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* Grup de Recerca en Remugants, Departament de Ciència Animal i dels Aliments, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
E. (kika) de la Garza American Institute for Goat Research, Langston University, P.O. Box 730, Langston, OK 73050, USA
Abstract
A total of 295 goats from 4 breeds (Alpine, n = 74; Angora, n = 75; Boer-cross, n = 73; Spanish, n = 73) were used to assess the retention of 3 types of electronic ruminal boluses (B1, 20 g, n = 95; B2, 75 g, n = 100; and B3, 82 g, n = 100) according to breed and feeding conditions. Time for bolus administration, reading with a handheld reader, and animal data recording (goat ID, breed, and bolus type) were registered. Each goat was also identified with 1 flag-button plastic ear tag (4.6 g, 51 x 41 mm). Retention of boluses and ear tags was regularly monitored for 1 yr. Ruminal fluid in 5 goats from each breed and management group was obtained with an oro-ruminal probe at 2 h after feeding. Ruminal pH was measured at 24 h, and at wk 1, 2, 3 and 4, and used as an indicator of feeding conditions on rumen environment. Time for bolus administration differed by bolus type (B1, 14 ± 2 s; B2, 24 ± 2 s; B3, 27 ± 2 s; P < 0.05) and goat breed (Alpine, 34 ± 3 s; Angora, 17 ± 2 s; Boer-cross, 16 ± 1 s; Spanish, 19 ± 2 s; P < 0.05), although differences were due to greater times for B2 and B3 in Alpine goats. Time for bolus administration averaged 22 ± 1 s, and overall time for bolusing, reading, and data typing was 49 ± 1 s on average. Ruminal pH differed according to breed and feeding management (lactating Alpine, 6.50 ± 0.07; yearling Alpine, 6.73 ± 0.07; Angora, 6.34 ± 0.06; Boer-cross, 6.62 ± 0.04; Spanish, 6.32 ± 0.08; P < 0.05) but no early bolus losses occurred; rumen pH did not differ according to bolus type (B1, 6.45 ± 0.05; B2, 6.39 ± 0.07; B3, 6.49 ± 0.05; P > 0.05). At 6 mo, electronic boluses showed greater retention than ear tags (99.7% vs. 97.2%; P < 0.05). At 12 mo, bolus retention was 96.3, 100 and 97.8% for B1, B2 and B3, respectively, not differing between B1 and B3 (P = 0.562). No effect of breed and bolus type on bolus retention was detected. No goat losing, at the same time, both bolus and ear tag was observed. Ear tag retention (91.7%) was lower (P < 0.05) than all types of bolus (98.1%) on average. Ear tag retention in Boer-cross (98.6%) and Alpine (96.9%) goats was greater (P < 0.05) than in Spanish (88.7%) and Angora (82.9%), and tended to differ (P = 0.095) between Spanish and Alpine. In conclusion, unlike flag-button visual ear tags and mini-boluses used here, properly designed boluses (e.g. standard bolus) met ICAR and NAIS retention requirements for goat identification under US conditions, and are recommended in practice.
Key Words: ear tag electronic identification goat rumen bolus traceability transponder
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