Calf Survival Rates Research Articles

Evaluation of the outcomes of right paralumbar fossa colostomy for type II colonic atresia in calves: a report of 24 cases

The aim of the present study was to evaluate the effectiveness of right fossa paralumbar colostomy on the survival rate of calves with atresia coli maintained under Anatolian farming conditions. The clinical diagnosis was confirmed by clinical findings, pain and contrast radiographic examination. In clinical and indirect radiographic examination, rectum and descending colon were seen as more constricted than usual. In surgery, the abdominal cavity was opened through a vertical incision from the right paralumbar fossa. The blind end of the ascending colon was fixed to the abdominal wall in order to create a stoma. The postoperative course of the calves was obtained from the owners of the calves during a period of four months. It was learned that only one calf survived and the others died because of diarrhea within the four month period. In conclusion, this study demonstrated that although right fossa paralumbar colostomy was successfully performed for type-II atresia coli, severe functional impairment and fluid imbalance due to the loss of an important fluid resorption resulted in the death of most calves that were kept under Anatolian farming conditions.

REPRODUCTION ABILITY OF BULLS BY VARIOUS BODY CONFORMATION TYPES AND EXPRESSION OF MEAT FORMS

In the complex of measures of beef cattle improvement, essential in breeding is the choice of the desired body conformation type, which corresponds to certain direction of productivity. Reproductive traits of the Prydniprovskii breed type (PM -1) sires in ALLC "Volia", Zolotonostha district, Cherkasy region were evaluated depending on the body conformation types and development of meat forms. Conformation types were studied by the method of model deviations in rump height and body length from points of shoulders to pin bones. Body measurements were determined with a measuring stick at 18 months of age. By spitting the distribution of frequencies of deviations of the variation series over the measurements, large frame animals (big height and long bodied animals) and compact (low height and short bodied bulls) types of body conformation have been segregated. The development of the meat forms was determined by testing of the bulls’ own performance. It has been proved that greater volume of ejaculation, bigger number of spermatozoa in ejaculation with straight progressive movement, higher fertilizing ability of spermatozoa were associated with the bulls of large frame type as compared to compact type contemporaries. Under the pure breeding methods of selection, cows bred by large frame sires, have had easier calving. The offspring from compact-type bulls had larger forehead width, head depth, width at points of shoulders, and hip width, and lower body lengthas compared to the offspring from large frame sires. Survival rate of calves born from large frame sires until 8 months of age was higher. Bulls with better developed meat forms tend to have lower volume of ejaculation, concentration, and fertilizing ability of spermatozoa. Cows fertilized with their semen were more likely have difficult calving, which affected calves’ survival rate from birth to weaning. According to the results obtained, compact type bulls and bulls with better expressed meat forms have lower reproductive ability.

How to Improve the Survival Rate of Milk Calves

As a reserve force for a pasture, calf determines the future of the ranch and the future profi t of the ranch. The calf's scientifi c rearing is the most important part of sustainable development of a ranch. Calf management is a complex and detailed work, breeders need to consider three factors: nutrition, disease, and environment. In order to make calves become a good reserve cattle, it is important to ensure that calves have a balanced, adequate nutrition, reduce calving morbidity, mortality, and a suitable environment. More excellent young cattle can produce more prolific lactation cattle. This article introduce the calf feeding and management work from the feeding and management, environmental management and other aspects.

Pathology and Effect of Soil Nutrient Management in Berseem Var. BL-10 and Vit. A, Vit. D3, Vit. E Supplementation on Calf Growth and Calf Survival Rate

Future of dairy farmers depends on the successful raising of the young calves. Main objective of this trial is the doubling farmer income by dairy farming, reduce the calf mortality and to reduce the age at first calving. On the basis of statistical analysis its found that there is significant variation is noticed among all parameters such as variation in length, girth, height and body weight. The mortality percent determined for calf during the study period was 6.66 percent. In the present study the calf mortality recorded at unorganised dairy farm was relatively low perhaps can be attributed to both good management, feeding practices. It is important that the calf is given nutritious feed in the form of balance ration, multivitamin and fodder from its initial stage of rumen development. This will ensure good milk yield when it becomes a cow or produce better germplasm when its becomes a bull.

