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K Frankena

Publications and source records attributed to K Frankena.

At least 55 records · Page 3Linked to original sources
PubMed1994

Salmonella enteritidis: clinical epidemiological approaches for prevention and control of S. enteritidis in poultry production.

Salmonella enteritidis infections in poultry appear to be of major public concern. Prevalence levels in veal calves and pigs are rather low. Because of the complex of socio-psychological, welfare, economic and public health aspects great emphasis should be put on prevention and control. This paper deals with some clinical epidemiological approaches for prevention and control of S. enteritidis. Emphasis is set on multifactorial background of infection occurrence, epidemiological methods and features of monitoring and surveillance for evaluation of measures taken during a follow-up period. Finally, it is stated that the application of Risk Assessment & Analysis principles in this problem area, integrating the concepts previously addressed, might prove to be a valuable perspective.

Animals↗
PubMed1994

PRRS: effect on herd performance after initial infection and risk analysis.

In early 1991, the Dutch pig industry was struck by Porcine Reproductive and Respiratory Syndrome (PRRS). Data from 91 breeding and/or farrow to finish herds that were positive for PRRS were used to investigate the impact of PRRS on productivity and to evaluate the relationship between PRRS and farm and management factors. The farms involved used the CBK management information system. Results show that herd performance was severely affected by PRRS over a period of 4-6 months. A rough economic evaluation, using a fixed price for piglets, indicated that the economic loss on the 91 farms averaged Hfl. 215,- (= 65 pounds) per sow per year due to a decreased number of piglets raised per sow per litter, a prolonged farrowing interval and a higher replacement rate of sows. The analysis of possible risk factors did not reveal major factors that could be helpful in reducing the negative effect of PRRS on Piglets Reared per Sow per Year and on the Economic Index of farms experiencing an outbreak of PRRS.

Animal Husbandry↗
PubMed1994

Double blind field evaluation of a trivalent vaccine against respiratory disease in veal calves.

A field trial was performed to determine the effect of a trivalent vaccine on Clinical Respiratory Tract Problems (CRTP) in veal calves. The vaccine has been developed to increase immunity against the causal agents of IBR, BVD and BRSV infection. In total 928 calves, housed in 16 compartments of one herd, were involved. In four compartments of 58 calves each, vaccinated and non-vaccinated calves were housed together. Four other compartments were treated as a whole and 8 compartments were left untreated. CRTP incidence, medications, weight gain, haemoglobulin and IgG level were recorded. From CRTP positive animals, seroconversion and presence of specific bacteriae and/or viruses were measured as well. Results of the compartments where vaccinated and non-vaccinated calves were housed together showed that the incidence of CRTP in vaccinated calves was 0.16 while it amounted to 0.28 in controls. Most cases were found between day 40 and 60 after the start of the trial. Seroconversion for vaccine specific viruses was sporadically found, but the presence of Pasteurella's was confirmed in the majority of cases. Presumably, the higher incidence of CRTP in the control group was due to a higher level of BVDV infection which might facilitate a clinical infection with Pasteurella's. Vaccination was also negatively related to the percentage of affected lungs at slaughter, the number of days antibiotics had to be administered and subsequently to medicine costs, although these effects were not significant. Daily weight gain was significantly affected by CRTP, but not by vaccination. The effects of vaccination in the compartments where calves were either all vaccinated or not-vaccinated, were similar or larger when compared to the effects in compartments where half of the calves were vaccinated.

Animals↗
PubMed1994

Impact of udder disorders on culling of dairy cows.

Data from a prospective longitudinal study carried out from 1986 to 1990 in 47 commercial Holstein dairy herds from western France were used to quantify the effects of udder health disorders on the risk of culling. Logistic regression was used to assess the relationship between 4 udder health disorders and early and late culling. Teat injuries were associated with an increased risk of early culling in the current and following lactations. Mastitis and high milk cell count were associated with an increased risk of late culling in the current and following lactations, respectively.

