Reproduction in yearling female Columbian ground squirrels (Spermophilus columbianus)

1981 ◽  
Vol 59 (6) ◽  
pp. 1032-1035 ◽  
Author(s):  
M. Festa-Bianchet
Keyword(s):  
Weight Gain ◽  
Sexual Development ◽  
Weather Conditions ◽  
Ground Squirrels ◽  
Lower Weight ◽  
Spermophilus Columbianus ◽  
Adult Females ◽  
Lower Weight Gain ◽  
Columbian Ground Squirrels ◽  
Similar Growth

In 1980, 4 of 13 yearling female Columbian ground squirrels in a colony in southwestern Alberta raised litters. Mean litter size was not significantly smaller than that of adult females. Breeding and nonbreeding yearling females had similar growth rates as juveniles in 1979, but the former had a lower weight gain in 1980 before their young were weaned. Breeding yearling females were more aggressive and played less than nonbreeders. A combination of apparently good habitat quality in the study area and favourable weather conditions during summer of 1979 and in May of 1980 may have produced early sexual development of these females.

Weight in relation to sex, age, and season in Columbian ground squirrels (Sciuridae: Rodentia)

1981 ◽  
Vol 59 (6) ◽  
pp. 999-1004 ◽  
Author(s):  
D. A. Boag ◽  
J. O. Murie
Keyword(s):  
Weight Gain ◽  
Ground Squirrels ◽  
Full Potential ◽  
Age Classes ◽  
Adult Weight ◽  
Spermophilus Columbianus ◽  
Large Colony ◽  
Potential Weight ◽  
Columbian Ground Squirrels

Annual weight gain in Columbian ground squirrels (Spermophilus columbianus) was studied over a period of 7 years in a large colony in southwestern Alberta. Juveniles approximately tripled their weight during the period from emergence to immergence, achieving about 60% of adult weight at onset of their first hibernation. Males were heavier than females and the weight gain in both sexes varied significantly among years. The weight characteristics of the age-classes up to 3 years were different from one another. Full potential weight was not achieved until squirrels were in their fourth summer. Males were always significantly heavier than females in nonjuvenile squirrels and the amount of weight gained by these classes varied significantly among years.

The proximate causes of male-biased natal emigration in Columbian ground squirrels

1993 ◽  
Vol 71 (1) ◽  
pp. 204-218 ◽  
Author(s):  
Darwin R. Wiggett ◽  
David A. Boag
Keyword(s):  
Ground Squirrels ◽  
Home Ranges ◽  
Adult Males ◽  
Spermophilus Columbianus ◽  
Adult Females ◽  
Study Support ◽  
Proximate Causes ◽  
Natal Home ◽  
And Behavior ◽  
Columbian Ground Squirrels

The results of this study support the hypothesis that male-biased emigration of yearling male Columbian ground squirrels (Spermophilus columbianus) is socially induced. The likelihood of emigration from both the natal site and the natal colony was correlated with parameters of social structure and behavior. Agonism by the mother and (or) neighboring adult females, in association with parturition and lactation, apparently caused the initial shifts of yearling males away from their natal home ranges. After these shifts, yearling males that lived in areas where the number of neighboring males (both adult and yearling) was high relative to the number of females emigrated to areas within the natal colony that were more female-biased (intracolony emigration), or emigrated from the natal colony (intercolony emigration). Reduced numbers of adult males apparently resulted in lower rates of emigration by yearling males. Among the latter, emigrants appeared to be subordinate to non-emigrants. We discuss these findings in light of current hypotheses concerning the proximate and ultimate causes of emigration in ground-dwelling sciurids.

