Comparing body condition of moose (Alces alces) selected by wolves (Canis lupus) and human hunters: consequences for the extent of compensatory mortality

2012 ◽  
Vol 90 (3) ◽  
pp. 403-412 ◽  
Author(s):  
H. Sand ◽  
C. Wikenros ◽  
P. Ahlqvist ◽  
T.H. Strømseth ◽  
P. Wabakken

Predators commonly select prey of inferior quality compared with the average animals found in the population. Consequently, predation may often be compensatory to other sources of mortality. We tested whether wolves ( Canis lupus L., 1758) in Scandinavia selected moose in poor body condition by comparing mandibular marrow fat (MMF) of wolf-killed moose ( Alces alces (L., 1758)) with harvested moose. Model selection analyses indicated that MMF levels were lower for wolf-killed moose compared with harvested moose, but an unbalanced sample design between years for the two causes of death (wolves and harvest) may have confounded a clear interpretation of the results. Nevertheless, corrected MMF levels (to 1 April) showed that a significantly (p = 0.006) higher proportion of the wolf-killed calves (18.5%) were below the level often assumed to reflect acute malnutrition (<20% MMF) compared with harvested moose calves (3.3%). For wolf-killed yearlings and adult females, 5.6% and 8.3%, respectively, had MMF below this level compared with 0% for harvested individuals. As a result, 15.1% of the total number of wolf-killed moose and 1.6% of the harvested moose during winter appear to be compensatory to mortality from starvation. Differences in body condition, and thus levels of compensatory mortality, found between wolf-killed and harvested moose in this study may reflect a stronger selection for individuals in poor body condition by wolves.

2007 ◽  
Vol 139 (5) ◽  
pp. 678-684 ◽  
Author(s):  
B.H. King

AbstractWhen habitat quality is variable, there should be strong selection for the ability to detect and respond to the variation. Adult females of the parasitoid wasp Nasonia vitripennis (Walker) are known to increase their restlessness (the proportion of time in locomotion) both during and after exposure to a poor quality host. Doing so provides a mechanism for leaving a poor host and potentially finding a better host. This study examined whether restlessness also changes in response to competition as indicated by the presence of adult conspecifics. Both restlessness and the probability of dispersing across an inhospitable environment were greater when a female was with another female than when she was alone. However, restlessness did not remain elevated after the other female was removed. In contrast with females, restlessness of males did not increase either during or after exposure to other males, and the probability of dispersing across an inhospitable environment was unaffected by the presence of another male. The difference between females and males may be related to differences in dispersal ability and in the abundance and distribution of hosts versus mates.


Reproduction ◽  
2002 ◽  
pp. 419-427 ◽  
Author(s):  
JG Gong ◽  
WJ Lee ◽  
PC Garnsworthy ◽  
R Webb

Although it has become increasingly clear that fertility in modern dairy cattle is declining in association with increased milk yields, the underlying mechanism is poorly understood. The first ovulation post partum is delayed in dairy cows undergoing selection for genetic merit for milk yield in association with lower circulating insulin concentrations. The aim of this study was to investigate whether feeding a diet to increase circulating insulin concentrations can overcome this delay in the first ovulation post partum. The experiment was a 2 x 2 factorial design (n = 10 per group) involving diet and genetic merit for milk yield. The dietary treatment started on the day of calving and lasted for 50 days. Plasma samples were collected each day and ovarian ultra-sonography was performed three times a week during the experimental feeding period. Milk yield was recorded each day, and body weight and body condition score were determined each week. Milk samples were collected three times a week from day 50 to day 105 post partum, and reproductive performance data were recorded for all the cows as part of the routine farm practice. The dietary treatment induced significant differences in plasma insulin concentrations in both high and low genetic merit cows. Although high genetic merit cows produced more milk, lost more body weight and had lower body condition scores during the experiment, no significant effect of diet was observed on these measurements. The high insulin inducing diet increased the proportion of cows ovulating within 50 days of calving and reduced the intervals from calving to first ovulation, and tended to reduce the intervals from calving to first service and to conception. These fertility parameters were also more favourable in low than in high genetic merit cows, but no interaction between diet and genetic merit was observed for any of these parameters. Genetic merit, but not diet, also affected the number of services required per conception and the conception rate. In conclusion, these results have confirmed that genetic selection for high milk yield is associated with a decrease in reproductive performance in dairy cows. More importantly, this study has demonstrated that it is possible to alleviate this problem by nutritional manipulation.


