Modeling the retention of rumen boluses for the electronic identification of goats.

We constructed a regression model to estimate the retention of electronic boluses in goats. With this aim, 2,482 boluses were administered to goats from dairy (Murciano-Granadina, n=1,326; French Alpine, n=381) and meat (Blanca de Rasquera, n=532) breeds. A total of 19 bolus types made of materials (ceramic, plastic tubes filled with concrete or silicone, and ballasts) differing in their specific gravity (SG) were used, thereby obtaining a wide variation in bolus features: diameter (9 to 22 mm), length (37 to 84 mm), weight (5 to 111 g), volume (2.6 to 26 mL), and SG (1.0 to 5.5). Each bolus contained a half-duplex glass encapsulated transponder (32 × 3.8mm) and was administered using adapted balling guns. Murciano-Granadina and Blanca de Rasquera goats also wore 2 visual plastic ear tags: V1 (double flag, 5.1g) and V2 (flag-button, 4.2g). No data on ear tags in French Alpine goats was available. Bolus and ear tag retention [(retained/monitored) × 100] was recorded for at least 1 yr. Dynamic reading efficiency [(dynamic reading/static reading) × 100] was also evaluated from 1,496 bolus readings. No administration incidences or apparent negative behavior or performance effects were observed for any bolus type. Static reading efficiency of retained boluses was 100%, except for the prototypes with metal ballasts, which yielded a 93.3% reading efficiency. Retention of metal-ballasted boluses was confirmed using x-ray equipment. Excluding ballasted boluses, a 99.5% dynamic reading efficiency was obtained. Ear tag losses were 6.5% for V1 and 3.7% for V2, ranging from 3.2 to 7.8% depending on ear tag type and goat breed. Bolus retention varied (0 to 100%) according to their physical features. Obtained data allowed the fitting of a logistic model of bolus retention rate according to bolus volume and weight (R(2) = 0.98); the SG was implicitly considered. Estimated weight and SG to produce medium- (15 mL) and standard-sized (22 mL) boluses for 99.95% retention rate in goats were 73.0 and 94.1g, and 4.87 and 4.28, respectively. Mini-boluses are not recommended, as none of the available radio translucent materials reach the required SG. In conclusion, increase of SG was fundamental to optimize bolus retention. Medium-sized boluses (10 to 15 mL; SG 5.8 to 4.9) for early administration and efficient retention in adult goats could be produced, thereby addressing the problem of using proper boluses for goat identification.

Long-term performance of visual and electronic identification devices in dairy goats.

Dairy goat kids born during a 3-yr period (n = 97) and their mothers (n = 29) were used for a long-term evaluation of the performance of 9 types of identification (ID) devices. Kids wore multiple ID devices: visual ear tags (V1, tip-tag, n = 47; V2, official, n = 50), electronic ear tags (E1, button-button, n = 46; E2, flag-button, n = 46), electronic rumen boluses (B1, mini-bolus 14 g, n = 92; B2, mini-bolus 20 g, n = 28; B3, standard bolus 75 g, n = 34) and glass-encapsulated transponders injected in the forefeet (T1, 15 mm, n = 75; T2, 12 mm, n = 100). Visual ear tags were applied at birth and removed in yearlings, whereas electronic ear tags were applied after bolusing with B1 (6.7 kg BW and 30 d, on average); B2 were administered in the event of a B1 loss, and B3 in case of a B2 loss and in goat does. At d 60 of age, kids were allocated into 2 groups to evaluate the effects of rearing system on ID. Treatments were: weaned (n = 46), and not weaned (n = 46) where kids suckled a milk substitute until d 150. Readability of ID devices (read/readable x 100) was monitored from 1 to 3 yr of age, depending on device and year of birth. Long-term readability was analyzed using a nonparametric survival analysis. A total of 3.3% infections and 6.5% tissue reactions were reported for electronic ear tags, but ears were fully healed in yearlings. Weaning numerically reduced B1 losses at d 150 (weaned, 84.8% vs. not weaned, 73.3%). Readability of visual ear tags in yearlings (V1, 82.9%; V2, 94.0%) was lower than for electronic ear tags (E1 and E2, 100%). Mini-bolus readability in yearlings did not differ by type (B1, 71.4%; B2, 84.6%) or with visual ear tags. No effect of inject type was reported (T1, 92.0%; T2, 96.0%). Survival analysis after yr 3 gave the greatest readability value for E1 (100%), which did not differ from B3 (96.8%). The lowest readability was estimated for B1 (66.3%), followed by E2 (79.8%), B2 (81.4%), and T1 (90.4%). In conclusion, button-button electronic ear tags and standard boluses were the more efficient devices under our conditions, their readability values being greater than injects, electronic mini-boluses, and visual and flag-button electronic ear tags. Transponders injected in the forefeet and mini-boluses used here are not recommended in practice. Further research on E1 and B3 electronic devices should be done in a higher number of goats to confirm the current results.

