Evaluation of methods for the euthanasia of cattle in a foreign animal disease outbreak.

In anticipation of the need to euthanize large numbers of cattle in the event of a foreign animal disease outbreak, two models of captive bolt gun and various firearms and ammunition loads were tested in order to assess their suitability. In the first phase of the project, two models of captive bolt stunner were used in an abattoir, and assessed for effectiveness. In the second phase, several firearms and ammunition were used on isolated bovine heads and assessed for effectiveness. Little difference was found between the two captive bolt stunners. Of the firearms and ammunition evaluated, the Ruger Mini-14 and the Core-Shot round, a prefragmented projectile, were determined to be most suitable. In situations where large herds of livestock are to be depopulated, and where the restraint required for the use of captive bolt stunners is not practical, there are commercially available firearms and ammunition that are suitable for this purpose.     

Electrical stunning of red deer (Cervus elaphus)

Eighteen of 23 red deer (Cervus elaphus) at a deer slaughtering premises were successfully stunned with an apparatus modified from that normally used to stun sheep. The five unsuccessful electrical stuns were associated with poor head restraint and poor head contact by the electrodes. The median stunning current was 0.9 A, and in the majority of cases the duration of stunning was less than 1 second. The signs of the electrically induced epileptiform seizures in the deer were dissimilar to those seen in sheep, cattle and pigs, in that the initial tonic phase was less marked, and of shorter duration. A similar shorter and less obvious tonic phase was noted in four deer shot with a captive bolt pistol. Two animals which were electrically stunned, and bled within 10 seconds, showed no signs of recovery while bleeding. The electroencephalograms of four deer stunned with currents of 1.3 A for a duration of either 0.5 or 1.0 seconds were recorded under more controlled conditions. All four animals developed electroencephalograms typical of an epileptiform seizure. The animals exhibited behavioural reactions similar to the other 18 animals in the trial at the deer slaughtering premises and were rendered unconscious for between 54 and 122 seconds. The electroencephalogram activity amplitude was greater than that recorded immediately before stunning and took between 6 and 9 seconds to build up to maximum value. It is concluded that, providing the heads of deer are adequately restrained, head-only electrical stunning can be incorporated into a humane method of slaughter for deer.     

Brain damage in sheep from penetrating captive bolt stunning

OBJECTIVE: To determine the severity and distribution of structural changes in the brains of adult sheep stunned by penetrating captive bolt. PROCEDURE: The unconstrained heads of ten, anaesthetised, unhorned, 2-year-old Merino sheep were impacted at the summit of the head with a penetrating captive bolt pistol. Six sheep were ventilated and four received no respiratory support. Two hours after impact, brains from the six ventilated sheep were perfusion-fixed with 4% paraformaldehyde. Sixteen whole, serial coronal sections from each brain were stained with haematoxylin and eosin and immunohistochemically for amyloid precursor protein, a sensitive marker of axonal and neuronal reaction in the brain after trauma. Pathological changes in these brains were then quantified by morphometric analysis. RESULTS: Structural change in all impacted brains was a mixture of focal injury around the wound track and more widely distributed damage in the cerebral hemispheres, cerebellum and brainstem, but varied considerably in severity between individual sheep. All nonventilated sheep died rapidly following respiratory arrest. CONCLUSIONS: After penetrating captive bolt stunning, damage to the central reticular formation, axonal connections, and the cortical mantle is the likely reason for failure of respiratory control and traumatic loss of consciousness.     

Brain damage in sheep from penetrating captive bolt stunning

Objective To determine the severity and distribution of structural changes in the brains of adult sheep stunned by penetrating captive bolt.
Procedure The unconstrained heads of ten, anaesthetised, unhorned, 2-year-old Merino sheep were impacted at the summit of the head with a penetrating captive bolt pistol. Six sheep were ventilated and four received no respiratory support. Two hours after impact, brains from the six ventilated sheep were perfusion-fixed with 4% paraformaldehyde. Sixteen whole, serial coronal sections from each brain were stained with haematoxylin and eosin and immunohistochemi-cally for amyloid precursor protein, a sensitive marker of axonal and neuronal reaction in the brain after trauma. Pathological changes in these brains were then quantified by morphometric analysis.
Results Structural change in all impacted brains was a mixture of focal injury around the wound track and more widely distributed damage in the cerebral hemispheres, cerebellum and brainstem, but varied considerably in severity between individual sheep. All nonventilated sheep died rapidly following respiratory arrest.
Conclusions After penetrating captive bolt stunning, damage to the central reticular formation, axonal connections, and the cortical mantle is the likely reason for failure of respiratory control and traumatic loss of consciousness.     