Abortion, Veterinary↗
PubMed1994

Applied epidemiology: another tool in dairy herd health programs?

Data bases of herd health programs concern data from individual animals mainly. Several parameters that determine herd performance can be calculated from these programs, and by comparing actual values with standard values, areas for further improvement of health (and production) can be advised. However, such advice is usually not backed up by the proper statistical analyses. Moreover, data concerning the environment of the animals are not present and hence advice concerning multifactorial diseases are based on common knowledge and experience. Veterinary epidemiology offers methods that might improve the value of herd health programs by identification and quantification of factors and conditions contributing to multifactorial disease occurrence. Implementation of these methods within herd health programs will lead to more scientifically sound advice.

Animals↗
PubMed1992

Establishment and pathogenicity of two strains of Ostertagia ostertagi and Cooperia oncophora in calves in different locations.

An experiment was carried out simultaneously in Glasgow and in Wageningen to investigate possible differences between the local strains of Ostertagia ostertagi and Cooperia oncophora. In each location calves of the local Friesian breed were infected with 100,000 larvae of either the Glasgow or Wageningen strain of O ostertagi or C oncophora. At both locations the calves received the same diet. The Glasgow strain of O ostertagi was more pathogenic than the Wageningen strain and a larger proportion of the worm burden was found in the abomasal mucosa. The number of ova per female was greater in the Wageningen strain. For C oncophora the Wageningen strain gave rise to higher worm burdens and longer worms. Differences were also present between locations. The British Friesians had higher worm burdens of C oncophora and the worms of this species were longer in this host. Compared with the Dutch Friesians the British calves had a higher proportion of O ostertagi in the mucosa. This experiment showed how difficult it is to compare data from the literature because of differences in parasite and host strains and laboratory techniques.

Abomasum↗
PubMed1992

Multivariate epidemiological approach to salmonellosis in broiler breeder flocks.

A retrospective, case-control study into risk factors of salmonellosis was undertaken using data from 111 broiler breeder flocks assembled during a 5-yr period. The results of both univariate and multivariate analyses are presented. Many different Salmonella species were detected. Multivariate models were created based on the outcome of univariate analyses. The following variables appeared to be the most relevant: disinfection tubs, hygiene barriers, the interaction of disinfection tubs by hygiene barriers, and feed mills. The final model indicated that flocks housed at farms without a disinfection tub, with poor hygiene barriers, and receiving their feed from a small feed mill had a 46.1 times greater risk of being Salmonella-positive than flocks housed at farms with a disinfection tub, with good hygiene barriers, and receiving their feed from a large feed mill. It is concluded that the application of quantitative epidemiological methods can be valuable not only to identify potential risk factors but also to quantify their contributory effect on the disease outcome. Hence, it may be a useful tool for application in "integrated food chain quality control programs".

Analysis of Variance↗
PubMed1991

Age resistance in calves to Ostertagia ostertagi and Cooperia oncophora.

Calves were infected repeatedly during a period of 6 weeks with Ostertagia ostertagi and Cooperia oncophora, at an age of 3, 6 or 9 months. The inoculations were performed during three periods, February-March, May-June and August-September, to account for possible seasonal effects or effects of larval batches. Observations were done on faecal egg output, antibody titres and weight gains. Calves were slaughtered for post mortem examinations 9 weeks after the start of infections. The influence of age on worm populations and egg output was significant for C. oncophora but not for O. ostertagi. The effect of season or larval batch on worm populations was significant for O. ostertagi but not for C. oncophora. The correlations between worm numbers and several other parameters found for Cooperia were strongly indicative of a process of worm expulsion taking place at the stage of infection (9 weeks after the start of infections) when post mortem examinations were done. Such correlations were absent for Ostertagia. It is concluded that within the range of ages examined here (the range to which first season grazing calves belong), there is no influence of age on Ostertagia populations but a clear effect of age on Cooperia. This difference strongly influences the total faecal egg output of grazing calves and its interpretation.

