Extended field test on the use of visual ear tags and electronic boluses for the identification of different goat breeds in the United States.

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 identification, 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 less (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 International Committee for Animal Recording and National Animal Identification System retention requirements for goat identification under US conditions and are recommended in practice.