www.elsevier.com/locate/vetpar
Veterinary Parasitology 146 (2007) 66–76
Combining the effects of supplementary feeding and copper
oxide needles for the control of gastrointestinal
nematodes in browsing goats
C. Martınez Ortiz de Montellano a, J.J. Vargas-Magana b, A.J. Aguilar-Caballero a,C.A. Sandoval-Castro a, L. Cob-Galera a, M. May-Martınez a, R. Miranda-Soberanis a,
H. Hoste c, R. Camara Sarmiento a, J.F.J. Torres-Acosta a,*a Facultad de Medicina Veterinaria y Zootecnia, Universidad Autonoma de Yucatan, Km. 15.5 carretera Merida-Xmatkuil,
Merida, Yucatan, Mexicob Escuela Superior de Ciencias Agropecuarias, Universidad Autonoma de Campeche, Calle 53 s/n X 18,
Col. Unidad Esfuerzo y Trabajo No. 2 Escarcega, Campeche, Mexicoc UMR 1225 INRA/DGER, Ecole Nationale Veterinaire Toulouse, 23 Chemin des Capelles,
31076 Toulouse Cedex, France
Received 10 November 2006; received in revised form 1 February 2007; accepted 14 February 2007
Abstract
The aim was to assess the benefits obtained from combining supplementary feeding and copper needles (COWP), compared
to the use of both approaches independently, for the control of gastrointestinal nematode (GIN) infections in browsing kids.
Forty-four nematode free Criollo kids were exposed to natural parasite infection. The kids were divided into six experimental
groups: not treated, supplemented (NT-S), not treated, not supplemented (NT-NS), moxidectin treated, supplemented (M-S),
moxidectin treated not supplemented (M-NS), copper treated, supplemented (COWP-S) and copper treated, non-supplemented
(COWP-NS). Copper treated groups received Copinox1 (2 g capsules) on day 0 and on day 60 of the trial. Moxidectin treated
groups received Cydectin1 (0.2 mg/kg of body weight sc) every 28 days. Three of the groups received individual
supplementation (100 g of feed/day fresh basis; 74% sorghum: 26% soybean meal; NT-S, M-S and COWP-S) and the other
three groups were not supplemented (NT-NS, M-NS and COWP-NS). Animals browsed native vegetation (6.5 h/day) during
the wet season (154 days). Kids were weighed every 14 days to determine live weight gain (LWG) and blood and faecal
samples were obtained to determine packed cell volume (PCV), haemoglobin (Hb), peripheral eosinophil counts (PEC) and
faecal egg counts (FEC). At the end of the trial, four kids of each group were euthanatized (six kids in each COWP treated
group). Worm burdens, female worm lengths and prolificacy were determined. Liver samples were used to determine copper
concentration and were stained with haematoxylin–eosin to determine microscopic lesions. Animals receiving the combination
of supplementary feeding and COWP improved their LWG, PCV and Hb to similar levels of animals with suppressive AH
treatment. This was not the case when COWP was used without supplementation. Liver copper concentration in COWP treated
groups increased significantly especially in the COWP-NS kids but this was not associated with liver lesions or clinical signs.
Post-mortem Haemonchus contortus and Trichostrongylus colubriformis worm counts had a tendency to be reduced in the
different groups (66–35% reduction) compared to NT-NS group at the end of the trial (P > 0.05). Also, COWP treatment and/
or supplementation reduced female worm length of T. colubriformis and prolificacy of H. contortus and T. colubriformis. This
study, confirmed the value of nutritional supplementation in the control of GIN in growing kids. The use of COWP in addition
* Corresponding author. Tel.: +52 999 942 3200; fax: +52 999 942 3205.
E-mail address: [email protected] (J.F.J. Torres-Acosta).
0304-4017/$ – see front matter # 2007 Elsevier B.V. All rights reserved.
doi:10.1016/j.vetpar.2007.02.012
C.M.O. de Montellano et al. / Veterinary Parasitology 146 (2007) 66–76 67
to supplementation had a limited contribution on the kids’ resilience against GIN. This may be due to the reduced infection of