1991 ◽  
Vol 69 (10) ◽  
pp. 2696-2699 ◽  
Author(s):  
Michael E. Nelson ◽  
L. David Mech

The survival of 159 yearling and adult deer (Odocoileus virginianus) was monitored by telemetry during 282 spring and 219 fall individual migrations to winter deeryards in northeastern Minnesota. A disproportionate number of deer were killed by wolves (Canis lupus) during fall migration relative to the short time they spent migrating, but not during spring migration. Predation was also significantly greater for male and female yearlings and adult females outside deeryards during winter. Survival of 79 yearlings dispersing from natal ranges was high (1.00). It appears that changing climatic conditions combined with unfamiliar terrain and undetermined factors predispose migratory deer to wolf predation during fall. These findings support an earlier hypothesis that winter yarding is an antipredator strategy.


2019 ◽  
Vol 59 (7) ◽  
pp. 1209 ◽  
Author(s):  
Viviane V. de Lacerda ◽  
Gabriel S. Campos ◽  
Daniel D. Silveira ◽  
Vanerlei M. Roso ◽  
Mario L. Santana ◽  
...  

The size and body condition of female livestock is critical for improving production efficiency. However, we know little about how height and body condition score in mature beef cattle are genetically related to traits observed when the animals are younger. In the present study, we used data from 321650 Nelore cattle, first, to compare genetic parameters and breeding values on the basis of different models employing weight (MW), height (MH) and body condition score (BCS) of mature cows (3–17 years old). Next, we estimated the genetic correlations between the three traits and assorted yearling traits (YW, weight; YC; conformation score; YP, precocity score; YM, muscling score; YN, navel score; LMA, longissimus muscle area; BF, back fat thickness). Finally, we obtained the expected direct responses to selection for MW, MH and BCS of cows and correlated responses for these traits when the selection was applied to yearling traits. For MW and MH, single-trait Bayesian analyses were used to evaluate the effects of including BCS when defining contemporary groups (BCS included, CG1; BCS not included, CG2). For BCS trait, linear and threshold animal models were compared. After, bi-trait analyses that included MW, MH or BCS with yearling traits were performed. The CG1 scenario resulted in a higher heritability for MW (0.45 ± 0.02) than did CG2 (0.39 ± 0.02). Both scenarios yielded the same heritability estimates for MH (0.35 ± 0.02). Sires’ rank correlations between predicted breeding values under CG1 and CG2 were 0.60–0.92 for MW and 0.90–0.98 for MH, considering different selection intensities. Thus, only for MW genetic evaluations, the incorporation of BCS in the definition of the contemporary groups is indicated. For BCS trait, the same sires were selected regardless of the model (linear or threshold). Genetic correlations between MW and five yearling traits (YW, YC, YP, YM and YN) ranged from 0.18 ± 0.03 to 0.84 ± 0.01. The MH had a higher and positive genetic association with YW (0.64 ± 0.02) and YC (0.54 ± 0.03), than with YN (0.18 ± 0.03). However, MH was negatively and lowly genetically correlated with YP (–0.08 ± 0.03) and YM (–0.14 ± 0.03). The BCS had positive genetic associations with all yearling traits, particularly with YP (0.61 ± 0.06) and YM (0.60 ± 0.07). Mature size and carcass traits exhibited a low to moderate negative genetic correlations. However, BCS had positive genetic associations with LMA (0.38 ± 0.12) and BF (0.32 ± 0.14). Despite a shorter generation interval, selection at the yearling stage will result in a slower genetic progress per generation than does direct selection for cow MW, MH or BCS. Moreover, using YW and YC as selection criteria will increase cattle size at maturity without altering BCS. Last, LMA or BF-based selection will reduce mature size, while improving BCS, as a correlated response.


2013 ◽  
Vol 127 (1) ◽  
pp. 70 ◽  
Author(s):  
L. David Mech ◽  
Michael E. Nelson

The ages of 77 adult Moose (Alces alces) killed by Gray Wolves (Canis lupus) during the period 1967–2011 in northeastern Minnesota were significantly older than those of a sample of 17,585 Moose killed by hunters in nearby Ontario. Our findings support those of earlier studies of protected Moose populations in national parks that found that Gray Wolves tend to kill disproportionately more older Moose.


