Effects of stocking rate and creep grazing on performance by Spanish and Boer × Spanish does with crossbred Boer kids

• Published in: Small ruminant research Vol. 71; no. 1; pp. 234 - 242
• Main Authors: Yiakoulaki, M.D., Goetsch, A.L., Detweiler, G., Sahlu, T.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2007
• Subjects: Creep grazing; Goats; Stocking rate; Goats; Stocking rate; Creep grazing
• ISSN: 0921-4488; 1879-0941
• DOI: 10.1016/j.smallrumres.2006.07.003

Twenty-six Spanish does with twin Boer × Spanish kids and 26 Boer × Spanish does with twin 3/4 Boer–1/4 Spanish kids were used in a 76-day experiment to determine effects of stocking rate (SR) and creep grazing on pre-weaning performance. The study commenced approximately 2 months after kidding. There were four treatments, three involving SR and one creep grazing, with two animal groups or replicates for each treatment (consisting of both genotype sets) per treatment. Groups had 4 does with 8 kids for the low SR (L), 6 does with 12 kids for a moderate SR (M), and 8 does with 16 kids for both the high SR (H) and creep grazing treatment (C). Groups grazed 0.4-ha pastures of various grasses and forbs, with the most prevalent forb being ragweed ( Ambrosia artemisifolia L.). Kids of C groups also had access to similar 0.4-ha pastures that contained the tree legume mimosa ( Albizia julibrissin Durazz). All pastures consisted of four equal size paddocks that were sequentially grazed twice by the same animal groups (i.e., phases 1 and 2 were 48 and 28 days in length, respectively). Post-grazing forage mass decreased linearly with increasing SR ( P < 0.01) (1902, 1454, 928, and 1150 kg/ha; S.E. = 51.2), and change in forage mass during the phases linearly increased ( P < 0.05) (1078, 1247, 1746, and 1493 kg/ha for L, M, H, and C, respectively; S.E. = 120.6). Change (pre-grazing–post-grazing %) during the experiment in the contribution of ragweed to the sward increased linearly with increasing SR ( P < 0.05) (−6, 12, 33, and 9% for L, M, H, and C, respectively; S.E. = 4.5). ADG by does (47, −16, −54, and −2 g/day; S.E. = 21.8) and kids (76, 61, 37, and 81 g/day; S.E. = 6.7) linearly decreased with increasing SR ( P < 0.03); however, kid BW gain per unit land area was similar among treatments (115, 138, 113, and 124 kg/ha for L, M, H, and C, respectively; S.E. = 21.7). Kid ADG was similar between genotypes but doe ADG differed ( P < 0.05) (−47 and 34 g/day for Spanish and Boer × Spanish, respectively; S.E. = 11.5). In conclusion, creep grazing with high SR for does can increase ADG of does and kids but not relative to lower SR for both does and kids. Spanish does with Boer × Spanish kids may be less able to maintain or increase BW while supporting kid growth compared with Boer × Spanish does.