Effects of injection position and transponder size on the performances of passive injectable transponders used for the electronic identification of cattle. (1/77)

A total of 686 Tiris half-duplex passive injectable transponders (PIT) of two sizes (23 and 32 mm) were randomly injected s.c. in three positions, armpit, ear scutulum, and upper lip, in 343 fattening calves (1 to 3 mo old). Injections were performed by two trained and two untrained operators. Losses and breakages on the farm were recorded at wk 1, 3, 7, 11, and 15 in restrained animals using two types of hand-held transceivers with a stick antenna. Dynamic reading efficiency (DRE) in animals running through a raceway was also evaluated at wk 1 and 3 and monthly until slaughter, using a stationary transceiver working at 137 dB x microV x m(-1) at 3 m. The total number of PIT that fell or broke in the slaughtering line, the location method, and the recovery time were also recorded. Results on the farm showed low breakages on average (0.4%) and differences (P < 0.05) in losses according to position (armpit, 1.7%; ear, 5.2%; and lip, 14.0%). An interaction (P < 0.05) between position x size was observed, and losses were greatest using a 32-mm PIT in the lip. The DRE was affected (P < 0.05) by PIT position and size, and values were greater for the 32-mm PIT in all positions (armpit: 99.9 +/- 0.1 vs 95.8 +/- 4.9%; ear: 93.8 +/- 2.2 vs 81.9 +/- 4.6%; lip: 66.8 +/- 4.9 vs 53.4 +/- 4.7%, respectively, for 32 vs 23 mm). Recovery of PIT in the abattoir was on average 96.7, 96.7, and 99.2% for armpit, ear, and lip, respectively (P > 0.05). Most of the PIT injected in the armpit were recovered by sight or palpation, but 31.9% were recovered after cutting the muscles around the area and 10.7% were recovered on the internal side of the hide, which jeopardized carcass identification. Recovery of PIT injected in the ear was 23.4% in the hide and 76.6% in the auricular muscles of the head. The easiest recovery was in the lip, 8.9% of PIT were located in the hide and 91.1% in the head. Recovery time was affected (P < 0.05) by position: the quickest was lip (27 +/- 2 s), followed by ear (52 +/- 5 s) and armpit (78 +/- 7 s). In conclusion, taking into account retention and reading performances, injection of a 32-mm PIT into the armpit showed the best results on the farm, but a careful and longer recovery was needed in the abattoir. Improvement of recovery methodology and time would be necessary in order to recommend injection of PIT in the armpit instead of in the ear for cattle tracking or monitoring.  (+info)

Evaluating mutant mice: anatomic pathology. (2/77)

As the human and mouse genome projects approach their goals, initiatives in functional genomics are advancing. When the nucleotide sequences are available, identification of gene functions will assume even greater importance. Determination of gene products and their proximal biochemical functions provide a part of the picture, but determination of their functions in the context of the whole organism is the ultimate goal. The manipulated mouse genome has become accepted as a model for understanding the genetic basis of human conditions and diseases. Consequently, biomedical research institutions have seen significant increases in the use of mice since the early 1980s, and these increases are largely attributable to the use of genetically modified mice. The role of comparative pathology in research on mutant mouse models of disease is increasing in response to these trends. Evaluation and phenotypic characterization of mutant mice, via clinical and anatomic pathology techniques, will be an important component of functional genomics initiatives.  (+info)

Individually measured feed intake characteristics and growth performance of group-housed weanling pigs: effects of sex, initial body weight, and body weight distribution within groups. (3/77)

