The seasonal fertility of North American bison (Bison bison) bulls.

The objective of this study was to determine the presence and magnitude of seasonal fluctuations in semen quality and other reproductive indices in bison bulls. Testicles from 288 commercially slaughtered bison bulls were collected monthly over a 1-year period. Carcass and testicle weight were determined and measurements of seminiferous tubule lumen, diameter, and epithelial thickness were made. Sperm cell morphology and defects were described and quantified using epididymal semen from each testicle. Twenty-one Plains (Bison bison bison) and Wood bison (Bison bison athabascae) breeding bulls, averaging 6.0 years of age (range 2.5-8.0), from three farms were selected for semen collection and evaluation on the basis of producer co-operation. Semen was collected by electro-ejaculation on four seasonal occasions during a 12-month period. Ejaculate quality was judged on the basis of volume, density, gross and individual motility, morphology, live/dead ratio, and concentration. Sperm cell morphologies were evaluated microscopically and classified according to criteria used for bovine semen. Fecal testosterone was measured at each semen collection using a commercial competitive binding radioimmunoassay. There was an increase in carcass weights over the study period and testis weights were moderately correlated (r=0.44) with carcass weights. However, mean testes weights were heavier (P<0.05) in the summer than in winter, spring, or fall periods. There were no differences in the proportion of normal and abnormal epididymal sperm between seasons but there were seasonal changes in the testicular parenchyma. Seminiferous tubule and lumen diameter, and epithelial thickness were greatest (P<0.05) in summer. Live bulls gained weight between April and November, but lost weight over the winter. Normal sperm cell percentages as well as individual sperm cell motility in electro-ejaculated sperm samples were higher (P<0.05) at the pre-breeding collection relative to other collections, but no change in sperm cell concentrations occurred over the study period. Fecal testosterone concentrations were highest at the pre-breeding period (June) but decreased (P<0.05) in each subsequent collection to reach their lowest levels in the April. While many changes in seen characteristics were not significant, overall results indicate the presence of some reproductive seasonality and increased testicular capacity in the summer breeding season. Bulls showing marginal semen quality in the winter but otherwise carrying desirable genetic traits may warrant another evaluation in late spring prior to being culled from a breeding program.

The onset of puberty in North American bison (Bison bison) bulls.

Prepubertal testicular development was evaluated in young North American bison (Bison bison) bulls over a 12 months period, by following various parameters of semen quality intended to measure sexual maturity level. The study goals were to characterize bison male reproductive development and to define the age and onset of puberty. Semen was collected by electro-ejaculation from 12 bulls once a month for a period of 12 months, from 13 through 24 months of age. Volume, density, gross motility, individual motility, morphology, live/dead ratio, and concentration were used to judge the quality of the ejaculates. Abnormal sperm were classified into categories according to descriptions used for bovine evaluations and guidelines created by the Western Canadian Association of Bovine Practitioners were used for determining satisfactory semen quality. Minimums of 60% progressive motility and 70% normal sperm cells identified samples as satisfactory. Puberty was defined as the point in testicular development where an ejaculate contains a minimum of 50 x 10(6)sperm cells, showing at least 10% progressive motility. Fecal samples collected from bulls prior to electro-ejaculation for testosterone determination by a commercial testosterone specific antibody radioimmunoassay showed no significant changes in mean fecal testosterone concentrations over time. Changes in mean body weights over the study period were calculated, the average body weight at 13 and 24 months of age were 263+/-18.6 and 475+/-52.2 kg, respectively. Under these experimental conditions, age was determined to be the most significant factor in determining the onset of puberty. On average, bulls reached puberty at 16.5+/-2.5 months. There was a significant increase in the number of normal sperm with increasing bull age as well as significant decreases in proximal cytoplasmic droplets and head defects, but no significant changes in midpiece and principal piece defects. There were significant increases with age in individual progressive motility, gross motility, concentration, density, and volume but not in the percent of live sperm. Bison bulls used for breeding should be capable of passing a breeding soundness evaluation by 24 months of age. The commercial bison industry semen tests, and possibly rejects, many developmentally incomplete bulls between 19 and 21 months of age. We suggest that these may actually be developing normally and should not be hastily discarded; it may be worth testing again at 24 months.