H. contortus during this trial.
# 2007 Elsevier B.V. All rights reserved.
Keywords: Supplementary feeding; Copper needles; Helminth; Browsing; Goats; Resilience
1. Introduction
Due to the constant development of anthelmintic (AH)
resistance in worm populations, the control of gastro-
intestinal nematodes (GIN) in livestock is now moving
from simply relying on drug treatments into a more
complex setting where several approaches are used
together. For this combination to be of any use for
commercial or resource-poor farmers, the benefits from
the interventions must outweigh the cost (Krecek and
Waller, 2006). Supplementary feeding is a good
alternative method for the control of GIN in goats both
in pen trials (Blackburn et al., 1991, 1992) as well as in
field trials (Faye et al., 2003). Field trials with goats in
Mexico showed that supplementary feeding was able to
improve resilience in an economically feasible manner
(Torres-Acosta et al., 2004, 2006). Supplementary
feeding may contribute to reduced economic losses
due to parasitism and, in some cases, to reduce pasture
infectivity (Ketzis et al., 2006). However, supplemented
infected animals still show a reduction in growth
compared to worm free supplemented kids. Therefore,
there is still room for improving the outcome of
supplementary feeding by combining it with another
strategy. Copper oxide wire particles (COWP) capsules
can be a suitable candidate to improve resilience of
naturally infected supplemented kids in tropical regions.
Recent work has shown that COWP capsules adminis-
tered orally to goats have an anthelmintic effect against
Haemonchus contortus with extended protection for up
to 8 weeks (Chartier et al., 2000; Waruiru et al., 2004). If
COWP can effectively control H. contortus for a
sufficient period of the wet season, goats may use the
extra nutrients from supplementary feeding for growth
(resilience) and/or resistance against the other worm
species found in their gastrointestinal tract. Thus, the
economic benefit of supplementary feeding might be
higher. However, the use of COWP might be limited by
the risk of potential copper toxicity (Waller et al., 2004).
The interaction between COWP and supplementary
feeding for the control of GIN in goats has not been
explored. The objective was to compare how beneficial
can be supplementary feeding and COWP combined, as
opposed to both approaches independently, in the control
of GIN infections of browsing kids.
2. Materials and methods
2.1. Location of the study
This study was performed at the FMVZ-UADY
(208520–198300 North, 908000–888500 West) during
the wet season (July–November 2002) for a total of
154 days.
2.2. Experimental animals
Forty-four worm free Criollo kids (8.94 � 1.42 kg
LW) were used from weaning (3 months of age).
2.3. Experimental groups
Animals were randomly distributed in six groups
balanced by weight.
� T
wo naturally infected groups:� NT-S: Seven kids infected with GIN and supple-
mented.
� NT-NS: Ten kids infected with GIN and non-
supplemented.
� T
wo groups with controlled infection (treated withinjectable moxidectin):
� M-S: Seven kids treated with moxidectin and
supplemented.
� M-NS: Seven kids treated with moxidectin and non-
supplemented.
� T
wo groups with partial control of infection (treatedwith copper needles):
� COWP-S: Six kids partially infected and supple-
mented.
� COWP-NS: Six kids partially infected and non-
supplemented.
2.4. Supplementary feeding
Supplemented animals received 100 g sorghum/
soybean meal (74:26) per day. Supplement provided
87.9 g of DM, 11.1 g of metabolizable protein and
0.27 MCal of metabolizable energy. Supplement was
provided in individual cages in the afternoon when the
animals returned from browsing.
C.M.O. de Montellano et al. / Veterinary Parasitology 146 (2007) 66–7668
2.5. Anthelmintic treatment
Animals received moxidectin treatment (Cydectin1,
Fort Dodge; 0.2 mg per kg BW s.c.) on day 0 and every
28 days during the experimental period.
2.6. Copper oxide wire particles (COWP)
Animals received COWP (Copinox1, Bayer; 2 g
capsules equivalent to 1.7 metallic copper) on day 0 and
day 60 of the trial per os. Dosing took place in the
afternoon. Animals were kept in individual cages after
dosing and animals were supervised during the after-
noon and the following morning in order to confirm that
capsules were not rejected. This dosing strategy was
based on previous epidemiological information which
indicated that H. contortus infectivity of the browsing
area was high from July to October (Torres-Acosta
et al., 2004). The use of COWP on day 0 aimed at
controlling H. contortus from the beginning of possible
challenge, avoiding possible inefficacy of COWP as an
AH due to an increased abomasal pH of kids (Bang
et al., 1990a).
2.7. Browsing management
Animals browsed daily in a native deciduous
tropical forest for 6.5 h every day (7:00–13:30 h).
The forest contained mainly forage trees and bushes
together with a small proportion of native grasses. The
kids browsed together with a herd of 300 naturally
infected adult goats in order to contribute to the
contamination of the browsing area during the
experimental period. This management was meant to
offer a continuous infection challenge for the experi-
mental animals. A goat keeper took all the animals to
the browsing area every day.
