Wild Dogs Research Articles

Reproductive performance of northern Australia beef herds. 6. Risk factors associated with reproductive losses between confirmed pregnancy and weaning

Context High and variable fetal and calf loss in beef herds occurs across northern Australia. Reasons for the majority of these losses, a major cost to the industry, have remained unknown. Aims The research question was, which of the 58 region-, property-, management group-, and animal-level risk factors measured are associated with pregnant females failing to wean their calf? Methods An epidemiological study measured fetal and calf loss (consistently expressed as % points) between confirmed pregnancy and weaning and the major associated risk factors using a selected population from 55 commercial beef breeding herds representing 23 166 pregnancies in the mostly dry tropical environment of northern Australia. Key results Median fetal and calf loss was 9.5% with large variation. Achievable levels appeared to be <10% for Northern Forest herds, and <5% for Southern Forest, Central Forest and Northern Downs herds. The risk factors most strongly associated with fetal and calf loss were low-fertility country type interacting with phosphorus inadequacy (up to 10% increase), low body condition score interacting with phosphorus inadequacy (up to 8% increase), tall cows (up to 4% increase), and high temperature–humidity index around calving interacting with country type (up to 7% increase). These are nutritional and environmental risk factors and had the combined highest individual effect and frequency. Other risk factors associated with fetal and calf loss included first-lactation cows, which interacted with mustering around calving (up to 9% increase), having not reared a calf in the previous year interacting with cow age (up to 8% increase), low mustering efficiency (up to 9% increase), perceived predation by wild dogs (4–5% increase), high prevalence of Campylobacter fetus sp. venerealis antibodies (7% increase), recent infection with bovine viral diarrhoea virus (9% increase), and inadequate dry-season protein (4% increase). Conclusions The combined effects of environmental, nutritional and management risk factors on fetal and calf loss in northern Australia were large and additive and were much greater, collectively up to 30–40%, and more consistent than that due to either endemic infectious diseases or animal factors. Implications Opportunity for remedial action is high and, for the effect of non-infectious risk factors, should target milk delivery to neonatal calves.

Enterocytozoon bieneusi in patients with diarrhea and in animals in the northeastern Chinese city of Yichun: genotyping and assessment of potential zoonotic transmission.

Enterocytozoon bieneusi is a common microsporidia species in humans and animals. Due to lack of effective vaccines and drugs, understanding of its epidemiological status and characteristics in different hosts is an important step in controlling the infection. The present study aimed at determining the prevalence of E. bieneusi in humans with diarrhea and animals in Yichun, in northeastern China, and assessing the epidemiological role of animals in the transmission of microsporidiosis. A total of 540 fecal samples were collected from diarrheal patients (n = 222) and 11 animal species (n = 318). Enterocytozoon bieneusi was identified and genotyped by polymerase chain reaction (PCR) and sequencing of the internal transcribed spacer (ITS) region of the rRNA gene. Enterocytozoon bieneusi was detected in 1.4% (3/222) of diarrheal patients, and genotype D and novel genotypes YCHH1 and YCHH2 were identified. Enterocytozoon bieneusi was detected in wild boars (7.7%), sika deer (8.2%), dogs (3.2%), and ostriches (10.7%), and genotypes D, Type IV, Peru6, BEB6 and novel genotypes YCHA1, YCHA2 and YCHA3 were identified. Genotypes YCHH1, YCHH2 and YCHA1 were phylogenetically assigned to group 1, while YCHA2 and YCHA3 to groups 2 and 11, respectively. The finding of genotype D in humans and animals, and the identification of zoonotic genotypes Peru6, Type IV, BEB6 in animal-derived E. bieneusi isolates indicate the potential of zoonotic transmission of microsporidiosis in the investigated area. The observation of the three novel genotypes in group 1 indicates their zoonotic potential.

Molecular survey and genetic diversity of Bartonella spp. in domestic cats from Paraguay.