Slaughter methods: electroencephalographic (EEG) studies on spinal cord section, decapitation and gross trauma of the brain in lambs

By means of electroencephalograms (EEG), attempts were made to determine when insensibility could be presumed in five lambs, two subjected to immobilisation by the punctilla method, two decapitated and one shot by a captive bolt in the poll region. Section of approximately 80% of the spinal cord by the punctilla method had no apparent effect on sensibility and the technique was considered to be inhumane. The EEG obtained from a decapitated bead showed no obvious change in pattern for eight seconds and subsequent changes were similar to those associated with exsanguination only. Thus no evidence was obtained to indicate that decapitation causes immediate insensibility, neither was the belief substantiated that severance of the spinal cord, during the slaughter of sheep, hastens the onset of insensibility. These results also provide additional evidence on the inhumane nature of punctilla slaughter of cattle. The animal shot with a captive bolt in the poll region, as opposed to the frontal region, showed EEG activity for 78 seconds.     

Brain damage in pigs produced by impact with a non-penetrating captive bolt pistol

OBJECTIVE: To assess the effect of impact with a nonpenetrating captive bolt pistol in pigs by studying the resulting traumatic brain injury (TBI) and to compare the pathological changes with those found previously in the brains of sheep using a similar experimental paradigm. PROCEDURE: The unrestrained heads of six, anaesthetised, 7- to 8-week-old, Large White pigs were impacted in the temporal region with a nonpenetrating captive bolt pistol. Four hours postimpact, brains were perfusion-fixed with 4% paraformaldehyde. Coronal sections from six levels along the brain were cut and stained with haematoxylin and eosin and immunohistochemically for amyloid precursor protein, a sensitive marker of axonal injury (AI) in the brain after trauma. RESULTS: TBI in pigs was characterised only by very mild AI, whereas AI in sheep after captive bolt impact to the same head region was much more severe and widely distributed and often associated with vascular damage such as contusions, subarachnoid and intraparenchymal haemorrhage. CONCLUSIONS: TBI in pigs was much less severe than in sheep after non-penetrating mechanical impact of similar magnitude, confirming the importance of interspecies differences in determining an appropriate physical method of euthanasia.     

The use of a shotgun for the emergency slaughter or euthanasia of large mature pigs

The isolated heads of a Friesian bull and three large, Large White pigs were shot from various aspects with a 12-gauge shotgun using both a single 28 g solid lead projectile and buckshot, the latter consisting of nine individual lead pellets with a combined mass of 28 g. The sites of impact to the skull included the conventional frontal region, an occipital site and immediately behind the ear. A live mature Large White sow was shot with buckshot in the depression just caudal to the right ear, resulting in immediate insensibility and death. The damage caused to the isolated heads indicated that similar effects could be expected if the heads had been part of intact living animals. It is suggested that buckshot (nine lead pellets with a combined mass of 28 g) fired from a 12-gauge shotgun may be suitable for the emergency slaughter or euthanasia of a wide variety of domestic livestock and other species of animal.     

Cattle stunning with a penetrative captive bolt device: A review

The captive bolt device has been used for stunning cattle at abattoirs for more than 100 years and is now one of the stunning devices used most widely. The aim of this review article was to assess the effects that are decisive during cattle slaughter on the quality of stunning with the use of a captive bolt stunning device. The basis of effective stunning is the use of a suitable type of device, with the speed of the bolt and the kinetic energy corresponding to the anatomical parameters of the slaughtered animal. The importance of the regular cleaning and maintenance of stunning devices and monitoring of the effectiveness of stunning goes without saying. The immediate loss of sensibility in the animal must occur after the first shot. The effectiveness of the stunning process can be quantified by regular monitoring of the behavior of animals after stunning with an emphasis on the loss of reflexes (corneal reflex, regular breathing, attempts to regain physiological posture) and checks on the shot location on the skulls of slaughtered animals.     