Hematologic, Blood Gas, Cardiac Biomarkers and Serum Biochemical Parameters in Calves with Atresia Coli and Theirs Relationship with Prognosis

Background: Atresia coli is an intestinal anomaly. Generally, absence of defecation in calves less than 10 days old, diminishing appetite, progressing abdominal distention and time-developing depression are reported in atresia coli. Although a calf consumes its milk normally in first days, loss of appetite develops over time. Occasional minor pain indications are observed. The objective of this study was to evaluate of hematologic, blood gases, cardiac biomarkers and serum biochemical parameters before operation in calves with atresia coli, and to investigate relationship with prognosis of these parameters.Materials, Methods & Results: Thirty calves with atresia coli and 6 healthy calves for control were used as material. Poor suction reflex, anorexia, dehydration, abdomen-kicking, frequent leg movement, abdominal distension and depression were observed in calves brought to the clinic. Some calves presented swashing sound depending on content of intestines when abdomen was shaken. Intestine atresia was diagnosed by history and clinical examination. After clinical examination, operation was performed. All calves were observed during 10 days after operation. Fifteen of 30 calves died during 10 days after operation. The blood lactate, WBC, LDH and CK-MB levels in non-surviving calves with atresia coli were significantly higher compared to control calves. The venous blood pH level was significantly lower in non-surviving calves compared to surviving calves. In addition, when compared to the control group, the blood pCO2 level was significantly higher in non-surviving and surviving calves with atresia coli while the pO2 and O2 saturation levels were significantly lower.Discussion: In calves with intestinal atresia, hematologic parameters are normal in first 48 h of disease. However, leukocytosis and shift to the left have been reported over time. However, leukocytosis due to peritonitis, bacterial overgrowth, etc. have been reported over time. It was seen that leukocyte numbers of non-surviving calves with atresia coli in this study were significantly higher, but leucocyte increase in surviving calves was seen to be statistically insignificant. Leukocyte increased in non-surviving calves with atresia may be associated with excessive bacterial reproduction and peritonitis. Blood lactate level is a commonly used marker for severity of disease in humans and lactate has a prognostic value in adult horses with colic and foals with critical disease. In this study, lactate level in non-surviving calves with atresia coli was significantly higher with respect to surviving calves and control calves. In this result, lactate can be evaluated as a prognostic indicator in calves with atresia coli. Creatine kinase-MB fraction and troponins are used in determination of cardiac damage in veterinary medicine. The fact that serum blood cTnI and CK-MB levels of non-surviving calves with intestinal atresia in this study were higher than surviving calves with atresia coli and control calves suggested that endotoxemia related cardiac damage may have developed. Surgical operation is necessary in the treatment of intestinal atresia. It was determined that the importance of calves age and colon integrity during time of surgical operation in survival of calves with atresia coli. The studies showed that survival rate in surgical operation conducted on calves under 3 days old was higher than calves over 5 day-old. Average of age of non-surviving calves with atresia coli in this study (4.67 ± 1.23 days) was higher than average of age of surviving calves with atresia coli (3.27 ± 0.51 days). It was also observed in our study that elapsed time affected prognosis of calves negatively. Thus, performing surgical operations as soon as possible may raise survival rate of calves with intestinal atresia as stated in previous studies.

REPRODUCTIVE PARAMETERS AND BIRTH STATISTICS FOR A HERD OF ASIAN ELEPHANTS ( ELEPHAS MAXIMUS) IN NORTH AMERICA OVER A 20-YEAR PERIOD.

We reviewed medical records documenting 28 pregnancies occurring within a herd of Asian elephants ( Elephas maximus) over a 20-yr (1994-2014) period at a private facility in the southeastern United States. Twenty-six pregnancies resulted in live calves and two ended in stillbirths. The 26 live births represented the offspring of 11 cows and 5 bulls. Twenty-four calves survived their first year, including two critically ill calves born after dystocias. Male and female calves occurred in almost equal numbers. Mean duration of labor in this group was 36 hr although the median duration was 13 hr. Although oxytocin was administered to several cows, parturition did not always immediately ensue. Female fecundity ranged from 1-6 calves while female age at parturition ranged from 9-46 yr. Females delivered their first calves between 9 and 26 yr of age whereas bulls sired their first calves in their 20s, on average. The number of live births and the 93% calf survival rate are among the highest reported in any western hemisphere elephant-holding facility. This may reflect the intensive management of cows before, during, and after each pregnancy, the number of experienced multiparous cows, and the skill level of staff, most of whom had worked with each other and with this herd for many years. The data presented here may assist facilities planning to breed Asian elephants.

