Effect of fall-grazed sericea lespedeza (Lespedeza cuneata) on gastrointestinal nematode infections of growing goats

Authors: MECHINENI, A - Fort Valley State University; KOMMURU, D - Fort Valley State University; GUJJA, S - Fort Valley State University; MOSJIDIS, J - Fort Valley State University; MILLER, J - Fort Valley State University; Burke, Joan; RAMSAY, A - University Of Reading; MUELLER-HARVEY, I - University Of Reading; KANNAN, G - Fort Valley State University; LEE, J - Fort Valley State University; KOUAKOU, B - Fort Valley State University; TERRILL, T - Fort Valley State University

Submitted to: Veterinary Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2014
Publication Date: 8/1/2014
Citation: Mechineni, A., Kommuru, D.S., Gujja, S., Mosjidis, J.A., Miller, J.E., Burke, J.M., Ramsay, A., Mueller-Harvey, I., Kannan, G., Lee, J.H., Kouakou, B., Terrill, T.H. 2014. Effect of fall-grazed sericea lespedeza (Lespedeza cuneata) on gastrointestinal nematode infections of growing goats. Veterinary Parasitology. 204:221-228. 10.1016/j.vetpar.2014.06.002.
DOI: https://doi.org/10.1016/j.vetpar.2014.06.002

Interpretive Summary: Sericea lespedea (SL), grazed or dried, has been used recently to aid in the control of internal parasites and coccidiosis in goats and sheep. Tannin-containing plants such as SL have also been shown to have potential beneficial nutritional and anti-microbial effects in the diet of ruminants, but little is known about anti-microbial effects of grazing goats on SL. Scientists at USDA, ARS in Booneville, AR, Louisiana State University, Fort Valley State University, GA, and Auburn University determined that feeding SL pellets had no effect on skin and carcass microbial loads and minimal effects on carcass quality of goats. This information is important to organic and conventional small ruminant producers, extension agents, and scientists.

Technical Abstract: Infection with gastrointestinal nematodes (GIN), particularly Haemonchus contortus, a highly pathogenic blood-feeder, has a major effect on profitability of goat production world-wide. High prevalence of anthelmintic-resistant GIN in goats has increased pressure to find effective, alternative non-synthetic control methods. One of these is feeding or grazing the high condensed tannin (CT)-containing forage legume sericea lespedeza [SL; Lespedeza cuneata (Dum.-Cours.) G. Don.]. This plant has potential to be productive during the late summer-autumn grazing season in the southern USA when perennial warm-season grass pastures are often low in quality. Tannin-containing plants have also been shown to have potential beneficial nutritional and anti-microbial effects in the diet of ruminants. A study was designed to determine the effects of autumn (September-November) grazing of SL pasture, bermudagrass [BG; Cynodon dactylon (L.) Pers.] pasture, or a combination of SL+BG pasture by naturally GIN-infected goats [intact male Spanish kids, 9 months old (20.7 +/- 1.1 kg), n = 10/treatment group] on GIN infections, carcass quality, and skin and carcass contamination with bacteria. Three grazing paddocks (0.40 ha) were set up at the Fort Valley State University Agricultural Research Station (Fort Valley, GA) for an 8-week trial. The goats in each paddock were supplemented with a commercial feed pellet at 0.454 kg/head/d for the first 4 weeks of the trial, and 0.272 kg/head/d for the final 4 weeks. Pasture samples were analyzed for crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) content, and a separate set of SL samples was analyzed for CT in leaves, stems, and whole plant using the benzyl mercaptan thiolysis method. Animal weights were taken at the start and end of the trial, and fecal and blood samples were collected weekly for determination of fecal egg counts (FEC) and packed cell volume (PCV), respectively. Adult GIN were recovered from the abomasum and small intestines of all goats at the end of the experiment for counting and speciation. Prior to slaughter, half the goats from each pasture treatment were subjected to 3 hours of transport stress. Skin and carcass swabs for estimation of microbial loads were taken at slaughter, and pH, color, and percentage cooking loss of Longissimus dorsi muscle (LM) of each goat were measured to determine effects on meat quality. The CP levels were highest for SL pasture, intermediate for SL+BG, and lowest for BG only pasture, while NDF and ADF values were the opposite, with highest levels in BG and lowest in SL pasture samples. Sericea lespedeza contains condensed tannins (CT) with a high percentage of prodelphinidins (PDs; 97%). These CT also have high molecular weights, with a mean degree of polymerization of 33, which is equivalent to 10,100 Daltons. Leaves had more CT than stems (16.0 vs 3.3 g/100 g dry weight), a slightly higher percentage of PDs (98 vs 94%) and cis-flavanols (91 vs 84%), and polymers of larger mean degrees of polymerization (42 vs 18). There were no differences in average daily gain or blood PCV between the pasture treatment groups, but SL-grazed goats had lower FEC (P < 0.05) than the BG or SL+BG-grazed goats throughout most of the trial. The SL+BG goats had lower FEC than the BG pasture animals by the end of the trial (week 8, P < 0.05). The SL goats had lower numbers (P < 0.05) of male H. contortus and tended to have fewer female (P <0.10) and total (P < 0.07) H. contortus compared with the BG goats. The predominant GIN in all the goats was Trichostrongylus colubriformis (73% of total GIN). Stress or pasture treatment had no effect on the goats' skin and carcass microbial loads and minimal effects on carcass quality. Autumn grazing of SL pasture reduced effects of GIN parasitism and gave comparable animal performance (including carcass qua