2012 ◽  
Vol 58 (5) ◽  
pp. 863-868 ◽  
Author(s):  
Therese Ramberg Sivertsen ◽  
Atle Mysterud ◽  
Hege Gundersen

2011 ◽  
Vol 47 (1) ◽  
pp. 30-40 ◽  
Author(s):  
Glenn D. DelGiudice ◽  
Barry A. Sampson ◽  
Mark S. Lenarz ◽  
Michael W. Schrage ◽  
Andrew J. Edwards
Keyword(s):  

1992 ◽  
Vol 70 (12) ◽  
pp. 2441-2443 ◽  
Author(s):  
R. D. Boertje ◽  
R. O. Stephenson

We compared wolf (Canis lupus) reproductive data for March and April, when ungulate biomass per wolf was high, moderate, and low. The percentage of reproductively active adult females was significantly lower (66% compared with ≥96%, P < 0.001) when ungulate biomass per wolf was low versus moderate or high. Reproductively inactive adult females had significantly less subcutaneous fat (P < 0.01) than reproductively active females when ungulate biomass per wolf was relatively abundant. Average litter size, estimated by counting blastocysts or fetuses, declined significantly (P < 0.001), from 6.9 to 4.6, as ungulate biomass per wolf declined. We conclude that wolf productivity declines as prey availability per wolf declines. However, only when ungulate biomass per wolf declined below levels previously reported in the literature did we observe significant declines in reproductive potential. Ungulate biomass per wolf was low because of large, rapid declines in ungulates and lesser declines in wolves. We recognize that functional relationships, e.g., prey vulnerability and feeding dominance, can influence wolf productivity independently of ungulate biomass per wolf.


2019 ◽  
Vol 46 (8) ◽  
pp. 679 ◽  
Author(s):  
Sanjeeta Sharma Pokharel ◽  
Polani B. Seshagiri ◽  
Raman Sukumar

Abstract ContextPhysiological stress has the potential to influence animal population persistence. The endangered Asian elephant (Elephas maximus) is involved in intense conflict with humans in many parts of its range, which likely leads to stress for individuals and groups, with consequences for population survival. Thus, it is important to understand how the elephants’ stress levels are influenced by socio-ecological factors when not directly exposed to human-induced threats, and to use this understanding to improve conservation and management strategies. AimsThe present study was designed to provide baseline information on the link between socio-ecological factors and stress levels of undisturbed populations of elephants. The main aim was to determine the influence of a number of factors – herd size, season, number of calves and adult females present in a herd and their lactational status and body condition – on the adrenocortical activity of free-ranging adult female Asian elephants living in protected forests (without any direct exposure to human-induced threats), by measuring their faecal glucocorticoid metabolite (fGCM) levels. MethodsA total of 145 fresh faecal samples were collected from 123 identified adult female elephants inhabiting Bandipur and Nagarahole National Parks of southern India, between the years 2013 and 2015. fGCM levels were measured by employing a group-specific standardised 11-oxoetiocholanolone enzyme immunoassay (EIA). A generalised linear mixed-effects model (GLMM) was used to assess the influence of socio-ecological factors on fGCM levels of adult female elephants. Key resultsWhen fGCM levels were analysed with a GLMM, the following patterns were observed: fGCM levels were negatively correlated with the number of adult females (herd size) and positively correlated with the number of calves in a herd and active lactational status of an adult female. fGCM levels of adult female elephants were higher during the dry season (February to May) than wet season (August to December) and negatively correlated with body condition scores. ConclusionsAdrenocortical activity of female elephants is significantly influenced by the number of calves and adult females present in the herd, seasonality and lactational status. ImplicationsIt is important to consider the influence of multiple ecological and social correlates when assessing and interpreting the adrenocortical activity of Asian elephants. Our findings highlight the importance of maintaining the social structure of elephants in the wild to avoid detrimental effects on their physiological health. Insights from such assessments could be used to evaluate the stress in elephants that are involved in direct conflicts with humans to take appropriate management decisions for mitigating conflicts.


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