Although Bartonella spp. is described in cats worldwide, little is known about the occurrence and genetic diversity of Bartonella spp. in cats from South America. To date, it has only been detected in cats from Brazil, Chile and Argentina. This study aimed to undertake a molecular survey and explore the genetic diversity of Bartonella spp. in domestic cats from Paraguay. A TaqMan real-time quantitative PCR (qPCR) targeting the nuoG gene (83 bp) for Bartonella spp. was used to screen 125 blood samples from cats in Asuncion, Paraguay. nuoG qPCR-positive samples were further submitted to conventional PCR assays based on the ITS (453- 717 bp), gltA (767 bp), ftsZ (515 bp), rpoB (333 bp), ribC (585-588 bp), and pap-31 (564 bp) loci. Positive samples were sequenced for species identification, phylogenetic, and haplotype analyses. Bartonella D.N.A. was present in 20.8% (26/125) cat blood samples, with low levels of Bartonella nuoG D.N.A. cPCR products targeting gltA, ftsZ, ITS, and rpoB loci from sixteen cats were successfully sequenced. However, all nouG qPCR-positive samples were negative for the ribC and pap-31 genes. Bartonella henselae [62.5% (10/16)] and Bartonella clarridgeiae [37.5% (6/16)] were identified among the sequenced samples. Upon phylogenetic analysis, B. henselae and B. clarridgeiae from Paraguay clustered with sequences detected in domestic and wild cats, dogs, and cat fleas worldwide. Two to four haplotypes of B. henselae and B. clarridgeiae in cats from Paraguay were observed, with some being exclusive and others shared with worldwide distributed haplotypes. Here, we report B. henselae and B. clarridgeiae for the first time in cats from Paraguay. Its circulation in cats suggests the need to consider Bartonellae when testing clinical samples from suspected infectious diseases in humans from Paraguay.

Значение диких животных и собак в формировании и функционировании природного очага эхинококкоза на территории Карачаево-Черкессии

The epizootic and epidemiological situation of echinococcosis of wild animals, dogs and humans has been studied according to reporting data and based on our own research. It has been established that echinococcosis is widespread in the territory of the Karachay-Cherkess Republic. As a result of the autopsy of wild carnivores, it was found that the extent of echinococcosis invasion ranged from 20 to 50 % with an invasion intensity from 65,0 to 213,0 specimens/animal, in wild artiodactyls and rodents – from 14.3 to 30.0 % with AI fluctuations from 1,0 to 5,0 specimens/ animal. The average long-term incidence of echinococcosis in the population of Karachay-Cherkessia for 2000-2017, according to the Rospotrebnadzor Department for the Republic, is 4,0±0,4 (per 100 thousand population). In 2017–2018, 7 cases were registered, in 2019 – 4 cases of the disease, in 2021 – 2 cases, and in 2020 cases of echinococcosis in humans were not registered.

Why is sustainable conservation of the remaining populations of endangered African wild dog (Lycaon pictus) important?

Why is sustainable conservation of the remaining populations of endangered African wild dog (Lycaon pictus) important?

A field-friendly alternative to freeze-drying faeces for glucocorticoid metabolite analyses of African wild dogs (Lycaon pictus)

Endocrine studies using faeces as hormone matrix have become increasingly popular to examine adrenocortical activity in wildlife. A prerequisite for this approach is to minimize alteration of faecal glucocorticoid metabolite (fGCM) composition post-defecation. This is done by freezing the collected material as soon as possible after collection, and removing moisture from the frozen faecal samples afterwards (usually by freeze-drying). In remote areas, freeze-drying opportunities are often limited, and in the case of the African wild dog (Lycaon pictus), established assays revealed that fGCM concentrations remain comparable for only ∼24h post-defaecation. In the present study, three cost-effective drying treatments (exposure to sunlight, placement in a solar oven, and use of a food dehydrator) were investigated as alternatives to the golden standard of freeze-drying faeces.•In comparison to freeze-dried material, African wild dog faecal samples dried through sunlight exposure, a solar oven, and use of a food dehydrator revealed no significant differences in respective fGCM concentrations measured.•A food dehydrator would be the preferable option to dry African wild dog faeces if limited electrical supply is available. This technique dries faeces the fastest, and negates any reliance on weather conditions.

Endangered African Wild Dogs: Ecological Disturbances, Habitat Fragmentations, and Ecosystem Collapse in Sub-Saharan Africa.