Susceptibility of cattle to first-passage intracerebral inoculation with chronic wasting disease agent from white-tailed deer

Fourteen, 3-month-old calves were intracerebrally inoculated with the agent of chronic wasting disease (CWD) from white-tailed deer (CWDwtd) to compare the clinical signs and neuropathologic findings with those of certain other transmissible spongiform encephalopathies (TSE, prion diseases) that have been shown to be experimentally transmissible to cattle (sheep scrapie, CWD of mule deer [CWDmd], bovine spongiform encephalopathy [BSE], and transmissible mink encephalopathy). Two uninoculated calves served as controls. Within 26 months postinoculation (MPI), 12 inoculated calves had lost considerable weight and eventually became recumbent. Of the 12 inoculated calves, 11 (92%) developed clinical signs. Although spongiform encephalopathy (SE) was not observed, abnormal prion protein (PrPd) was detected by immunohistochemistry (IHC) and Western blot (WB) in central nervous system tissues. The absence of SE with presence of PrPd has also been observed when other TSE agents (scrapie and CWDmd) were similarly inoculated into cattle. The IHC and WB findings suggest that the diagnostic techniques currently used to confirm BSE would detect CWDwtd in cattle, should it occur naturally. Also, the absence of SE and a distinctive IHC pattern of CWDwtd and CWDmd in cattle suggests that it should be possible to distinguish these conditions from other TSEs that have been experimentally transmitted to cattle.     

EPIZOOTIOLOGY OF BLUETONGUE: THE SITUATION IN THE UNITED STATES OF AMERICA

Bluetongue was first reported in the United States in 1948 in sheep in Texas. The virus has now been isolated from sheep in 19 States. When the disease first occurs in a flock, the morbidity may reach 50 to 75% and mortality 20 to 50%. In subsequent years, the morbidity may be only 1 to 2% with very few deaths. Difference in breed susceptibility has not been observed. Natural bluetongue infection has not been observed in Angora or dairy goats. Bluetongue virus was first isolated from cattle, in Oregon, in 1959. The virus has now been isolated from cattle in 13 States. In cattle, the disease is usually inapparent but can cause mild to severe clinical disease and neonatal losses. Natural clinical bluetongue has also been reported in bighorn sheep, exotic ruminants in a zoo, mule deer, and white-tailed deer. Serological evidence of exposure to the virus has also been found in other species of ruminants in the wild. Inoculation of virulent bluetongue virus, vaccine virus, or natural disease can cause congenital deformities and neonatal losses in calves, lambs, and white-tailed deer fawns. Culicoides is considered the important insect vector of bluetongue. The virus has also been isolated from sheep keds and cattle lice. U.S. field strains of the virus fit into four serologic groups. No cross reactions were found between bluetongue and epizootic haemorrhagic disease of deer viruses. Cattle are considered significant virus reservoirs. It is necessary to use washed erythrocytes, rather than whole blood, and to inoculate susceptible sheep, rather than embryonated chicken eggs, to detect longer-term viraemia in cattle.     

Evaluation of brain damage resulting from penetrating and non-penetrating captive bolt stunning using lambs

OBJECTIVE: To compare the brain damage in sheep resulting from penetrating and non-penetrating captive bolt stunning. DESIGN: The unrestrained heads of anaesthetised lambs were impacted in the temporal region with penetrating and non-penetrating captive bolt pistols (humane stunners) using a constant charge. Two hours after head impact, brains were perfusion-fixed with 4% paraformaldehyde. Coronal sections were stained with haematoxylin and eosin and immunohistochemically for amyloid precursor protein, a sensitive marker of axonal and neuronal reaction in brains after trauma. Pathological changes in these brains were then quantified by morphometric analysis. RESULTS: The skull was fractured in 50% of lambs after a non-penetrating head impact and in all animals after a penetrating head wound. Impact contusions were present in 80% of lambs receiving a non-penetrating head injury and in all of those with a penetrating wound. Total contusion area was similar in both groups. Amyloid precursor protein-positive axons and neurons, and haemorrhage, were widely distributed in the brain after both head impact types, but there was no statistically significant difference between the two groups. Multifocal necrosis of the cerebellar granular layer was found in all lambs with non-penetrating head injury, but in none with a penetrating injury. CONCLUSIONS: The structural brain damage, a mixture of focal and diffuse injury, produced by penetrating and non-penetrating captive bolt pistols was overall similar and of sufficient severity to suggest that both types of weapon are acceptable for euthanasia.     