Aging↗
PubMed1990

EPISCOPE: computer programs in veterinary epidemiology.

Veterinary epidemiology is a rapidly developing science. However, many veterinarians are unfamiliar with the relevant techniques because veterinary schools have not introduced biostatistics as a core element of their courses or adopted epidemiology as a specific discipline. EPISCOPE, the computer software presented in this paper, covers many epidemiological principles and calculations. It can assist both the teaching of epidemiology and the analysis of field data.

Animal Diseases↗
PubMed1990

Increased establishment of lungworms after exposure to a combined infection of Ostertagia ostertagi and Cooperia oncophora.

Three-month-old calves were infected three times weekly during a 5-week period with Cooperia oncophora, Ostertagia ostertagi or a combination of these two species. For each type of infection two dose levels were applied. In addition one group of calves was kept uninfected. After removal of the primary infection by anthelmintic treatment all calves were challenged with lungworm larvae and slaughtered 5 weeks later. The groups receiving either C. oncophora or O. ostertagi as a monospecific infection did not differ from the naïve controls. The group receiving the combination of both species differed significantly from the other groups, the establishment of the lungworms being 177%, and the faecal excretion of larvae being 325% of that of the other groups.

Analysis of Variance↗
PubMed1990

Effect of nematode infections and management practices on growth performance of calves on commercial dairy farms.

Liveweight of calves on 86 dairy farms was measured at the end of the grazing season and related per herd to the level of exposure to nematode infection estimated in October and December. There were significant between-herd variations in all the serological infection parameters measured. On average 20.5 larvae per gram faeces (geometric mean) were found in October. Faecal samples of 20.5% of the herds contained lungworm larvae. Liveweight of calves deviated per herd from -59.8 kg to +52.2 kg from an age-adjusted population mean after their first grazing season. Growth performance was significantly related negatively to several serological and parasitological parameters. Data were fitted by means of both linear and segmented curvilinear regression. By combining infection parameters 19% of the variation in growth performance among herds could be explained. Infection parameters involved were antibody titre against Cooperia spp., egg output and lungworm larval count. It was found that antibody titres were significantly correlated positively to herd age, while pepsinogen values and egg output were negatively correlated to age. Combining supplementary feeding and anthelmintic treatment during the grazing season with the infection parameters into one model explained approximately 30% of the observed variation in growth performance among herds. It was shown that these findings were consistent with those of a similar study conducted on the same farms a year earlier, although there were clear differences between the years. Finally, significant positive relations were found between the levels of exposure to nematode parasites within farms between two consecutive years.

Age Factors↗
PubMed1989

Increased establishment of lungworms (Dictyocaulus viviparus) in calves after previous infections with gastrointestinal nematodes (Ostertagia ostertagi and Cooperia oncophora).

The influence of a priming infection with gastrointestinal nematodes on the subsequent establishment of lungworms was studied. Repeated inoculations of calves with Ostertagia ostertagi and Cooperia oncophora during 3, 5 or 7 weeks resulted in an establishment of lungworms that was 191% of the establishment found in naïve controls. The higher take was associated with a higher faecal output of lungworm larvae and with lower weight gains of calves. The effect was not significantly influenced by the duration of the primary infections or by the actual presence or absence of worms in the gastrointestinal tract.

Analysis of Variance↗
PubMed1988

Interactions between lungworms and gastrointestinal worms in calves.

Interactions between gastrointestinal worms (Ostertagia ostertagi, Cooperia oncophora) and lungworms (Dictyocaulus viviparus) in calves were studied by assessing the effect of primary infections with either group of worms on the development of homologous or heterologous challenge infections. Primary infections with lungworms resulted in some degree of resistance to challenge with gastrointestinal worms, but this resistance was lower than that found after homologous infection. Primary infections with gastrointestinal worms did not confer any resistance to challenge with lungworms. On the contrary, an indication was found of some enhancing effect of previous gastrointestinal worm infection on the establishment of lungworms. The highest degree of resistance against lungworm challenge was found where calves have been primarily infected with lungworms. Lungworm infections produced some elevation of serum pepsinogen levels. Gastrointestinal worms evoked a rise in circulating eosinophils, although this rise was smaller and occurred later than in lungworm-infected calves. Under the conditions of the experiment, the effect of 6000 infective lungworm larvae on weight gain was larger than the effect of 100,000 L3 of Ostertagia ostertagi and 100,000 L3 of Cooperia oncophora.