The African wild dog (Lycaon pictus) is among the species that have declined to the point where it is now listed as endangered by the International Union for the Conservation of Nature (IUCN, 2012). Formerly, the African wild dog population was estimated to span 39 African countries, but today, they have disappeared from much of their former habitats, now occupying just 7% of their former geographic range. They are presently found in only 14 countries primarily in the southern part of the continent, including South Africa, Tanzania, Kenya, Zimbabwe, Namibia, and Botswana. The largest populations are presently found in northern Botswana, the Selous Game Reserve in Tanzania, and in Kruger National Park in South Africa. In East Africa, the largest population is found in Tanzania and Kenya in the Serengeti-Maasai-Mara ecosystems and in the Selous Game Reserve. The current, global population is estimated to be between 3000-5000 which is comprised of less than 1400 mature individuals. Methodically, this study deeply underscored these data from critical library research i.e., archival sources, books and articles, and other published literatures across the globe which are pertinent to this research topic.

Analysis of the microbial diversity in the fecal material of the critically endangered African wild dog, Lycaon pictus.

The African wild dog (AWD) (Lycaon pictus) is a critically endangered species. These animals are hypercarnivores, hunting mostly medium-sized antelope. In this study, using bacterial tag-encoded FLX-Titanium amplicon pyrosequencing (bTEFAP®), the microbiota in the fecal material of AWDs living in the Great Plains Zoo & Delbridge Museum of Natural History was investigated. In both samples, the most predominant bacterial phylum was the Firmicutes with members of the genus Blautia spp. being the most dominant bacteria.

CANINE DISTEMPER AND PARVOVIRUS VACCINATION WITH RECOMBITEK C3 IN AFRICAN WILD DOGS (LYCAON PICTUS).

Infectious disease threats are increasingly recognized as a major contributor to mortality in wild populations of African wild dog (Lycaon pictus, AWD). Canine distemper virus (CDV) infection has been implicated as a cause of pack mortality in both captive and wild AWD populations. Ten animals were vaccinated with RecombitekTM C3, a vaccine containing a recombinant CDV, and modified live canine parvovirus (CPV) and adenovirus-2 components, at 8, 12, and 16 wk of age. Half of the pups received the vaccine IM and the other half SC. All ten pups had a positive serological response to CDV after the second vaccination, which decreased or stagnated after the third vaccination. Half of the pups had CDV titers ≥32 at 20 wk of age. Titers to CPV were high in all pups prior to vaccination and dropped precipitously over the course of the vaccine series. At the last sampling period, only 50% of the pups had measurable CPV titers. An initially higher titer was seen for CDV in the IM administration group; however, this was not significant at later time points. Vaccination with Recombitek C3 appears to be safe and effected a sustained serological response to CDV in AWD.

Quantitative photogrammetric methodology for measuring mammalian belly score in the painted dog.

The use of “belly scoring” can offer a novel, non-invasive objective management tool to gauge food intake between individuals, groups, and populations, and thus, population fitness. As food availability is increasingly affected by predation, ecological competition, climate change, habitat modification, and other human activities, an accurate belly scoring tool can facilitate comparisons among wildlife populations, serving as an early warning indicator of threats to wildlife population health and potential population collapse. In social species, belly scores can also be a tool to understand social behavior and ranking. We developed and applied the first rigorous quantitative photogrammetric methodology to measure belly scores of wild painted dogs (Lycaon pictus). Our methodology involves: (1) Rigorous selection of photographs of the dorso/lateral profile of individuals at a right angle to the camera, (2) photogrammetrically measuring belly chord length and “belly drop” in pixels, (3) adjusting belly chord length as a departure from a standardized leg angle, and (4) converting pixel measurements to ratios to eliminate the need to introduce distance from the camera. To highlight a practical application, this belly score method was applied to 631 suitable photographs of 15 painted dog packs that included 186 individuals, all collected between 2004–2015 from allopatric painted dog populations in and around Hwange (n = 462) and Mana Pools National Parks (n = 169) in Zimbabwe. Variation in mean belly scores exhibited a cyclical pattern throughout the year, corresponding to biologically significant patterns to include denning demand and prey availability. Our results show significant differences between belly scores of the two different populations we assessed, thus highlighting food stress in the Hwange population. In the face of growing direct and indirect anthropogenic disturbances, this standardised methodology can provide a rapid, species-specific non-invasive management tool that can be applied across studies to rapidly detect emergent threats.

