Studies in Herd Analysis

1. A statistical study of the causes of variation in milk yield, persistency and butterfat percentage has been made on the basis of 5000 lactation records from 12 leading herds of Ayrshire cattle in south-west Scotland, for the period 1930-1959. 2. The unit of measurement of milk production employed was the yield during the first 180 days of the lactation period. This eliminated the effect of variations in length of current calving interval on milk yield. Persistency was measured as the ratio of A-B to B where A was the milk yield during the first 180 days and B was the initial milk yield during the first 10 weeks of lactation. For the investigations on butterfat percentage, the average butterfat percent- age of the milk secreted during the total lactation period was utilised, since calving interval was found to have little or no influence on it. 3. A study of the accuracy of milk yield deter- minations made under the official Scottish milk record-ing system was carried out by using data from the Kirk-hill herd belonging to the Hannah Institute. This herd was recorded on the official system since its inception, and daily records were also kept. It was found that although the yields by the official recording system were, on the average, about 5% higher than the corresponding yields obtained by daily recording, they are sufficiently accurate to be used for genetical studies 4. Preliminary analyses of the data from the 12 herds investigated, showed an average 180 day milk yield of 6600 lb, for the total population. The mean age at first calving was 2 years and 9 months, and the calving intervals were about 30 days longer for the first lactation than for subsequent ones. Length of dry periods, however, varied very little from one lactation to another. 5. From a study of the non-genetic causes of variation in milk yield, it was concluded that the interrelations among the non-genetic variables should be considered when devising suitable corrections for their influence on milk yield. Corrections were found to be necessary for four factors; month of calving, lactaticin number, age at calving and length of preceding calving interval. 6. The effect of month of calving on milk yield varied significantly between herds, and it was shown that correction factors for month of calving should be calculated on a within-herds basis. The average diff erence in 180 day milk yield between the summer and winter calvers of all herds was about 10 per cent, in favour of winter calvers. 7. A study of the variation of milk yield with age showed that the milk yield of a cow is influenced both by the number of her previous lactations and also by her age at calving. The types of corrections for age employed by previous investigators have been discussed, and it was shown that percentage corrections are the most satisfactory. 8. The variation of milk yield with length of preceding calving interval showed a pronounced positive trend. From an economic point of view, however, the optimum length of calving interval was found to be about 400 days for the first lactation, and about a year for subsequent ones. Corrections for length of preceding calving interval, like those for age, were most satisfactory when they were proportionate and not additive. 9. The effect of corrections for non-genetic influences on the variance in milk yields has been discussed. It was estimated that a reduction of 27. 1% of the total variance was accomplished through these corrections. (Abstract shortened by ProQuest.)

General anaesthetic and airway management practice for obstetric surgery in England: a prospective, multi-centre observational study

There are no current descriptions of general anaesthesia characteristics for obstetric surgery, despite recent changes to patient baseline characteristics and airway management guidelines. This analysis of data from the direct reporting of awareness in maternity patients' (DREAMY) study of accidental awareness during obstetric anaesthesia aimed to describe practice for obstetric general anaesthesia in England and compare with earlier surveys and best-practice recommendations. Consenting patients who received general anaesthesia for obstetric surgery in 72 hospitals from May 2017 to August 2018 were included. Baseline characteristics, airway management, anaesthetic techniques and major complications were collected. Descriptive analysis, binary logistic regression modelling and comparisons with earlier data were conducted. Data were collected from 3117 procedures, including 2554 (81.9%) caesarean deliveries. Thiopental was the induction drug in 1649 (52.9%) patients, compared with propofol in 1419 (45.5%). Suxamethonium was the neuromuscular blocking drug for tracheal intubation in 2631 (86.1%), compared with rocuronium in 367 (11.8%). Difficult tracheal intubation was reported in 1 in 19 (95%CI 1 in 16-22) and failed intubation in 1 in 312 (95%CI 1 in 169-667). Obese patients were over-represented compared with national baselines and associated with difficult, but not failed intubation. There was more evidence of change in practice for induction drugs (increased use of propofol) than neuromuscular blocking drugs (suxamethonium remains the most popular). There was evidence of improvement in practice, with increased monitoring and reversal of neuromuscular blockade (although this remains suboptimal). Despite a high risk of difficult intubation in this population, videolaryngoscopy was rarely used (1.9%)

Thermal, electronic and magnetic properties of the cage-structured rare-earth system RT₂ A1₁₀ (R = rare earth and T = d-electron element)

D.Phil. (Physics)Please refer to full text to view abstrac

Effect of Plant Population on Yield and Yield Components in Main and Ratoon Crops of Pigeonpea in Sri Lanka

In a field experiment in 1990/91 in Sri Lanka, pigeonpeas cv. ICPL 2 were sown during the rainy season at densities of 4-66 plants/m². The crop was harvested on 14 March 1991 by pod picking and at the onset of postrainy season rains it was ratooned to a height of 45 cm. The highest combined yield of the main (1.77 t/ha) and the ratoon (1.93 t) crops was obtained at the density of 17 plants/m². Data on yield components are given

Key Features in the Management of Pulmonary Carcinosarcoma

Pulmonary carcinosarcoma represents a category of extremely rare tumours accounting for 0.1% of all lung malignancies. It is defined as a poorly differentiated non-small-cell carcinoma that contains a component of sarcoma or sarcoma-like elements. These biphasic tumours typically have a poor prognosis due to late diagnosis and early metastases. Preoperative tissue diagnosis is usually difficult due to the heterogeneity of the tumour, with biopsies often just reflecting one element of the tumour. By means of a case illustration and review of the literature, we discuss the optimal management of patients with pulmonary carcinosarcoma

A retained foreign body granuloma mimicking a left ventricular psuedoanuerysm

Introduction: Gossypiboma, also referred to as a textiloma, gauzoma or muslinoma describe a mass in the body composed of a central cotton core surrounded by a foreign body reaction. It has an estimated incidence of 1/1000–1/10000 surgeries, occurring in the abdomen (56%), pelvis (18%) and least commonly the thorax (11%) and represents an unfortunate event for both the patient and the operating surgeon with severe liability implications. Presentation of case: We report a case of a 49-year-old male with Marfan Syndrome who was admitted to the cardiology department with a four day history of shortness of breath and associated dull, non-radiating chest pain. Past history included a previous Bentall procedure for a type-A aortic dissection and coronary artery bypass grafting involving a saphenous vein graft to the right coronary artery. A computed tomography (CT) scan showed a round, heterogeneous mass measuring 14 × 9 cm with lobulated contours, situated adjacent to the left ventricle along the left posterior region of the aorta. The mass was resected and further dissection revealed a plastic band harboured from the core of the mass. Discussion: The majority of cases of intrathoracic gossypiboma present as intractable cough or an incidental finding on radiological evaluation. Dyspnoea alone is relatively underreported as a presenting symptom of this condition Conclusion: This case highlights the important clinical history features for diagnosing this surgical error, including persistent respiratory symptoms and a history of cardio-thoracic surgery. It also emphasizes on the need for implementing definite strategies to prevent the occurrence of gossypiboma in surgical practice