VITAL SIGNS AND FIRST OCCURRENCES IN NORMAL AND ABNORMAL NEWBORN ASIAN ELEPHANT ( ELEPHAS MAXIMUS) CALVES.

Sixteen years of medical records documenting 19 births within a herd of Asian elephants ( Elephas maximus) at a private facility in the southeastern United States were reviewed. Of the 19 calves, 11 were normal at birth, requiring no additional veterinary care, and eight were abnormal, requiring veterinary care immediately or within the first week of birth. Descriptive statistics were used to evaluate morphometrics, vital signs, and behavioral milestones in newborn calves both normal and abnormal. Blood work and urinalysis results from all calves were compared to values for adult elephants. Medical management of abnormal calves is described. All calves had faster heart rates and respiratory rates than did adult elephants, but rectal temperatures were the same. Calves were precocious with regard to sitting and standing but could be very slow to nurse. The most-common medical conditions of newborn calves were umbilical abnormalities and problems associated with nursing. Two calves required cardiopulmonary resuscitation after birth but made full recoveries. Some conditions were not apparent at birth but were recognized a few hours or days later. Following veterinary intervention, six of the eight calves made full recoveries, suggesting that early identification and treatment of problems can greatly decrease mortality. This is the first report of multiple veterinary and behavioral parameters in normal and abnormal neonatal Asian elephants from a facility with a calf survival rate above 90%. This information may be helpful to other elephant-holding facilities in providing care to their newborn elephant calves.

Female reproductive success and calf survival in a North Sea coastal bottlenose dolphin (Tursiops truncatus) population.

Between-female variation in reproductive output provides a strong measure of individual fitness and a quantifiable measure of the health of a population which may be highly informative to management. In the present study, we examined reproductive traits in female bottlenose dolphins from the east coast of Scotland using longitudinal sightings data collected over twenty years. From a total of 102 females identified between 1997 and 2016, 74 mothers produced a collective total of 193 calves. Females gave birth from 6 to 13 years of age with a mean age of 8. Calves were produced during all study months, May to October inclusive, but showed a seasonal birth pulse corresponding to the regional peak in summer water temperatures. Approximately 83% (n = 116) of the calves of established fate were successfully raised to year 2–3. Of the known mortalities, ~45% were first-born calves. Calf survival rates were also lower in multiparous females who had previously lost calves. A mean inter-birth interval (IBI) of 3.80 years (n = 110) and mean fecundity of 0.16 was estimated for the population. Calf loss resulted in shortened IBIs, whilst longer IBIs were observed in females assumed to be approaching reproductive senescence. Maternal age and size, breeding experience, dominance, individual associations, group size and other social factors, were all concluded to influence reproductive success (RS) in this population. Some females are likely more important than others for the future viability of the population. Consequently, a better knowledge of the demographic groups containing those females showing higher reproductive success would be highly desirable for conservation efforts aimed at their protection.

Demography of the Pacific walrus (Odobenus rosmarus divergens) in a changing Arctic

AbstractThe Pacific walrus (Odobenus rosmarus divergens) is a candidate to be listed as an endangered species under United States law, in part, because of climate change‐related concerns. While the population was known to be declining in the 1980s and 1990s, its recent status has not been determined. We developed Bayesian models of walrus population dynamics to assess the population by synthesizing information on population sizes, age structures, reproductive rates, and harvests for 1974–2015. Candidate models allowed for temporal variation in some or all vital rates, as well as density dependence or density independence in reproduction and calf survival. All selected models indicated that the population underwent a multidecade decline, which began moderating in the 1990s, and that annual reproductive rate and natural calf survival rates rose over time in a density‐dependent manner. However, selected models were equivocal regarding whether the natural juvenile survival rate was constant or decreasing over time. Depending on whether juvenile survival decreased after 1998, the population growth rate either increased during 1999–2015 or stabilized at a lesser level of decline than seen in the 1980s. The probability that the population was still declining in 2015 ranged from 45% to 87%.