Cave canem! The earliest Canis (Xenocyon) (Canidae, Mammalia) of Europe: Taxonomic affinities and paleoecology of the fossil wild dogs

Unlike their medium-sized relatives of the genus Canis, whose arrival is dated around 3 Ma, the appearance in western Europe of large-sized hypercarnivorous canids took place at the beginning of the late Villafranchian (ca 2 Ma). Here, we report the earliest occurrence in this part of Eurasia of a Canis (Xenocyon) from the French site of Roca-Neya (Perrier area, recently dated to 2.6 Ma). Although represented only by mandibular specimens, the morphological and morphometric features resemble those of Canis (Xenocyon) falconeri (Forsyth Major, 1877), a large-sized canid with clear dentognathic adaptations to hypercarnivory, yet less developed compared to other later forms of this group. In our analysis, we revised the features of the subgenus Xenocyon and the present knowledge about these enigmatic forms. Following several studies, we performed analyses with the aim of providing the first estimate of the dietary preferences of Canis (Xenocyon) using selected morphometric ratios. The hypercarnivorous diet of this group was supported, while also the results indicate peculiar dentognathic proportions possessed by these fossil canids that differ from modern ones. The stoutness and development of some characteristics in the sample from Roca-Neyra (e.g., the depth of the mandible, the arched lower toothrow, the sturdy teeth) suggest high regimes of stresses in the mandible related to its predatory behavior.

Captive rearing of orphaned African wild dogs (Lycaon pictus) in Namibia: A case study.

African wild dogs (AWDs; Lycaon pictus) are an endangered canid species facing drastic decline throughout their range due to habitat fragmentation and persecution by humans over livestock depredation, resulting in dens destroyed and adult members of packs and pups often being killed. Breeding of captive AWDs is challenging due to high juvenile mortality, only marginally improved from wild conditions, thus both in situ and ex situ conservation remains critical. As a result of human-wildlife conflict, between 2017 and 2018, the Namibian Ministry of Environment, Forestry and Tourism confiscated three litters of orphaned AWD pups from rural farmers who had destroyed the dens in Eastern Namibia and placed the pups with the Cheetah Conservation Fund. Seventeen of the 18 pups were successfully reared to yearlings with 15 individuals translocated for eventual soft release into a private game reserve. This case study provides information on the successful rearing of three litters of orphaned wild dog pups on behavior, housing, husbandry, diet, growth and medical issues as limited information is available for rearing orphaned pups from the age of 2.5 weeks old.

OCORRÊNCIA DO VÍRUS DA RAIVA NA POPULAÇÃO SELVAGEM DE SAGUIS CALLITHRIX GEOFFROYI (HUMBOLDT, 1812) NO SUDESTE DO BRASIL

Background: Zoonosis, which causes acute and lethal encephalitis, is transmitted through the inoculation of the virus present in the saliva of mammals of several species. In Brazil, wild rabies is a challenge for epidemiological surveillance and a significant increase has already been observed in human cases. Some of the main wild reservoirs are: wild dog (Cerdocyon thous), marmosets (Callithrix sp) and hematophagous bats (Desmodus rotundus). Considering cases of positivity in marmosets in the Northeast of Brazil, together with the increasing number of cases in wild animals, this work aimed to survey the occurrence of the virus in a wild population. The animals were necropsied from the tramway ES-060, all of the Callithrix geoffroyi. The material collected for analysis of the rabies virus consisted of brain, which was conditioned and identified for later analysis at the Institute of Agricultural and Forest Defense of Espírito Santo (IDAF). The 44 samples gave negative results. The study suggests that the occurrence of the virus should be investigated in other localities, especially in regions closer to sites that have already been reported cases of rabies, and that the use of trampled animals is feasible for a better understanding of wildlife health.

A spatial capture-recapture model for group-living species.

Group living in species can have complex consequences for individuals, populations, and ecosystems. Therefore, estimating group density and size is often essential for understanding population dynamics, interspecific interactions, and conservation needs of group-living species. Spatial capture-recapture (SCR) has been used to model both individual and group density in group-living species, but modeling either individual-level or group-level detection results in different biases due to common characteristics of group-living species, such as highly cohesive movement or variation in group size. Furthermore, no SCR method currently estimates group density, individual density, and group size jointly. Using clustered point processes, we developed a cluster SCR model to estimate group density, individual density, and group size. We compared the model to standard SCR models using both a simulation study and a data set of detections of African wild dogs (Lycaon pictus), a group-living carnivore, on camera traps in northern Botswana. We then tested the model's performance under various scenarios of group movement in a separate simulation study. We found that the cluster SCR model outperformed a standard group-level SCR model when fitted to data generated with varying group sizes, and mostly recovered previous estimates of wild dog group density, individual density, and group size. We also found that the cluster SCR model performs better as individuals' movements become more correlated with their groups' movements. The cluster SCR model offers opportunities to investigate ecological hypotheses relating group size to population dynamics while accounting for cohesive movement behaviors in group-living species.

