Fatal myocardial infarct in a Greyhound

Death is reported in a 3-year-old Greyhound due to an acute myocardial infarction, consequent upon thrombo-embolic occlusion of the left descending coronary artery, subsequent to dislodgement of a vegetative lesion of the left lateral aortic valve, secondary to sub-acute bacterial endocarditis. A comparison between some aspects of cardio-vascular disease in man and dogs is made, and the term ‘heart attack’ as used in the human condition is investigated and its legitimate application to veterinary conditions discussed. The main difference between human and animal coronary disease is the widespread occurrence of atherosclerosis in humans and its absence in animals.     

Involvement of PAPP‐A and IGFR1 in Cystic Ovarian Disease in Cattle

Cystic ovarian disease (COD) is one of the main causes of infertility in dairy cattle. It has been shown that intra‐ovarian factors, such as members of the insulin‐like growth factor (IGF) system, may contribute to follicular persistence. The bioavailability of IGF to initiate its response by binding to specific receptors (IGFRs) depends on interactions with related compounds, such as pregnancy‐associated plasma protein A (PAPP‐A). The aim of this study was to determine IGFR1 and PAPP‐A expression both in follicles at different stages of development and in cysts, to evaluate the roles in the etiopathogenesis of COD in cattle. The mRNA expression of PAPP‐A was higher in granulosa cells of large tertiary follicles than in cysts, whereas the protein PAPP‐A present in the follicular fluid from these follicles showed no differences. Although no PAPP‐A mRNA expression was detected in smaller tertiary follicles, in their follicular fluid, this protease was detected in lesser concentration than in cysts. The mRNA expression of IGFR1 was lower in granulosa cells from cystic follicles than in those from tertiary ones. However, the protein expression of this receptor presented the highest levels in cystic structures, probably to increase the possibility of IGF response. The data obtained would indicate that animals with COD have an altered regulation of the IGF system in the ovary, which could be involved in the pathogenesis of this disease in cattle.     

IMPURITY IN HALOTHANE ANESTHETIC

A halogenated butene has been isolated from commercially available halothane (Fluothane). Its concentration increases under the conditions in which halothane is commonly used in clinical work.     

A mathematical model of the aerobic deterioration of silage

A mathematical model of the aerobic deterioration of silage is described that includes the physical processes of gas and heat Rows, as well as an established model of microbial growth and the associated chemical changes. Yeasts and acetic acid bacteria are included in the growth model. The version of the model described relates to a cylinder of silage subject to forced aeration, a common experimental configuration. The model was very sensitive to variations in insulation thickness and yeast growth rate, and to initial pH, especially when maize was the forage. Great care is needed when selecting input data for use in the model to be sure that the physical and chemical properties are accurate. The model solution was sensitive to grid size, but with 361 cells, the maximum grid resolution that could be used on a 486 series PC, solutions were achieved with an acceptably small loss of accuracy. The model predicted the results of an experiment on silage deterioration quite accurately. However, the model also predicted that considerable spatial gradients of parameters, such as temperature, pH, and lactic acid, would occur. This indicates the need for care when taking samples or making temperature measurements in deterioration experiments. The model is potentially a useful tool in predicting the optimal time and position to take samples for analysis in a time-course experiment.     

Further studies on the effect of phosphate fertilizer and propyzamide on the growth of white clover slot-seeded into permanent pasture

Assessments were made of the clover yield and clover content between early June and late July 1984 of white clover in a permanent pasture which had been slot-seeded in spring 1982.
Past reserves of phosphate or application of propyzamide alone only slightly increased clover dry matter yield but together they increased it from 13 to 785 kg dry matter ha^-1 and gave 31% clover in the total herbage yield. Applications of P₂O₅ during the experiment, alone or together with past reserves of phosphate, Iased clover yield from 13 to 242 kg dry matter ha^-1 and the proportion of clover from 1 to 10%. However, highest yields (1282 kg) and clover content (37%) were attained when P₂O₅ and propyzamide were applied to treatments with past reserves of phosphate.
These results confirmed the trends evident during the second year and also indicated a potential role for grass-suppressants in increasing management options during the early years after slot-seeding.     

The influence of seed rate and pesticides on the establishment and growth of white clover slot-seeded into a permanent pasture

The establishment and growth of white clover (cv. Grasslands Huia) was investigated in two experiments with seeds sown in slots cut in old permanent pasture in early May 1982. In the first experiment, fully protected from pests and diseases, either 50 (low), 100 (medium) or 200 (high) seeds were sown evenly per metre length of slot; 100 seeds were also sown in a clumped pattern unevenly. In the second experiment, the effects of various combinations of molluscicide, insecticide and fungicide were investigated.
Nine weeks after sowing there were 27, 37, 34 and 62 seedlings m⁻¹ on the low, medium even, medium uneven and high seed-rate treatments, representing percentage establishments of 54, 37, 34 and 31 respectively. By September, however, there were no significant differences between the dry weights m^−l of any of the treatments. In the second experiment, damage by slugs occurred early in treatments without molluscicide and caused a mean reduction of 70% in seedling establishment. As a result significantly smaller dry weights m⁻¹ of clover were recorded in September in these than in other treatments. Failure to protect against insects resulted in smaller seedlings.
The results indicated that variations in seed rate within the range investigated were not critical but that failure to protect against pests decreased percentage establishment and subsequent growth.     