Comparison of manual versus semiautomatic milk recording systems in dairy goats.

A total of 24 Murciano-Granadina dairy goats in early-midlactation were used to compare the labor time and data collection efficiency of using manual (M) vs. semiautomated (SA) systems for milk recording. Goats were milked once daily in a 2 x 12 parallel platform, with 6 milking units on each side. The M system used visual identification (ID) by large plastic ear tags, on-paper data recording, and data manually uploaded to a computer. The SA system used electronic ID, automatic ID, manual data recording on reader keyboard, and automatic data uploading to computer by Bluetooth connection. Data were collected for groups of 2 x 12 goats for 15 test days of each system during a period of 70 d. Time data were converted to a decimal scale. No difference in milk recording time between M and SA (1.32 +/- 0.03 and 1.34 +/- 0.03 min/goat, respectively) was observed. Time needed for transferring data to the computer was greater for M when compared with SA (0.20 +/- 0.01 and 0.05 +/- 0.01 min/goat). Overall milk recording time was greater in M than in SA (1.52 +/- 0.04 vs. 1.39 +/- 0.04 min/goat), the latter decreasing with operator training. Time for transferring milk recording data to the computer was 4.81 +/- 0.34 and 1.09 +/- 0.10 min for M and SA groups of 24 goats, respectively, but only increased by 0.19 min in SA for each additional 24 goats. No difference in errors of data acquisition was detected between M and SA systems during milk recording (0.6%), but an additional 1.1% error was found in the M system during data uploading. Predicted differences between M and SA increased with the number of goats processed on the test-day. Reduction in labor time cost ranged from euro0.5 to 12.9 (US$0.7 to 17.4) per milk recording, according to number of goats from 24 to 480 goats and accounted for 40% of the electronic ID costs. In conclusion, electronic ID was more efficient for labor costs and resulted in fewer data errors, the benefit being greater with trained operators and larger goat herds.

Suitability of electronic mini-boluses for early identification of lambs.

Three types of ceramic mini-boluses, B1 [13.8 g; 10.5 x 51.0 mm (o.d. x length)], B2 (16.2 g; 12.2 x 42.2 mm), and B3 (20.1 g; 11.2 x 56.4 mm), were used to electronically identify as soon as possible after birth a total of 545 lambs of 3 breeds: Ripollesa (meat breed, n = 274), Manchega (dairy breed, n = 129), and Lacaune (dairy breed, n = 142). Boluses were administered by a trained operator using a balling gun or directly by hand. Lambs were also identified with 2 types of plastic ear tags in the left (temporary, 1.5 g) and the right (permanent, 4.1 g) ears. Lamb and identification device performances were checked during suckling (to wk 5 or 7) and fattening. At 24 kg of BW, lambs were slaughtered (n = 385) or kept for breeding (n = 144). No differences in performance were observed between the 2 dairy breeds, and their data were pooled. Minimum BW for bolus administration was lower in dairy than in meat lambs (P < 0.001). Across breeds, B1 and B3 did not differ in lamb age (27 d) and weight (9.2 kg) at administration, but B2 required older and heavier lambs (33 d and 11.1 kg; P < 0.01). Boluses did not affect lamb performance, but final readability at slaughter differed between B1 and B2 (97.7 and 95.2%, respectively) and B3 (100%), and between ear tags (temporary, 98.1; permanent, 100%). Bolus recovery was 100% in all cases, but the proportion of boluses found in the reticulum varied among bolus type (83.3 to 93.8%; P < 0.05). Three B1 (2%) were recovered from the abomasum. In a second experiment, effects of the intermediate mini-bolus (B2) on diet digestibility were evaluated. Digestibility of control and bolus-administered, Manchega ram lambs (14.9 kg of BW; n = 8) fed ad libitum with 2 pelleted concentrates and barley straw was assessed in digestibility crates. Feed intake and nutrient digestibility were measured in four 21-d periods, during which lambs received the 2 diets consecutively. No differences in intake, growth performance, or nutrient digestibility were observed between control and bolused lambs. In conclusion, the B3 mini-bolus proved to be an efficient device for identification of lambs before weaning (recommended age, >4 wk; recommended BW, >10 kg), allowing a reliable traceability of dairy and meat lambs until slaughter.