西藏马鹿亚种头骨的形态学观察

通过大体解剖学和动物学头骨测定的方法对马鹿头骨进行观察,并与牛、羊、马、鬣羚相比较。雄性马鹿头骨呈狭长的角锥性,额骨上有角突,角突长而分叉；鼻骨较短前窄后宽,前端呈水平状,边缘呈锯齿状,这与马、鬣羚鼻骨不相似；上颌骨接近颌前骨部位有一个犬齿齿槽,齿槽部位有6个臼齿齿槽,下颌骨有6.5个,因此上颌骨臼齿齿列比下颌骨臼齿齿列短；颧骨的前下方、鼻骨的侧面、泪骨的前上方及上颌骨的后上方,形成一个等边三角形缝隙；缝隙与鼻腔之间由一形状不规则的薄骨片隔开,这与牛、羊、马、鬣羚都不相似。     

Role of insects in the transmission of bovine leukosis virus: potential for transmission by stable flies, horn flies, and tabanids

The ability of stable flies (Stomoxys calcitrans), horn flies (Haematobia irritans), and tabanids (Diptera: Tabanidae) to transmit bovine leukosis virus (BLV) was investigated. Stable flies and horn flies were fed on blood collected from an infected cow, and the flies' mouthparts were immediately removed, placed in RPMI-1640 medium, ground, and inoculated into sheep and calves. Infection of sheep occurred with mouthparts from as few as 25 stable flies or 25 horn flies. However, sheep were not infected when removal of stable fly mouthparts was delayed greater than or equal to 1 hour after blood feeding. Infection of calves occurred after inoculation of mouthparts removed immediately after feeding from as few as 50 stable flies or 100 horn flies. Infected blood, applied by capillary action to the mouthparts (labella) of 15 deer flies (Chrysops sp) and a single horse fly (Tabanus atratus) caused infection in each of 2 sheep. Infection did not occur in 2 calves inoculated daily for 5 days with mouthparts from 50 horn flies collected after feeding on a BLV-infected steer. Four calves receiving bites from 75 stable flies interrupted from feeding on a BLV-positive cow also were not infected. Seronegative cattle held for 1 to 4 months in a screened enclosure with positive cattle in the presence of biting flies were not infected with BLV. The feeding behavior of each insect is discussed to assess their potential as vectors of BLV.     

Free-ranging livestock altered the spatiotemporal behavior of the endangered North Chinese leopard (Panthera pardus japonensis) and its prey and intensified human–leopard conflicts

Widespread distribution of livestock in the natural habitats of large carnivores may negatively impact carnivore populations by reducing wild prey availability and increasing human–carnivore conflicts. In this study, we used camera-trapping data collected in the temperate forests of the Taihang Mountains in North China during 2016–2019 to examine whether and how free-ranging cattle affected habitat use and Diel activity patterns of the endangered North Chinese leopard (Panthera pardus japonensis) and its 2 wild prey species, Siberian roe deer (Capreolus pygargus), and wild boar (Sus scrofa). Residents were also interviewed to record livestock depredation events by leopards during 2015–2019. We found that roe deer spatially avoided sites frequented by cattle, but wild boar did not. In the growing seasons, leopards shared habitats with cattle and tended to increase their diurnal activities where cattle were present. All 3 study species exhibited fine-scale spatial-temporal segregation to cattle. Leopards selectively preyed on calves over adult cattle and livestock depredation frequency was positively correlated with the detection rates of cattle and wild prey, but not that of leopard. These findings not only show that through behavioral adaption large carnivores and their ungulate prey may persist under livestock disturbance, but also highlight how important proper livestock management is for conserving North Chinese leopards in this region. To enhance livestock management and mitigate human–leopard conflicts, we recommend specific actions, such as better guarding of free-ranging cattle or adoption of a captive farming system.     

Neuropathological changes produced by non-penetrating percussive captive bolt stunning of cattle

A blunt, non-missile head injury inflicted by a non-penetrating captive bolt pistol in cattle at slaughter resulted in immediate loss of consciousness, a depressed fracture of the frontal bone and widespread subarachnoid haemorrhage, particularly beneath the impact site, in the temporal and frontal lobes, and around the brainstem. There was also invariably petechial haemorrhage in the basal ganglia and thalamus. The large concussive force applied to the cranium by the stunner was probably responsible for rendering the animal insensible and the vascular damage produced by this force and the sudden ventrocaudal acceleration of the brain after impact. These findings supported the use of this mode of stunning, followed by exsanguination, as an acceptable form of slaughter of cattle in abattoirs.     