Relation between diarrhea and infection by protozoans in dairy calves

Infections caused by protozoa often cause diarrhea in newborn calves, leading to high economic losses to dairy farms, diarrhea, often characterized by malabsorption of nutrients, may lead to malnutrition, weight loss, and high mortality rates. Diarrhea is a common clinical sign found in the first days of a calf life in many dairy and beef cattle farms. Therefore, the aim of our study was to verify if during the first 60 days of live, there was a relationship between the presence of Eimeria, Cryptosporidium, Giardia, and the occurrence of diarrhea in calves, and the association of age and parasite presence. In this study, newborn calves were selected from farms with history of protozoa infections and diarrhea. A total of 26 calves were used in the study, 18 were positives for Giardia spp., 17 for Emeria spp., and 21 for Cryptosporidium spp., considering single and mixed infections. Furthermore, the survival rate of calves due to the presence of diarrhea was significantly different compared to the group without diarrhea, for all three protozoa. In addition, according to this study, it is possible to indicate that the occurrence of diarrhea is highly correlated to the presence of Giardia sp., leading to economic losses due to a low performance and weight gain of infected animals.

Factors influencing heterogeneity in female reproductive success in a Critically Endangered population of bottlenose dolphins

For threatened species or populations, variation in reproductive success among females may be explicitly linked with vulnerability to extinction. Thus, an understanding of factors that may cause variability in reproductive success is important. The population of bottlenose dolphins in Doubtful Sound, New Zealand, has a recent history of rapid population decline and low calf survival rates. A previous study has shown high variability in calf survival among multi- parous females. This study addresses the factors that seem most important in explaining variation in calf survival and thus reproductive success among females in this population. Reproductive data were sourced from a long-term photo-identification dataset, which allowed tracking the fate of 49 calves born into the population between 1995 and 2012. General linear mixed models combined with model averaging were used to assess how birth timing, maternal size, age and potential anthropogenic impacts contributed to variation in calf survival. Models show that a female's size and her ability to give birth at an optimum time in the calving season are significant predictors of calf survival to an age of 1 and 3 yr. This is the first study to demonstrate how birth timing and mother size are correlated with female reproductive success in a cetacean species. These results confirm the importance of demographic stochasticity and reproductive hetero - geneity in small, threatened marine mammal populations.

Comparisons of life-history parameters between free-ranging and captive killer whale (Orcinus orca) populations for application toward species management.

Data collected on life-history parameters of known-age animals from the northern (NR) and southern resident (SR) killer whales (Orcinus orca) of the eastern North Pacific were compared with life-history traits of killer whales located at SeaWorld (SEA) facilities. For captive-born SEA animals, mean age and body length at 1st estrus was 7.5 years and 483.7cm, respectively. Estimated mean age at 1st conception was different (P < 0.001) for the combined data from both northern and southern resident (NSR) free-ranging populations (12.1 years) compared to SEA (9.8 years), as was the estimated mean age at 1st observed calf (SEA: 11.1 years, NSR: 14.2 years, P < 0.001). Average calf survival rate to 2 years of age for SEA animals (0.966) was significantly greater (P = 0.04) than that for SR (0.799). Annual survival rate (ASR) for SEA increased over approximately 15-year increments with rates in the most recent period (2000–2015 ASR: 0.976) improved (P < 0.05) over the first 2 periods of captivity (1965–1985: 0.906; 1985–2000: 0.941). The SR (0.966) and NR ASR (0.977) were higher (P ≤ 0.05) than that of SEA until 2000, after which there were no inter-population differences. Based on ASR, median and average life expectancy were 28.8 and 41.6 years (SEA: 2000–2015), 20.1 and 29.0 years (SR), and 29.3 and 42.3 years (NR), respectively. The ASR for animals born at SEA (0.979) was higher (P = 0.02) than that of wild-caught SEA animals (0.944) with a median and average life expectancy of 33.1 and 47.7 years, respectively. These data present evidence for similar life-history parameters of free-ranging and captive killer whale populations and the reproductive potential and survivorship patterns established herein have application for use in future research concerning the overall health of both populations.

How does social behavior differ among sperm whale clans?

