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Sixty growing 3/4 Boer x 1/4 Spanish (BS) and Spanish (SP) wethers were used to determine influences of diet and breed on growth and body composition. A pelleted 50% concentrate diet (CD) and a diet based on grass hay (HD) were fed for ad libitum intake. Six wethers of each breed were slaughtered at 0 wk (total of 12). Six wethers of each diet-breed combination were slaughtered at 14 and 28 wk (24 per time) after consumption of the CD or HD. Initial BW of fed wethers were 21.6 and 18.8 kg for BS and SP, respectively (SEM = 0.7). Average daily gain during the entire experiment was influenced by an interaction (P < 0.05) between breed and diet (199, 142, 44, and 50 g/d for BS:CD, SP:CD, BS:HD, and SP:HD, respectively). Carcass mass was greater (P < 0.05) for CD vs. HD (56.2, 56.2, 53.2, and 54.0% of empty BW for BS:CD, SP:CD, BS:HD, and SP:HD, respectively). Mass of the liver (2.11, 1.92, 2.00, and 1.98% of empty BW; SEM = 0.05) and gastrointestinal tract (5.50, 4.83, 8.43, and 8.36% of empty BW for BS:CD, SP:CD, BS:HD, and SP:HD, respectively; SEM = 0.16) tended (P < 0.07) to be influenced by an interaction between breed and diet. Mass of internal fat (12.2, 12.1, 3.4, and 3.4% empty BW for BS:CD, SP:CD, BS:HD, and SP:HD, respectively; SEM = 0.3) differed (P < 0.05) between diets. Energy in the carcass (320, 236, 87, and 79 M J), noncarcass tissues (318, 237, 77, and 72 M J), and empty body (638, 472, 164, and 150 M J) ranked (P < 0.05) BS:CD > SP:CD > BS:HD and SP:HD. Empty body concentration of protein was 18.3, 17.5, 18.3, and 19.7% (SEM = 0.3) and of fat was 24.0, 23.4, 10.8, and 10.3% for BS:CD, SP:CD, BS:HD, and SP:HD, respectively (SEM = 0.6). Energy concentration in accreted tissue was 17.0, 18.7, 16.3, and 6.4 MJ/kg for CD:wk 1 to 14, CD:wk 15 to 28, HD:wk 1 to 14, and HD:wk 15 to 28, respectively (SEM = 1.4). In conclusion, relatively high growth potential of growing Boer crossbred goats with a moderate to high nutritional plane does not entail a penalty in realized growth when the nutritional plane is low. Body composition of growing Boer and Spanish goats is fairly similar regardless of growth rate. For growing meat goats other than with a prolonged limited nutritional plane, an average energy concentration in accreted tissue is 17.3 MJ/kg. Key words: body composition, diet, goat

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 [+ or -] 2 s; B2, 24 [+ or -] 2 s; B3, 27 [+ or -] 2 s; P < 0.05) and goat breed (Alpine, 34 [+ or -]3 s; Angora, 17 [+ or -0] 2 s; Boer-cross, 16 [+ or -] 1 s; Spanish, 19 [+ or -] 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 [+ or -] 1 s, and overall time for bolusing, reading, and data typing was 49 [+ or -] 1 s on average. Ruminal pH differed according to breed and feeding management (lactating Alpine, 6.50 [+ or -] 0.07; yearling Alpine, 6.73 [+ or -] 0.07; Angora, 6.34 [+ or -] 0.06; Boer-cross, 6.62 [+ or -] 0.04; Spanish, 6.32 + or -] 0.08; P < 0.05), but no early bolus losses occurred; rumen pH did not differ according to bolus type (B1, 6.45 [+ or -] 0.05; B2, 6.39 [+ or -] 0.07; B3, 6.49 [+ or -] 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 Boercross (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. Key words: ear tag, electronic identification, goat, rumen bolus, traceability, transponder

Goat research in the United States has increased but at a rate less than that in production. Research on goat meat includes nutritional quality, packaging, color, sensory characteristics, and preslaughter management. Goat skins have value for leather, but quality of goat leather has not been extensively studied. Research in the production, quality, antibiotic residues, and sensory characteristics of goat milk and its products has aided development of the US dairy goat industry. Limited progress has been made in genetic improvement of milk or meat production. There is need to explore applications of genomics and proteomics and improve consistency in texture and functionality of goat cheeses. New goat meat and milk products are needed to increase demand and meet the diverse tastes of the American public. Despite research progress in control of mohair and cashmere growth, erratic prices and sale of raw materials have contributed to further declines in US production. Innovative and cooperative ventures are needed for profit sharing up to the consumer level. Internal parasites pose the greatest challenge to goat production in humid areas largely because of anthelmintic resistance. Study of alternative controls is required, including immunity enhancement via nutrition, vaccination, pasture management such as co-grazing with cattle, and genetic resistance. Similarly, the importance of health management is increasing related in part to a lack of effective vaccines for many diseases. Nutrition research should address requirements for vitamins and minerals, efficiencies of protein utilization, adjusting energy requirements for nutritional plane, acclimatization, and grazing conditions, feed intake prediction, and management practices for rapid-growth production systems. Moreover, efficient technology transfer methods are needed to disseminate current knowledge and that gained in future research. Key words: goat, research