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Dose titration of sericea lespedeza leaf meal on Haemonchus contortus infection in lambs and kids
Veterinary Parasitology 181 (2011) 345–349
Contents lists available at ScienceDirect
Veterinary Parasitology journal homepage: www.elsevier.com/locate/vetpar
Short communication
Dose titration of sericea lespedeza leaf meal on Haemonchus contortus infection in lambs and kids J.M. Burke a,∗ , N.C. Whitley b , D.A. Pollard c , J.E. Miller c , T.H. Terrill d , K.E. Moulton b , J.A. Mosjidis e a b c d e
Dale Bumpers Small Farms Research Center, USDA, ARS, Booneville, AR 72927, USA North Carolina A&T State University, Cooperative Extension, PO Box 21928, Greensboro, NC 27420, USA Louisiana State University, Baton Rouge, LA 70803, USA Fort Valley State University, Fort Valley, GA 31030, USA Auburn University, Auburn, AL 36849, USA
a r t i c l e
i n f o
Article history: Received 11 January 2011 Received in revised form 28 April 2011 Accepted 3 May 2011 Keywords: Condensed tannins Gastrointestinal nematodes Goats Lambs Sericea lespedeza
a b s t r a c t The objective of three experiments was to determine the impact of supplementing sericea lespedeza (Lespedeza cuneata; SL) in three concentrations in a loose or pelleted diet on gastrointestinal nematodes (GIN) in small ruminants. Experiments on lambs were conducted at the USDA, Agricultural Research Service in Booneville, AR (Exp. 1) and at Louisiana State University in Baton Rouge, LA (Exp. 2); an experiment on goat kids occurred at University of Maryland-Eastern Shore (Exp. 3). Exp. 1 used crossbred hair sheep lambs naturally infected with GIN that were randomly allocated to diets containing 0, 25, 50, and 75% SL diets (n = 11 or 12/diet). Exp. 2 consisted of Haemonchus contortus-inoculated crossbred wool breed lambs that were blocked by gender and FEC and randomly assigned to 0, 25, 50, or 75% SL diet (n = 8/diet). Fecal egg counts (FEC) and blood packed cell volume (PCV) were not influenced by SL supplementation in Exp. 1 and 2. Exp. 3 consisted of naturally GIN infected Boer crossbred goat kids in individual pens. Kids were blocked by FEC and randomly allotted to treatments of 0, 20, 40, or 60% SL with 9–13 goats/diet. The more SL fed, the greater the reduction in FEC (P < 0.001). There was an increase in PCV in SL fed goats (P < 0.001). Larval speciation at the end of the experiment indicated that feces from control animals produced 43% H. contortus larva while 20, 40 and 60% SL resulted in 39%, 35% and 31% H. contortus larvae, respectively. Feeding dried SL may be less effective in lambs than kids, though concurrent studies must be conducted to confirm this. Published by Elsevier B.V.
1. Introduction Gastrointestinal nematodes (GIN) infect ruminants worldwide and result in major production losses in small ruminants. Haemonchus contortus is the most prevalent and pathogenic in warm, humid climates of the US and worldwide. Anthelmintics were used almost exclusively to control GIN infection over the past few decades, result-
∗ Corresponding author. Tel.: +1 479 675 3834; fax: +1 479 675 2940. E-mail address: [email protected] (J.M. Burke). 0304-4017/$ – see front matter. Published by Elsevier B.V. doi:10.1016/j.vetpar.2011.05.005
ing in a high level of anthelmintic resistance. Complete anthelmintic failure has been reported on some farms and may be widespread in the southeastern U.S. (Kaplan et al., 2005; Howell et al., 2008). Condensed tannin-containing plants may be an option for controlling GIN (Niezen et al., 1998; Paolini et al., 2003; Min et al., 2004; Iqbal et al., 2007). Sericea lespedeza (Lespedeza cuneata; SL) is a legume that contains condensed tannins and grows in the southeastern U.S. Sericea lespedeza has been at the forefront of current condensed tannin research in the U.S. for control of GIN, where grazing or feeding hay or pellets has been shown to reduce
346
J.M. Burke et al. / Veterinary Parasitology 181 (2011) 345–349
Table 1 Percent dietary ingredients (dry matter basis) fed to lambs in Experiment 1. Lambs were fed between 0 and 75% sericea lespedeza (SL) pellets (n = 11 or 12/diet).
a
Corn/soybean meal mix Alfalfa pelletsb Sericea lespedeza pellets Soy hull pellets Estimated crude protein
0% SL
25% SL
50% SL
75% SL
17.1 38.1 0 44.8 13.81
16.4 29.1 25.0 29.5 13.59
17.2 18.7 50.0 14.1 13.34
17.0 3.4 74.6 5.0 12.82
a 78% corn, 18% soybean meal, 3.5% molasses, 0.007% calcium carbonate (14% CP, dry matter basis). b 14% crude protein, dry matter basis.
fecal egg counts (FEC), reduce worm burdens and, in some cases, negatively affect larval development and survival in the feces (Min et al., 2005; Lange et al., 2006; Shaik et al., 2006; Terrill et al., 2007). Use of dry SL products would be beneficial when SL cannot be planted or grown; however, the optimal level of SL intake required to aid in the control of GIN infection has not been determined. Therefore, the objective of the current experiments was to examine the effect of increasing levels of SL on GIN infection in sheep and goats.