AbstractWhen individuals primarily associate with and learn from those who behave similarly, society and culture become closely tied. Sperm whales (Physeter macrocephalus) exhibit multilevel social structure, the levels of which are differentiated in part by characteristic cultural behaviors. Sperm whales are organized into sympatric clans, with distinctive vocal repertoires that are socially learned. Other behaviors, such as movement patterns and foraging, also differ among clans. Here we ask whether the clan partition also includes divergences in social behavior. Off the Galápagos Islands, members of two clans differed consistently in diving synchrony, heterogeneity, and temporal stability of social relationships. While number of associates (indicated by social unit, group, and cluster sizes) were similar between clans, Regular clan members dived more synchronously and had more homogeneous relationships than the Plus‐One clan members. Plus‐One social units had generally longer associations than those of the Regular clan. Differences in surface‐time coordination and quality of social relationships are likely byproducts of the clan segregation, which could affect alloparental care giving, therefore scaling up to differential calf survival rates between clans. This new dimension of behavioral divergence between sperm whale clans indicates that sympatric, socio‐cultural entities of nonhumans can also display characteristic social behavior.

Bottom-up and top-down influences on pregnancy rates and recruitment of northern Yellowstone elk

Declines in calf recruitment in some Rocky Mountain elk populations have raised concerns that recovering carnivore populations may be limiting elk population growth. To help resolve continuing questions about the influence of wolves (Canis lupus) reintroduced during 1995–1997 on elk calf production and survival, we conducted retrospective modeling of factors such as weather, elk density, and recovering carnivore populations potentially affecting northern Yellowstone elk pregnancy and calf survival using a long-term data set collected during 1985–2008. We found elk density negatively affected yearling pregnancy rate but had little effect on adult pregnancy rate. Adult pregnancy rate declined as individuals aged and increased following summers with higher precipitation but did not vary across a wide range of carnivore densities. Fall lactation rates, an indicator of early-season calf survival, increased with elk age and decreased as the ratio of grizzly bear (Ursus arctos horribilis) per elk increased. Over the 23 years of this study, the index of calf recruitment decreased as the wolf/elk ratio increased, decreased following severe winters, and increased as elk density decreased. Estimates of the wolf/elk ratio effect on calf recruitment were negative and confidence intervals did not overlap 0, whereas estimates of the wolf/elk ratio effect on elk pregnancy and early calf survival were positive and confidence intervals did overlap 0. Although a myriad of factors affect each stage leading to calf recruitment, and some of these factors such as weather are out of management control, management actions aimed at reducing wolf densities may result in increasing calf survival and elk population growth rates. However, the desire to manage wolf numbers to achieve a balance with ungulate population objectives must be balanced with other social considerations such as the desire to maintain wolf populations for tourism and wildlife-watching opportunities. © 2014 The Wildlife Society.

Higher than expected growth rate of the Endangered West African giraffeGiraffa camelopardalis peralta: a successful human–wildlife cohabitation

AbstractThe West African giraffe is a genetically unique population represented only by the subspeciesGiraffa camelopardalis peralta, categorized as Endangered on the IUCN Red List. These giraffes live outside protected areas, without natural predators and share their habitat with local people and their livestock. This study provides demographic data on this poorly studied megaherbivore and documents its recovery. We analysed the results of photo-identification censuses from 1996 to 1999 (count data) and from 2005 to 2008 (count and demographic data). From 1996 to 1999 the annual growth rate was c. 19% because of an unbalanced population structure after a period of severe poaching. From 2005 to 2008 an annual growth rate of c. 12–13% was estimated from both count data and demographic parameters. This value fits with the maximum growth rate calculated for a browser species based on the allometric relationship linking growth rate and body mass. During the period 2005–2008 adult and subadult females had a constant survival rate of 0.94 and a constant recapture rate of 0.97. Annual calf survival rate was 1. Observed sex ratio at birth was 0.57 and mean reproductive success was 0.257. Generation time was estimated to be 9.66 years. This spectacular population growth was mostly attributed to the absence of predators and the ongoing monitoring to limit illegal hunting.