2.8. Paddock infectivity
Infectivity of the browse was monitored for the
duration of the trial by means of consecutive pairs of
tracer kids which browsed for a period of 30 days after
which they were kept in pens with concrete floor for 21
days before being humanly slaughtered.
2.9. Live weight gain
All the kids were weighed on a calibrated scale and
sampled on day 0 and every 14 days. Weighing and
samplings took place at 7:00 a.m. 16 h after their last
daily meal.
2.10. Haematological techniques
At each sampling point animals were sampled 3 ml
of blood from the jugular vein of each kid using tubes
previously identified. Blood samples were processed for
packed cell volume (PCV), haemoglobine (Hb) and the
peripheral eosinophil counts (PEC) as described by
Torres-Acosta et al. (2004).
2.11. Parasitological techniques
Individual faecal samples were collected (3 g faeces/
animal) directly from the rectum to determine the faecal
egg counts (FEC) by means of a modified McMaster
technique with a sensitivity of 50 eggs/g (EPG)
(Withlock, 1948). Every 28 days faeces were pooled
for each experimental group to identify the genus of
infective larvae (days 28, 56, 84, 112 and 140 of the
trial). Each animal in the experimental groups
contributed with 1 g of faeces for the bulk culture.
Faeces were gently mixed, pellets were broken and
placed in a Petri dish. The bulk faecal culture was
placed inside a bigger Petri dish containing a thin layer
of water to keep the culture moisten. Every second day
the culture was aerated and misted with water. Third
stage larvae were collected from the group faecal
cultures after 7 days using the Corticelli–Lai technique
(Corticelli and Lai, 1963). The genera of GIN present in
the cultures were identified using adequate keys of
identification (Bowman and Lynn, 1999). The purpose
of producing pooled faecal cultures per group every 28
days was to monitor indirectly the tendency of
nematode genus present in the experimental animals
on different windows of time during the trial (Burke
et al., 2005a).
2.12. Post-mortem studies
At the end of the trial (day 154), four animals per
group were humanly slaughtered. The abomasums,
small intestine and large intestine were ligated and
removed from the animal. The organs were processed
separately immediately after slaughter. In the COWP
treated groups all the animals were slaughtered. This
took place 94 days after the last dose with COWP.
2.13. Worm count and worm identification
Worm counts (adults and immature adults) were
determined in 10% aliquots from the contents and
washings obtained from the abomasum, small intestine
and large intestine separately as described by MAFF
C.M.O. de Montellano et al. / Veterinary Parasitology 146 (2007) 66–76 69
(1986). In order to assure total worm recovery, each
aliquot was screened twice by two trained workers.
Worm identification was made using all the specimens
found in the aliquots obtained from the abomasum,
small and large intestine, respectively using the keys of
identifications of Barth and Visser (1991).
2.14. Length of female worms
Up to 40 adult female worms from each section of
the gastrointestinal tract (abomasums, small and large
intestines) of each slaughtered kid were measured using
a calibrated grid in a stereo microscope (4�).
2.15. Number of eggs in utero of female worms
Previously identified adult female H. contortus and
Oesophagostomum columbianum were placed in
Eppendorf tubes and were ground with a rod to release
the eggs from the uterus. The tube was filled with 1 ml
of water and a 0.1 ml aliquot withdrawn using a 1 ml
syringe. This was placed in a microscope slide (five
drops) and the number of eggs was determined at 10�magnification. Eggs counted in the five drops were
added and then multiplied by 10 to give the total number
of eggs. The number of eggs in the uterus of
Trichostrongylus colubriformis females was directly
observed in the microscope (40�).
2.16. Number of histotropic or inhibited larvae
The abomasum, small and large intestines of
slaugthered kids were artificially digested separately
using the technique described by MAFF (1986). The
number of histotropic or inhibited larvae (fourth-stage
larvae) was counted from 10% aliquots (20 ml each)
from the digestion material of abomasums, small and
large intestines, respectively. In order to assure total
larvae recovery, each aliquot was screened twice by two
trained workers. Aliquots were coloured with iodine
before being examined for worms.
2.17. Histopathology of the liver and liver copper
concentration
Two samples were obtained from the liver of the
slaughtered kids. One tissue sample was preserved in
10% neutral buffered formalin (pH 7.4) and dehy-
drated through graded alcohols before being
embedded in paraffin wax, in accordance to standard
procedures (Luna, 1965). Sections (5 mm) were
stained with haematoxylin and eosin (HE) for
histopathological examination. A second sample
(10 g fresh tissue) was used to determine the
concentration of copper with a colorimetric spectro-
photometer at 440 NM (FMVZ-UADY Diagnostic
Laboratory, Merida, Yucatan).
