Intraperitoneal Radio Transmitters Research Articles

Long-Term Safety of Intraperitoneal Radio Transmitter Implants in Brown Bears (Ursus arctos).

Intraperitoneal radio transmitters have been widely used in free-ranging wild mammals, but there are no long-term studies on their biocompatibility or technical stability within the abdominal cavity of animals. Possible negative health effects may bias results from ecological studies on instrumented animals and raise concerns over animal welfare issues. The aim of this study was to evaluate the long-term technical stability and pathological effects of Telonics intraperitoneal very high frequency (VHF) radio transmitters in brown bears (Ursus arctos). We instrumented 305 individual bears with intraperitoneal VHF radio transmitters during a 19-year period. We surgically removed devices that had been in bears for 1–9 years and collected transmitters from animals that died 1–13 years after implantation. We took biopsies for histopathology from tissue encapsulating implants in live bears. Retrieved transmitters underwent a technical inspection. Of the 125 transmitters removed from live bears, 66 were free-floating in the peritoneal cavity [a mean (SD) of 3.8 (1.5) years after implantation], whereas 59 were encapsulated in the greater omentum [4.0 (1.8) years after implantation]. Histopathology of biopsies of the 1–15 mm thick capsules in 33 individuals showed that it consisted of organized layers of connective tissue. In one third of the bears, the inner part of the capsule was characterized by a foreign body reaction. We inspected 68 implants that had been in bears for 3.9 (2.4) years. The batteries had short-circuited four (5.9%) of these devices. This resulted in the death of two animals 10 and 13 years after implantation. In two other bears that underwent surgery, we found the short-circuited devices to be fully encapsulated within the peritoneal cavity 5 and 6 years after implantation. A significant proportion of the other 64 inspected implants showed serious technical problems, such as corrosion of metal parts or the batteries (50%), detachment of the end cap (11.8%), and erosion (7.4%) or melting (5.9%) of the wax coating. We conclude that the wax coating of the transmitters was not biocompatible, that the technical quality of the devices was poor, and that these implants should not be used in brown bears.

Assisted colonisation trial of the eastern barred bandicoot (Perameles gunnii) to a fox-free island

Context Assisted colonisation has the potential to protect species from intractable threats within their historical ranges. The Australian mainland subspecies of the eastern barred bandicoot (Perameles gunnii) is extinct in the wild, with surviving populations restricted to small sites protected by predator–barrier fences. PVA modelling shows that a self-sustaining bandicoot population would require an area free of the introduced red fox (Vulpes vulpes) of at least 2500ha. French Island is outside the historic range of the species, but is fox-free and contains around 9000ha of potentially suitable habitat. Aims This study will assess the suitability of French Island as a potential site for a self-sustaining eastern barred bandicoot population by conducting a 1-year assisted colonisation trial to assess habitat use, body condition and survival. Methods Between July and September 2012, 18 adult bandicoots were released. We radio-tracked bandicoots using intraperitoneal radio-transmitters for up to 122 days and trapped fortnightly. Key results The release group met the three measures of success: (1) appropriate habitat use; (2) recovery of post-release bodyweight; and (3) founder survival exceeding 100 days. Habitat use and body condition throughout the trial reflected that of mainland populations, and seven bandicoots survived longer than 100 days. Mortality was greatest in the first month, with veterinary investigations confirming two deaths due to cat predation, two deaths from toxoplasmosis and one unknown cause of death. Bandicoots that survived longer than 100 days occupied higher, drier ground than those that did not. Toxoplasmosis cases were associated with lower topographic position on the site. Conclusions Our results suggest that French Island provides suitable habitat for the establishment of a population of eastern barred bandicoots. On French Island, toxoplasmosis was identified as an important source of mortality in addition to cat predation, and warrants further investigation. Implications Given the costs and challenges of predator control and the maintenance of predator exclusion fences, assisted colonisation to one or more fox-free islands remains the most viable option to establish self-sustaining bandicoot populations. Our results highlight the value in conducting trial releases ahead of major translocations.

Use of intraperitoneal radiotransmitters to study mountain lion (Puma concolor) Kittens

AbstractImplantation of radiotransmitters in juvenile carnivores allows researchers to study little‐known life stages. In the field, we successfully implanted 7 mountain lion (Puma concolor) kittens from 2 litters in the Santa Monica Mountains (Los Angeles and Ventura Co., CA), 1 in 2004 and 1 in 2010, with intraperitoneal very high frequency radiotransmitters. We used Global Positioning System location data downloaded from their mothers' collars to locate the dens in their absence, and we hand‐captured the kittens at 3–4 weeks of age. The implant surgery proceeded without complication and the mothers returned promptly afterward. The transmitters allowed us to track these young mountain lions for 13–17 months, from neonates to subadults. Upon necropsy of 3 of the individuals as subadults, the implants appeared to have had no negative impacts on the animals. Implantable radiotransmitters provided a safe and effective method for following young mountain lions. © 2012 The Wildlife Society.

