Effects of heather (Ericaceae) supplementation on gastrointestinal nematodes and live weight changes in naturally-infected Cashmere goats managed under two different stocking rates

Abstract

The aim of this study, performed on 62 adult dry CAshmere goats grazing pernnial ryegrass-shite clover pastures and naturally-infected with gastrointestinal nematodes, was to investigate the effects of tannin-containing heather supplementation on faecal egg counts, parasite burden and body weight changes in goats managed under two different stocking rates. Goatas were randomly assigned to four treatmentes in a 2 x 2 factorial arrangement: two feeding treatments (supplementation with heather vs non-supplementation) and two stocking rates (24 vs 38 goats/ha). Six goats per treatment were slaughtered at the end of the grazing period, with adult worms in the abomasum and small and large intestines of each animal recovered, counted, and identified according to species. Results showed that goats gained significantly (P < 0.001) more body weight when supplemented with heather. Faecal egg counts were significantly (P < 0.01) affected by socking rate, however for heather supplementation, no differences were observed in goats under the lower stocking rate, but lower mean values were found throughout the experiment in the group receiving heather under the higher stocking rate (P = 0.07). Mean total abomasal worm counts of Teladorsagia circumcincta were lower in supplemented animals, but the difference was only significant (P < 0.01) in those managed under the higher stocking rate. In conclusion, although feeding heather to goats has the potential to contribute to the control of some abomasal nematode parasites, it could be dependent on grazing pressure and climatic conditions.