2.18. Data analysis
PCV, Hb, PEC and EPG, were analyzed with
repeated measures ANOVA of the general linear
models (GLM) using the SPSS software. The model
used treatment, day, treatment by day and a repeated
statement for day of measurement. PEC and EPG
transformed to log 10 (value+1) before their respec-
tive analysis. The EPG data analysis included from
day 28 of the trial, when infection was patent in all
the groups. In the variables where the null hypothesis
was rejected a tukey post-hoc analysis was per-
formed. The mean total LWG of each group were
compared with the ANOVA test with the tukey post-
hoc test.
The post-mortem variables (number of worms,
number of eggs in utero and female worm length)
were checked for normality by means of a Kolmo-
gorov–Smirnov test for each worm species (H.
contortus, T. colubriformis, and O. columbianum).
Variables that normally distributed were analyzed
using a GLM procedure and their respective tukey
post-hoc tests. Variables that were not normally
distributed were transformed by means of the Box–
Cox procedure. Variables that were not normally
distributed, even after transformation, were compared
using the Kruskal–Wallis tests, one for each worm
species. When a Kruskal–Wallis test was significant,
Wilcoxon rank sum tests were used to determine
which pairs of groups differ (Petrie and Watson,
2006). Only adult worms were included in the
analysis of female worm lengths and the number of
eggs in utero.
Data of Cu concentration (ppm fresh tissue)
determined in the liver of kids of the NT-S, COWP-S
and COWP-NS groups were analyzed by ANOVA using
GLM procedure and the tukey post-hoc test. The
frequency of lesions in the liver, determined by
histopathology, was compared between groups using
Fisher exact tests (EPIinfo v 6.0).
Costs (COWP capsules, food and AH treatment) and
incomes (LWG) from the different groups were
recorded and a partial budget analysis performed as
described by Torres-Acosta et al. (2004). All the
comparisons were made against the costs and incomes
of the NT-NS kids.
C.M.O. de Montellano et al. / Veterinary Parasitology 146 (2007) 66–7670
Table 1
Effect of supplementary feeding and/or copper oxide wire particles
(COWP) on the mean total liveweight gain (kg) of Criollo kids
naturally infected with GIN in tropical Mexico
Supplementation Worm control Live weight gain
(mean � S.E.)*
S Moxidectin (M) 7.86 � 0.54 a
NS Moxidectin (M) 5.47 � 0.47 b
S Not-treated (NT) 4.94 � 0.51 b
NS Not-treated (NT) 1.90 � 0.54 c
S COWP 7.16 � 0.57 ab
NS COWP 1.27 � 0.52 c
* Means with different letters (a–c) in a column indicate significant
difference (P < 0.05).
3. Results
3.1. Rainfall pattern during the trial
The total amount of rain recorded during this trial was
880 mm. A hurricane (Isidore) hit the study area on the
22nd of September (day 80 of the trial). As a result the
amount of rain recorded around that period accounted for
almost half of the total rainfall during the study period. In
the months of October and November the amount of
rainfall was negligible. One animal in the COWP-S group
died during the hurricane due to asphyxia.
3.2. Infectivity of the browsing area
Consecutive pairs of tracer kids showed that the
browsing area had a fluctuating infectivity which
included larvae of H. contortus, T. colubriformis and
O. columbianum (Fig. 1). Mean H. contortus burden of
the tracer kids was lower than 500 adult worms during
the study except in September when worm burdens
average 2000. T. colubriformis were consistently more
abundant in the tracer kids with the exception of
September. O. columbianum worm burdens of tracer
kids were low for the duration of the trial.
3.3. Live weight gain
The combination of supplementary feeding and
COWP (COWP-S) helped to achieve similar total
LWG than that of the group maintained free of infection
(M-S) (Table 1 and Fig. 2). Meanwhile, the use of
supplementation only (NT-S) did not show the same
degree of effectiveness and LWG was smaller than that
of M-S group. Although COWP-S kids showed a
tendency to have higher LWG than NT-S kids
Fig. 1. Mean worm burdens from pairs of tracer kids corresponding to
the month when they browsed during the trial. Hc: Haemonchus
contortus; Tc: Trichostrongylus colubriformis; Oc: Oesophagosto-
mum columbianum.
(7.16 � 0.57 versus 4.94 � 0.51), this was not sig-
nificantly different probably due to sample size.
Another important finding is that the use of COWP
alone (COWP-NS group) did not have a positive impact
on growth compared to the infected non-supplemented
group (P > 0.05).
