VARIATIONS IN THE WEIGHT OF THE ADRENAL GLANDS OF THE FIELD VOLE, MICROTUS AGRESTIS

1961 ◽  
Vol 22 (4) ◽  
pp. 387-393 ◽  
Author(s):  
HELEN CHITTY
Keyword(s):  
Body Weight ◽  
Breeding Season ◽  
Social Behaviour ◽  
Adrenal Glands ◽  
Microtus Agrestis ◽  
Field Vole ◽  
Lactating Females ◽  
Males And Females ◽  
The Mean ◽  
Fluctuating Populations

SUMMARY 1. Mean weights are given for the adrenal glands of 1167 male and 806 female voles from naturally fluctuating populations at Lake Vyrnwy, Wales, during 1952–58. 2. Although the mean standardized adrenal weights of both males and females varied from year to year, no consistent relationship with population trend could be found, except that females from expanding populations tended to have the heaviest adrenals. 3. The adrenal weights increased seasonally each year from low values in the spring to maxima in midsummer and decreased again to low values in the autumn. 4. This fluctuation was exhibited not only by breeding animals but also by those that were sexually immature. It therefore seems unlikely that the seasonal enlargement is entirely a direct effect of gonadal activity, though it may be due to changes in social behaviour during the breeding season. 5. In each month the adrenals of pregnant or lactating females were heavier than those of nulliparous animals of the same body weight.

scholarly journals Seasonal variations in blood parameters of the Amazonian manatee, Trichechus inunguis

2000 ◽  
Vol 43 (2) ◽  
pp. 165-171 ◽  
Author(s):  
Elton P. Colares ◽  
Ioni G. Colares ◽  
Adalto Bianchini ◽  
Euclydes A. Santos
Keyword(s):  
Body Weight ◽  
Blood Glucose ◽  
Seasonal Variations ◽  
Crude Protein ◽  
Blood Parameters ◽  
Total Proteins ◽  
Daily Food ◽  
Males And Females ◽  
The Mean ◽  
Mean Blood Glucose

Seasonal variations in body weight, food consumption and blood glucose, total lipids, urea, total proteins, albumin and globulins of captive Amazonian manatees, Trichechus inunguis, were determined. Body weight changed significantly along the year, increasing from autumn to spring and decreasing in summer. The mean daily food intake of paragrass remained almost unchanged along the year. Paragrass administered to the manatees showed important variations in crude protein and lipid content along the year. No significant differences in blood parameters were registered between males and females in all seasons. Further, there were no significant differences in blood total proteins, albumin and globulins along the year. On the other hand, significant differences in the mean blood glucose, lipids and urea were registered. An increase in the blood glucose in the spring and summer was observed. Blood urea and lipids levels were positively related to paragrass protein and lipids content. These two correlations suggested that these blood parameters are good indicators of the animal nutritional status in the Amazonian manatee.

Effect of body weight on the attainment of puberty and reproductive performance of Galway and Fingalway female lambs

1979 ◽  
Vol 28 (3) ◽  
pp. 297-307 ◽  
Author(s):  
J. F. Quirke
Keyword(s):  
Body Weight ◽  
Breeding Season ◽  
Litter Size ◽  
Conception Rate ◽  
Restricted Feeding ◽  
Ewe Lambs ◽  
Younger Age ◽  
Body Weights ◽  
The Mean ◽  
Ad Libitum