Life-Threatening Panfacial Wild Dog Bites in a Child

Infants and toddlers can sustain grievous craniofacial injuries after dog bites, some of which may be life-threatening. An 18-mo-old male child presented to our emergency department with complex panfacial wounds after being bitten by an unvaccinated wild dog 6 h earlier. Primary management, hemostasis, and rabies postexposure prophylaxis were performed near his home. Initially, he was resuscitated from severe hemorrhagic shock and anemia in a pediatric intensive care unit. After stabilization, early primary repair of all facial injuries was performed. Surgical exploration revealed multiple full-thickness avulsions, lacerations, nasal bone fractures, facial muscle injuries, and right ear necrosis. Gentle tissue-handling and meticulous reconstruction satisfactorily restored his facial soft-tissue contours about 64 h after the bite injury. Postoperatively, recovery was uneventful except for localized soft-tissue infection caused by multidrug-resistant Pseudomonas, which resolved with appropriate antibiotics. Nine months later, his face and ear appeared almost symmetrical with well-settled scars. Psychological recovery progressed smoothly, excepting few incidences of panic attacks that were triggered by loud noises. Here, we observed that early primary reconstruction of severely mauled soft tissues after wild dog bites, performed within 72 h with adequate precautions, safely produced satisfying long-term outcomes.

Cryptocotyle lata (Trematoda: Heterophyidae) Adult from a Korean Raccoon Dog, Nyctereutes procyonoides koreensis.

Total 513 heterophyid flukes were collected from a carcass of wild Korean raccoon dog, Nyctereutes procyonoides koreensis, in Korea. With morphological and molecular characteristics, the flukes were identified to Cryptocotyle lata. The adult C. lata were minute, transparent, pentagonal, 522 μm long by 425 μm wide. Ceca extended into post-testicular region. Ventrogenital sac elliptical, 79 μm by 87 μm with genital pore and ventral sucker. Two testes semielliptical and slightly lobed, located in the posterior region, right testis 173 μm by 155 μm, left testis 130 μm by 134 μm. In a phylogenetic tree, the fluke specimen of this study was grouped with C. lata divergent from Cryptocotyle lingua. We report here N. procyonoides koreensis first as a natural definitive host of C. lata.

Feeding Ecology of the Large Carnivore Guild in Madikwe Game Reserve, South Africa

Southern Africa has a diverse large carnivore guild. When this large carnivore guild is confined to fenced protected areas, the degree of intraguild competition may increase. Dietary overlap is a notable point of competition and can have considerable effects on lower trophic levels. We considered the prey preferences, dietary overlap, and dietary niche breadth of the large carnivore guild in Madikwe Game Reserve through direct observations and scat analysis, over one year of sampling. These data were analysed using the Jacobs' index for prey preference, the Pianka's index for dietary overlap and Levin's index for dietary niche breadth. Leopards (Panthera pardus), cheetahs (Acinonyx jubatus) and African wild dogs (Lycaon pictus) had a high degree of dietary overlap and were specialized in their diet selection. Lions (Panthera leo), brown (Parahyaena brunnea) and spotted hyaenas (Crocuta crocuta) also showed a high degree of dietary overlap and had broad diets. Our results show similarities to those of open systems, suggesting that large carnivore diet selection may not be negatively affected when they are confined by fences. We recommend further investigations into the variables which may affect site-specific carnivore diet selection.

Prevalence of Echinococcus Species in Wild Foxes and Stray Dogs in Qinghai Province, China.