2. Materials and methods All animal-related procedures were approved by the Animal Care and Use Committee of each research institution.
2.1. Experiment 1. Dose titration in hair breed lambs Experiment 1 was conducted at the USDA, Agricultural Research Service, Dale Bumpers Small Farms Research Station, Booneville, AR, in June (early summer). Dorper × St. Croix (n = 32) or Dorper × Katahdin (n = 15) crossbred, mixed gender lambs at approximately 3 months of age and 28 kg body weight were used. All animals were naturally infected through grazing contaminated pastures with their dams before the experiment began. Lambs were housed in concrete floor pens in an open sided barn. Body weights were determined on days 0 (first day of experimental diet) and 28 (last day). Coprocultures were not conducted, but the predominant GIN found in grazing lambs on a concurrent study on the same farm was H. contortus (Burke et al., 2009). Lambs were blocked by breed and gender and assigned randomly to four treatment groups (n = 11/control group; n = 12/SL groups; two pens/diet). Lambs were fed approximately 4.3% body weight to meet nutritional requirements (NRC, 2007) for 28 days once per day in the morning. Lambs consumed all feed offered. Diets consisted of 0, 25, 50 or 75% SL whole hay pellets as a percentage of a complete ration (Table 1) that was mixed to be approximately 14% crude protein (CP) and 55% total digestible nutrients (TDN). Trace mineralized salt (Land O’Lakes Sheep and Goat Mineral, Shoreview, MN) and water was provided free choice.
Table 2 Percent dietary ingredients fed to lambs in Experiment 2. Lambs were fed between 0 and 75% sericea lespedeza (SL) leaf meal (n = 8/diet). Molasses was sprayed on SL diets after mixing to increase palatability. Feed provided 15% crude protein (dry matter basis).
SL leaf meal Corn Alfalfa pellets Soybean meal Bermudagrass hay
0% SL
25% SL
50% SL
75% SL
0 10.0 75.0 0.0 15.0
25.2 7.5 49.9 1.0 16.5
50.3 5.0 24.9 1.5 18.4
75.3 4.9 0.0 2.5 17.3
2.2. Experiment 2. Dose titration in wool breed lambs Experiment 2 was conducted at Louisiana State University School of Veterinary Medicine, Baton Rouge, LA. Gulf Coast Native × Suffolk crossbred lambs of mixed gender were 6–7 months of age when the study was initiated in August (late summer). Lambs were dewormed 49 days before the study began. Two weeks later, lambs were inoculated with approximately 5000 H. contortus infective larvae (L3). After allowing five weeks for the infection to mature, the lambs were blocked by gender and fecal egg counts (FEC) and randomly assigned to a mixed ration containing 0, 25, 50, or 75% SL leaf meal (n = 8 per diet; 1 group/diet). Animals were housed in covered concrete pens bedded with wood shavings. Prior to the start of the study, lambs were fed bermudagrass hay and a commercial feed (Purina Lamb Chow Ration, 16% crude protein; Purina Mills, St. Louis, MO). At the start of the trial (day 0), experimental diets were fed once daily in the morning and bermudagrass hay was fed in the evening (Table 2) for 35 days. The mixed ration was formulated to be 15% CP and 61% TDN. During the first 7 days it was noted that the 75% group was consuming little of the SL diet. In addition, the daily 75% SL feed refusals were inadvertently fed to the control group during this time. 2.3. Experiment 3. Dose titration in meat goat kids Experiment 3 was conducted at the University of Maryland Eastern Shore in Princess Anne, MD, in July (summer). Naturally GIN infected, mixed gender Boer crossbred meat goat kids at 6–8 months of age and approximately 22 kg body weight were used. Goats were removed from pasture and placed in individual pens with concrete-slatted or expanded metal flooring. Animals were stratified by sex and randomly allotted to treatments of 0, 20, 40, or 60% SL (n = 13, 9, 13 and 12 goats/treatment, respectively). Diets were mixed to be an average of 15% CP and 46% TDN using commercial alfalfa pellets and/or whole plant pelleted SL (same used in Exp. 1), commercial goat pellets (Southern States 15% Meat Goat Feed, Medicated with Decoquinate; Richmond, VA) and urea along with a commercial sheep mineral (Southern States, Richmond, VA) and ammonium chloride (Table 3). Pre-mixed rations were fed twice daily beginning at 2% body weight and increased over time as unconsumed feed was visually 20% or less of the ration at each feeding. Feed refused was weighed (and discarded) on days 7, 14, 21 and 28 to determine intake. Body weights were measured and recorded on all sampling dates.
The mean FEC (P = 0.26; Table 4) and PCV (P = 0.26) were similar between treatments and there was no interaction with time. The FEC of the Dorper × St. Croix lambs were less than that of the Dorper × Katahdin (1652 ± 124 < 2102 ± 183; P = 0.04), but PCV was similar (P = 0.42).
0.5 0.4 0.5 0.4 ± ± ± ± 29.5x 31.7y 32.1y 30.1x ± ± ± ± 35.0 33.6 34.6 34.3
0.7 0.4 0.4 0.4
29.7 28.6 29.3 28.8 ± ± ± ±
0.4 (30.0 ± 0.4) 0.4 (28.9 ± 0.4) 0.4 (29.7 ± 0.4) 0.4
Exp. 3a
265 216 229 188 ± ± ± ± Least square means within column are different when superscript letters differ (P < 0.01).