ABSTRACTGroups of spring-born Galway (G) and Fingalway (F) ewe lambs were fed a concentrate diet either ad libitum (H) or at a restricted level (L) during the period 25 July to 16 October 1974 in order to induce differences in body weight at the start of the breeding season. The mean live weights of the GL, GH, FL and FH groups on 16 October 1974 were 37·8 ± 1·3, 44·6 ± 1·3, 35·1 ± 1·1 and 41·9 ± 1·2 kg respectively. More than 95% of the lambs in all four groups attained puberty before 28 February 1975. Galway ewe lambs reached puberty later in the breeding season and were older and heavier at puberty than Fingalways. Animals fed ad libitum were heavier at puberty and attained puberty earlier in the season and at a younger age than those on the restricted feeding regime.Both conception rate and litter size were lower in Galways than Fingalways. There was no evidence of any effect of the nutritional treatments on conception rate or litter size. The mean body weights at puberty for ewes which lambed and those which were barren were 41·9 ± 0·49 and 41·5 ± 0·78 kg respectively. The birth weight and growth rate of the progeny of the ewe lambs was similar for the two breeds and was not influenced by the previous nutritional treatment of the dams. The total lamb mortality between birth and weaning was 40·3%, and 72% of all deaths occurred within 48 h of birth. Losses among twins (48%) were particularly heavy.

scholarly journals Factors affecting velvet antler weights in free-ranging reindeer in Alaska

Rangifer ◽  
1999 ◽  
Vol 19 (2) ◽  
pp. 71 ◽  
Author(s):  
Alexander K. Prichard ◽  
Greg L. Finstad ◽  
Drew H. Shain
Keyword(s):  
Body Weight ◽  
Positive Relationship ◽  
Factors Affecting ◽  
Significant Positive Relationship ◽  
Julian Date ◽  
Velvet Antler ◽  
Lactating Females ◽  
Males And Females ◽  
Seward Peninsula ◽  
Free Ranging

<p>Free-ranging reindeer on the Seward Peninsula in western Alaska are rounded up from late May to early July and antlers are removed. We used data collected from 1987 to 1997 to determine how velvet antler weights of males and females varied with age, year, reproductive status, Julian date, and body weight. Male antler weights increased with age up to age five years, and were lower in castrates than in bulls. There was a significant positive relationship between body weight and antler weight in both sexes. Female antler weights increased with age until at least age nine. Lactating females had lower antler weights than non-lactating females, but this effect is better explained by differences in body weight. Antler weight of individual reindeer at age two years was better predicted by their antler weights as yearlings than their body weight as yearlings.</p>

Serum cholesterol levels of inbred rats

1964 ◽  
Vol 207 (3) ◽  
pp. 631-633 ◽  
Author(s):  
David Kritchevsky ◽  
Shirley A. Tepper
Keyword(s):  
Body Weight ◽  
Serum Cholesterol ◽  
Inbred Strains ◽  
Female Rats ◽  
Male Rats ◽  
Liver Cholesterol ◽  
Cholesterol Levels ◽  
Male And Female Rats ◽  
Males And Females ◽  
The Mean

Changes in serum cholesterol levels with age have been studied in male and female rats of three inbred strains (BN, DA, and Lewis) and one random-bred strain (Wistar). The mean serum cholesterol levels at each age differed among strains. Serum cholesterol levels (mg/100 ml) for male rats at 30, 60, and 90 days were: BN-65, 46, and 47; DA-105, 85, and 101; Lewis-79, 76, and 57; and Wistar-64, 63, and 73. For female rats the values were: BN-56, 45, and 47; DA-86, 74, and 91; Lewis-77, 83, and 67; and Wistar-59, 71, and 83. The variation of serum cholesterol with age was different between strains, but similar for males and females within each strain. There was no correlation between body weight and serum cholesterol. Liver cholesterol levels (mg/100 g) determined at 90 days were, for the males, BN-187, DA-233, Lewis-247, and Wistar-300, and for the females, BN-188, DA-244, Lewis-216, and Wistar-249. No correlation with body weight or serum cholesterol was observed.

Reproduction in Sminthopsis-Longicaudata (Marsupialia, Dasyuridae) - Laboratory Observations

1986 ◽  
Vol 13 (1) ◽  
pp. 7 ◽  
Author(s):  
PA Woolley ◽  
A Valente
Keyword(s):  
Endangered Species ◽  
Breeding Season ◽  
Early Summer ◽  
Oestrous Cycle ◽  
Gestation Period ◽  
Late Winter ◽  
Breeding Condition ◽  
Males And Females ◽  
The Mean

Observations on the pattern of reproduction in Sminthopsis longicaudata, at present considered to be an endangered species, are presented. S. longicaudata is polyoestrous and in the laboratory females are in breeding condition from late winter (August) to early summer (December). They enter oestrus up to four times during the breeding season. Two litters were born 17 and 19 days post-mating, but the gestation period may be less than 15 days. The mean length of the oestrous cycle is 34.4 days. Both males and females may be able to breed in more than one season.

