Effects of Prolonged Exposure to Low‐Dose Fumonisin B1 in Pigs     

M. ZOMBORSZKY‐KOVCS  F. VETSI  P. HORN  I. REPA  F. KOVCS 《Zoonoses and public health》2002,49(4):197-201

From the point of view of human exposure, fumonisins (FB₁, FB₂, FB₃, FB₄), a relatively recently (1988) discovered and identified group of mycotoxins, represent one of the five most important mycotoxin groups causing human disease. In an earlier experiment studying the effects of relatively low doses (10, 20 and 40 p.p.m.) of FB₁ in weaned piglets, it was established that the 4‐week feeding of 10 p.p.m. (mg/kg feed) FB₁ produced mild pulmonary oedema. This suggested the importance of studies with even lower doses of the toxin to determine the tolerable limits. The objective of this experiment was therefore to study the effects of prolonged (8‐week) exposure to still lower concentrations (0, 1, 5 and 10 mg/kg feed) of FB₁. The 8‐week feeding of FB₁ in low concentrations (1–10 p.p.m.) did not cause clinical signs and significant performance impairment in pigs, but rendered irreversible the chronic changes that had already developed in the animals in a dose‐dependent manner. Dissection revealed pathological alterations of the lungs in one of the animals given 1 p.p.m. (n=4), in two animals exposed to 5 p.p.m. (n=5), and in three animals given 10 p.p.m. (n=4). In all three treatment groups, proliferation of the connective tissue fibres, primarily of those around the lymphatic vessels, in the subpleural and interlobular connective tissue of the lungs, extending to the peribronchial and peribronchiolar areas, was seen. The results of this experiment call attention to the risk of prolonged low‐dose toxin exposure, which has very important public health implications.  相似文献   

Experimental Leptospira borgpetersenii serovar hardjo infection of pregnant cattle     

CR SMITH  MR McGOWAN  CS McCLINTOCK  BG CORNEY  PJ KETTERER  L. SMYTHE  W. WARD 《Australian veterinary journal》1997,75(11):822-826

Objective To observe the effect upon the foetus of experimental infection of pregnant cattle with Leptospira borg-petersenii serovar hardjo .
Design A disease transmission study using pregnant cattle.
Procedure Fourteen heifers serologically negative to L hardjo were artificially inseminated and later challenged with a north-Queensland isolate of L hardjo by conjunctival inoculation. The heifers were serologically monitored and their urine examined for the presence of leptospires using culture and fluorescent-antibody tests at appropriate intervals. Elective caesarean sections were performed on pregnant heifers at 6.5 weeks after the challenge. Foetuses were examined using serological, histopathological, microbiological and fluorescent-antibody tests.
Results Ten of the heifers became pregnant, but three subsequently aborted before challenge. After challenge, all 14 heifers seroconverted and L hardjo was isolated from the urine of 6 of the 7 pregnant heifers. No evidence of foetal L hardjo infection was detected. Two of the foetuses had histopatho-logical lesions consistent with Neospora s p infection.
Conclusion It is likely that the isolate of L hardjo used in this study does not normally infect the foetus. Neospora s p may be a more significant cause of bovine reproductive wastage.  相似文献   

Resumption of Post-partum Ovarian Activity Monitored by Plasma Progesterone in Anoestrous Zebu (Bos indicus) Cattle Following Temporary Weaning and Progestogen Treatment     

JM Bolaños  CS Galina  S Estrada  M Forsberg 《Reproduction in domestic animals》1997,32(5):267-271

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Evaluation of an Artificial Insemination Programme in a Seasonal Breeding Dairy System through Milk Progesterone     

D Cavestany  & CS Galina 《Reproduction in domestic animals》2001,36(2):79-84

In order to evaluate an artificial insemination programme and reproductive efficiency of dairy herds in Uruguay, a survey was conducted with five dairy farms, utilizing a total of 768 lactating Holstein cows. Precision of oestrous detection was assessed by one milk progesterone sample taken on day of breeding and was 11.1%. Two additional samples taken at day 10 and 23 were used to confirm ovulation and early pregnancy. Accuracy of pregnancy estimation by milk progesterone was 70.4%. Reproductive efficiency was determined by the analysis of records. Average intervals from calving to first service were 101 days and to conception 132 days and these were affected by parity, body weight and body condition at calving, but not at breeding, or by milk production. Oestrous detection rates and pregnancy rates were 37.5 and 15.6%, respectively. It was concluded that losses in reproductive efficiency in dairy farms of Uruguay in a seasonal artificial insemination programme were mainly due to unobserved heats, rather than incorrect oestrous detection.  相似文献   

Growth and heritability estimates among clones of <Emphasis Type="Italic">Dalbergia sissoo</Emphasis> Roxb. in a clonal seed orchard     

Arvind SHARMA  Meena BAKSHI 《中国林学(英文版)》2011,13(3):211-217

The study of genetic variability is a prerequisite for any tree improvement program. Screening of clones showing the effect of dominance in growth and tree form is essential to identify productive clones, matched to sites. Our study performed in a clonal seed orchard at Lacchiwala of India, represented by 31 clones of Dalbergia sissoo (Shisham) Roxb. from diverse locations revealed significant variability at the 0.1% level of significance in various morphological traits. At the age of 13 years, clone 196 (Gonda) revealed maximum height of 20.2 m and a girth at breast height of 74.2 cm. The five identified clones viz. 196, 198, 192, 123 and 235 were well adapted to the climatic conditions of this zone, hence survived well and showed good performance compared to other clones. Heritability estimates of 87%, 83% and 80% for height, crown width and crown length respectively coupled with high genetic gains indicated strong genetic control of these variables. A correlation matrix of various growth attributes revealed positive correlation among these attributes. On the basis of the entire set of growth variables, the clones were grouped into two major clusters with three subgroups.  相似文献   