3.1. Experiment 1. Hair breed lambs
a
3. Results
2097 2179 1685 1709
Data were analyzed using the mixed models procedure (SAS Inst. Inc., Cary, NC; version 9.1). The mathematical model used for the analysis of FEC and PCV included dietary treatment (SL dose), breed (Experiment 1), day, interactions if significant, and a repeated statement for day of measurement (Littell et al., 1996). An autoregressive covariance structure was used in Experiments 1 and 3, and unstructured was the best fit in Experiment 2. Replicate was not significant in Experiment 1 and omitted from the model. The FEC data were log transformed, ln(FEC + 1). Statistical inferences were made on log transformed data, but least squares means and standard errors were reported as untransformed data. Means were separated using the PDIFF procedure if treatment effects were significant (P < 0.05). In Experiment 2, analyses were conducted with and without the 75% SL diet because of the reduction in intake in this group. In Experiments 2 and 3, initial PCV for the treatment groups was used as a covariate (P < 0.001). In Experiments 1 and 3, initial FEC were used as a covariate (P < 0.001).
287 (3861 ± 284) 287 (3029 ± 284) 287 (3023 ± 284) 287
2.5. Statistical analysis
± ± ± ±
In all experiments, on day 0 and every 7 days thereafter, feces were collected directly from the rectum of individual animals to determine FEC according to Whitlock (1948; sensitivity of 50 eggs/g) and blood was collected from the jugular vein to determine blood packed cell volume (PCV). In Experiment 2, feces not used for FEC were pooled in each treatment and cultured in duplicate to identify GIN species. Coproculture was also conducted for Experiment 3 at the end of the study using feces collected from individual animals, pooled by treatment and cultured in duplicates.
3921 3082 3118 3249
2.4. Blood and fecal sampling procedures and analysis
243 200 200 201
a Southern States 15% Meat Goat Feed, Medicated; coccidiostat medication; Richmond, VA. b Southern States, Richmond, VA.
± ± ± ±
60.0 21.0 14.0 1.5 1.0 2.5
1905 2493 1465 1644
40.0 17.5 38.1 0.9 1.0 2.5
0 25 (or 20, Exp. 3) 50 (or 40, Exp. 3) 75 (or 60, Exp. 3)
20.0 13.0 63.0 0.5 1.0 2.5
Exp. 2
0.0 5.5 91.0 0.0 1.0 2.5
Exp. 1
SL pellets Goat feeda Alfalfa pellets Urea Ammonium chloride Mineral mixb
PCV (%)
60% SL
Exp. 3
40% SL
Exp. 2
20% SL
Exp. 1
0% SL
FEC (eggs/g)
Ingredient (% as fed)
347
SL in diet (%)
Table 3 Percent dietary ingredients fed to goats in Experiment 3. Goats were fed 0–60% sericea lespedeza (SL) pellets. Feed provided 15% crude protein (dry matter basis).
Table 4 Least square means and standard error of fecal egg counts (FEC) and packed cell volume (PCV) in lambs consuming 0, 25, 50, or 75% sericea lespedeza (SL) in Experiments 1 (P > 0.10 for each response variable) and 2 (P > 0.10 for each response variable, except for FEC model without 75% SL group in Exp. 2, P = 0.09), and goat kids consuming 0, 20, 40, or 60% SL in Experiment 3 (FEC, P = 0.05; PCV, P < 0.001). Means are presented for statistical model with and without (in parentheses) the 75% SL for Exp 2.
J.M. Burke et al. / Veterinary Parasitology 181 (2011) 345–349
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J.M. Burke et al. / Veterinary Parasitology 181 (2011) 345–349
3.2. Experiment 2. Wool breed lambs H. contortus was the predominant GIN present (97–99%) followed by Trichostrongylus spp. (1–3%) and was similar among groups. The FEC were not influenced by treatment (P = 0.23; Table 4), and there was no diet by time interaction. When the 75% SL group was omitted from the model because of reduced feed intake by this group, diet tended to influence FEC (P = 0.09; Table 4), but not PCV (P = 0.11). Feed intake was observed to be lower in the 75% group during the first 14 days of the trial, but increased to approximately 95% or greater thereafter, which was similar to the other groups. 3.3. Experiment 3. Meat goat kids In goats, FEC were influenced by treatment (P = 0.05) with kids fed 60% SL having lower (P < 0.03) FEC than those fed both 0 and 20% SL, and those fed 40% SL having intermediate FEC (Table 4). Untransformed means were presented in Table 4; log transformed means were 7.35 ± 0.14, 7.29 ± 0.11, 7.09 ± 0.11, 6.97 ± 0.09 eggs/g for the 0, 20, 40, and 60% SL fed groups, respectively. There was a linear relationship between percent SL in diet and log transformed FEC (y = 7.37 − (6.7 × 10−3 )x, where y = log FEC and x = % SL in diet; R2 = 0.03; P < 0.01). This was equivalent to approximately 150 fewer eggs/g for every 20% increase in SL pellets fed. The PCV was reduced by SL feeding (P < 0.001), but the regression was not significant. Larval speciation at study end indicated that feces from control animals produced 43% H. contortus larvae while 20, 40 and 60% SL resulted in 39%, 35% and 31% H. contortus larvae, respectively. Remaining GIN were primarily Trichostrongylus spp. Feed intake (734 ± 16 g/day; P = 0.90), approximately 3.3% of body weight, and body weight (22.5 ± 0.8 kg on day 0 and 23.0 ± 0.9 kg on day 28; P = 0.18) were not influenced by treatment.