Fig. 2. Effect of supplementation (S) and copper oxide wire particles
(COWP) on the CLWG, PVC and HB in Criollo goats.
C.M.O. de Montellano et al. / Veterinary Parasitology 146 (2007) 66–76 71
3.4. Haematological values
The NT-NS group had lower PCVand Hb compared to
that of the M-S, NT-S and COWP-S groups (P < 0.05;
Fig. 2). Although the mean PCV and the Hb of the
COWP-NS group seemed to be lower than that of the
M-S, NT-S and COWP-S groups, the difference was not
significant. Furthermore, there was no difference
between groups in the PEC.
3.5. Worm egg counts and faecal cultures
Faecal egg counts of the different infected groups
(NT-S, NT-NS, COWP-S and COWP-NS) were similar
for the duration of the trial (P < 0.05; Fig. 3).
Faecal cultures on day 28 were not made as most
experimental animals started shedding nematode eggs
after that time. Faecal cultures showed that on day 56 of
the trial (end of August) the faeces of the infected groups
(NT-S, NT-NS, COWP-S and COWP-NS) had larvae of
Haemonchus spp., Trichostrongylus spp. and Oesopha-
gostomum spp. On day 84 of the trial (end of September),
the groups treated with COWP had mostly Trichos-
trongylus spp. larvae and the NT-S and NT-NS groups
had Haemonchus spp., Trichsotrongylus spp. and
Oesophagostomum spp. On day 112 (end of October),
the faecal culture of the COWP treated groups had mostly
Oesophagostomum spp., a little proportion of Trichos-
trongylus spp., and even fewer Haemonchus spp. Finally,
on day 140 (end of November) all the infected groups had
similar quantities of larvae of the three nematode species.
3.6. Worm burdens
Slaughtered animals from the moxidectin treatment
(M-S and M-NS) had no worms at the end of the trial
Fig. 3. Effect of supplementation (S) and copper oxide wire particles
(COWP) on the nematode eggs per gram of faeces (EPG) of Criollo
goats.
(17 days after the last moxidectin treatment). Worm
burdens of infected groups (median, range, mean and
standard error of the mean) are shown in Table 2.
There were no significant differences between worm
burdens of the different groups. However, mean adult
H. contortus and T. colubriformis worms (male, female
and total) in the NT-S and the COWP-S groups were one
third or smaller than that of NT-NS group. Slaughter
took place 94 days after last dose with COWP.
3.7. Female worm length and eggs in uterus
Female worm lengths and the number of eggs in
utero of H. contortus, T. colubriformis, O. columbianum
are shown in Table 3. Female worm length of
T. colubriformis was larger in the NT-NS group
compared to that of copper treated and/or supplemented
groups (P < 0.05). A similar tendency was found in the
H. contortus females (P > 0.05). Copper treatment and/
or supplementary feeding induced a reduction in the
number of eggs in utero of the H. contortus and
T. colubriformis female worms compared to NT-NS
(P < 0.05).
3.8. Copper concentration in the liver
Both COWP treated groups had higher copper
concentration in the liver than that of the control
animals (43.6 � 5.9 ppm fresh weight; n = 8;
P < 0.05). However, kids in the COWP-NS group
had a higher mean Cu concentration in the liver
(103.7 � 6.9 mg/kg fresh weight; n = 6) compared to
the kids in the COWP-S group (66.8 � 7.5 mg/kg fresh
weight; n = 5; P < 0.05).
3.9. Histopathological findings
The different experimental groups had similar
proportions of animals with microscopic lesions in
the liver (P > 0.05). Lesions did not show any
association with copper treatment. The most frequent
lesions observed in the liver of the animals were
lipidosis, necrosis, cholestasis and tumefaction. Also,
several kids showed regeneration processes.
3.10. Economic analysis
The use of supplementary feeding increased eco-
nomic income by 2.9 USD per animal compared to NT-
NS kids. However, the combination of supplementary
feeding and COWP doubled the income per animal
reaching 6.0 USD. This result was close to that of
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Table 2
Effect of supplementary feeding and/or copper oxide wire particles (COWP) on the worm burdens of Criollo kids browsing in tropical Mexico
Worm species Stage NT-S (n = 4) NT-NS (n = 4) COWP-S (n = 6) COWP-NS (n = 6)
Median (range) Mean � S.E.M. Median (range) Mean � S.E.M. Median range Mean � S.E.M. Median range Mean � S.E.M.