Viral, parasitic and prion diseases of farmed deer and bison.

The most important viral disease of farmed deer and bison is malignant catarrhal fever. The other herpesviruses which have been isolated from these species are briefly described. Other viral agents that are recognised in these animals, including adenovirus, parapox, foot and mouth disease, bluetongue, epizootic haemorrhagic disease, bovine virus diarrhoea, rotavirus and coronavirus, are also discussed. Ectoparasites of importance in this group in various parts of the world include a variety of ticks, as well as lice, keds, Oestridae, mange mites and fire ants. Helminth parasites include liver flukes (Fascioloides and Fasciola), gastrointestinal nematodes of the family Trichostrongylidae, pulmonary lungworms of the genus Dictyocaulus and extra-pulmonary lungworms of the family Protostrongylidae. Chronic wasting disease is principally important in North America, where the disease occurs in wild cervids in a limited area and has been reported in farmed deer in a small number of states in the United States of America and one province in Canada. These diseases are summarised in terms of their classification, epidemiology, clinical signs, pathology, diagnosis, treatment and control.

Bacterial diseases of farmed deer and bison.

The most important aerobic bacterial diseases of farmed deer and bison include bovine tuberculosis, Johne's disease (paratuberculosis), yersiniosis, leptospirosis, brucellosis, pasteurellosis, anthrax, salmonellosis and colibacillosis. Anaerobic bacterial infections affecting the same animals include necrobacillosis and a number of clostridial diseases such as tetanus, blackleg, malignant oedema and pulpy kidney. The relative importance of these diseases will vary throughout the world according to timing and circumstance, but bovine tuberculosis and Johne's disease are likely to present the most significant problems with respect to diagnosis, control, trade in live animals and the establishment of wildlife reservoirs of infection. The authors summarise the aetiology, the principal species of animal affected, geographical distribution, transmission, clinical signs, pathology, diagnosis, treatment and control of these diseases.

The gestation length of wapiti (Cervus elaphus) revisited.

As an ancillary activity to an artificial insemination program in farmed wapiti, the length of gestation of 28 wapiti hinds that delivered single calves of established parentage was calculated. Estrus was synchronized in 47 wapiti using progesterone impregnated devices (controlled internal drug release, CIDR) and an injection of PMSG. All hinds were artificially inseminated between 60 and 63h after CIDR removal. Pregnancy was determined between 45 and 65 days by ultrasound. A verifiable figure for gestation length was obtained based both upon timed-artificial insemination, date of parturition, and confirmation of sire identity through microsatellite DNA technology. The calculated gestational length of 247 +/- 5 days was significantly (P < 0.0001) shorter than the generally quoted figure of 255 +/- 7 days.

Comparative cardiopulmonary effects of carfentanil-xylazine and medetomidine-ketamine used for immobilization of mule deer and mule deer/white-tailed deer hybrids.

Three mule deer and 4 mule deer/white-tailed deer hybrids were immobilized in a crossover study with carfentanil (10 microg/kg) + xylazine (0.3 mg/kg) (CX), and medetomidine (100 microg/kg) + ketamine (2.5 mg/kg) (MK). The deer were maintained in left lateral recumbency for 1 h with each combination. Deer were immobilized with MK in 230+/-68 s (mean +/- SD) and with CX in 282+/-83 seconds. Systolic, mean and diastolic arterial pressure were significantly higher with MK. Heart rate, PaO2, PaCO2, pH, and base excess were not significantly different between treatments. Base excess and pH increased significantly over time with both treatments. Both treatments produced hypoventilation (PaCO2 > 50 mm Hg) and hypoxemia (PaO2 < 60 mm Hg). PaO2 increased significantly over time with CX. Body temperature was significantly (P<0.05) higher with CX compared to MK. Ventricular premature contractions, atrial premature contractions, and a junctional escape rhythm were noted during CX immobilization. No arrhythmias were noted during MK immobilization. Quality of immobilization was superior with MK, with no observed movement present for the 60 min of immobilization. Movement of the head and limbs occurred in 4 animals immobilized with CX. The major complication observed with both of these treatments was hypoxemia, and supplemental inspired oxygen is recommended during immobilization. Hyperthermia can further complicate immobilization with CX, reinforcing the need for supplemental oxygen.

