Inbreeding effects among inbred and outbred laboratory colonies of Peromyscus maniculatus

1992 ◽  
Vol 70 (4) ◽  
pp. 820-824 ◽  
Author(s):  
David O. Ribble ◽  
John S. Millar

We examined the effects of sibling matings upon reproductive performance among inbred and outbred laboratory colonies of Peromyscus maniculatus. The inbred colony was founded by 12 females collected from one locality in Alberta and bred for 20 generations, with 35–45 pairs each generation. The outbred colony consisted of first-generation mice born of wild-caught females from diverse areas in Alberta. Consistent with theoretical expectations, there were no differences in reproductive performance between sibling and control (outbred) pairs within the inbred colony of mice. In contrast, sibling pairs had significantly fewer young per litter than control pairs within the outbred colony. Reproductive performance measures (proportion breeding, days from pairing to first litter, number of litters, and total number of offspring produced) were also significantly lower among sibling pairs from the outbred colony than among sibling pairs from the inbred colony. Lastly, we predicted that reproductive performance of the control pairs from the outbred colony would be less than that of control pairs from the inbred colony, due to outbreeding depression. Contrary to our predictions, average litter survival rates were greatest among the outbred colony control pairs. We suggest that the benefits of inbreeding or outbreeding extend broadly across the inbreeding–outbreeding continuum in natural populations of northern Peromyscus.

1983 ◽  
Vol 61 (5) ◽  
pp. 958-969 ◽  
Author(s):  
Arthur M. Martell

Populations of Clethrionomys gapperi and Peromyscus maniculatus were investigated on newly harvested upland black spruce (Picea mariana) clear-cuttings and in control areas (uncut, selective cut, older clear-cuttings) near Manitouwadge, Ontario. On control areas Clethrionomys had increased breeding intensity, better summer survival rates, and a relatively greater number of young in 1978 relative to 1976 and 1977. Those conditions appeared to be unrelated to summer weather and occurred after a cold, wet spring with a delayed snowmelt. Numbers of Clethrionomys on new clear-cuttings declined to nil over the first two summers following timber harvest. Demography on new clear-cuttings was similar to that on control areas except for poorer juvenile survival rates and fewer young. The disappearance of Clethrionomys from recent clear-cuttings was likely due to direct mortality. Demography of Peromyscus on control areas was similar each year except in 1978 when there was an increase in the breeding intensity of males and a decrease in the proportion of young. Numbers of Peromyscus on new clear-cuttings increased over the 3 years. Demography was similar on clear-cuttings and control areas in 1978, but in 1976 and 1977 the clear-cutting population had an excess of males, greater reproductive intensity of both males and females, more wounding of males, and less wounding of females. A highly mobile, young, male-dominated population with a high reproductive rate and a good summer survival rate was present on the 1- and 2-year-old cuts. Recent clear-cuttings in upland black spruce act as dispersal sinks for Peromyscus and provide new habitat for colonization by presaturation dispersers.


Animals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 197
Author(s):  
Hiroaki Okawa ◽  
Missaka M.P. Wijayagunawardane ◽  
Peter L.A.M. Vos ◽  
Osamu Yamato ◽  
Masayasu Taniguchi ◽  
...  

This study investigated the efficacy of intrauterine infusion of a chitosan solution (CHT) on uterine recovery in early postpartum dairy cows with or without endometritis, and their subsequent reproductive performance. In Experiment 1, cows with endometritis at 3 weeks postpartum were administered CHT (n = 5) and prostaglandin F2α (PGF2α) (n = 4). Untreated cows (n = 7) served as the control group. In Experiment 2, 18 cows with a normally recovered uterus at the fresh cow check (mean, 35 days postpartum) were assigned to the CHT (n = 10) and control (n = 8) groups, and intrauterine infusion was conducted in the CHT group. Overall, in Experiment 1, the percentage of polymorphonuclear leukocytes significantly declined in the CHT group (32.3 ± 10.2 to 5.5 ± 2.4, p < 0.05) from week 3 to week 5, but no decline occurred in the PGF2α and control groups. In Experiment 2, the CHT and control groups showed no significant differences in reproductive parameters, suggesting the absence of adverse effects of CHT on fertility. These results suggest that intrauterine infusion of CHT in the early postpartum period effectively accelerates uterine recovery from endometritis and might be a suitable replacement for PGF2α administration.


2017 ◽  
Vol 92 (6) ◽  
pp. 662-667 ◽  
Author(s):  
A.S.S. Sandri ◽  
R. Rodriguez ◽  
M.M. Costa ◽  
S.M. Porto ◽  
D. Schwingel ◽  
...  