H. contortus Larvae 270 (80–560) 303.0 � 241.7 415 (80–750) 415.0 � 473.8 200 (70–680) 200.0 � 251.1 375 (240–570) 375.0 � 155.9
Juvenile 91 (40–390) 153.0 � 54.0 0 (0–0) 0.0 � 54.0 75 (10–300) 103.3 � 44.1 165 (0–240) 131.7 � 44.1
Male 315 (200–1540) 592.5 � 296.7 1005 (370–1860) 1060.0 � 296.7 215 (0–1500) 488.3 � 242.2 595 (250–1500) 685.0 � 242.2
Female 445 (190–1660) 685.0 � 349.1 1360 (370–2300) 1347.0 � 349.1 320 (0–1600) 541.7 � 285.0 675 (270–1720) 808.3 � 285.0
Total 816 (340–1900) 995.0 � 530.3 2365 (340–4000) 2885.0 � 530.3 610 (30–3100) 1531.7 � 433.0 1480 (1260–2340) 1880.0 � 433.0
T. colubriformis Larvae 0 (0–10) 3.3 � 5.8 a 215 (150–280) 215.0 � 91.9 b 40 (0–80) 38.0 � 33.5 a 30 (20–90) 41.7 � 28.6 ab
Juvenile 95 (20–230) 110.0 � 19.5 a 15 (0–30) 15.0 � 19.5 b 0 (0–0) 0.0 � 15.9 c 0 (0–0) 0.0 � 15.9 c
Male 755 (460–2400) 1092.5 � 449.0 3010 (560–3200) 2445.0 � 449.0 1315 (20–2290) 1285.0 � 366.6 1630 (830–2400) 1608.3 � 366.6
Female 870 (340–1900) 995.0 � 530.3 3600 (340–4000) 2885.0 � 530.3 1430 (30–3100) 1531.7 � 433.0 1930 (1260–2340) 1880.0 � 433.0
Total 1640 (1100–4410) 2197.5 � 962.1 6625 (930–7200) 5345.0 � 962.1 2745 (50–5300) 2816.7 � 785.5 3470 (2090–4700) 3488.3 � 785.5
O. columbianum Larvae 6 (0–60) 6.0 � 33.0 ab 155 (150–160) 155.0 � 7.1 b 40 (10–110) 40.0 � 41 ab 10 (0–40) 10.0 � 15.1 a
Juvenile 15 (4–30) 16.0 � 11.2 0 (0–50) 12.5 � 11.2 20 (0–40) 20.3 � 9.1 15 (10–80) 29.2 � 9.1
Male 65 (13–150) 73.3 � 17.9 20 (0–100) 35.0 � 17.9 20 (0–50) 21.7 � 14.6 75 (40–90) 67.5 � 14.6
Female 65 (3–190) 80.8 � 24.3 20 (10–100) 37.5 � 24.3 30 (0–90) 35.0 � 19.9 45 (20–110) 56.7 � 19.9
Total 145 (20–370) 170.0 � 46.9 40 (10–250) 85.0 � 46.9 66 (30–150) 77.0 � 38.3 130 (90–280) 153.3 � 38.3
Means with different letters (a–c) in the same line between columns indicate significant difference (P < 0.05); S.E.M., standard error of the means; NT-S, not treated—supplemented; NT-NS, not
treated—not supplemented; COWP-S, copper oxide wire particles—supplemented; COWP-NS, copper oxide wire particles—not supplemented.
C.M.O. de Montellano et al. / Veterinary Parasitology 146 (2007) 66–76 73
Table 3
Female worm length and number of eggs in utero of H. contortus, T. colubriformis and O. columbianum in browsing Criollo kids supplemented and/
or treated with copper oxide wire particles (COWP) during the wet season
Nematode species Groups n Female worm length* Eggs in utero*
Median (range) Mean � S.E.M. Median (range) Mean � S.E.M.
