Evaluation of Body Size and Body Condition Indices in Muskrats

1993 ◽  
Vol 57 (4) ◽  
pp. 854 ◽  
Author(s):  
John A. Virgl ◽  
Francois Messier
2010 ◽  
Vol 31 (4) ◽  
pp. 558-562 ◽  
Author(s):  
Rodica Plăiaşu ◽  
Tibor Hartel ◽  
Raluca Ioana Băncilă ◽  
Dan Cogălniceanu ◽  
Joost Smets

AbstractBody condition is important because it is correlated with population and habitat quality parameters. Since the direct measurements are either lethal or unreliable, a wide range of non-lethal body condition indices has been proposed. The aim of our study was to apply and compare three body condition indices (Fulton's index, relative body condition mass index and residual index) using body size indicator – body mass data for 24 populations of the yellow bellied toad (Bombina variegata). The condition index should be independent of body size indicator, in this case snout vent length (SVL). Therefore we tested all three indices for the statistical independence of SVL and for the normality of distribution. Fulton's index violated the independence assumption, whereas the relative body condition mass index did not have a normal distribution. Residual index was found both independent of SVL and normally distributed. Moreover, the residual index highlighted biological significant differences on the basis of altitude and season. Our results recommend the residual index as a useful tool in amphibian monitoring and conservation.


1977 ◽  
Vol 24 (3) ◽  
pp. 377-385 ◽  
Author(s):  
M. J. Ducker ◽  
J. S. Boyd

SUMMARYBody size was estimated for 255 Greyface ewes using five linear body dimensions. On the basis of this calculated measure combined with a subjective measure of body size 50 small and 50 large ewes were selected for use in the experiment. Precise ovulation data were obtained by endoscopy and this technique allowed the ewes to be mated subsequently.Body size did not affect the mean ovulation rate of the ewes although, at the same level of body condition, the large ewes were 25% heavier than the small ewes. The ovulation rates and the numbers of lambs born were influenced by changes in live weight and body condition. For these reasons live weight per se was not a good indicator of ovulation rate as ewe live weight was a combination of both body size and body condition. At the same live weight small ewes in improving body condition had a significantly higher ovulation rate than large ewes in reducing body condition.The onset of the breeding season of the ewes was not affected by their body size. The mean date of onset of oestrous activity for both large and small ewes was 17 October 1972 at a latitude 55° 52′ N.


2013 ◽  
Vol 34 (4) ◽  
pp. 505-516 ◽  
Author(s):  
Carmen Burghelea ◽  
Dragos Zaharescu ◽  
Antonio Palanca

The great sensitivity of amphibians to land disturbance is one of the main causes that contributed to their worldwide decline. One fundamental approach in assessing amphibian ability to reflect habitat degradation is to measure their phenotypic changes in contrasting environments. We examined the extent to which several morphological traits of the endemic anuran Pelophylax perezi responded to agricultural conversion in Monegros, an arid region in NE Spain. Specifically, we determined how body size, body mass, body condition (BC) and fluctuating asymmetry (FA) of different frog classes varied among habitats with different degree of management, i.e. rice fields vs. control ponds (i.e. small reservoirs). Pelophylax perezi juveniles showed a decrease in size and mass in rice fields, revealing that early life stages are generally more susceptible to habitat alteration. Adult body condition, on the other hand, increased significantly in cultivated habitats, which apparently indicates a good fitness in this size class. Nonetheless, skeletal asymmetry of both, juveniles and adults was significantly higher in rice fields. Moreover, during postmetamorphic development FA increased significantly towards adult stage indicating that the development controlling mechanisms were not able to buffer the stress induced by land use change. Among traits, humerus, radio-ulna and metatarsal were highly sensitive in terms of expressing significant FA differences between habitats, contrary to tibio-fibula, whose precise symmetry is essential for animal locomotion. The former bones have therefore the potential to be used as sensitive indicators of stress in amphibians. FA showed no relationship with body condition. This, together with the previous results demonstrates that FA is able to capture habitat stress more reliably than the morphological estimates such as body size, mass and BC. Therefore, FA is a useful morphological tool, highly recommended to monitor stress levels in amphibian populations.