southeast is H. contortus, the animals in Experiment 1 and 3 were not exhibiting symptoms of haemonchosis. Because these were short term experiments, it was not surprising that PCV was not influenced by diet, especially in animals with relatively high PCV. This indicates a greater tolerance to GIN which could have occurred with the high quality of the diets offered (Coop and Holmes, 1996; Coop and Kyriazakis, 1999). The linear reduction in FEC associated with increasing SL in the diet in Experiment 3 differs from Terrill et al. (2007), in which SL whole plant ground hay fed at both 50 and 75% of the diet reduced FEC in goats while the 25% SL hay diet did not. Lower FEC were also noted by Shaik et al. (2006) in goats artificially infected with H. contortus and fed 75% SL hay. 5. Conclusion Although the feeding of SL did not have consistent effects in these studies, it has been shown in other trials to effectively reduce FEC, especially in animals with a primarily H. contortus infection. The results of this study indicate that additional research is needed, especially in determining why SL may fail to reduce FEC in a H. contortus dominant infection. Acknowledgements This research was supported in part by USDA Sustainable Agriculture Research and Education (SARE) program (Project No. LS05-177). Authors are grateful for the assistance of J. Cherry, G. Robson, D. Disney, and R. Stengel (Booneville, AR), as well as L. Davis and G.L. Summers (NC A&T SU) and staff at LSU. Mention of trade names or commercial products in this manuscript is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.
4. Discussion References The purpose of these experiments was to determine the effects of SL fed at varying percentages of the diet on GIN infection in lambs and kids. In lambs, SL did not reduce FEC (Experiments 1 and 2), though there was a tendency for reduction in lambs in Experiment 2 when the 75% treatment was dropped. In goats, there was a dose response to SL fed, but no diet by time interaction (Experiment 3). Sericea lespedeza hay has been shown to be effective in controlling H. contortus infection in sheep, reducing FEC and worm burden (Lange et al., 2006). In a previous study, FEC were not reduced in lambs grazing SL mixed with grass compared with lambs grazing pastures without SL (Burke, unpublished data). This was attributed to lambs not consuming the forage. Alternatively, there may be unknown factors involved precluding efficacy of SL on FEC reduction in sheep. The metabolism differs between sheep and goats and could account for the apparent differences in response to SL on worm infection. Sericea lespedeza reduces egg production of H. contortus, but not intestinal species of GIN (Shaik et al., 2006; Terrill et al., 2009). Although the primary GIN in the
Burke, J.M., Miller, J.E., Terrill, T.H., 2009. Impact of rotational grazing on management of gastrointestinal nematodes in weaned lambs. Vet. Parasitol. 163, 67–72. Coop, R.L., Holmes, P.H., 1996. Nutrition and parasite interaction. Int. J. Parasitol. 26, 951–962. Coop, R.L., Kyriazakis, I., 1999. Nutrition–parasite interaction. Vet. Parasitol. 84, 187–204. Howell, S.B., Burke, J.M., Miller, J.E., Terrill, T.H., Valencia, E., Williams, M.J., Williamson, L.H., Zajac, A.M., Kaplan, R.M., 2008. Prevalence of anthelmintic resistance on sheep and goat farms in the southeastern United States. J. Am. Vet. Med. Assoc. 233, 1913–1919. Iqbal, Z., Sarwar, M., Jabbar, A., Ahmed, S., Nisa, M., Sajid, M.S., Khan, M.N., Mufti, K.A., Yaseen, M., 2007. Direct and indirect anthelmintic effects of condensed tannins in sheep. Vet. Parasitol. 144, 125–131. Kaplan, R.M., Burke, J.M., Howell, S.B., Rocconi, J.R., 2005. Total anthelmintic failure on a meat goat farm in Arkansas, USA. In: American Association of Veterinary Parasitologists, 50th Annual Meeting , Minneapolis, MN. Lange, K.C., Olcott, D.D., Miller, J.E., Mosjidis, J.A., Terrill, T.H., Burke, J.M., Kearney, M.T., 2006. Effect of sericea lespedeza (Lespedeza cuneata) fed as hay, on natural and experimental Haemonchus contortus infection in lambs. Vet. Parasitol. 141, 273–278. Littell, R.C., Milliken, G.A., Stroup, W.W., Wolfinger, R.D., 1996. SAS System for Mixed Models. SAS Institute Inc., Cary, NC. Min, B.R., Hart, S.P., Miller, D., Tomita, G.M., Loetz, E., Sahlu, T., 2005. The effect of grazing forage containing condensed tannins on
J.M. Burke et al. / Veterinary Parasitology 181 (2011) 345–349 gastro-intestinal parasite infection and milk composition in Angora does. Vet. Parasitol. 130, 105–113. Min, B.R., Pomroy, W.E., Hart, S.P., Sahlu, T., 2004. The effect of short-term consumption of a forage containing condensed tannins on gastrointestinal nematode parasite infections in grazing wether goats. Small Ruminant Res. 51, 279–283. National Research Council, 2007. Nutrient Requirements of Small Ruminants: Sheep, Goats, Cervids, and New World Camelids. National Academies Press, Washington, DC. Niezen, J.H., Robertson, H.A., Waghorn, G.C., Charleston, W.A.G., 1998. Production, faecal egg counts and worm burdens of ewe lambs which grazed six contrasting forages. Vet. Parasitol. 80, 15–27. Paolini, V., Bergeaud, J.P., Grisez, C., Prevot, F., Dorchies, Ph., Hoste, H., 2003. Effects of condensed tannins on goats experimentally infected with Haemonchus contortus. Vet. Parasitol. 113, 253–261.
