenatal and some instances of neonatal mortality in these animals are associated with deficient luteal function and progesterone secretion during the first third of the gestational period. The urinary excretion of pregnanediol during this period appears to be a useful prognostic guide as to the outcome of gestation in pregnant Angora ewes.The articles have been scanned in colour with a HP scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to final presentation PDF-Format

The open solution methodology approach to problem solving

The Open Solution Methodology is a generic problem solving methodology which is used to solve system related problems through the application of problem solving techniques. The focus of the application of this methodology is aimed at modelling organisations, or areas within organisations. The application ofthe Open Solution Methodology provides the benefit of having the ability to comprehend and integrate all aspects of the system, while having a formal and structured approach for problem solving. Together with the reduction in system analysis time, problem solving techniques such as simulation modelling are focused through the Open Solution Methodology models to enhance the quality Ofsolutions.Die "Open Solution Methodology" is 'n generiese probleemoplossingsmetodologie wat gebruik word om stelselverwante probleme op te los deur die toepassing van problemoplossingstegnieke. Die fokus van hierdie metodologie toepassing is gernik op die modellering van organisasies, of gedeeltes van organisasies. Die "Open Solution Methodology" toepassing verskaf die voordeel om aile aspekte van die stelsel te verstaan en te integreer, terwyl daarvan 'n formele en gestruktureerde benadering tot probleemoplossing gebruik gemaak word. Tesame met die gepaardgaande verkorting van stelselanalisetyd, word die "Open Solution Methodology" modelle gebruik om die toepassing van probleemoplossingstegnieke te fokus omsodoende kwaliteit van die oplossings te verhoog

Gas Chromatography Results Interpretation: Absolute Amounts Versus Relative Percentages

Geneeskunde en GesondheidswetenskappeChemiese PatologiePlease help us populate SUNScholar with the post print version of this article. It can be e-mailed to: [email protected]

Psychiatric nurse practitioners' experiences of working with mental health care users presenting with acute symptoms

Psychiatric nurse practitioners (PNPs) working with mental health care users presenting with acute symptoms work in a complex environment. This environment is characterised by mental health care users who may present with a history of violence, sexual assault and substance misuse. The objectives of this study were twofold: firstly, to explore and describe the experiences of PNPs working with mental health care users (MHCUs) presenting with acute symptoms; and secondly, to make recommendations for the a vanced PNPs to facilitate promotion of the mental health of PNPs with reference to nursing practice, research and education. A qualitative, explorative, descriptive and contextual design was used. The target population was PNPs working with MHCUs presenting with acute symptoms in a public mental health care institution in Gauteng. Data were collected by means of four focus group interviews involving 21 PNPs. The researcher made use of drawings, naïve sketches and field notes for the purpose of data triangulation. Data were analysed in accordance with Tesch’s method of open coding. The three themes that emerged were: PNPs experienced working with these MHCUs as entering an unsafe world where care became a burden; they experienced negative emotional reactions and attitudes towards these MHCUs that compromised quality nursing care; and they made a plea for a nurturing environment that would enhance quality nursing care. The PNPs suggest skills and competency development, organisational support, and a need for external resources. Creation of a positive environment and mobilisation of resources as well as the identification and bridging of obstacles are essential in the promotion of the overall wellbeing and mental health of PNPs.J.K.N. (University of Pretoria & South Africa Medical Research Council) was a Master’s candidate, E.v.R. (University of Pretoria) was a Supervisor, and S.M. (University of Pretoria) was a co-supervisor.http://www.curationis.org.zaam2013ay201