Feed intake characteristics of 192, 27-d-old weanling pigs housed in groups and given ad libitum access to feed and water were measured individually with the use of computerized feeding stations. The groups were either homogeneous or heterogeneous as to BW distribution; pigs of three defined initial BW classes were used (mean BW of 6.7, 7.9, or 9.3 kg). The effects of BW distribution, BW class, and sex were studied with regard to average performance traits, latency time (interval between weaning and first feed intake), initial feed intake (intake during the first 24 h following first feed intake), and daily increase in feed intake during the interval between first feed intake and the day on which energy intake met or exceeded 1.5 times the maintenance requirement. Homogeneous and heterogeneous groups had similar latency times, initial feed intakes, and daily increases in feed intake. For the period 0 to 34 d after weaning, ADFI and ADG were also similar for homogeneous and heterogeneous groups, but gain:feed ratio was greater (P < 0.05) in the homogeneous groups. Gilts had higher (P < 0.05) initial feed intakes than barrows and also had greater (P < 0.05) ADFI and ADG during the period 0 to 13 d after weaning. Pigs with average BW of 6.7 kg had higher (P < 0.05) initial feed intakes than their counterparts with average BW of 7.9 kg and 9.3 kg, but the daily increase in feed intake was similar for the three groups. The lighter pigs had more daily visits and a lower feed intake per visit and tended to have a shorter postweaning latency to the onset of feeding than the heavier pigs. This study indicates that the high variability in early feeding behavior among group-housed weanling pigs may be related to BW and sex.  (+info)

Migratory movements, depth preferences, and thermal biology of Atlantic bluefin tuna. (4/77)

The deployment of electronic data storage tags that are surgically implanted or satellite-linked provides marine researchers with new ways to examine the movements, environmental preferences, and physiology of pelagic vertebrates. We report the results obtained from tagging of Atlantic bluefin tuna with implantable archival and pop-up satellite archival tags. The electronic tagging data provide insights into the seasonal movements and environmental preferences of this species. Bluefin tuna dive to depths of >1000 meters and maintain a warm body temperature. Western-tagged bluefin tuna make trans-Atlantic migrations and they frequent spawning grounds in the Gulf of Mexico and eastern Mediterranean. These data are critical for the future management and conservation of bluefin tuna in the Atlantic.  (+info)

The use of passive injectable transponders in fattening lambs from birth to slaughter: effects of injection position, age, and breed. (5/77)

A total of 1,159 Tiris half-duplex passive injectable transponders (PIT) of 32-mm length were used to study the electronic identification of 618 fattening lambs of two breeds used for different production purposes (Ripollesa, meat breed, n = 271, and Manchega, dairy breed, n = 347). The lambs were s.c. injected in the armpit and the retro-auricular positions at 2, 15, and 30 d of age. All lambs were also tagged with a small plastic ear tag after birth. A group of 76 lambs were injected only in the right armpit and were kept for breeding. The PIT losses, breakages, and electronic failures were evaluated at weekly weight recordings throughout the fattening period using two types of hand-held transceivers. Fattened lambs were harvested in a commercial abattoir between 3 and 4 mo of age when they reached market weight (11 to 12 kg hot carcass weight). The total number of PIT that fell or broke in the slaughtering line, the location method, and the recovery time were recorded. On the farm PIT losses were not affected (P > 0.05) by age at injection, injection position, or breed. Mean losses of PIT and ear tags during the same period were 5% and 6.3%, respectively (P > 0.05). No PIT breakages or failures were observed during the fattening period. Mean recovery of PIT in the abattoir (85.6%) was affected (P < 0.05) by breed and injection position. Losses of PIT in the abattoir were greater (P < 0.05) in the Ripollesa breed (18.4%) than in Manchega (10.0%), and for both breeds losses were greater (P < 0.05) in the retro-auricular than in the armpit positions (18.6 vs 10.8%, respectively). The percentage of PIT broken during slaughtering was low (0.3%). The mean recovery times (18 +/- 2 s) were not affected (P > 0.05) by breed, injection position, or age, thus allowing a harvesting speed of 200 lambs/h on average. In conclusion, the injection of 32-mm PIT into the armpit or the retro-auricular region is not recommended as a practice for the electronic identification of fattening lambs, even though they perform similarly to small plastic ear tags. This is partly a consequence of the PIT losses observed on the farm but mainly because of the difficulties with recovering the PIT in the abattoir. More research will determine whether the use of smaller transponders or injection in other positions could improve their performance in fattening lambs.  (+info)

FasL deficiency enhances the development of tumors in p53+/- mice. (6/77)