ABSTRACT.Echinococcosis is a zoonotic parasitic disease that is highly endemic to the Qinghai province of China. Limited data are available on the prevalence of the causal pathogen, Echinococcus spp., in definitive hosts in this region. Thus, the aim of this study was to evaluate the prevalence of Echinococcus spp. in wild foxes and stray dogs in Qinghai province. Five hundred and twenty-eight feces from wild foxes and 277 from stray dogs were collected from 11 counties in the Golog, Yushu, and Haixi prefectures and screened for Echinococcus spp. using copro-DNA polymerase chain reaction (PCR). In total, 5.5% of wild foxes and 15.2% of stray dogs tested positive for Echinococcus spp. The prevalence rates of Echinococcus spp. in wild foxes in Golog, Yushu, and Haixi were 7.3%, 5.2%, and 1.9%, respectively. In stray dogs, these rates were 13.3%, 17.3%, and 0%, respectively. Sequencing analysis determined that Echinococcus multilocularis was the most prevalent species, occurring in 4.0% and 12.6% of wild foxes and stray dogs, respectively. Echinococcus shiquicus was observed in 1.5% of wild foxes and 0.7% of stray dogs. Echinococcus granulosus was observed only in wild dogs, with a prevalence rate of 1.8%. To our knowledge, this is the first report on the prevalence of E. shiquicus in dogs in Qinghai province. The current results improve our understanding of the transmission and dissemination of human echinococcosis and suggest that exposure to the eggs of E. multilocularis harbored by wild foxes and stray dogs may pose a great risk of alveolar echinococcosis to humans in Qinghai province.

A Case Study Exploring the Use of Virtual Reality in the Zoo Context

Virtual Reality (VR) is now a popular tool in education and for engagement with the natural world, but to date little research has investigated its potential in a zoo setting. We aimed to gauge the interest of the visiting public in using VR technology at Royal Zoological Society of Scotland’s (RZSS) Edinburgh Zoo. A VR (n = 12) and a video condition (n = 12), both introducing the lives and conservation concerns of African wild dogs (Lycaon pictus), were used to gain greater insight of the thoughts and perceptions of how individuals evaluated a purpose-built VR experience and to enable comparisons of learning outcomes for both technologies. We used semi-structured interviews; responses were evaluated through thematic analysis and descriptive analysis. Younger participants (aged 13-18 years) emphasized that VR allowed them close and personal access to the animals. Adult participants (aged 19 and above) pointed out the entertainment value of the VR experience while highlighting the potential of its educational aspect; that of enabling visitors to see animals in their natural habitat. While our results require further confirmation due to the limited sample size and restricted circumstances of data collection, we suggest that VR could be usefully introduced as a public education and visitor engagement tool that would benefit the visitors’ learning and overall experience at the zoo.

Automated behavioural monitoring allows assessment of the relationships between cow and calf behaviour and calves' survivability and performance

Calf mortality in northern Australia is one of the largest welfare and productivity constraints in the industry. The proximity of cows and their calves in the days after birth may provide valuable information linked to calf performance and survival. In this study, ten cows (n = 10) and their ten calves (n = 10) were monitored using Global Navigation Satellite System (GNSS) collars to measure the proximity between cow and calf, and their behaviours from birth. Cows were fitted with GNSS collars at time of pregnancy testing and calves were fitted with GNSS collars shortly after birth. Cows and calves maintained longer distances from other cows and calves during the first 3 days after calving compared to days 4–14 after calving (P < 0.05). Cows travelled longer distances than their calves during the first 4 days after calving (P < 0.05). Cows also travelled similar distances throughout the calving period however calves travelled shorter distances during the first week after birth (P < 0.05). Calving occurred at 1.35 ± 0.91 km from the water point on average and calves travelled up to 5.66 km/d on the day of birth. Daily distance travelled by both cows and calves, and distance from birth site increased during the first week (P < 0.05). Calf growth rate had a strong negative correlation with the distance cows travelled in the two weeks prior to calving (r = −0.79, P < 0.05) and a strong positive correlation with the time the cow spent near the water point in the first week after birth (r = 0.84, P < 0.05). Cow age was positively correlated with the distance between cows and calves during the first week after birth (r = 0.87, P < 0.05). Results from the present study showed that GNSS devices offer a powerful tool to understand the behaviour of cows and calves around the time of calving in extensive commercial conditions. This information may be helpful to understand risk factors of mortality in the early stages of calves’ lives, such as the separation between cows and their calves in the first week after birth which may expose calves to predation by wild dogs and dehydration in tropical regions. Further investigation is required to understand the impact of these behaviours on calf survival in extensive breeding operations.