Reproduction in Sminthopsis-Macroura (Marsupialia, Dasyuridae) .1. The Female

1990 ◽  
Vol 38 (2) ◽  
pp. 187 ◽  
Author(s):  
PA Woolley
Keyword(s):  
Body Weight ◽  
Reproductive Tract ◽  
Corpora Lutea ◽  
Laboratory Colony ◽  
Histological Appearance ◽  
Lactating Females ◽  
Sminthopsis Macroura ◽  
The Mean ◽  
Mean Cycle ◽  
Breeding Seasons

A laboratory colony of S. macroura, founded by three females and four males, was maintained over four breeding seasons. Reproductive success was high and four generations were produced before the colony was disbanded. Descendants of these animals are still breeding in another laboratory 11 years after the founding of the colony. A detailed prescription for the maintenance and management of a breeding colony is given. The animals bred between June and February, most females first entering oestrus in the early months of the season, in July or August. Female young born early in the season (before mid-October) matured in the season of their birth at an age of 86-159 days; those born later matured in the following season at an age of 185-262 days. In each group, those born later matured earlier. Minimum body weight at sexual maturity was 12.5 g. At least two litters can be reared in a season and individuals may breed in more than one season. S. macroura is polyoestrous with a mean cycle length of 23.25 days. The gestation period is about 11 days and up to eight young can be accommodated in the pouch. Lactating females may return to oesrrus up to 10 days before the young are weaned at 70 days old. Ovulation occurs spontaneously and the mean number of corpora lutea formed was 20.7. The corpora lutea reach maximal size late in pregnancy and they regress more rapidly in lactating than in non- lactating females. Up to three generations of corpora lutea could be recognised in the ovaries of females undergoing cycles uninterrupted by lactation. Changes In body weight, the pouch, and the gross and histological appearance of the reproductive tract were the same in pregnant and pseudopregnant females.

Body weight and population dynamics: cyclic demography in a noncyclic population of the field vole (Microtus agrestis)

1992 ◽  
Vol 70 (3) ◽  
pp. 494-501 ◽  
Author(s):  
J. Agrell ◽  
S. Erlinge ◽  
J. Nelson ◽  
M. Sandell
Keyword(s):  
Body Weight ◽  
Population Growth ◽  
Unique Feature ◽  
Reproductive Season ◽  
Individual Growth ◽  
Microtus Agrestis ◽  
Field Vole ◽  
Extrinsic Factors ◽  
Body Weights ◽  
Individual Growth Rate

Differences in body weight, individual growth rate, survival, and recruitment of young between years were analysed in a noncyclic population of field voles (Microtus agrestis) to determine the respects in which this population differed from cyclic ones. Large differences in body weight, survival of both sexes, and recruitment of young existed between years. Over 4 years, body weight was positively related to population growth (measured as the change in density over the reproductive season). Also, the recruitment of young was higher in years when female voles were heavier and survived longer. Thus, the occurrence of high body weights in years when density is increasing or high is not a unique feature of populations showing cyclic density changes. Our findings indicate that survival is the primary factor connecting body weight to population growth. Neither genotypic changes nor variable predation pressure were likely to account for the between-years differences in body weight, survival, and recruitment. Instead food quality and (or) quantity, possibly affected by density, seem to be the primary extrinsic factors influencing individual quality, thereby influencing population growth. We propose that this population of field voles does in fact carry the potential for cyclic density changes, although predation prevents the manifestation of such a pattern.