In the multistep process of tumor development, several events occur to transform cells from normal to malignant. Although p53 is one of the most commonly mutated genes in a wide variety of tumors, how other genes interact with p53 to transform cells is only just beginning to be understood. To study the effects of the interaction of the Fas system with p53 in tumor progression and development, mice with a targeted disruption of the p53 tumor supressor gene and a mutation in Fas ligand were bred. Organ weights, life expectancy, and tumor and tissue histology were assessed. Although spleen weights were drastically increased in FasL -/- p53 -/- mice, the FasL deficiency had no effect on life expectancy or the tumor spectrum of homozygous p53-deficient mice. The FasL deficiency reduced the median time to death from 12.1 months in FasL +/+ p53 +/- mice to 9.6 months in FasL -/- p53 +/- mice, and led to a shift in tumor spectrum from predominantly sarcomas (63%) when FasL was present to a large number of lymphomas (76%) in FasL -/- p53 +/- mice. Given the reduced life span and increased incidence of lymphoma in FasL -/- p53 +/- mice, these mice could be useful in carcinogenicity testing, particularly for understanding mechanisms of compounds that are nongenotoxic.  (+info)

Effects of small ruminal boluses used for electronic identification of lambs on the growth and development of the reticulorumen. (7/77)

Fifty-four male lambs were used to study the effects of two types of small electronic boluses on the dimensions and epithelial characteristics of their reticulorumen. Newborn lambs were assigned according to bolus type and age of application to the following treatments: 1) control (C, n = 21), without bolus; 2) mini (M, n = 21), identified with a 9.3 x 37.4-mm, 5.2-g bolus during the first week after birth; and 3) small (S, n = 12), identified with a 15.0 x 39.1-mm, 20-g bolus after weaning at wk 5, when lambs weighed more than 12 kg. After weaning, lambs were given ad libitum access to concentrate and barley straw. Six lambs were euthanized at the start of the experiment to measure initial reticulorumen characteristics. Ten lambs (five from M and five from C treatments) were slaughtered at weaning and 24 (eight per treatment) were slaughtered when they reached 24 kg. After bolus recovery, the reticulorumen was emptied and filled with polyurethane foam to obtain reticulorumen casts. Weight of the emptied reticulorumen and volume of the casts were measured. Four representative lambs from each treatment were also slaughtered at 24 kg, and their reticulorumen used to evaluate papillae size, number of dead cells, and degree of keratinization of both the reticulum wall and the rumen wall epithelia. Weight at weaning (13.8 kg), age at the end of fattening (65 d), and mortality rate (4%) did not differ among treatments. Retention rate for M and S boluses was 82.4 and 100%, respectively. Fresh weight and volume of the reticulorumen did not differ among treatments at weaning (130 g and 1,679 mL) or at the end of the fattening period (640 g and 5,931 mL). Lambs in the M treatment had greater (P < 0.05) rumen papillae size and lower (P < 0.10) keratinization than C lambs; values in the S lambs were intermediate between M and C lambs. Neither the M nor S type of bolus affected dimensions of the reticulorumen, but the earlier presence of M boluses induced a greater papillae size, with no negative effects on health and fattening performances of young lambs.  (+info)

Dispersal of Aedes aegypti and Aedes albopictus (Diptera: Culicidae) in an urban endemic dengue area in the State of Rio de Janeiro, Brazil. (8/77)

Experimental releases of female Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus were performed in August and September 1999, in an urban area of Nova Igua u, State of Rio de Janeiro, Brazil, to estimate their flight range in a circular area of 1,600 m where 1,472 ovitraps were set. Releases of 3,055 Ae. aegypti and 2,225 Ae. albopictus females, fed with rubidium (Rb)-marked blood and surgically prevented from subsequent blood-feeding, were separated by 11 days. Rb was detected in ovitrap-collected eggs by atomic emission spectrophotometry. Rb-marked eggs of both species were detected up to 800 m from the release point. Eggs of Ae. albopictus were more numerous and more heterogeneously distributed in the area than those of Ae. aegypti. Eggs positively marked for Rb were found at all borders of the study area, suggesting that egg laying also occurred beyond these limits. Results from this study suggest that females can fly at least 800 m in 6 days and, if infected, potentially spread virus rapidly.  (+info)

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