Osteochondrosis and epiphyseal bone abnormalities associated with copper deficiency in bison calves.

Two bison calves were submitted to the Western College of Veterinary Medicine to confirm suspected copper deficiency. In addition to clinical signs, there were pathologic changes in the cartilage and subchondral bone of several joints. Water analysis indicated high levels of sulfate in the drinking water, contributing to a secondary copper deficiency.

Innervation and anesthesia of the antler pedicle in wapiti and fallow deer.

The heads from 6 mature male wapiti and 8 mature male fallow deer were dissected to provide a description of the nerves supplying the antler pedicles. Innervation in both species was found to resemble that of the red deer, with major contributions coming from the infratrochlear and zygomaticotemporal nerves. All heads displayed a dorsal branch from the auriculopalpebral nerve, but in only 2 wapiti and 3 fallow deer heads was this branch observed travelling to the pedicle. The dorsal branches of the 2nd cervical nerve were isolated in each head but could not be traced to the pedicles. Failure to induce anesthesia of the antler employing specific nerve blocks on the infratrochlear and zygomaticotemporal nerves can occur if the dorsal branch of the auriculopalpebral nerve is not blocked.

Management practices to minimise infectious and parasitic diseases of farmed and ranched cervids and bison.

The game farming and ranching industries have evolved in the late 20th century from earlier domestication efforts in many parts of the world. Preventing transmissions of infectious diseases to, between and from farmed and ranched cervids and bison involves management components similar to those used for other species of domestic livestock. Fencing, handling systems, individual identification, knowledge of the biology of the species and potential pathogens, disease testing, quarantine and vaccination all serve to control the possible negative effects of disease on the commercial success of an operation.

Capture of wood bison (Bison bison athabascae) using carfentanil-based mixtures.

Between 1986 and 1991, 155 wood bison (Bison bison athabascae) (33 adult females, 92 adult males, twelve 6 mo-old calves, eighteen 1 to 2 mo-old calves) in the Mackenzie Bison Sanctuary, Northwest Territories, Canada, and adjacent area were captured by dart immobilization. Initial trials with carfentanil, xylazine and R51163 as immobilizing agents were conducted. Subsequently, carfentanil alone, or in combination with xylazine, was used. Small doses of xylazine were used when required to control head and hind limb movement of recumbent bison. The mean dose of carfentanil used was 7.0 micrograms/kg. Narcotic antagonists used were naltrexone, naloxone and M5050. Narcotic recycling was seen in animals treated with naloxone and low doses of naltrexone. Furthermore recycling was suspected in the deaths of several animals treated with these antagonist regimes. No recycling was seen when doses of naltrexone in excess of 90:1 naltrexone:carfentanil were used. We recommend using a naltrexone:carfentanil dose in excess of 125:1 to ensure uneventful recovery.

Diagnosis of pregnancy in moose using a bovine assay for pregnancy-specific protein B.

Blood samples were collected from 26 moose (Alces alces ) and evaluated for the presence of an antigen that cross-reacted with antisera to bovine pregnancy-specific protein B (P-SPB). The objective of this study was to determine if the P-SPB radioimmunoassay (RIA) was a reliable indicator of pregnancy in these animals. In the first year of the study calf production the following summer was used as the index of previous pregnancy. In the second year all females were subjected to palpation per rectum after chemical immobilization. Seven of the 10 cows sampled in the first year were also sampled in the second year. All animals determined pregnant by rectal palpation were positive for P-SPB; however, P-SPB was not detected in males.