Retention of different sizes of electronic identification boluses in the forestomachs of sheep.

Twelve types of electronic identification ruminal boluses of different dimensions were used to obtain a model for predicting their retention in the forestomachs of sheep. Boluses (n = 1,662) were made of ceramic materials, and their dimensions varied in o.d. (9 to 21 mm), length (37 to 68 mm), volume (2.5 to 21.0 mL), and specific gravity (0.85 to 3.91). Each bolus contained a half-duplex, standardized, glass-encapsulated transponder (32 x 3.8 mm). Boluses were administered to sheep (n = 1,497) of different ages by using the appropriate balling guns, and their retention under semiintensive conditions was recorded for at least 2 yr. When a bolus was lost, the sheep was rebolused with a heavier bolus. All sheep wore 2 plastic ear tags: one for the official control of health programs and the other for farm use. To determine the anatomical limit for a bolus passing through the gastrointestinal tract, the size of the reticulo-omasal orifice was measured in 46 adult sheep (male, n = 14; female, n = 32) that died by causes not related to bolus administration during the experiment. No signs of disease or growth alteration were detected in the bolused sheep. Total ear tag losses during the experiment period were 7.5% on average. Bolus retention (5 to 100%) varied according to bolus features and age of the sheep, but it showed a plateau after 18 mo. Inadequately dimensioned boluses were regurgitated or passed through the gastrointestinal tract and were excreted with the feces. The diameter of the reticulo-omasal orifice in adult sheep differed between male and female (23.1 and 21.8 mm, respectively; P < 0.01) and was greater than the o.d. of the retained boluses. Retention rate was predicted from bolus weight and volume by a logistic regression (R2 = 0.997; P < 0.001). When retention data from the literature (59.0 to 100%) were included in the model, the adjustment was slightly lower (R2 = 0.967). As a result, the minimum bolus weight estimated to reach a 99.5% retention rate in sheep varied between 16 and 45 g when volume varied between 3 and 22 mL, for boluses with a specific gravity between 2.0 and 5.2. In conclusion, bolus retention rate in sheep varied dramatically according to their features. For safe and efficient retention of electronic identification boluses in sheep, boluses of small volume and diameter (e.g., < 15 mm) with specific gravity and weight greater than 3.0 and 20 g, respectively, are recommended.

Comparison of visual and electronic identification devices in pigs: on-farm performances.

A total of 1,822 pigs from 2 farms (farm A, n = 1,032; farm B, n = 790) were used to evaluate pig traceability under on-farm conditions by using identification devices (n = 4,434) of different technologies. The devices were visual ear tags (n = 1,533; Model 1, n = 776; Model 2, n = 757), electronic ear tags (n = 1,446; half-duplex, n = 702; full-duplex, n = 744), and intraperitoneally injected transponders (n = 1,455; half-duplex, n = 732; full-duplex, n = 723). A group of 790 pigs wore 3 types of devices, and 1,032 wore 2 devices. Piglets were identified before (wk 1 to 3 of age; farm A) or after (wk 3 to 4 of age; farm B) weaning and intensively fattened until approximately 100 kg of BW. Readability of devices was checked at each farm operation by using standardized handheld transceivers. No negative effects of the identification devices on animal health (mortality rate, 8.4%) or performance were detected. On-farm losses averaged 1.6% for ear tags (visual, 0.8%; half-duplex, 1.9%; full-duplex, 2.7%; P > 0.05) and 1.8% for intraperitoneally injected transponders (half-duplex, 1.7%; full-duplex, 1.9%; P > 0.05). Moreover, 1.4% electronic failures occurred in the electronic ear tags (half-duplex, 2.2%; full-duplex, 0.6%; P < 0.05) but not in the intraperitoneally injected transponders. Final on-farm readability was greater (P < 0.05) for visual ear tags (99.2%) than for electronic ear tags (half-duplex, 95.9%; full-duplex, 96.7%; P > 0.05). Readability for intraperitoneally injected transponders was intermediate (half-duplex, 98.3%; full-duplex, 98.1%; P > 0.05). Electronic devices were in all cases easier and faster to read than the visual ear tags. Visual ear tags and intraperitoneally injected transponders were efficiently retained under conditions of commercial pig farms, which agrees with the minimum values recommended by the International Committee for Animal Recording (> 98%). When readability and reading ease were also included as decision criteria, injectable transponders were preferred.

