An Epidemiological Investigation into Coccidiosis and Drug Resistance in Broiler Chickens

Hamet, N.; Josse, J.; Robin, Boris; Toucas, L.

doi:10.1079/wps19850018

Cited by 7 publications

(4 citation statements)

References 13 publications

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“…The OPG level criterion for defining risk flocks was based on practical experience gathered at the laboratory at the National Veterinary Institute in Sweden (Per Thebo, personal communication). Hamet et al (1985) also found that, on average, an infection level of 50 000 OPG (faeces collected from 4week-old broiler chickens) constituted a threshold for influence of oocyst output on performance. However, in another detailed study, no association between OPG!…”

Section: Discussionmentioning

confidence: 89%

“…However, in another detailed study, no association between OPG! 50 000 and performance was found (Hamet et al, 1985).…”

Section: Discussionmentioning

confidence: 93%

“…Furthermore, husbandry and prophylactic regimes also vary. Therefore, finding a threshold level in infection intensity from which a negative impact on broiler chicken performance might be predicted, has proven difficult (Braunius, 1980;Hamet et al, 1985;Graat et al, 1996;Williams, 2006a).…”

Section: Introductionmentioning

confidence: 99%

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A survey of the economic impact of subclinicalEimeriainfections in broiler chickens in Norway

et al. 2008

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The objective of this work was to examine the impact of subclinical coccidial infection on commercial performance, expressed as a modified European Production Index, in broilers. Performance data, and litter and faecal samples, were collected from two independent observational surveys of Norwegian broilers receiving in-feed narasin during 2000 to 2004. Numbers of oocysts per gram (OPG) of litter collected during rearing (Study 1) or faecal samples collected at slaughter (both studies), and relative frequencies of Eimeria species categories (both studies) were calculated. Polymerase chain reaction-based identification of Eimeria species was performed in Study 2. A definition of flocks at risk of impaired performance associated with coccidia ("risk flock"), using the predominant species and OPG level as criteria, was tested. Coccidia had a significant effect on performance in the first, but not the second study. In Study 1 the following coccidia variables were found to be associated with impaired performance in multivariate models: OPG at slaughter (ordinal), mean OPG during rearing (ordinal) and "risk flock" (binomial). The European Production Index was approximately 9% lower in flocks with infection levels >50 000 OPG at slaughter in Study 1. The composition of coccidial populations shifted between Study 1 and Study 2, from a dominance of medium and large oocysts to a dominance of small oocysts. There was a substantial increase in prevalence of coccidial infection from Study 1 to Study 2, but mean infection levels were similar in the two surveys. The "risk flock" definition was useful as an indicator of coccidia-associated performance loss in Study 1, where subclinical coccidiosis was an important factor. The results suggest that the economic importance of subclinical coccidiosis may vary substantially with time, and they emphasize the need for population studies on the importance and dynamics of specific coccidial infections under different field conditions.

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Section: Discussionmentioning

confidence: 89%

“…However, in another detailed study, no association between OPG! 50 000 and performance was found (Hamet et al, 1985).…”

Section: Discussionmentioning

confidence: 93%

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A survey of the economic impact of subclinicalEimeriainfections in broiler chickens in Norway

et al. 2008

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“…administering synthetic or ionophorous anticoccidials in-feed, or applying a live vaccine early in life (Williams 1998). The development of varying degrees of drug tolerance against in-feed coccidiostats in European countries (Hamet et al 1985, Peeters et al 1994, Peek and Landman 2003, and the inherent side effects of ionophorous coccidiostats (Dowling 1992) urges producers to explore other control measures.…”

Section: Introductionmentioning

confidence: 98%

A Field Study Assessing Control of Broiler Coccidiosis by Paracox™ Vaccination or by Toltrazuril (Baycox®) Stand-Alone Treatment

et al. 2007

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Toltrazuril (Baycox ® ) stand-alone treatment and Paracox-5 (live attenuated vaccine) were assessed in a field trial for broiler coccidiosis control. The feed did not contain coccidiostats or antimicrobial performance enhancers. Fifteen farms encompassing 90 flocks were followed over three trial episodes (Vaccination-1, Toltrazuril and Vaccination-2). Each episode included two successive flocks/growouts. Daily weight gain, feed conversion ratio, production number and mortality rate were assessed as performance parameters, indicative of coccidiosis control. No cases of clinical coccidiosis were diagnosed during the course of the trial. In general, there was a wide variability in production number within most of the farms, with only a few showing a more consistent performance. Although descriptive statistics showed small differences between the treatments, an analysis of covariance revealed no significant (P < 0.005) treatment effect on any of the four efficacy parameters. The age at processing and farm significantly affected the feed conversion ratio, daily weight gain and production number, but not mortality. Within treatment groups, the feed conversion ratio and daily weight gain were significantly influenced by the month of hatch. It was concluded that a single treatment with toltrazuril is a valuable alternative to vaccination for coccidiosis control in a rotation programme.

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Chemotherapy and Other Control Measures of Parasitic Diseases in Domestic Animals and Man

Raether¹,

Mehlhorn²

1988

Parasitology in Focus

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An Epidemiological Investigation into Coccidiosis and Drug Resistance in Broiler Chickens

Cited by 7 publications

References 13 publications

A survey of the economic impact of subclinicalEimeriainfections in broiler chickens in Norway

A survey of the economic impact of subclinicalEimeriainfections in broiler chickens in Norway

A Field Study Assessing Control of Broiler Coccidiosis by Paracox™ Vaccination or by Toltrazuril (Baycox®) Stand-Alone Treatment

Chemotherapy and Other Control Measures of Parasitic Diseases in Domestic Animals and Man

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