H. contortus COWP-NS 138 17 (11–22) 17.1 � 0.19 a 130 (20–490) 132.9 � 8.05 a
COWP-S 97 18 (15–22) 18.1 � 0.23 b 120 (30–400) 130.4 � 9.60 a
NT-NS 87 20 (10–24) 18.6 � 0.25 b 190 (30–610) 221.7 � 10.14 c
NT-S 97 18 (12–22) 18.1 � 0.23 b 140 (20–610) 178.6 � 9.60 b
T. colubriformis COWP-NS 231 7 (6.0–9.0) 7.2 � 0.04 a 14 (2–30) 14.1 � 0.33 a
COWP-S 171 7 (5.0–9.0) 7.2 � 0.05 a 15 (4–33) 14.8 � 0.39 a
NT-NS 98 8 (6.0–10.0) 7.7 � 0.06 b 17 (3–32) 16.9 � 0.51 b
NT-S 107 7 (5.5–8.5) 7.0 � 0.06 a 10 (1–23) 10.6 � 0.49 c
O. columbianum COWP-NS 28 17.0 (9–19) a 15.1 � 0.57 130 (60–700) 223.2 � 30.75 a
COWP-S 28 17.5 (11–20) a 16.6 � 0.57 105 (10–400) 137.1 � 30.75 a
NT-NS 18 17.0 (9–19) a 15.4 � 0.71 150 (20–500) 162.2 � 38.36 a
NT-S 14 16.0 (9–20) a 15.6 � 0.81 435 (130–790) 427.9 � 43.49 c
NT-S, not treated—supplemented; NT-NS, not treated—not supplemented; COWP-S, copper oxide wire particles—supplemented; COWP-NS,
copper oxide wire particles—not supplemented.* Different letters (a–c) in the same column of the same worm species represents significant differences (P < 0.05).
animals kept under suppressive AH treatment and
supplemented (6.7 USD per animal).
4. Discussion
This trial explored the potential benefit of combining
two alternative methods for the control of GIN. The
rational behind this attempt was to control H. contortus,
one of three worm species common to goats under
browsing conditions of Yucatan, and leave the animals
to defend themselves against the other two important
worm species in the area: T. colubriformis and
O. columbianum (Torres-Acosta et al., 2004, 2006).
H. contortus is considered to be the most pathogenic
parasite of small ruminants on a worm-for-worm basis
(Krecek and Waller, 2006). H. contortus population was
meant to be partially and temporarily under control for a
considerable proportion of the trial by dosing worm free
kids with one 2 g capsule of COWP on day 0 and a
second 2 g capsule on day 60 of the trial. COWP has
being proven to be an efficacious non-conventional
anthelmintic particularly against H. contortus in sheep
(Bang et al., 1990b; Goncalves and Menezes, 2004;
Burke et al., 2004, 2005a) and goats (Chartier et al.,
2000). By using COWP to control H. contortus, treated
kids were expected to have an additional improvement
on their resilience and/or resistance from supplemen-
tary feeding against the other two species of GIN. In this
trial, H. contortus infectivity of the browsing area was
mild (according to tracer kids). Thus the potential
benefit might have been limited. In spite of that, the
results are encouraging since the combination of COWP
and supplementary feeding showed a tendency to
improve LWG in the browsing kids compared to the use
of supplementation alone (P > 0.05). This combination
of supplementary feeding and COWP treatment may
have allowed the kids to take advantage of the time
when H. contortus was under some level of control
improving their growth rate and blood parameters
(improved resilience).
This trial also showed that the sole use of COWP
(COWP-NS) was less effective for improving growth of
kids than the sole use of suppressive AH treatment
(moxidectin treatment every 28 days) (M-NS). Further-
more, the sole use of COWP did not improve LWG or
haematological values compared to NT-NS kids.
The COWP treated groups did not show a reduction
in FEC during this trial. The low efficacy may be due to
the low proportions of H. contortus compared to other
worm species as reported by Burke et al. (2005b) and
Burke and Miller (2006). In this trial, tracer kids showed
that infectivity with H. contortus was lower than that of
T. colubriformis for most of the trial (except for
September). Previous epidemiological information
suggested a higher H. contortus infectivity than that
of T. colubriformis from August and reduced gradually
from October onwards (Torres-Acosta et al., 2004).
However, results of tracer kids showed that the
hurricane which hit the site of the study, Yucatan, at
the end of September, reduced the infectivity of the
browse during October possibly affecting the pattern of
infectivity in the last months of the wet season.
C.M.O. de Montellano et al. / Veterinary Parasitology 146 (2007) 66–7674
Even when FEC were not reduced by COWP, the
faecal cultures showed that H. contortus larvae were
present in COWP treated groups on day 56 post-copper
treatment, time when this copper was not expected to
have an effect. The following faecal cultures of COWP
treated groups (24 and 52 days after the 2nd COWP
treatment) showed negligible levels of H. contortus
larvae. It is likely that cultures of day 24 post-COWP
treatment show an effect of copper on the H. contortus
population in these experimental groups. However,
on day 52 post-second treatment the low levels of
H. contortus may only indicate that re-infection did not
occurred. Finally, in the faecal cultures of November
(94 days after 2nd COWP treatment), there were
H. contortus larvae in all the experimental groups. The
reduction in H. contortus cultured in faeces from
COWP-treated groups has been reported earlier in sheep
(Burke et al., 2005a).