Evaluation of the retention of electronic identification boluses in the forestomachs of cattle.

A total of 1,203 beef calves were used to evaluate 2 series of electronic identification boluses. Calves were intensively fattened and slaughtered at approximately 1 yr of age. Series 1 (n = 576 calves) consisted of 10 types of boluses with the same external dimensions (o.d. x length: 21 x 68 mm) but varying in weight (11 to 75 g) and specific gravity (0.63 to 3.36). Six boluses were made of ceramic (5 prototypes and 1 commercial bolus) and 4 were tubes made of plastic filled with concrete. Series 2 (n = 627 calves) consisted of 3 prototypes and 5 commercial boluses of different ceramic materials varying in external dimensions (o.d.: 15 to 21 mm; length: 39 to 78 mm), weight (20 to 73 g), and specific gravity (3.00 to 3.87). Boluses were administered to milk-fed calves (2 to 5 wk of age) by using adapted balling guns. To determine the anatomical limit for a bolus passing through the gastrointestinal tract, the size of the reticuloomasal orifice was measured in 90 male and 62 female fattened calves at slaughter. Three calves in series 1 (0.3%) could not swallow the 21-mm (o.d.) bolus at the first attempt and received the bolus 1 wk later. No problems for early administration were found with thinner boluses (o.d. < 20 mm) in series 2, and no signs of disease or growth alteration were detected in any bolused calves. Retention rate until slaughter varied according to bolus features and ranged from 0 to 100% (series 1), and from 69.7 to 100% (series 2). Inadequately dimensioned boluses were regurgitated or passed through the gastrointestinal tract and were excreted with the feces. The diameter of the reticuloomasal orifice differed between male and female yearling calves (32.5 and 29.9 mm, respectively; P < 0.01) and was greater than the o.d. of the retained boluses. Retention rate was predicted from bolus weight and volume by a logistic regression (R2 = 0.99, P < 0.001), in which the minimum bolus weight estimated to reach a 99.5% retention rate was 61 g when volume and specific gravity were 22.4 mL and 2.72, respectively. To achieve an effective retention rate of electronic identification boluses in the forestomachs of fattening calves, bolus volume and specific gravity, in addition to weight, should be optimized. No boluses of specific gravity lower than 3.0 and thicker than 20 mm o.d. are recommended for identification of cattle from early rearing (< 20 d of age) to slaughtering.

Cost evaluation of the use of conventional and electronic identification and registration systems for the national sheep and goat populations in Spain.

A cost model was developed to compare different implementation strategies of the new European Commission regulation for sheep and goat identification and registration (EC 21/2004) in Spain. Strategies were as follows: 1) conventional identification (CID) by two ear tags; 2) electronic identification (EID) by one bolus and one ear tag; and 3) mixed CID and EID strategy (MID), consisting of CID for fattening stock and EID for breeding stock. Complete and simplified implementations of the regulation were considered as options. Total costs per animal identified for all strategies and options varied according to the implementation option, ranging from Euros 2.48 and 4.64. The EID was the most expensive strategy (Euros 4.47 to 4.64) for all implementation options. Cost of CID and MID strategies ranged from Euros 2.63 to 2.98 and from Euros 2.48 to 3.03, respectively. The model was submitted to a sensitivity analysis without considering extra benefits of sheep and goat identification. Critical values for which the cost of MID equaled CID depended on strategy and option, and ranged from 7.5 to 11.5% for ear tag losses and from Euros 1.80 to 3.30 for bolus price. In conclusion, the use of a mixed strategy combining conventional ear tags (animals intended for slaughter) and electronic boluses (breeding stock) seems to be an affordable strategy that fulfills the European Commission regulation requirements for the identification of sheep and goats in Spain. Price reductions for devices and equipment would make the full electronic identification strategy less expensive in the future.