Effects of a late snowstorm and rain on survival and reproductive success in Columbian ground squirrels (Spermophilus columbianus)

1999 ◽  
Vol 77 (6) ◽  
pp. 879-884 ◽  
Author(s):  
Peter Neuhaus ◽  
Ron Bennett ◽  
Anne Hubbs
Keyword(s):  
Mortality Rate ◽  
Reproductive Success ◽  
Weather Conditions ◽  
Ground Squirrels ◽  
Mating Season ◽  
Spermophilus Columbianus ◽  
Adverse Weather Conditions ◽  
Adverse Weather ◽  
Body Mass Changes ◽  
Columbian Ground Squirrels

Body mass changes, reproductive success, and mortality were studied in Columbian ground squirrels (Spermophilus columbianus) in southern Alberta from 1994 to 1996. Spring weather conditions varied widely between years: 1994 was a dry, warm spring, 1995 was extremely rainy, and in 1996 a major snowstorm during the first 2 weeks of May stopped foraging by ground squirrels during the latter part of their mating season. We predicted that adverse weather conditions during the mating season in general, and this snowstorm specifically, would influence reproductive success and survival. Mass changes during the first 2 weeks of May varied from year to year and reflected major differences in spring weather. Female reproductive success was highest in 1994 and lowest in 1996. In 1996, we observed a higher mass loss during the first 2 weeks of May in females that subsequently did not wean a litter than in those that did. Weaning success was higher for females that mated after the snowstorm than for those that mated before or during the snowstorm. The mortality rate during mating in 1996 was higher in males than in females and was higher than in 1994 or 1995 for both sexes. Overall weaning success of females was highest in 1994 and lowest in 1996. We concluded that the energetic costs of mating can lead to a high mortality rate for males and low reproductive success for females.

The resident fitness hypothesis and dispersal by yearling female Columbian ground squirrels

1992 ◽  
Vol 70 (10) ◽  
pp. 1984-1994 ◽  
Author(s):  
Darwin Wiggett ◽  
David A. Boag
Keyword(s):  
Resource Availability ◽  
Ground Squirrels ◽  
Home Ranges ◽  
Adult Males ◽  
Data Set ◽  
Individual Basis ◽  
Spermophilus Columbianus ◽  
Adult Females ◽  
Fitness Benefits ◽  
Columbian Ground Squirrels

The emigratory behavior of yearling female Columbian ground squirrels (Spermophilus columbianus) in southwestern Alberta was studied for 25 active seasons among five colonies. From this data set we tested six predictions of the resident fitness hypothesis. The data strongly supported all six predictions: (1) yearling females were highly philopatric; (2) mothers behaved cohesively towards their yearling daughters (adult females tended to shift their home ranges in the presence of yearling daughter(s), often facilitating the recruitment of the latter to the natal site); (3) as densities of adult resident females rose and resource availability on an individual basis presumably declined, agonism from parous mothers and neighboring females caused greater proportions of yearling females to emigrate; (4) sibling daughters competed for access to the natal site when this space became vacant (parous yearlings were more successful than their nonparous siblings, and among the latter, dominant individuals were more successful than their subordinate siblings); (5) resident adult females were highly aggressive towards immigrant yearling females; and (6) resident adult males behaved cohesively with all yearling females, whether resident or immigrant, and were significantly more cohesive towards yearling females than towards yearling males. The results of this study suggest that emigration is not adaptive for yearling female Columbian ground squirrels. Rather, we suggest that female Columbian ground squirrels gain fitness benefits through philopatry and the retention of daughter(s) on the natal site when resources are not limiting.

The effects of capital on an income breeder: evidence from female Columbian ground squirrels

2005 ◽  
Vol 83 (4) ◽  
pp. 546-552 ◽  
Author(s):  
David R Broussard ◽  
F Stephen Dobson ◽  
J O Murie
Keyword(s):  
Path Analysis ◽  
Observational Data ◽  
Life Histories ◽  
Reproductive Investment ◽  
Ground Squirrels ◽  
Initial Capital ◽  
Spermophilus Columbianus ◽  
Live Trapping ◽  
Investment In Reproduction ◽  
Columbian Ground Squirrels