Slot-seeding investigations. 5 The effects of simulated delayed emergence and propyzamide on the spread and growth of white clover in permanent pasture

The effects of delayed emergence of white clover (cv. Grasslands Huia) seedlings, following slot-seeding during spring and early summer 1983, were simulated by sowing seeds at intervals into slots cut in turves of permanent grassland in soil-filled tanks or in the field. The resulting spread and growth of the species were assessed during the following 15–18 months. The effects of propyzamide, a grass-suppressing herbicide (at 0·2 kg ha^-1), were also investigated in the field.
A delay of 10 or 18 days in the sowing of seeds in turves in the tanks reduced clover dry weight yield from 23 to 11 during 1983 and from 118 to 96 g (0·12 m)^-2 during 1984. Spread of stolons from the slots was also greatly delayed and effects persisted for at least a year. Increased clover growth on the earliest sown treatment more than compensated for a slightly smaller yield of grass.
In the field, yields of clover from late summer 1983 until spring 1984 closely reflected the order of emergence. Afterwards, differences were less clear-cut but the cumulative yield of clover until August 1984 of the earliest-sown treatment was twice that of a treatment sown 20 d later. Effects of delayed sowing in summer 1983 were more pronounced on stolons than on foliage growth when measured in September 1984, with significant reductions in many stolon attributes even with 8 d delay in sowing. Application of propyzamide in autumn 1983 increased clover yield during 1984 from 1·7 to 3·0 and total herbage yield from 7·1 to 8·6 t ha^-1.
The results demonstrated some of the benefits of rapid seedling emergence and of the use of a grass-suppressing herbicide, but did not indicate any interaction between the two factors.     

美国堪萨斯州不同天气事件与土壤类型条件下作物产量预测

Computer simulation was used for predictive analysis of the effects of weather and soil type on crop yield in the U.S.crop insurance program.The Environmental Policy Integrated Climate (EPIC) model was modified to include hail weather events,which completed the modifications necessary to simulate the four most frequent causes of crop yield loss (hail,excessive wet,excessive cold,and excessive dry) associated with soil type in Kansas,USA.At the region level,per hectare yields were simulated for corn,wheat,soybean,and sorghum.We concluded that it was possible to predict crop yields through computer simulation with greater than 93% accuracy.The hail damage model test indicated EPIC could predict hail-soil-induced yield losses reasonably well (R² > 0.6).The investigation of soil type influence on dryland sorghum and wheat production indicated that Wymore silty clay loam soil and Kenoma silt loam produced the highest sorghum yields statistically;Kuma silt loam,Roxbury silt loam,Crete silty clay loam,and Woodson silt soils produced the second highest sorghum yields statistically;and Richfiled silt loam,Wells loam,and Canadian sandy loam produced the lowest sorghum yields.By contrast,wheat production showed less sensitivity to soil type variation.The less sensitive response of wheat yields to the soil type could be largely due to the unconsidered small-scale variability of soil features.     

Estrus Synchronization in Sheep and Goats Using Combinations of GnRH,Progestagen and Prostaglandin F2α

The objective of this experiment was to evaluate the effect of GnRH, progestagen and prostaglandin F_2α on estrus synchronization in sheep and goats. Sixty Awassi ewes and 53 Damascus does were used in the study. The experiment started at the beginning of the breeding season (June/July). The same treatments were applied to sheep and goats as follows: no treatment (CON), 14‐day progestagen sponges and 600 IU equine chorionic gonadotropin (S), gonadotropin releasing hormone followed 5 days later by prostaglandin F_2α (GP) and gonadotropin releasing hormone, progestagen sponges for 5 days and prostaglandin F_2α on the day of sponge removal (GSP). None of the ewes in the S group lambed from mating during the induced cycle. A greater lambing rate (p < 0.05) was observed in the GSP group compared with the CON and S groups while the GP group was intermediate. The number of lambs born per lambed ewe was similar among the CON, GP and GSP groups. However, the number of lambs per exposed ewe was greater (p < 0.05) in the GSP than the remaining groups. The induced cycle kidding rate was 77% for all treatments combined. Similar kidding rate were observed among treatments. The numbers of kids born per kidded and exposed doe from mating during the induced estrus were also similar among treatments. Greater numbers of multiple births were observed in the GP and GSP than in the S group. In conclusion, a combination of GnRH, progestagen sponges and PGF_2α can be effective in synchronizing estrus and improving fecundity in sheep and goats. Although the use of GnRH–PGF_2α was effective, the addition of progestagen sponges at the time of GnRH administration appeared to improve reproductive parameters.