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Shaik, S.A., Terrill, T.H., Miller, J.E., Kouakou, B., Kannan, G., Kaplan, R.M., Burke, J.M., Mosjidis, J.A., 2006. Sericea lespedeza hay as a natural deworming agent against gastrointestinal nematode infection in goats. Vet. Parasitol. 139, 150–157. Terrill, T.H., Dykes, G.S., Shaik, S.A., Miller, J.E., Kouakou, B., Kannan, G., Burke, J.M., Mosjidis, J.A., 2009. Efficacy of sericea lespedeza hay as a natural dewormer in goats: dose titration study. Vet. Parasitol. 163, 52–56. Terrill, T.H., Mosjidis, J.A., Moore, D.A., Shaik, S.A., Miller, J.E., Burke, J.M., Muir, J.P., Wolfe, R., 2007. Effect of pelleting on efficacy of sericea lespedeza hay as a natural dewormer in goats. Vet. Parasitol. 146, 117–122. Whitlock, H.V., 1948. Some modifications of the McMaster helminth egg-counting technique apparatus. J. Counc. Sci. Ind. Res. 21, 177–180.
Contents lists available at ScienceDirect
Veterinary Parasitology journal homepage: www.elsevier.com/locate/vetpar
Short communication
Dose titration of sericea lespedeza leaf meal on Haemonchus contortus infection in lambs and kids J.M. Burke a,∗ , N.C. Whitley b , D.A. Pollard c , J.E. Miller c , T.H. Terrill d , K.E. Moulton b , J.A. Mosjidis e a b c d e
Dale Bumpers Small Farms Research Center, USDA, ARS, Booneville, AR 72927, USA North Carolina A&T State University, Cooperative Extension, PO Box 21928, Greensboro, NC 27420, USA Louisiana State University, Baton Rouge, LA 70803, USA Fort Valley State University, Fort Valley, GA 31030, USA Auburn University, Auburn, AL 36849, USA
a r t i c l e
i n f o
Article history: Received 11 January 2011 Received in revised form 28 April 2011 Accepted 3 May 2011 Keywords: Condensed tannins Gastrointestinal nematodes Goats Lambs Sericea lespedeza
a b s t r a c t The objective of three experiments was to determine the impact of supplementing sericea lespedeza (Lespedeza cuneata; SL) in three concentrations in a loose or pelleted diet on gastrointestinal nematodes (GIN) in small ruminants. Experiments on lambs were conducted at the USDA, Agricultural Research Service in Booneville, AR (Exp. 1) and at Louisiana State University in Baton Rouge, LA (Exp. 2); an experiment on goat kids occurred at University of Maryland-Eastern Shore (Exp. 3). Exp. 1 used crossbred hair sheep lambs naturally infected with GIN that were randomly allocated to diets containing 0, 25, 50, and 75% SL diets (n = 11 or 12/diet). Exp. 2 consisted of Haemonchus contortus-inoculated crossbred wool breed lambs that were blocked by gender and FEC and randomly assigned to 0, 25, 50, or 75% SL diet (n = 8/diet). Fecal egg counts (FEC) and blood packed cell volume (PCV) were not influenced by SL supplementation in Exp. 1 and 2. Exp. 3 consisted of naturally GIN infected Boer crossbred goat kids in individual pens. Kids were blocked by FEC and randomly allotted to treatments of 0, 20, 40, or 60% SL with 9–13 goats/diet. The more SL fed, the greater the reduction in FEC (P < 0.001). There was an increase in PCV in SL fed goats (P < 0.001). Larval speciation at the end of the experiment indicated that feces from control animals produced 43% H. contortus larva while 20, 40 and 60% SL resulted in 39%, 35% and 31% H. contortus larvae, respectively. Feeding dried SL may be less effective in lambs than kids, though concurrent studies must be conducted to confirm this. Published by Elsevier B.V.
1. Introduction Gastrointestinal nematodes (GIN) infect ruminants worldwide and result in major production losses in small ruminants. Haemonchus contortus is the most prevalent and pathogenic in warm, humid climates of the US and worldwide. Anthelmintics were used almost exclusively to control GIN infection over the past few decades, result-
∗ Corresponding author. Tel.: +1 479 675 3834; fax: +1 479 675 2940. E-mail address: [email protected] (J.M. Burke). 0304-4017/$ – see front matter. Published by Elsevier B.V. doi:10.1016/j.vetpar.2011.05.005
ing in a high level of anthelmintic resistance. Complete anthelmintic failure has been reported on some farms and may be widespread in the southeastern U.S. (Kaplan et al., 2005; Howell et al., 2008). Condensed tannin-containing plants may be an option for controlling GIN (Niezen et al., 1998; Paolini et al., 2003; Min et al., 2004; Iqbal et al., 2007). Sericea lespedeza (Lespedeza cuneata; SL) is a legume that contains condensed tannins and grows in the southeastern U.S. Sericea lespedeza has been at the forefront of current condensed tannin research in the U.S. for control of GIN, where grazing or feeding hay or pellets has been shown to reduce
346
J.M. Burke et al. / Veterinary Parasitology 181 (2011) 345–349
Table 1 Percent dietary ingredients (dry matter basis) fed to lambs in Experiment 1. Lambs were fed between 0 and 75% sericea lespedeza (SL) pellets (n = 11 or 12/diet).