Animals↗
PubMed1987

Use of an oxfendazole pulse release bolus in the control of parasitic gastroenteritis and parasitic bronchitis in first-season grazing calves.

The efficacy of the oxfendazole pulse release bolus system for the control of parasitic gastroenteritis and parasitic bronchitis in first-season grazing calves was evaluated in Belgium. Twenty-two calves were allocated to two groups. The calves in one group received a bolus at the time of turn out, while the other group remained untreated. The efficacy of the bolus was assessed by comparison of faecal worm egg counts, plasma pepsinogen concentrations, the antibody response to Ostertagia, Cooperia and Dictyocaulus species total plasma protein and albumin concentrations, and weight gains throughout the grazing season and the housing period. The oxfendazole pulse release bolus provided good control of parasitic gastroenteritis dominated by ostertagia. The effects of parasitic gastritis were greatly reduced as shown by the significantly lower values of serum pepsinogen and ostertagia antibody titres. The use of the bolus further reduced the adverse effects of parasitism as indicated by better liveweight gains and normal total plasma protein and albumin concentrations whereas in the untreated control group hypoproteinaemia and hypoalbuminaemia were observed. Most animals exhibited clinical signs of parasitic bronchitis at the end of the grazing season, and the bolus may not adequately control parasitic bronchitis in all cases at all times.

Animals↗
PubMed1986

Some observations on the use of the morantel sustained-release bolus in first season-grazing calves on a Belgian dairy cattle farm.

The efficacy of the morantel sustained-release bolus (MSRB) in controlling gastrointestinal parasites in first-season grazing calves was evaluated on a dairy cattle farm in Belgium. The calves grazed a pasture which had been used by bolus-treated animals in the three previous years. The effect of bolus administration was determined with respect to live weight gain, faecal egg shedding, herbage larval counts, serum pepsinogen levels and ELISA antibody titres. In spite of an incomplete reduction of faecal egg shedding during the first months of the grazing season, bolus administration resulted in the prevention of parasitic gastro-enteritis in the calves. A weight gain advantage of 35,2 kg of the bolus-treated animals over the controls was noted already at two months after turnout. This weight gain advantage was maintained until housing. The usefulness of serum pepsinogen values and ELISA antibody titres as parameters in prevention experiments is stressed. Both serological parameters gave more information concerning infection level than did the faecal egg output and the herbage larval counts.

Animals↗
PubMedDate not supplied

An inactivated gE-negative marker vaccine and an experimental gD-subunit vaccine reduce the incidence of bovine herpesvirus 1 infections in the field.

An inactivated glycoprotein E-negative vaccine and an experimental glycoprotein D-subunit vaccine against bovine herpesvirus 1 (V1) were examined for their effectiveness in a randomized, double-bline, placebo-controlled field trial comprising 130 dairy farms. The use of these marker vaccines enabled us to monitor the incidence of infections in vaccinated populations. The aims of this trial were to evaluate whether these vaccines: (1) reduce the proportion of outbreaks in dairy herds; and (2) reduced virus transmission within dairy herds and to what extent. Vaccination with either of the two vaccines significantly reduced the proportion of herds wherein an outbreak occurred as well as the virus transmission within herds, as compared to placebo-treated herds. The estimated number of secondary cases caused by one infectious animal, expressed as the reproduction ratio R, was for both vaccines significantly > 1. This indicates that when BHV1 is introduced into vaccinated herds, major outbreaks may still occur.

Animals↗