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Although goat meat production could be an option for diversification in improved upland pastures in northern Spain, precise information on the optimal grazing management to enhance goat performance and maximize production per unit land area is lacking. The objective of this study was to compare the effects of 3 stocking rates, high stocking rate (HSR; 20 goats/ha), medium stocking rate (MSR; 15 goats/ ha), and low stocking rate (LSR; 10 goats/ha), on gastrointestinal (GI) nematode infections and productive responses of Cashmere goats grazing such pastures. Treatments were replicated twice on 6 paddocks sown with Lolium perenne and Trifolium repens and with a high presence of the native grass Agrostis capillaris. The experiment lasted 3 grazing seasons (from spring to autumn). Pastures were sampled for sward height and botanical and proximate composition. Body weight and BCS changes of goats were monitored and GI nematode infections were assessed by fecal egg counts (FEC). The established treatments resulted in lower mean sward height in the HSR than in the MSR and LSR (9.6, 11.5, and 14.4 cm, respectively; P < 0.001). Pasture botanical composition and nutritive quality did not differ between treatments. The mean FEC of does across the 3 grazing seasons were greater (P < 0.05) in the HSR than in the LSR. Trichostrongylus spp., Oesophagostomum columbianum, and Teladorsagia circumcincta were the most prevalent nematode species identified in coprocultures. Does showed more favorable (P < 0.001) BW and BCS changes in the LSR than in the MSR and HSR (-14, -30, and -52 g/d and -0.1, -0.3, and -0.7 BCS units [scale 1 to 5], respectively). Greater (P < 0.001) kids' BW gains were observed in the LSR and MSR (average 94 g/d) compared with the HSR (70 g/d). Inversely, kid output per unit land area was greater in the HSR than in the MSR and LSR (320, 258, and 192 kg·ha-1·yr-1, respectively; P < 0.001), whereas daily kids' BW gains per hectare were greater (P < 0.001) in the HSR and MSR (average 1.37 kg·d-1·ha-1) compared with the LSR (0.98 kg·d-1·ha-1). A medium stocking rate of 15 goats/ha could represent the best compromise between animal health, performance, and productivity per unit land area in this type of upland pastures, but stricter controls of parasite levels during the grazing season would be necessary to avoid production losses, unless alternative nutraceuticals are provided. [ABSTRACT FROM AUTHOR]

Abstract: This study was performed in Cashmere goats that were experimentally infected with Teladorsagia circumcincta to investigate the effects of heather consumption on the establishment of incoming infective larvae (experiment 1) and on an adult nematode population (experiment 2). In experiment 1, 24 non-lactating goats were divided into 2 groups: heather-supplemented vs. non-supplemented. After 2 weeks of adaptation to the diet, all of the goats were experimentally infected with 6000 infective larvae of T. circumcincta. Twelve animals (6 controls and 6 supplemented with heather) were slaughtered at 6 days and at 3 weeks post-infection (pi). After slaughter, the worms were counted and the female worm fecundity and development were determined. Heather consumption was associated with a significant reduction in larval establishment at 6 days (P =0.033) and at 3 weeks (P =0.041) pi. No differences in worm counts between the slaughter times were found. In the goats slaughtered at 3 weeks pi, the number of eggs in utero and length of the female worms were significantly (P <0.001) lower than those of control group. In experiment 2, 24 non-lactating goats were experimentally infected with 10,000 T. circumcincta infective larvae daily for 5 consecutive days (total infection of 50,000 larvae). After 3 weeks, 2 groups were established: control and heather-supplemented. The faecal egg output of each animal was measured at 2-days interval during the experimental period. The goats were slaughtered after 3 weeks of heather administration for parasitological studies. Heather administration was associated with a significant decrease in egg excretion between 25 and 29 days pi. The worm counts were similar in both groups, but the female length and fecundity were significantly (P <0.001) lower in supplemented goats. These results show that heather consumption reduces the establishment of T. circumcincta larvae in goats and the development and fecundity of female adult parasites. [Copyright &y& Elsevier]

Abstract: In the last decade, numerous studies have been carried out to evaluate the potential anthelmintic benefit of the consumption of bioactive plants in small ruminants, in order to reduce the dependence on conventional chemotherapy and supporting a sustainable control of gastrointestinal (GI) parasitism. This review summarizes the anthelmintic and nutritional effects of heather (shrub species belonging to the Ericaceae family, such as Erica spp. or Calluna vulgaris) supplementation in grazing goats naturally infected by GI nematodes. The experiments were carried out in a mountain area in north-western Spain where shrubby heather-gorse vegetation is dominant. Some plots were established, in which the vegetation had been improved by soil ploughed and dressing and sowing perennial ryegrass (Lolium perenne) and white clover (Trifolium repens), and removing any heather that was present. Cashmere goats reared outdoors under pasture conditions were used in the experiments. The trials compared the response to GI nematode infections, animal performance and nutrition in goats supplemented or not with heather. Interactions between heather availability and other alternative methods to control GI nematode infections based on grazing management (stocking rate) or nutrition (energy supply) as well as the potential adaptation of the rumen microbiota to the consumption of tannins, were also studied. The results suggest that (i) heather supplementation in grazing goats significantly reduces the level of GI nematode egg excretion, (ii) the faecal nematode egg count reduction could be associated with a decrease in worm fertility and/or reduction in the establishment of incoming third-stage larvae, (iii) consumption of heather is associated with an apparent greater resilience of goats to GI nematode infections, and (iv) the amount of tannins consumed by the goats supplemented with heather does not seem to be associated to anti-nutritional effects which eventually resulted in a better animal performance in the animals incorporating these shrubs in their diet. Practical application of this knowledge in temperate areas would support the management of plots integrating improved pastures with high nutritive value (ryegrass-white clover) with natural vegetation communities. [Copyright &y& Elsevier]