Growth performance in naturally infected lambs under selective treatment with FAMACHA method and preventive treatment

Abstract

The objective of the present work
was to evaluate the weight gain in lambs using two
systems of parasite control in between 14/11/04 and
14/03/05. Thirty four animals of the Ile de France
breed where used in two groups of 17 animals
(G1 and G2). The G1 group was evaluated at
14-days interval using Famacha, diarrhea and body
condition score and fecal exam (EPG) at the same
frequency being treated with moxidectin in case
they manifested any clinical sign. The G2 group was
treated with the same compound at 30-days interval.
The correlation of Famacha 2, 3 and 4 and the
variables EPG and weight was of 0,903 and 0,662,
respectively. The groups demonstrated no difference
on their final weight gain (P=0,110). There was the
predominance of the Haemonchus contortus species
for G1 (62,94%) and G2 (64,14%). The option to
treat animals using the selective system reduced by
87,5% the treatment cost when compared with the
preventive regime. The target selective treatment
using the Famacha method allows a very efficient
parasite control when there is a high prevalence of
the parasite H. contortus. The data permit inferring
about the possibility to select less tolerant animals
during a period of heavier parasite challenge.