Use of Nest Trees by the Mountain Brushtail Possum (Trichosurus caninus) (Phalangeridae : Marsupialia). III. Spatial Configuration and Co-occupancy of Nest Trees

1997 ◽  
Vol 24 (6) ◽  
pp. 661 ◽  
Author(s):  
D. B. Lindenmayer ◽  
A. Welsh ◽  
C. F. Donnelly
Keyword(s):  
Breeding Season ◽  
Spatial Configuration ◽  
Brushtail Possum ◽  
Adult Males ◽  
Long Distance ◽  
The Core ◽  
Eastern Australia ◽  
Large Trees ◽  
Males And Females ◽  
The Mean

Radio-tracking was used to examine the spatial configuration and co-occupancy of large trees with hollows occupied by 16 mountain brushtail possums (Trichosurus caninus) at Cambarville in the central highlands of Victoria, south-eastern Australia. The distance that animals moved between trees on successive days was also examined. Our analyses showed that animals often remained in a given den tree on successive days. On nights when animals did shift between den sites, they typically moved to a new tree that was relatively nearby (< 200 m). Long-distance movements (e.g. > 300 m) between den trees were rare. Considerable variation was found between individuals in the size of areas encompassing trees used frequently (≥5 times) (‘core denning range’) and those encompassing all occupied trees [i.e. including those used infrequently (< 5 times)] (‘total denning range’). The mean area of the core denning range averaged about 1·1 ha for males and 0·7 ha for females. The mean value for the total denning range was approximately 2·6 ha for males and females respectively. Considerable overlap was found in the total denning ranges of pairs of adult males and pairs of adult females. For most animals, the total denning range was shared with the total denning ranges of several other animals. There was substantial variation in the extent of this overlap, ranging from complete enclosure to the sharing of a single tree. The extent of overlap was more limited for the core denning ranges, particularly among females. We observed differences in the extent of the overlap of the total denning ranges of pairs of males and pairs of females in the breeding season (January–March) and non-breeding season (the remaining months of the year). Fewer instances of overlapping total denning ranges among pairs of both males and females were found during the breeding season. The total denning ranges in the breeding season were generally smaller than those in the non- breeding season. Simultaneous co-occupancy of a given den tree by T. caninus was relatively common. Unexpectedly, there was a number of instances of groups of three or four adult animals sharing the same den site on the same night. We recorded several instances of sharing by pairs of animals of the same sex, especially adult males. However, most records of simultaneous tree use were by an adult male and an adult female T. caninus. The extent of overlap in the denning ranges of animals and the prevalence of simultaneous co-occupancy of den trees indicate that the social behaviour of T. caninus at Cambarville may be different from that observed among populations of the species elsewhere in Australia. Possible reasons for these differences are outlined.

Changes in body size in fluctuating populations of the collared lemming: age and photoperiod influences

1981 ◽  
Vol 59 (2) ◽  
pp. 174-182 ◽  
Author(s):  
Frank F. Mallory ◽  
J. Richard Elliott ◽  
Ronald J. Brooks
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Breeding Season ◽  
Sexual Maturation ◽  
Population Fluctuations ◽  
Total Variability ◽  
And Shifts ◽  
Fluctuating Populations ◽  
Best Fit

Paired wet lens weights of 115 laboratory-reared collared lemmings were plotted against known age, to assess the reliability of this parameter, as a means of estimating age. Approximately 85% of the total variability in In age (A) was accounted for by In paired wet lens weight (W) (equation of best fit; In A (days) = −0.9771 + 2.186 In W (milligrams). In addition, variation in gender and photoperiod did not influence lens weight, although other parameters such as body weight and pelage were significantly affected.Field data from Eskimo Point, N. W.T., indicated that animals were older and heavier during the peak year (1973). Reduced recruitment and length of breeding season were observed during high densities, and sexual maturation was delayed in the nonbreeding segment of the population. Fluctuations in body size during microtine cycles were discussed as influenced by age, photoperiod, and shifts in the breeding season.

Sign in / Sign up

Export Citation Format

Share Document