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Use of biooc technology nn the production / Gregorio, J. y col.
INTRODUCTION
Both, internal (gastrointestinal, pulmonary, hepatic, hematic,etc.)
and external (ticks, ies, lice, mites, etc.) cause high economic
losses to cattle industry worldwide.
Bovine (Bos taurus) trypanosomosis in Africa (caused mainly
by Trypanosoma vivax (T. vivax) and Trypanosoma congolense),
only in the Tse-Tse y belt, causes losses estimated in United
States of America (USA) $ 4,75 billions/year (yr) [18]. In Colombia
[5], where the disease is endemic in regions like Inter Andean
Valleys, Middle Magdalena, Caribbean Coast and Eastern Plains
[6], several studies conrm the economic importance of the disea-
se. Betancourt and Wells [8] recall an episode of trypanosomosis
in a dairy in the Cauca Valley where losses went up to USA$
5,654. Studies conducted in the State of Cordoba in 1996 found
that, in three months, calves infected with T. vivax, gained an ave-
rage of 6.0 kg less than non infected calves [1, 34].
Gastrointestinal worms severely aect the productivity of cattle
ranches, since it produces anorexia, loss of blood and plasmatic
proteins, lung damage, metabolic disturbance, diarrhea, and re-
tarded growth [14, 40].
In South America, the control of bovine trypanosomosis has
been based for many years on diminazene aceturate and, more
recently on isometamidium chloride [11,12].. Both compounds are
of common use also in Africa [24, 25, 29] and are marketed as
single molecules. Control of gastrointestinal parasitism (GIP) is
mainly done with benzimidazol derivatives (albendazol, fenben-
dazol and others), imidazotiazols (levamisol, tetramizol), macro-
ciclic lactones (Ivermectinas, milbemicines), organophosphates
(haloxon, triclorfon). All of them are also sold as single molecules.
[13, 27, 33].
The colombian veterinary market does not have a compound
containing both, isometamidium and ivermectin. Such a product
would be useful, considering that a high worm burden produces
immunodepression and could complicate a trypanosomosis clini-
cal episode. Reveex Laboratory has developed a mixed product
containing both drugs. It is expected that the product, while con-
trolling gastrointestinal parasitism, favors the preventive and cu-
rative eect on trypanosomes. The present work was conducted
to evaluate the ecacy of isometamidium and ivermectin combi-
nation, on the control of mixed infections by gastrointestinal para-
sites (GIP) and T. vivax in cattle.
Trypanosomosis
Bovine trypanosomosis produced by T. vivax is known in Co-
lombia since 1931 [37, 49] and it is considered endemic in regions
like: the Atlantic Coast, Cauca and Magdalena River Valleys and
the Eastern Planes [6, 22, 34, 46] in warm zones and under 1500
meters above sea level (m.a.s.l). Recently the presence of the
parasite was reported in cattle in Antioquia, at 2.486 m.a.s.l. [50].
The disease has a strong economic impact due to abortions,
anaemia, reduction of milk yield and control costs. [ 3, 4, 8, 9,
16, 34, 47].
Gastrointestinal parasites
Most known nematode genera have been reported in associa-
tion with GIP in cattle in Colombia. In the Eastern Planes, Coope-
ria, Haemonchus, Ostertagia, Oesophagostomum, Trichostron-
gylus, Trichuris, Bunostomum, Capillaria, Agriostomum, Toxocara
and Mecistocirrus have been found by dierent workers [32, 35,
39, 44]. In the Atlantic Coast, the genera Strongyloides, Toxoca-
ra, Cooperia, Haemonchus, Mecistocirrus, Oesophagostomum,
Bunostomum, and Ostertagia have been registered in Cordoba
State and the genera Strongyloides, Haemonchus, and Trichos-
trongylus in Cesar State [36, 41].
In the Middle Magdalena the genera Strongyloides, Coope-
ria, Ostertagia, Haemonchus, Oesophagostomum, Trichostron-
gylus and Bunostomum have also been found [13]. Another stu-
dy conducted in Santander State, found that the most common
nematodes infecting bovine in the García Rovira Province were
Toxocara, Cooperia, Haemonchus, Ostertagia, Nematodirus and
Trichostrongylus [38].
Generally speaking, GIP is more prevalent and severe in young
calves. Villar and Arguelles [43], found the highest counts of eggs
in faeces in calves 105 to 130 days (d). Some genera, like To-
xocara and Strongyloides, are more common in younger calves
[41, 44].
As for anthelmintics used in controlling GIP worms in bovine,
studies in a milk producing area of Boyacá, found that Albendazol
was the most commonly used (30%) [47], followed by ivermectin
(14%) and levamisol (7%) [33]. Another work reported the oral
use of 1% diatomaea sands as anthelmintic for cattle and repor-
ted 84 and 100% reduction in egg per gram (epg) of faeces count
on d 90 and 135, respectively [28]. Marquez et al. [30], repor-
ted anthelmintic resistance in 25% of the farms examined at the
Altiplano Cundiboyacense region. Resistance to albendazol and
ivermectin was reported on 17 and 8% of these farms, respecti-
vely.
MATERIALS AND METHODS
The study was conducted at the Román Gómez Farm of the
Jaime Isaza Cadavid Polytechnic in Marinilla, Antioquia located
at 6º11’47” North; 75º 20´ 0” West.
The drug tested: The Hemoveex
®
(Reveex Laboratories, Vene-
zuela), compound tested on its trypanocidal and anthelmintic e-
cacy, is an association of isometamidium chlorhidrate 2,4% and
ivermectin 2,0%. Ivermectin is an endectocide known for over 30
years. It works by stimulating the presynaptic GABA relaxation
with the resultant blockage of the nervous impulse in the post-