a
Corn/soybean meal mix Alfalfa pelletsb Sericea lespedeza pellets Soy hull pellets Estimated crude protein
0% SL
25% SL
50% SL
75% SL
17.1 38.1 0 44.8 13.81
16.4 29.1 25.0 29.5 13.59
17.2 18.7 50.0 14.1 13.34
17.0 3.4 74.6 5.0 12.82
a 78% corn, 18% soybean meal, 3.5% molasses, 0.007% calcium carbonate (14% CP, dry matter basis). b 14% crude protein, dry matter basis.
fecal egg counts (FEC), reduce worm burdens and, in some cases, negatively affect larval development and survival in the feces (Min et al., 2005; Lange et al., 2006; Shaik et al., 2006; Terrill et al., 2007). Use of dry SL products would be beneficial when SL cannot be planted or grown; however, the optimal level of SL intake required to aid in the control of GIN infection has not been determined. Therefore, the objective of the current experiments was to examine the effect of increasing levels of SL on GIN infection in sheep and goats.
2. Materials and methods All animal-related procedures were approved by the Animal Care and Use Committee of each research institution.
2.1. Experiment 1. Dose titration in hair breed lambs Experiment 1 was conducted at the USDA, Agricultural Research Service, Dale Bumpers Small Farms Research Station, Booneville, AR, in June (early summer). Dorper × St. Croix (n = 32) or Dorper × Katahdin (n = 15) crossbred, mixed gender lambs at approximately 3 months of age and 28 kg body weight were used. All animals were naturally infected through grazing contaminated pastures with their dams before the experiment began. Lambs were housed in concrete floor pens in an open sided barn. Body weights were determined on days 0 (first day of experimental diet) and 28 (last day). Coprocultures were not conducted, but the predominant GIN found in grazing lambs on a concurrent study on the same farm was H. contortus (Burke et al., 2009). Lambs were blocked by breed and gender and assigned randomly to four treatment groups (n = 11/control group; n = 12/SL groups; two pens/diet). Lambs were fed approximately 4.3% body weight to meet nutritional requirements (NRC, 2007) for 28 days once per day in the morning. Lambs consumed all feed offered. Diets consisted of 0, 25, 50 or 75% SL whole hay pellets as a percentage of a complete ration (Table 1) that was mixed to be approximately 14% crude protein (CP) and 55% total digestible nutrients (TDN). Trace mineralized salt (Land O’Lakes Sheep and Goat Mineral, Shoreview, MN) and water was provided free choice.
Table 2 Percent dietary ingredients fed to lambs in Experiment 2. Lambs were fed between 0 and 75% sericea lespedeza (SL) leaf meal (n = 8/diet). Molasses was sprayed on SL diets after mixing to increase palatability. Feed provided 15% crude protein (dry matter basis).
SL leaf meal Corn Alfalfa pellets Soybean meal Bermudagrass hay
0% SL
25% SL
50% SL
75% SL
0 10.0 75.0 0.0 15.0
25.2 7.5 49.9 1.0 16.5
50.3 5.0 24.9 1.5 18.4
75.3 4.9 0.0 2.5 17.3
2.2. Experiment 2. Dose titration in wool breed lambs Experiment 2 was conducted at Louisiana State University School of Veterinary Medicine, Baton Rouge, LA. Gulf Coast Native × Suffolk crossbred lambs of mixed gender were 6–7 months of age when the study was initiated in August (late summer). Lambs were dewormed 49 days before the study began. Two weeks later, lambs were inoculated with approximately 5000 H. contortus infective larvae (L3). After allowing five weeks for the infection to mature, the lambs were blocked by gender and fecal egg counts (FEC) and randomly assigned to a mixed ration containing 0, 25, 50, or 75% SL leaf meal (n = 8 per diet; 1 group/diet). Animals were housed in covered concrete pens bedded with wood shavings. Prior to the start of the study, lambs were fed bermudagrass hay and a commercial feed (Purina Lamb Chow Ration, 16% crude protein; Purina Mills, St. Louis, MO). At the start of the trial (day 0), experimental diets were fed once daily in the morning and bermudagrass hay was fed in the evening (Table 2) for 35 days. The mixed ration was formulated to be 15% CP and 61% TDN. During the first 7 days it was noted that the 75% group was consuming little of the SL diet. In addition, the daily 75% SL feed refusals were inadvertently fed to the control group during this time. 2.3. Experiment 3. Dose titration in meat goat kids Experiment 3 was conducted at the University of Maryland Eastern Shore in Princess Anne, MD, in July (summer). Naturally GIN infected, mixed gender Boer crossbred meat goat kids at 6–8 months of age and approximately 22 kg body weight were used. Goats were removed from pasture and placed in individual pens with concrete-slatted or expanded metal flooring. Animals were stratified by sex and randomly allotted to treatments of 0, 20, 40, or 60% SL (n = 13, 9, 13 and 12 goats/treatment, respectively). Diets were mixed to be an average of 15% CP and 46% TDN using commercial alfalfa pellets and/or whole plant pelleted SL (same used in Exp. 1), commercial goat pellets (Southern States 15% Meat Goat Feed, Medicated with Decoquinate; Richmond, VA) and urea along with a commercial sheep mineral (Southern States, Richmond, VA) and ammonium chloride (Table 3). Pre-mixed rations were fed twice daily beginning at 2% body weight and increased over time as unconsumed feed was visually 20% or less of the ration at each feeding. Feed refused was weighed (and discarded) on days 7, 14, 21 and 28 to determine intake. Body weights were measured and recorded on all sampling dates.