Mortalities due to constipation and dystocia caused by intraperitoneal radio-transmitters in Eurasian lynx (Lynx lynx)

Three lynx (Lynx lynx) were found dead following complications after a surgically implanted free-floating intraperitoneal radio-transmitter became lodged within the pelvic canal. Two yearling lynx died due to consequences following severe constipation as the transmitter compressed the colon. Both were emaciated, with no abdominal or intrapelvic fat, which allowed the transmitter implant to fit into the pelvic canal. An adult female lynx died of dystocia when the pelvic birth canal was blocked by the transmitter when parturition began, leading to uterine rupture and subsequent peritonitis. A total of 41 lynx were implanted with this type of intraperitoneal transmitter in Scandinavia in 1997–2002. After the three transmitter-associated mortalities, the transmitter type used in lynx cubs was exchanged for another model, and further fatalities due to the implants have not been documented.

Long-term Survival and Reproduction in a North American River Otter (<em>Lontra canadensis</em>) with an Intraperitoneal Radio-Transmitter

Intraperitoneal implantation of radio-transmitters is a useful method of monitoring free-ranging aquatic and semi-aquatic mammals; however, some researchers are concerned about the physiological effects of such implants. Few studies have investigated the long-term consequences of intraperitoneal implants on survival or reproductive performance. An adult female North American River Otter (Lontra canadensis) surgically equipped with an intraperitoneal radio-transmitter and released in northwestern Pennsylvania in June 1990 as part of a reintroduction project was killed in March 1999. The North American River Otter was estimated to be 10 years old and was pregnant with two fetuses at the time of her death. Our observation suggests that wild North American River Otters surgically equipped with intraperitoneal radio-transmitters can live long after implantation of the radio-transmitter and continue to reproduce successfully.

Protein malnutrition and aging affects entraining and intensity of locomotor activity and body temperature circadian rhythms in rats

Independently, chronic protein malnutrition and aging have been shown to affect locomotor activity (LA) and body temperature (BT) rhythms in mammals. The objective of the present study was to ascertain the combined effects of these two factors by examining period, entrainment and other circadian parameters between LA and BT rhythms. Chronic protein malnourished (PM) and well-nourished (WN) male Sprague–Dawley rats (550–590 days of age) were implanted with activity temperature intraperitoneal radio transmitters (Mini Mitter) and exposed to different lighting protocols during at least 10 days – light-dark cycles (LD 12:12), constant darkness (DD), skeleton photoperiod (SP) and again LD. Results indicate that parametric entrainment, achieved by means of complete photoperiod, is not negatively affected in malnourished rats; however, it is affected under non-parametric entrainment like SP. A different free running period between the LA and BT circadian rhythms was detected for well-nourished and malnourished aged rats.

CAPTURE AND MEDETOMIDINE-KETAMINE ANESTHESIA OF FREE-RANGING WOLVERINES (GULO GULO)

Capture and anesthesia with medetomidine-ketamine were evaluated in free-ranging wolverines (Gulo gulo) immobilized for marking with radiocollars or intraperitoneal radiotransmitters in Norrbotten, Sweden, during early June 2004 and 2005. Twelve juvenile wolverines were captured by hand and injected with 0.14 +/- 0.03 mg/kg (mean +/- SD) medetomidine and 7.5 +/- 2.0 mg/kg ketamine. Twelve adult wolverines were darted from a helicopter or the ground, or captured by hand. Adults received 0.37 +/- 0.06 mg/kg medetomidine and 9.4 +/- 1.4 mg/kg ketamine. Arterial blood samples were collected between 15 min and 30 min and between 45 min and 60 min after drug administration and immediately analyzed for selected hematologic and plasma variables. Hyperthermia was recorded initially in one juvenile wolverine and 11 adults. Rectal temperature, heart rate, and lactate decreased significantly during anesthesia, whereas hemoglobin oxygen saturation, pH, partial pressure of arterial carbon dioxide, and base excess increased. Adult wolverines darted from a helicopter had a significantly higher rectal temperature, higher glucose and hematocrit values, and a lower heart rate than juveniles captured by hand. Impaired arterial oxygenation was evident in all wolverines. This study provides baseline data on physiologic variables in adult and juvenile wolverines captured with different methods and anesthetized with medetomidine-ketamine.