Worm burdens at the end of the trial (day 154)
were not significantly different between infected
groups. This was expected as the last COWP
treatment was performed 94 days before slaughter
and the persistent effect reported for COWP against
H. contortus in sheep varies from 21 to 42 days (Bang
et al., 1990b; Knox, 2002; Goncalves and Menezes,
2004). Animals in this trial received a constant
natural infection which is different to the experi-
mental protocols used previously elsewhere. Thus,
any anthelmintic effect in the first days after COWP
treatment may be masked by further establishment of
incoming L3 larvae in the following weeks post-
COWP treatment (Waller et al., 2004). However,
despite the lack of statistical differences, the
following tendencies can still be suggested. The
supplementation was associated with substantial
reduction in H. contortus and T. colubriformis
populations, associated with a decreased fecundity
in both worm species and a reduced female length in
the last one. This confirms previous results obtained
with naturally infected Criollo kids under browsing
conditions (Gutierrez-Segura et al., 2003). On the
other hand, the use of COWP alone also showed
similar effects on worm burdens of H. contortus and
even T. colubriformis. This non-significant reduction
in H. contortus worm burdens was similar to that
reported in trials were H. contortus was trickle
infected in goats (Chartier et al., 2000; 39.2% on day
70 post-COWP treatment, P > 0.05) and also in sheep
(Knox, 2002; 54% on day 42 post-COWP treatment,
P = 0.058). Although kids in the COWP-S treated
groups tended to have nearly one third of the H.
contortus and T. colubriformis worm burdens of the
NT-NS kids, the combination of COWP and
supplementation did not appear to add much
compared to supplementation alone in regard of
effects on biology of worm populations although the
benefit for resilience has been previously underlined.
Last, for O. columbianum populations, whatever the
treatment, no effects were found.
Copper levels in the liver of browsing kids without
COWP treatment were within normal levels of goats
and sheep receiving no copper supplementation in
other latitudes (Glennon et al., 2004; Waller et al.,
2004). This is consistent with findings of Millan-
Cortes et al. (1990) who reported that grass of the
region have sufficient copper for ruminant nutrition
(8–10 ppm) although it can reach levels of deficiency
during the wet season. COWP treated groups (COWP-
S and COWP-NS) increased their copper concentra-
tion in the liver, being significantly higher in COWP-
NS. This increment of copper concentration in the
liver due to COWP treatment has been reported in
sheep (Bang et al., 1990b; Goncalves and Menezes,
2004; Waller et al., 2004) and goats (Chartier et al.,
2000; Glennon et al., 2004). However, no overt signs
of copper toxicity have been found in previous trials
and the same is true for the present study.
Interestingly, we found evidence indicating that
copper liver concentration in COWP treated kids
depended on the availability of supplementary
feeding contrary to early evidence with sheep (Burke
et al., 2004). It is possible that the higher copper
concentration in the COWP-NS kids resulted from
their low growth rate compared to COWP-S. Both
groups were exposed to the same amount of copper
but the faster growing COWP-S kids might have used
more copper for their metabolic processes such as
erythropoiesis, protection from oxidants, develop-
ment of heart and central nervous system, immuno-
competence (Underwood and Suttle, 2001) than the
COWP-NS kids. It is important to point out that using
COWP without supplementary feeding increases the
risk of chronic copper toxicity compared to supple-
mented kids even when animals are eating in the same
browsing area.
This trial showed that the use of supplementation
may be more reliable and easy to implement than
COWP (either combined or alone). This trial showed
that COWP treatment cannot be widely recommended
for the control of GIN in tropical farming systems
because it is difficult to foresee the H. contortus
challenge that animals will have before and after COWP
treatment. In addition, the risk of chronic copper
toxicity exists.
C.M.O. de Montellano et al. / Veterinary Parasitology 146 (2007) 66–76 75
5. Conclusions
This study, confirmed the value of nutritional
supplementation in the control of GIN in growing
kids. The use of COWP in addition to supplementation
had a limited contribution on the kids’ resilience against
GIN. This may be due to the reduced infection of H.
contortus during this trial. Thus, relaying on COWP
treatment alone was ineffective. An accumulation of
copper in the liver COWP treated animals was observed,
thus veterinary advice is crucial to limit chronic toxicity
problems.
Acknowledgments
This work was financially supported by the
Universidad Autonoma de Yucatan, Mexico (project
PRIORI-FMVZ 02-011) and ECOS-Nord (France)/
ANUIES-CONACyT (Mexico) (project M03-A03). We
thank Animax Ltd. for providing the COWP capsules
for this trial.
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