The mean FEC (P = 0.26; Table 4) and PCV (P = 0.26) were similar between treatments and there was no interaction with time. The FEC of the Dorper × St. Croix lambs were less than that of the Dorper × Katahdin (1652 ± 124 < 2102 ± 183; P = 0.04), but PCV was similar (P = 0.42).
0.5 0.4 0.5 0.4 ± ± ± ± 29.5x 31.7y 32.1y 30.1x ± ± ± ± 35.0 33.6 34.6 34.3
0.7 0.4 0.4 0.4
29.7 28.6 29.3 28.8 ± ± ± ±
0.4 (30.0 ± 0.4) 0.4 (28.9 ± 0.4) 0.4 (29.7 ± 0.4) 0.4
Exp. 3a
265 216 229 188 ± ± ± ± Least square means within column are different when superscript letters differ (P < 0.01).
3.1. Experiment 1. Hair breed lambs
a
3. Results
2097 2179 1685 1709
Data were analyzed using the mixed models procedure (SAS Inst. Inc., Cary, NC; version 9.1). The mathematical model used for the analysis of FEC and PCV included dietary treatment (SL dose), breed (Experiment 1), day, interactions if significant, and a repeated statement for day of measurement (Littell et al., 1996). An autoregressive covariance structure was used in Experiments 1 and 3, and unstructured was the best fit in Experiment 2. Replicate was not significant in Experiment 1 and omitted from the model. The FEC data were log transformed, ln(FEC + 1). Statistical inferences were made on log transformed data, but least squares means and standard errors were reported as untransformed data. Means were separated using the PDIFF procedure if treatment effects were significant (P < 0.05). In Experiment 2, analyses were conducted with and without the 75% SL diet because of the reduction in intake in this group. In Experiments 2 and 3, initial PCV for the treatment groups was used as a covariate (P < 0.001). In Experiments 1 and 3, initial FEC were used as a covariate (P < 0.001).
287 (3861 ± 284) 287 (3029 ± 284) 287 (3023 ± 284) 287
2.5. Statistical analysis
± ± ± ±
In all experiments, on day 0 and every 7 days thereafter, feces were collected directly from the rectum of individual animals to determine FEC according to Whitlock (1948; sensitivity of 50 eggs/g) and blood was collected from the jugular vein to determine blood packed cell volume (PCV). In Experiment 2, feces not used for FEC were pooled in each treatment and cultured in duplicate to identify GIN species. Coproculture was also conducted for Experiment 3 at the end of the study using feces collected from individual animals, pooled by treatment and cultured in duplicates.
3921 3082 3118 3249
2.4. Blood and fecal sampling procedures and analysis
243 200 200 201
a Southern States 15% Meat Goat Feed, Medicated; coccidiostat medication; Richmond, VA. b Southern States, Richmond, VA.
± ± ± ±
60.0 21.0 14.0 1.5 1.0 2.5
1905 2493 1465 1644
40.0 17.5 38.1 0.9 1.0 2.5
0 25 (or 20, Exp. 3) 50 (or 40, Exp. 3) 75 (or 60, Exp. 3)
20.0 13.0 63.0 0.5 1.0 2.5
Exp. 2
0.0 5.5 91.0 0.0 1.0 2.5
Exp. 1
SL pellets Goat feeda Alfalfa pellets Urea Ammonium chloride Mineral mixb
PCV (%)
60% SL
Exp. 3
40% SL
Exp. 2
20% SL
Exp. 1
0% SL
FEC (eggs/g)
Ingredient (% as fed)
347
SL in diet (%)
Table 3 Percent dietary ingredients fed to goats in Experiment 3. Goats were fed 0–60% sericea lespedeza (SL) pellets. Feed provided 15% crude protein (dry matter basis).
Table 4 Least square means and standard error of fecal egg counts (FEC) and packed cell volume (PCV) in lambs consuming 0, 25, 50, or 75% sericea lespedeza (SL) in Experiments 1 (P > 0.10 for each response variable) and 2 (P > 0.10 for each response variable, except for FEC model without 75% SL group in Exp. 2, P = 0.09), and goat kids consuming 0, 20, 40, or 60% SL in Experiment 3 (FEC, P = 0.05; PCV, P < 0.001). Means are presented for statistical model with and without (in parentheses) the 75% SL for Exp 2.
