Prevalence of Coccidia in French Calves: Results of Several Surveys


A. RICHARD (1),,C. RIZET (2),L. LARAILLET (3)
(1) Alpharma, Silic 411, 3 Impasse de la Noisette, 91374 Verrières le Buisson,France,
alain.richard@alpharma.com
(2) Cabinet vétérinaire, Rue du Général de Gaulle, 03130 Le Donjon,France
(3) Centre Lait, 1 Bd du Vialenc , 15000 Aurillac,France

 


Coccidia are parasites which have an underestimated economic importance in ruminants.
The aim of the surveys was to have a better knowledge of oocyst shedding in dairy calves during weaning and in sucking calves aged 4 to 7 weeks.
On farms where animals did not show clinical signs of coccidiosis, faecal samples were taken from 2 to 10 calves. The 4 labs, each of which participating in one of the 4 surveys, all used an iodomercurate flotation method. Identification of the different species of coccidia was carried out by examining the oocysts.
3 surveys were performed on milk calves.
In 1997, on a total of 338 calves tested on 66 farms all over France, 94 % of the calves and 61 % of the farms were positive, Eimeria Bovis being observed in 25 % of the cases, E.subspherica in 21 %, E.zuernii in 18 %, and finally auburnensis in12 %.
In 2001, on a total of 54 farms in the Massif Central region, 51 were positive, 47% of them with an oocyst-per-gram count between 100 and 1,000 and 6 % with one greater than 1,000.
In 2002, in a survey carried out in Brittany (western France) the 18 farms assessed were all positive (96 heifers) with 8 % of the calves shedding between 1,000 and 10,000 oocysts per gram. Eimeria bovis was found on 18 farms and on 55 % of the calves, followed by E.alabamensis, then subspherica and finally zuernii and auburnensis.
The survey on sucking calves was carried out in the Allier region (central France) using groups of 7 calves aged 4 to 7 weeks from 10 farms. There again all farms were positive and the oocyst count was significant : 14 calves out of 70 shed between 1,000 and 10,000 oocysts per gram of faeces and 5 calves out of 70 shed between 10,000 and 100,000.
The various species of coccidia were frequently associated on a same animal and on the farms. Thus, in the sucking calves survey, all farms hosted 3 different species (up to 5 in heifers in 2002).
These surveys carried out in different regions, by different laboratories, show that coccidia are present on the almost total of calves farms.
They provide a better understanding of growth improvements obtained on several farms with decoquinate (a synthetic molecule active on certain protozoa: coccidia, cryptosporidia, toxoplasma…and having no antibiotic action), and this, even in the absence of clinical signs of the disease.