Comment to “Acute Arthritis Secondary to Intravesical Bacillus Calmette-Guérin for Bladder Cancer”

A longitudinal observational study of 15 red deer (Cervus elaphus) farms was carried out in New Zealand for 2 years from Mar 1992. Management of hind mobs and their composition during mating, calving, and weaning were recorded. About 2700 hinds were individually monitored for live weight, body condition score and reproductive success. All hinds were pregnancy tested in June by ultrasound and classified as having conceived before May 1, after May 1, or as being not pregnant. Calving dates and dam–offspring pairs were recorded on four farms. The lactational status of hinds and live weight of calves were recorded at weaning. Mean pre-mating live weights of yearling hinds were 81.3–82.8 kg and of adult hinds 98.0–98.7 kg, respectively, for each year of study. The percentage of yearling and adult hinds conceiving before May ranged from 8.3 to 95.0% and from 77.6 to 98.4%, respectively, between farms. Overall, the proportion of yearling and adult hinds not pregnant was 15.3% and 3.2%, respectively. Pregnancy rates at scanning of adult hinds within mating mobs were generally over 90%, and 41.7% of mating mobs had 100% pregnancy rates. In contrast, the pregnancy rates of yearling hind mobs were more variable, with five mobs below 50%, and 34.1% of mating mobs achieving 100% pregnancy rate. Estimated in utero loss rates from pregnancy diagnosis to calving were 0.66 and 0.79% for yearling and adult hinds, respectively. From four farms, median calving dates of yearling and adult hinds were Dec 13 and Nov 30, respectively. Overall, calf survival rates to weaning of yearling and adult offspring were 84.1 and 91.6%, respectively, while the reproductive efficiencies (number of calves weaned per hind mated) were 70 and 83.6%, respectively. Farm mean weaner live weights standardised on Apr 1 ranged from 42–59 kg and 39–51 kg for stags and hinds, respectively. These data are currently the best estimates of reproductive parameters of New Zealand red deer herds, and highlight a wide variability in reproductive indices between farms.

Moose (Alces alces) calf survival rates in the presence of wolves (Canis lupus) in southeast Norway

Wolves (Canis lupus) are recolonizing Scandinavia and becoming a new limiting factor that should be taken into account in the management of moose (Alces alces). However, there is a lack of empirical estimates of moose survival after wolf recolonization. We investigated the effects of wolf abundance, moose litter size (single/twin calves), and climatic factors on annual and seasonal calf survival rates in a moose population in southeast Norway. We used data that were obtained over 7 years by radio-tracking and regular visual observations of 68 moose cows to determine the presence or absence of calves at heel. Annual and winter calf survival rates were 20–40 percentage points lower in the wolf territory compared with previous estimates of moose calf survival in similar areas that lacked wolves. Cause-specific studies of mortality would further enhance our ability to determine the relative role of various limiting factors. Our study suggests that moose managers should regulate quotas to buffer the lower survival rates after wolf recolonization.

Calving rate, calf survival rate, and habitat selection of forest‐dwelling caribou in a highly managed landscape

AbstractLogging negatively affects the threatened forest‐dwelling caribou (Rangifer tarandus caribou) through its positive effects on large predator populations. As recruitment is a key component of caribou population growth rate, we assessed calving rates of females and calf survival rates during the most critical period for calf survival, the calving period. We also identified causes of calf mortality and investigated the influence of predation risk, food availability, and human disturbance on habitat selection of females during the calving period at both the home‐range and forest stand scales. We hypothesized that caribou should display habitat selection patterns to reduce predation risk at both scales. Using telemetry, we followed 22 females and their calves from 2004 to 2007 in a highly managed study area in Québec, Canada. Most females (78.5 ± 0.05 [SE]) gave birth each year, but only 46.3 ± 8.0% of the calves survived during the first 50 days following birth, and 57.3 ± 14.9% of them died from black bear (Ursus americanus) predation. At the home‐range scale, caribou selected calving areas located at upper slope positions and avoided high road density areas. Surprisingly, they also selected the forested habitat type having the lowest lateral cover (mixed and deciduous stands) while avoiding the highest cover (regenerating conifer stands). At the forest stand scale, caribou selected areas located at relatively high elevations and with a lower basal area of black spruce trees. The selection of upper slope positions likely favored spatial segregation between calving females and wolves (Canis lupus) but not black bear. Our results suggest that calving females used areas from which they could visually detect approaching predators. While wolf avoidance appeared to be effective in a highly managed landscape, caribou did not appear to have adjusted their predator avoidance strategy to the recent increase in black bear abundance, who have benefited from increased food abundance. This situation requires focused attention from wildlife managers as logging activities are progressing towards the north within the core of forest‐dwelling caribou range. © 2011 The Wildlife Society.

