| Abstrakt: |
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] |