2009 ◽  
Vol 59 (2) ◽  
pp. 201-209 ◽  
Author(s):  
John Maerz ◽  
Joseph Milanovich ◽  
Andrew Davis ◽  
Jayna DeVore

AbstractAmphibians have long been known to display wide variation in erythrocyte morphology across species, but within species there has been little attention given to individual variation in red blood cell morphology. We captured 49 red-backed salamanders (Plethodon cinereus) from central Pennsylvania, USA and used image analysis procedures to measure erythrocyte morphology (size and shape) on blood smears made from all individuals. We then statistically examined whether variation in snout-vent-length, sex, tail loss, or capture location influenced these cell variables. Only snout-vent-length affected erythrocyte size and shape, with increasing body sizes associated with increasing cell areas and increasingly rounder cells. Further, erythrocyte shape was also associated with a measure of body condition that was corrected for body size, such that individuals with high body condition scores had rounder cells. Given the oxygen-carrying role of erythrocytes in all vertebrates, we suspect this discovery is related to size-related changes in oxygen demand, since total oxygen consumption increases with body size in an allometric manner. While our results warrant further investigation to understand the mechanism, the association we found between cell roundness and both body size and condition nevertheless indicates this parameter could be used to assess the health state of plethodontid salamanders in future research, provided non-destructive sampling is employed. Our results also underscore the value of hematological investigations in the study of animal biology.


1972 ◽  
Vol 78 (2) ◽  
pp. 245-249 ◽  
Author(s):  
J. C. Guerra ◽  
C. J. Thwaites ◽  
T. N. Edey

SUMMARYGroups of mature Merino ewes selected on the basis of either large or small bodysize were differentially fed during a pre-experimental period to produce subgroups of high and low body condition. These levels of body condition were maintained for 2 weeks before mating and for the first 5 weeks of gestation. Thereafter, the four subgroups grazed together until lambing.Big ewes had more multiple ovulations than small ewes (14/41 υ 6/53; P < 0·01), and there was a significant linear regression of ovulation rate on body size. Body condition was positively related to the incidence of multiple ovulations, but the regression of ovulation rate on body condition at mating failed to reach significance. Body weight was significantly related to both ovulation rate and the incidence of multiple ovulations, and proved to be a more effective predictor of ovulation rate than either body size or condition.These results make it clear that size and condition, the two components of body weight, each have a considerable independent influence on some aspects of reproduction, and that the precision of some experiments and the effectiveness of some production routines could be improved by considering them separately.


2019 ◽  
Vol 65 (1) ◽  
pp. 117-126
Author(s):  
Kaarina Kauhala ◽  
Mika Kurkilahti

Abstract Environmental conditions of mammalian juveniles may have delayed effects on their life histories and fitness, such as body size or reproductive rate later in their lives. In the present study, we tested this hypothesis on Baltic grey seals (Halichoerus grypus) and examined (1) the possible effects of prey fish quality and winter temperature on body condition of grey seal pups of both sexes and (2) the possible delayed impacts of pup environment on the body size and birth rate of adult grey seals. Body condition (blubber thickness) of especially female pups in April–May correlated negatively with winter temperatures, and body condition of male pups correlated positively with prey fish quality (herring Clupea harengus and sprat Sprattus sprattus weight). Males reached the asymptotic length at the age of 10.3 years, and body length of adult males (≥ 10 years old) was positively related to herring and sprat weight in their birth year. Females reached the asymptotic length at the age of 5.9 years. Birth rate of females (age 7–24 years) was negatively related to winter temperature in their birth year. We conclude that both changes in prey fish quality and climate may affect body condition of pups and thus also cause delayed effects on adult fitness: body size and reproductive rate of Baltic grey seals.


2000 ◽  
Vol 16 (2) ◽  
pp. 427-436 ◽  
Author(s):  
K. W. Pitcher ◽  
D. G. Calkins ◽  
G. W. Pendleton

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