Effects of predator treatments, individual traits, and environment on moose survival in Alaska

AbstractWe studied moose (Alces alces) survival, physical condition, and abundance in a 3‐predator system in western Interior Alaska, USA, during 2001–2007. Our objective was to quantify the effects of predator treatments on moose population dynamics by investigating changes in survival while evaluating the contribution of potentially confounding covariates. In May 2003 and 2004, we reduced black bear (Ursus americanus) and brown bear (U. arctos) numbers by translocating bears ≥240 km from the study area. Aircraft‐assisted take reduced wolf (Canis lupus) numbers markedly in the study area during 2004–2007. We estimated black bears were reduced by approximately 96% by June 2004 and recovered to within 27% of untreated numbers by May 2007. Brown bears were reduced approximately 50% by June 2004. Late‐winter wolf numbers were reduced by 75% by 2005 and likely remained at these levels through 2007. In addition to predator treatments, moose hunting closures during 2004–2007 reduced harvests of male moose by 60% in the study area. Predator treatments resulted in increased calf survival rates during summer (primarily from reduced black bear predation) and autumn (primarily from reduced wolf predation). Predator treatments had little influence on survival of moose calves during winter; instead, calf survival was influenced by snow depth and possibly temperature. Increased survival of moose calves during summer and autumn combined with relatively constant winter survival in most years led to a corresponding increase in annual survival of calves following predator treatments. Nonpredation mortalities of calves increased following predator treatments; however, this increase provided little compensation to the decrease in predation mortalities resulting from treatments. Thus, predator‐induced calf mortality was primarily additive. Summer survival of moose calves was positively related to calf mass (β &gt; 0.07, SE = 0.073) during treated years and lower (β = −0.82, SE = 0.247) for twins than singletons during all years. Following predator treatments, survival of yearling moose increased 8.7% for females and 21.4% for males during summer and 2.2% for females and 15.6% for males during autumn. Annual survival of adult (≥2 yr old) female moose also increased in treated years and was negatively (β = −0.21, SE = 0.078) related to age. Moose density increased 45%, from 0.38 moose/km2 in 2001 to 0.55 moose/km2 in 2007, which resulted from annual increases in overall survival of moose, not increases in reproductive rates. Indices of nutritional status remained constant throughout our study despite increased moose density. This information can be used by wildlife managers and policymakers to better understand the outcomes of predator treatments in Alaska and similar environments. © 2011 The Wildlife Society.

Survival and cause‐specific mortality of elk Cervus canadensis calves in a predator rich environment

AbstractQuantification of basic demographic parameters such as survival rates and cause‐specific mortality is important for effective species management. We conducted a 4‐year study (during May 2005‐June 2009) of elk Cervus canadensis calf survival and cause‐specific mortality in Pennsylvania, USA. We captured and radio‐collared 93 elk calves ≤ 7 days old and monitored them weekly to detect mortality and cause of death. Of the 93 radio‐collared elk calves, 15 (16%) died during our study. Despite high black bear Ursus americanus and coyote Canis latrans densities, none of the mortalities were the result of predation. Causes of death included poaching (N = 3), legal harvest (N = 2), road kill (N = 2), pneumonia (N = 1) and rumen acidosis (N = 1). We were unable to determine the cause of mortality for six of the elk calves; however, predation was eliminated as a possible source of mortality in all unknown cases. Survival probabilities were similar between sexes and among years. Summer survival (birth‐31 October) was 0.92 (SE = 0.03, N = 93) and winter survival (1 November ‐ 1 April) was 0.90 (SE = 0.04, N = 79). Annual estimated elk calf survival was 0.82 (SE = 0.04, N = 93). Our findings suggest that Pennsylvania elk calves have a &gt; 80% chance of survival to one‐year of age, despite high densities of predators known to influence elk calf survival elsewhere. The high calf survival rates that we observed indicate the availability of high quality habitat leading to excellent physical condition of elk.