Mortality of fallow deer (Dama dama) experimentally-infected with meningeal worm, Parelaphostrongylus tenuis.

Six fallow deer (Dama dama) fawns died after receiving 25 to 150 infective larvae of Parelaphostrongylus tenuis. Fawns given higher doses usually died sooner (6 to 23 days) than those given lower doses (54 to 67 days). Early deaths were associated with severe acute peritonitis resulting from perforation of the intestinal wall; later deaths were associated with paralysis and inability to rise. Numerous adult P. tenuis were found within neural tissues of the brain and spinal cord in the three fawns with paralysis. One white-tailed deer (Odocoileus virginianus) exposed to infective larvae from the same source survived infection without exhibiting clinical signs and began passing larvae in feces 88 days post-exposure. At the doses used in this study, meningeal worm caused fatal infections in fallow deer. Results are compared to published observations of fallow deer naturally-infected with P. tenuis.

Diagnosis of pregnancy in wood bison using a bovine assay for pregnancy-specific protein B.

Blood samples were collected from 51 wood bison (Bison bison athabascae ) and evaluated for the presence of an antigen that cross-reacted with antisera to pregnancy-specific protein B(PSPB). The objective of this study was to determine if the PSPB radioimmunoassay (RIA) was a reliable indicator of pregnancy in these animals. Pregnancy of mature females was determined either at autopsy (20 animals) or by palpation per rectum after chemical immobilization (18 animals). The antigen was not detected in either males or juvenile females. There was minor cross-reaction in sera of one of nine nonpregnant females that had been exposed to males. The antigen was found in the sera of 25 of 27 females that were confirmed pregnant. It was concluded that the PSPB RIA was a useful tool in the determination of pregnancy in wood bison.

Artificial insemination of red deer (Cervus elaphus) with frozen-thawed wapiti semen.

Semen collected from wapiti (Cervus elaphus) in Canada in 1983 was frozen in two extenders. In 1988, the semen was used to inseminate 200 red deer hinds on 2 farms in New Zealand. Oestrus was synchronized in the hinds with progesterone-impregnated intravaginal devices (CIDR); 200 iu pregnant mares' serum gonadotrophin was given to each hind on Day 11. The CIDRs were removed on Day 12 at 20/h, as the numbers of the hinds were recorded. On Day 14, 54-56 h after CIDR removal, the hinds were brought into the yards in the same batches and laparoscopically inseminated. Semen from three sires was used. The overall conception rate was 51%. Gestation length ranged from 239 to 247 days. One hind was lost at calving, 3 calves had to be hand raised and there were 2 neonatal calf deaths.

Immobilization of polar bears (Ursus maritimus Phipps) with a mixture of tiletamine hydrochloride and zolazepam hydrochloride.

A 1:1 mixture of tiletamine hydrochloride and zolazepam hydrochloride was tested on 39 polar bears in and near Churchill, Manitoba, Canada during October 1983. The mean dose for satisfactory immobilization with a single injection was 5.1 mg/kg. Bears showed signs of ataxia from 1-3 min following injection and were usually sitting within 4 min. The mean induction time, taken as the adoption of sternal recumbency, was 5.1 min. Maximum relaxation was usually seen by about 20 min post-injection. The duration of immobilization appeared to be related to the dose of drug received. In bears that received a dose near the mean, recumbency lasted about 2 hr. Cubs of the year recovered more quickly than adults. Preliminary results indicated that the bears did not suffer respiratory depression and were able to thermoregulate while immobilized. Bears could be handled safely while under the effects of the drug and workers could readily evaluate the state of their sedation by their reactions. The drug did not appear to provide good analgesia at the doses tested.