Factors affecting the breeding success of the African Black Oystercatcher (Haematopus moquini): a perspective on protection and food availability

Breeding success (fledglings pair^?1 y^?1) of the Red-listed African Black Oystercatcher (Haematopus moquini) is highly variable, both spatially and temporally. Despite a diversity of natural factors causing this variability, there is evidence that two anthropogenic factors, i.e. disturbance and an introduced mussel (Mytilus galloprovincialis), are having an impact on the local breeding success of this species. Using a data set comprising 87 site-years of nest-monitoring data across most of the species’ breeding range, we analysed the extent and causes of variability in breeding success. Breeding success differed across three population categories defined by varying levels of human disturbance: island populations, protected mainland populations, and unprotected mainland populations. Differences in breeding success between island populations and protected mainland populations were likely due to differing exposure to predators; however, differences between protected and unprotected mainland populations were unlikely caused by this as both experience equivalent predation levels (although from different predators). Protection only improved the breeding success of oystercatchers in very high-quality habitats (with a high biomass of alien mussels), and where populations were ‘released’ from high levels of human disturbance. In unprotected mainland areas, human activity impacted on the breeding success of local populations primarily through predation of small chicks by uncontrolled dogs, and by rising tides drowning chicks that were hiding from human disturbance. The findings of this study note the potential conservation dilemma resulting from an invasive species improving the conservation status of a Red-listed species, and encourage the implementation of restricted sites in high-quality habitats with high breeding pair densities.     

Epidemic of blindness in kangaroos - evidence of a viral aetiology

OBJECTIVE: To determine the cause of an epidemic of blindness in kangaroos. DESIGN AND PROCEDURES: Laboratory examinations were made of eyes and brains of a large number of kangaroos using serological, virological, histopathological, electron microscopical, immunohistochemical methods, and PCR with cDNA sequencing. In addition, potential insect viral vectors identified during the disease outbreak were examined for specific viral genomic sequences. SAMPLE POPULATION: For histopathological analysis, 55 apparently blind and 18 apparently normal wild kangaroos and wallabies were obtained from New South Wales, Victoria, South Australia, and Western Australia. A total of 437 wild kangaroos and wallabies (including 23 animals with apparent blindness) were examined serologically. RESULTS: Orbiviruses of the Wallal and Warrego serogroups were isolated from kangaroos affected with blindness in a major epidemic in south-eastern Australia in 1994 and 1995 and extending to Western Australia in 1995/96. Histopathological examinations showed severe degeneration and inflammation in the eyes, and mild inflammation in the brains. In affected retinas, Wallal virus antigen was detected by immunohistochemical analysis and orbiviruses were seen in electron microscopy. There was serological variation in the newly isolated Wallal virus from archival Wallal virus that had been isolated in northern Australia. There were also variations of up to 20% in genotype sequence from the reference archival virus. Polymerase chain reactions showed that Wallal virus was present during the epidemic in three species of midges, Culicoides austropalpalis, C dycei and C marksi. Wallal virus nucleic acid was also detected by PCR in a paraffin-embedded retina taken from a blind kangaroo in 1975. CONCLUSION: Wallal virus and perhaps also Warrego virus are the cause of the outbreak of blindness in kangaroos. Other viruses may also be involved, but the evidence in this paper indicates a variant of Wallal virus, an orbivirus transmitted by midges, has the strongest aetiological association, and immunohistochemical analysis implicates it as the most damaging factor in the affected eyes.     

Interactions Among Different Devices and Electrical Stimulus on the Electroejaculation of Captive Agoutis (Dasyprocta leporina)

The interactions among different electroejaculation devices associated with serial or continuous stimuli were investigated to improve the efficiency of the electroejaculation for semen collection in agoutis. Ten sexually matured male Dasyprocta leporina were restrained by the intramuscular administration of xylazine–ketamine association. Each individual was randomly subjected to four electroejaculation protocols, by combining two devices (one presenting longitudinal electrodes emitting square waves and other presenting ring electrodes emitting sine waves) and two electrical stimuli protocols (serial or continuous). A total of 40 attempts for electroejaculation were conducted in agoutis, being 10 per treatment. The most efficient treatment in providing ejaculates containing sperm (p < 0.05) was that using and electroejaculator connected to a probe with ring electrodes and associated with serial stimuli (4/7; 57%). In spite of semen parameters obtained by sine waves were adequate for using the samples for assisted reproduction, higher values for sperm motility and functional membrane integrity were obtained in the use of the square wave, independently of the electric stimulation protocol used (p < 0.05). In conclusion, we verified that the use of a device presenting a probe with ring electrodes and emitting sine waves, associated with a serial stimuli protocol, improves the efficiency for semen obtaining by electroejaculation in adults D. leporina.     

A survey of owners' perceptions of fear of fireworks in a sample of dogs and cats in New Zealand

Abstract

AIMS: To establish reliable information regarding the behavioural responses of dogs and cats to fireworks in New Zealand; record interventions used by owners, and their perceived efficacies; and establish the prevalence of firework-related injury, and quantify owners' attitudes towards fireworks.