Neuropathological changes produced by non-penetrating percussive captive bolt stunning of cattle

A blunt, non-missile head injury inflicted by a non-penetrating captive bolt pistol in cattle at slaughter resulted in immediate loss of consciousness, a depressed fracture of the frontal bone and widespread subarachnoid haemorrhage, particularly beneath the impact site, in the temporal and frontal lobes, and around the brainstem. There was also invariably petechial haemorrhage in the basal ganglia and thalamus. The large concussive force applied to the cranium by the stunner was probably responsible for rendering the animal insensible and the vascular damage produced by this force and the sudden ventrocaudal acceleration of the brain after impact. These findings supported the use of this mode of stunning, followed by exsanguination, as an acceptable form of slaughter of cattle in abattoirs.     

Investigation into the principal determinants of effective captive bolt stunning of sheep

In order to identify the physical component of captive bolt stunning responsible for abolishing visual evoked responses, experimental forms of captive bolt stunning were carried out on anaesthetised sheep. Supporting the captive bolt pistol away from the skull to permit limited penetration of the brain was found to be as effective as conventional shooting methods at abolishing visual evoked responses (responses were lost in all animals). Whereas, manual insertion of the bolt through a trephined hole or shooting through a trephined hole was significantly less effective (respectively, one of eight and four of eight animals lost responses). It is concluded that the impact of the bolt with the cranium is the principal determinant of effective stunning, rather than the penetration of the bolt into the brain tissues.     

Investigation of the transmission of Mycobacterium bovis from deer to cattle through indirect contact

OBJECTIVE: To investigate the infection of calves with Mycobacterium bovis through oral exposure and transmission of M. bovis from experimentally infected white-tailed deer to uninfected cattle through indirect contact. ANIMALS: 24 11-month-old, white-tailed deer and 28 6-month-old, crossbred calves. PROCEDURE: In the oral exposure experiment, doses of 4.3 x 10(6) CFUs (high dose) or 5 x 10(3) CFUs (low dose) of M. bovis were each administered orally to 4 calves; as positive controls, 2 calves received M. bovis (1.7 x 10(5) CFUs) via tonsillar instillation. Calves were euthanatized and examined 133 days after exposure. Deer-to-cattle transmission was assessed in 2 phases (involving 9 uninfected calves and 12 deer each); deer were inoculated with 4 x 10(5) CFUs (phase I) or 7 x 10(5) CFUs (phase II) of M. Bovis. Calves and deer exchanged pens (phase I; 90 days' duration) or calves received uneaten feed from deer pens (phase II; 140 days' duration) daily. At completion, animals were euthanatized and tissues were collected for bacteriologic culture and histologic examination. RESULTS: In the low- and high-dose groups, 3 of 4 calves and 1 of 4 calves developed tuberculosis, respectively. In phases I and II, 9 of 9 calves and 4 of 9 calves developed tuberculosis, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that experimentally infected deer can transmit M. bovis to cattle through sharing of feed. In areas where tuberculosis is endemic in free-ranging white-tailed deer, management practices to prevent access of wildlife to feed intended for livestock should be implemented.     

青海省湟源县本地黄牛四项血清钙指标的测定

对30头湟源县本地黄牛的4项血清钙指标进行了测定。结果表明：犊牛的血清总钙、血清结合钙和血清游离钙含量均显著高于成年牛（P＜0．01），而两者的血清游离钙百分率相似（P＞0．05）。     

北美地区鹿的慢性消耗性疾病

鹿慢性消耗性疾病(CWD)是鹿类动物的传染性海绵状脑病(TSE)。它是由朊病毒(PrP)引起的,临床主要表现为慢性型消耗,体重逐渐下降,行为异常,最后致死。该病主要感染北美地区的黑尾鹿、白尾鹿和美洲马鹿,一些野生和家养的反刍动物如牛、绵羊和山羊与染病鹿直接或间接接触也可被感染。目前还不能确定CWD与人和其它动物的TSE类疾病的关系。它的起源、发病机理、传播机制和途径尚不清楚。尽管还没有证据证明CWD可传染给人类,但是它对人类有潜在威胁。