To maximize fitness, organisms must optimally allocate resources to reproduction, daily metabolic maintenance, and survival. We examined multiple years of live-trapping and observational data from a known-aged population of female Columbian ground squirrels, Spermophilus columbianus (Ord, 1815), to determine the influences of stored resources and daily resource income on the reproductive investments of females. We predicted that because yearling females were not fully grown structurally while producing their first litter, they would rely exclusively on income for reproduction, while reproductive investment in older females (≥2 years of age) would be influenced by both stored resources (capital) and daily income. Results from path analysis indicated that both yearlings and older females were income breeders. However, initial capital indirectly influenced investment in reproduction of yearling and older females. Females with the greatest initial capital maintained high body masses while investing relatively more income in reproduction. By considering influences of both capital and income, important relationships can be revealed between these resources and their influence on life histories.

Lower weight gain and higher expression and blood levels of adiponectin in rats fed medium-chain TAG compared with long-chain TAG

Lipids ◽  
2006 ◽  
Vol 41 (2) ◽  
pp. 207-212 ◽  
Author(s):  
Hiroyuki Takeuchi ◽  
Osamu Noguchi ◽  
Seiji Sekine ◽  
Aiko Kobayashi ◽  
Toshiaki Aoyama
Keyword(s):  
Weight Gain ◽  
Blood Levels ◽  
Medium Chain ◽  
Lower Weight ◽  
Lower Weight Gain ◽  
Long Chain

scholarly journals Influence of tail biting on weight gain, lesions and condemnations at slaughter of finishing pigs

2012 ◽  
Vol 32 (10) ◽  
pp. 967-974 ◽  
Author(s):  
Brenda Maria F.P.P. Marques ◽  
Mari L. Bernardi ◽  
Carolini F. Coelho ◽  
Mirian Almeida ◽  
Oscar E. Morales ◽  
...  
Keyword(s):  
Weight Gain ◽  
Finishing Pigs ◽  
Lesion Score ◽  
Farm Level ◽  
Lower Weight ◽  
Tail Biting ◽  
Condemnation Rate ◽  
Lower Weight Gain ◽  
Degree Of Severity ◽  
Lesion Severity

The present study assessed the association of tail-biting lesions in finishing pigs with weight gain, occurrence of locomotion or respiratory disorders and abscesses during finishing period, and carcass condemnation at slaughter. The study was carried out on 4 different farms. For each animal with a tail biting lesion, two control pigs were selected. The total number of animals in the study was 312, with 104 of them being tail-bitten. Tail lesions were classified according to the degree of severity into four scores: score 0 -normal tail withou lesion; score 1-3 - increasing lesion severity, and score 4 - healed lesions. Overall, the occurrence of severe tail lesions (score 3) varied from 55 to 73% of tail-bitten pigs among farms. On all farms, healing of tail lesions was observed in 95% to 100% of the animals at the evaluation performed within 41-43 days after the commencement of the study. In two out of the four evaluated farms, pigs with score of 3 showed lower weight gain (P<0.05) compared with score 0 pigs. Before slaughter, the occurrence of locomotion problems and nodules/abscesses was associated (P<0.05) with the presence of tail-biting lesions. At slaughter, tail-biting lesions were associated (P<0.05) with the presence of abscesses, lung lesions (pleuritis and embolic pneumonia) or arthritis in carcasses. Carcass condemnation was associated with the presence of tail-biting lesions (P<0.05). Overall, carcass condemnation rate was 21.4%, of which animals with tail-biting lesions accounted for 66.7% of condemnations. Among the animals diagnosed with cannibalism at farm level, only two had not healed their lesions at slaughter. The fact that there were a lot of carcass condemnations, despite the fact that tail-bitten animals had no more active lesions, suggests that different situations may be observed between the field and slaughter, reinforcing the need to analyze pigs both at farm and slaughter to allow proper assessment of losses related to tail biting. Collectively, the observations of the present study show that complications associated with tail-biting found in slaughterhouses are probably underestimating field prevalence.

Sign in / Sign up

Export Citation Format

Share Document