FIELD IMPLANTATION OF INTRAPERITONEAL RADIOTRANSMITTERS IN EASTERN WOLF (CANIS LYCAON) PUPS USING INHALATION ANESTHESIA WITH SEVOFLURANE

In a study of wolf pup survival, intraperitoneal radio transmitters were surgically implanted in 53 (27 male and 26 female) 3.5- to 8-wk-old Eastern wolf (Canis lycaon) pups at den sites in Algonquin Provincial Park, Ontario, Canada, over two whelping seasons (2004 and 2005). Pups were manually removed from dens and initially injected with butorphanol at a dosage of 0.1 mg/kg for sedation and intra-operative analgesia. Anesthesia was induced and maintained with 3% sevoflurane in oxygen via a face mask. Meloxicam (0.3 mg/kg intramuscularly) was given to provide additional analgesia. All surgeries were completed without complications, and pups were readily accepted back into the packs. No postoperative complications were identified, but two pups from a single litter drowned as a result of being moved by the pack to a flooded den following the surgery. In five pups necropsied following natural deaths, transmitters were found lying free within the peritoneal cavity, and there was no evidence of infection at the surgical site or peritonitis. Inhalation anesthesia provided extremely rapid induction (1 min) and recovery (<3 min) and was completely controllable with no residual anesthetic effects. The equipment for inhalation anesthesia was readily portable in field packs, and it has considerable advantages over injectable drugs for small and very young animals such as wolf pups. The utility of the procedure is demonstrated by the minimal effect it had on subsequent pup survival, the rapid recovery of pups following surgery, and the lack of long-term complications as determined by necropsies of pups following natural deaths.

A Novel Method for Capturing and Implanting Radiotransmitters in Nutria

As part of a multi-phase study aimed at examining the impact, habitat use, and movement patterns of the invasive rodent the nutria (Myocastor coypus), we developed a methodology to most effectively capture and implant these animals with radiotransmitters. Using a hand-held fishing net, we captured 20 adult nutrias from an airboat and implanted them with intraperitoneal radiotransmitters. We used the anesthetic tiletamine-zolazepam (Telazol®, Ft Dodge Animal Health, Ft. Dodge, Iowa) to immobilize the animals during surgery. We released all individuals back into a fresh water floating marsh habitat within 24 hours of implantation. There was increased survivorship when we placed animals in a predator-free enclosure for a minimum of 3 days. We found that the combination of airboat capture, Telazol® anesthesia, and 24-hr post-surgery release was successful only if animals could be kept in a predator-free environment for at least 72 hours. Therefore, if holding facilities and sufficient temporal, monetary, and human resources are available, these methods may result in sufficient survivorship to allow for the monitoring of these and other medium-sized, semi-aquatic mammals.

Field anaesthetic and surgical techniques for implantation of intraperitoneal radio transmitters in Eurasian beavers Castor fiber

Radio transmitters were implanted intraperitoneally in 22 (nine females, 13 males) adult, territorial Eurasian beavers Castor fiber under field conditions. Two different injectable anaesthestic drug combinations were tested. Access to the peritoneal cavity was made through a ventral midline incision. The animals in group # 1 (N = 10) were initially injected with medetomidine (0.05 mg/kg), ketamine (5 mg/kg) and butorphanol (0.1 mg/kg). Three animals needed additional injections of the drug combination. Muscle relaxation was poor and variable and some of the animals were sound sensitive. When midazolam (0.25 mg/kg) was added to the drug combination (group # 2), muscle relaxation was excellent and the beavers (N = 12) did not react to sound stimuli. All surgeries were successfully performed. One animal in group # 1 died postoperatively due to circulatory failure. The behaviour and movements of the beavers did not appear to be affected by the procedure or the implant, except for the first few days when more time was spent inside the lodges. All beavers stayed in their original territory until they died, or as long as 17–24 months after the implantation. Based on these results, it appears that an injectable drug combination based on medetomidine, ketamine, butorphanol and midazolam and a surgical access through the ventral midline is suitable for implanting radio transmitters intraperitoneally in beavers under field conditions.

AN INTRAPERITONEAL RADIO TRANSMITTER FOR SEA OTTERS

AbstractA small intraperitoneal radio transmitter was developed and used successfully in California sea otters. The transmitter weighs about 120 g and has an internal antenna. Thirty‐five implanted transmitters were located for an average of 526 d. The carcasses of five animals that died were recovered; there were no complications associated with the transmitters in these individuals. Reproductive performance of the adult females with implanted transmitters appeared normal. The main advantages of this transmitter are its reliability and long life. It has enabled the collection of significant new information on California sea otters.

Effects of suprachiasmatic nuclei lesions on circadian and ultradian rhythms in body temperature in ocular enucleated rats

Abstract To test the hypothesis that an oscillator located outside the suprachiasmatic nuclei (SCN) controls the circadian rhythm of body temperature, we conducted a study with 14 blinded rats, 10 of which receiving a SCN lesion. Body temperature was automatically and continuously recorded for about one month by intraperitoneal radio transmitters. Food intake, drinking and locomotor activity were also recorded. Periodograms revealed that 3 rats with histologically verified total bilateral SCN lesions did not exhibit any circadian rhythmicity. The 7 other rats appeared to have partial lesions. They showed shortening of period and severe amplitude reduction in all functions. Thus, no support was found for the hypothesis of a separate circadian ‘temperature oscillator’ located outside the SCN. Nevertheless, after large partial lesions body temperature showed more persistency than some of the other behavioral rhythms. Ultradian rhythms in temperature persisted after partial and total lesions. Other functions ...