55 kb Plasmid and Virulence-Associated Genes are Positively Correlated with Salmonella enteritidis Pathogenicity in Mice and Chickens     

Bakshi CS  Singh VP  Malik M  Singh RK  Sharma B 《Veterinary research communications》2003,27(6):425-432

Twenty-four strains of Salmonella enteritidis, isolated from several outbreaks of salmonellosis from different poultry farms in India, were checked for the plasmid profile and detection of virulence gene(s) by PCR. Most of the strains contained only a single plasmid of 55 kb. Additional plasmids of 23.2 kb and 8.7 kb were seen in one of the strains, and another strain carried only two plasmids of 23.2 kb and 8.7 kb. Four strains did not carry any plasmid. PCR amplification showed the presence of virulence-associated genes in all the isolates harbouring the 55 kb plasmid. Intraperitoneal inoculation of mice, with most of the strains carrying the 55 kb plasmid, caused 100% mortality. Most strains lacking the 55 kb plasmid were avirulent. In chickens, oral inoculation of the S. enteritidis strains carrying the 55 kb plasmid produced 40–100% mortality, with characteristic signs of salmonellosis. Oral inoculation of strains lacking the 55 kb plasmid did not cause any mortality. Hence, it appears that the large plasmid of S. enteritidis probably contributes towards virulence in mice and chickens.  相似文献   

Relationship Among Follicular Growth, Oestrus, Time of Ovulation, Endogenous Estradiol 17β and Luteinizing Hormone in Bos Indicus Cows After a Synchronization Program     

M Maquivar  A Verduzco  CS Galina  A Pulido  S Rojas  K Forster  G Van der Laan  R Arnoni 《Reproduction in domestic animals》2007,42(6):571-576

To determine the pattern of follicular growth during oestrus and the relationship with estradiol and luteinizing hormone in ovulating and non-ovulating cows, three groups of (n = 10), thirty cyclic, Bos indicus cows were synchronized with CIDR, consecutively at 9-day intervals. Twenty-four hours after implant withdrawal, all cows synchronized in the same group with other cows displaying estrous behaviour after implant withdrawal were subjected to an intensive period of ultrasonographic observations (every 6 h for 120 h). Blood samples were taken to evaluate LH surge and 17-beta estradiol. No differences were observed in follicular growth, ovulatory diameter and growth average in the three groups of synchronized cows. Cows ovulating (CO) had a better growth average in comparison with the group of cows not ovulating (CNO) (1.4 +/- 0.7 mm vs 0.7 +/- 0.5 mm, p < 0.06). The average time from estradiol release to LH surge was 39.3 +/- 24.6 h. Differences were also observed between CO and CNO with respect to both the first concentration (27.7 +/- 5.2 vs 58.6 +/- 31.9, p < 0.004) and last concentration (79.3 +/- 23.3 vs 99.2 +/- 27.3, p < 0.05) of estradiol above 5 pg/ml. The average time from overt signs of oestrus to LH release was 8.4 +/- 7.7 h. In the CNO, the increase in LH concentration was never above two SD from the basal average. In conclusion, there is a wide variability in follicular growth and ovulatory diameter between CO and CNO, which can affect the intervals of LH release, estradiol peak and ovulation. Yet, LH surge might be a good marker for timing ovulation in Zebu cows.  相似文献   

The effect of processing on the nutritional value of guar meal for broiler chicks     

J. R. Couch  Y. K. Bakshi  T. M. Ferguson  E. B. Smith  C. R. Creger 《British poultry science》1967,8(4):243-250

Guar meal contains two factors which are detrimental to the growth rate and food conversion of chicks. One of the factors is the trypsin inhibitor which can be destroyed by cooking the raw guar meal for a period of 1 hr at a temperature of 110° C. with the injection of super‐heated steam for a period of 15 min. after the cooker attains a temperature of 110°C. The second deterimental factor in guar meal is the guar gum which causes a depression in growth and sticky droppings when the total level of the gum in the diet exceeds 1.8 per cent. The usage of heated guar meal in chick diets is apparently limited by the gum content of the meal. Pectinase, an enzyme preparation added to a chick ration which contained 15 per cent processed guar meal, produced an increase in the weight gain of chicks fed the ration over those fed 15 per cent processed guar meal. Hypertrophy of the pancreas resulted in the chicks fed 20 and 30 per cent processed guar meal and in all groups fed raw guar meal.  相似文献   

Raw beef bones as chewing items to reduce dental calculus in Beagle dogs          下载免费PDF全文

FR Marx  GS Machado  JG Pezzali  CS Marcolla  AM Kessler  Ø Ahlstrøm  L Trevizan 《Australian veterinary journal》2016,94(1-2):18-23

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A quick method of recording plant growth stages     

A. I. KOVÀCS 《Weed Research》1976,16(1):43-45

The recording of the stage of growth of crops and weeds by directly photocopying the plants is described.  相似文献