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3.2. Experiment 2. Wool breed lambs H. contortus was the predominant GIN present (97–99%) followed by Trichostrongylus spp. (1–3%) and was similar among groups. The FEC were not influenced by treatment (P = 0.23; Table 4), and there was no diet by time interaction. When the 75% SL group was omitted from the model because of reduced feed intake by this group, diet tended to influence FEC (P = 0.09; Table 4), but not PCV (P = 0.11). Feed intake was observed to be lower in the 75% group during the first 14 days of the trial, but increased to approximately 95% or greater thereafter, which was similar to the other groups. 3.3. Experiment 3. Meat goat kids In goats, FEC were influenced by treatment (P = 0.05) with kids fed 60% SL having lower (P < 0.03) FEC than those fed both 0 and 20% SL, and those fed 40% SL having intermediate FEC (Table 4). Untransformed means were presented in Table 4; log transformed means were 7.35 ± 0.14, 7.29 ± 0.11, 7.09 ± 0.11, 6.97 ± 0.09 eggs/g for the 0, 20, 40, and 60% SL fed groups, respectively. There was a linear relationship between percent SL in diet and log transformed FEC (y = 7.37 − (6.7 × 10−3 )x, where y = log FEC and x = % SL in diet; R2 = 0.03; P < 0.01). This was equivalent to approximately 150 fewer eggs/g for every 20% increase in SL pellets fed. The PCV was reduced by SL feeding (P < 0.001), but the regression was not significant. Larval speciation at study end indicated that feces from control animals produced 43% H. contortus larvae while 20, 40 and 60% SL resulted in 39%, 35% and 31% H. contortus larvae, respectively. Remaining GIN were primarily Trichostrongylus spp. Feed intake (734 ± 16 g/day; P = 0.90), approximately 3.3% of body weight, and body weight (22.5 ± 0.8 kg on day 0 and 23.0 ± 0.9 kg on day 28; P = 0.18) were not influenced by treatment.
southeast is H. contortus, the animals in Experiment 1 and 3 were not exhibiting symptoms of haemonchosis. Because these were short term experiments, it was not surprising that PCV was not influenced by diet, especially in animals with relatively high PCV. This indicates a greater tolerance to GIN which could have occurred with the high quality of the diets offered (Coop and Holmes, 1996; Coop and Kyriazakis, 1999). The linear reduction in FEC associated with increasing SL in the diet in Experiment 3 differs from Terrill et al. (2007), in which SL whole plant ground hay fed at both 50 and 75% of the diet reduced FEC in goats while the 25% SL hay diet did not. Lower FEC were also noted by Shaik et al. (2006) in goats artificially infected with H. contortus and fed 75% SL hay. 5. Conclusion Although the feeding of SL did not have consistent effects in these studies, it has been shown in other trials to effectively reduce FEC, especially in animals with a primarily H. contortus infection. The results of this study indicate that additional research is needed, especially in determining why SL may fail to reduce FEC in a H. contortus dominant infection. Acknowledgements This research was supported in part by USDA Sustainable Agriculture Research and Education (SARE) program (Project No. LS05-177). Authors are grateful for the assistance of J. Cherry, G. Robson, D. Disney, and R. Stengel (Booneville, AR), as well as L. Davis and G.L. Summers (NC A&T SU) and staff at LSU. Mention of trade names or commercial products in this manuscript is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture.
4. Discussion References The purpose of these experiments was to determine the effects of SL fed at varying percentages of the diet on GIN infection in lambs and kids. In lambs, SL did not reduce FEC (Experiments 1 and 2), though there was a tendency for reduction in lambs in Experiment 2 when the 75% treatment was dropped. In goats, there was a dose response to SL fed, but no diet by time interaction (Experiment 3). Sericea lespedeza hay has been shown to be effective in controlling H. contortus infection in sheep, reducing FEC and worm burden (Lange et al., 2006). In a previous study, FEC were not reduced in lambs grazing SL mixed with grass compared with lambs grazing pastures without SL (Burke, unpublished data). This was attributed to lambs not consuming the forage. Alternatively, there may be unknown factors involved precluding efficacy of SL on FEC reduction in sheep. The metabolism differs between sheep and goats and could account for the apparent differences in response to SL on worm infection. Sericea lespedeza reduces egg production of H. contortus, but not intestinal species of GIN (Shaik et al., 2006; Terrill et al., 2009). Although the primary GIN in the
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J.M. Burke et al. / Veterinary Parasitology 181 (2011) 345–349 gastro-intestinal parasite infection and milk composition in Angora does. Vet. Parasitol. 130, 105–113. Min, B.R., Pomroy, W.E., Hart, S.P., Sahlu, T., 2004. The effect of short-term consumption of a forage containing condensed tannins on gastrointestinal nematode parasite infections in grazing wether goats. Small Ruminant Res. 51, 279–283. National Research Council, 2007. Nutrient Requirements of Small Ruminants: Sheep, Goats, Cervids, and New World Camelids. National Academies Press, Washington, DC. Niezen, J.H., Robertson, H.A., Waghorn, G.C., Charleston, W.A.G., 1998. Production, faecal egg counts and worm burdens of ewe lambs which grazed six contrasting forages. Vet. Parasitol. 80, 15–27. Paolini, V., Bergeaud, J.P., Grisez, C., Prevot, F., Dorchies, Ph., Hoste, H., 2003. Effects of condensed tannins on goats experimentally infected with Haemonchus contortus. Vet. Parasitol. 113, 253–261.
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