METHODS: A questionnaire targeting dog and cat owners was distributed via the Auckland Society for the Prevention of Cruelty to Animals (SPCA) Animals Voice magazine and 25 veterinary clinics. The questionnaire covered demographics of animals, fear of fireworks, severity of the fear, and behaviours exhibited. Also included were treatments tried, source and perceived efficacy, prevalence of injury, and owners' attitudes towards the sale of fireworks for private use.

RESULTS: From a total of 8,966 questionnaires distributed, 1,007 valid questionnaires were returned, representing 3,527 animals. Of these 1,635 (46%) animals displayed a level of fear of fireworks recognisable to their owners. Owners of dogs identified a significantly higher fear response than owners of cats but the duration of these fear responses did not differ between species. Fear of fireworks frequently resulted in dogs exhibiting active fear behaviours, whereas cats were more likely to exhibit hiding and cowering behaviours. A significantly increased severity and duration of fear response over time in dogs and cats was associated with owners who comforted them when they displayed a fearful response. Only 141/890 (15.8%) of owners sought professional treatment from a veterinarian, animal behaviourist or animal trainer for their animals, with variable efficacy. Six percent (51/923) of animals had received physical injuries from fireworks. The majority (837/1,007; 83%) of respondents, regardless of whether they owned a fearful animal or not, supported a ban on the sale of fireworks for private use.

CONCLUSIONS: The results provide valuable information that is, as yet, unsubstantiated in New Zealand, although potential biases exist due to the non-random selection of respondents. Differences between dogs and cats were likely due to differing responses to fear-provoking stimuli between the species. Owner-reported increase in fearful response over time for comforted animals may indicate a negative impact on the longer-term psychological welfare of their animal.

CLINICAL RELEVANCE: The greater the awareness of effective treatment plans for animals that suffer from a fear of fireworks, the greater the possibility that this fear can be reduced. Wider dissemination of effective owner behaviour and treatment programmes for firework fears is needed to improve levels of professional treatment for dogs and cats.     

A survey of the efficacy of sustained-release monensin capsules in the control of bloat in dairy cattle

SUMMARY Thirty-four farms in the Macalister Irrigation District in Gippsland, Victoria, using sustained-release monensin capsules in 5102 cattle in the 1990 bloat season were surveyed. Questions were asked about the prevention and incidence of bloat in 1989 and 1990. Eight farms not using the capsules were selected to act as controls. Relatively low rates of broken capsules (0.6%), injury to animals at administration (0.06%) and regurgltation (1.02%) were reported. A variety of preventive techniques were used. There was a significant decrease in the use of pasture spraying, drinking water administration and flank spraying of anti-bloat substances on the farms using the capsules in the 1990 season, with no compensatory rise in the use of other techniques. There was no significant change in bloat prevention techniques used on the control farms over the same period. Significantly fewer cattle on the farms using capsules were treated for, and fewer died of clinical bloat in 1990 than in 1989. There was no significant change in the incidence of bloat on the control farms over the same period. It was considered that the anti-bloat capsules were effective in reducing the incidence of clinical bloat in pasture-fed dairy cattle.     

Influence of Progesterone Withdrawal on Pregnancy-Related Parameters During Post-Implantation Early Pregnancy Loss

Pharmacologically-induced luteolysis or treatment with an antiprogestin in early post-implantation pregnancy in dogs results in asynchronous death and resorption of conceptuses, indicating variable rates of response of individual conceptuses towards progesterone deficiency. This variability also seems to occur in bitches showing pregnancy failure in response to spontaneous luteal deficiency. In a total of 10 beagle pregnancies (two consecutive pregnancies of five bitches), abortifacient treatments beginning on day 24 after ovulation (ov) involved either administration of a progestin antagonist (total of six pregnancies, in three bitches) or a luteolytic regimen of prostaglandin F_2α-analogue together with a dopamine agonist (total of four pregnancies, in two bitches). The outcomes were evaluated in relation to four control pregnancies in two bitches by assay of serum progesterone, prolactin and relaxin at selected time points or within selected time periods, by ultrasound of conceptuses including measurement of uterine blood flow, and parameters of the blood fibrinolytic system including plasma fibrinogen and plasminogen. The process of embryonic death and conceptus resorption was variable in onset and duration both in bitches that received the progesterone antagonist aglepristone (AGLE) and in those under the luteolytic treatment (cloprostenol combined with cabergoline). Pregnancy termination (death of all embryos or foetuses, respectively) occurred as early as day 29 and as late as day 41 after ov in AGLE-treated bitches, and not earlier than day 37 after ov in luteolytic-treatment bitches. Impending embryonic death was not predicted by changes in relaxin concentration, parameters of the fibrinolytic system, or in the perfusion of small uteroplacental vessels.