AbstractAbdominal angiostrongyliasis (AA) is caused by Angiostrongylus costaricensis, which inhabits mesenteric arteries. There is no drug treatment for AA, and since intestinal infarction due to thrombi is one of the main complications of the disease, the use of anticoagulants may be a treatment option. Thus, we aimed to assess the effect of high doses of enoxaparin on the prevention of ischaemic intestinal lesions and on the survival of mice infected with A. costaricensis. Twenty-four mice were infected with L3 of A. costaricensis and divided equally into two groups: Group 1, control treated with placebo, and Group 2, treated daily with enoxaparin (2.5 mg/kg) for 50 days. All mice were subjected to necropsy and histological analysis. The results from gross and microscopic assessments showed no variation in the prevalence of lesions between the groups. An analysis was also performed among survivors and non-survivors, showing that animals that died often presented lesions, such as granulation tissue in the serosa, and intestinal infarction and adhesion. The mortality rate did not vary between the enoxaparin-treated and control groups. Thus, we showed that high doses of enoxaparin have no protective effect against AA, as the survival rates and lesions of mice did not vary between the treated and control groups. Considering that the use of prophylactic doses was also shown to be ineffective in a previous study, we do not recommend the use of enoxaparin for AA treatment.


1988 ◽  
Vol 45 (8) ◽  
pp. 1490-1494 ◽  
Author(s):  
Eric A. Parkinson ◽  
Kanji Tsumura

Coho (Oncorhynchus kisutch) and kokanee salmon (O. nerka) were sterilized using 17α-methyltestosterone treatments and released into a lacustrine environment. The treatment appeared to be successful and sizes at capture were similar for treated and control fish. Return rates of hormone-treated groups of fish were much lower than those of the control groups. Differences in return rates were assumed to be due to differences in survival rates but the possibility of differential vulnerability to the capture gear could not be ruled out. The proportion of treated kokanee in the catch increased with age, indicating that treated kokanee survived beyond the normal life span of the species.


1987 ◽  
Vol 65 (10) ◽  
pp. 2519-2523
Author(s):  
Gregory H. Adler ◽  
Mark L. Wilson ◽  
Michael J. DeRosa

A population of Peromyscus leucopus (white-footed mouse) in northeastern Massachusetts was manipulated for 3 years to determine the effects of adults on survival and recruitment. Two experimental grids were established, from which either all adult males or all adult females were removed continually. The effects of these two manipulations were compared with demography on a control grid. Manipulations had no apparent effect on breeding intensity of young, survival rates of adults, or residency rates of adults and young. Recruitment of adult males was higher on the adult male removal grid than on the control grid. Recruitment rates of adult males and of young males and young females were lower on the adult female removal grid than on the control grid. Survival rates of young males were higher on the adult female removal grid than on the control grid; this effect may have been due to either reduced adult female residency or adult male recruitment. All differences between experimental and control grids were noted only during breeding seasons. Adult males apparently limited recruitment of adult consexuals. The effects of manipulations on other measured parameters were inconclusive because of high immigration rates of adult males onto the adult male removal grid and reduced recruitment of adult males and decreased production of young on the adult female removal grid.


2008 ◽  
Vol 91 (10) ◽  
pp. 3869-3879 ◽  
Author(s):  
D.J. Wilson ◽  
Y.T. Grohn ◽  
G.J. Bennett ◽  
R.N. González ◽  
Y.H. Schukken ◽  
...  

1991 ◽  
Vol 71 (2) ◽  
pp. 589-591 ◽  
Author(s):  
R. N. Kirkwood ◽  
P. A. Thacker

One hundred gilts and one hundred mixed-parity sows of Yorkshire and Landrace breeding were inseminated with semen with or without an additional 10 μg estradiol-17β. Pregnancy rates of gilts receiving estradiol-supplemented and control semen were 90 and 79%, respectively (P < 0.09). The estradiol supplementation of semen did not improve the pregnancy rates or litter size in sows. Key words: Swine, artificial insemination, estradiol


Author(s):  
Charles R Siegel ◽  
Anjan Chakrabarti ◽  
Lewis Siegel ◽  
Forrest Winslow ◽  
Thomas Hall

Introduction: Out-of-hospital cardiac arrest (OHCA) remains a highly morbid public health problem. Despite improving practices and clear guidelines, mortality from this condition remains high at 90%, with survivors often suffering from poor neurologic outcomes. To determine the feasibility of quality improvement collaboratives to narrow gaps between evidence-based practice and patient care for OHCA, we conducted a pilot study of the AHA Resuscitation Collaborative. Methods: Eight emergency medical service agencies participated in the quality improvement collaborative pilot project. We identified several OHCA performance measures to assess the quality of care, guide collaborative activities, and monitor change in performance over time. Over the course of four learning sessions, participants were trained in quality improvement and performance measurement, analyzed performance measure results, and shared successes and challenges. Results: Five remaining agencies underwent the process outlined in Figure 1. Adherence to performance measures, including compression rate compliance (Figure 2), improved over the course of the collaborative. Compression rate compliance in Figure 2 corresponds to the process improvement efforts of the Chesapeake Fire Department with achievement of goals for optimal range of chest compression rate between 100 and 120 compressions per minute during resuscitations. Conclusion: As demonstrated in Virginia, the collaborative approach was an effective framework to improve OHCA care. Improvement in performance measures, the evident commitment of dedicated peers and colleagues, consistent collaboration, and the effective diffusion of best practices all support the continued use of this model.


Author(s):  
Norman B. Williamson ◽  

Reproduction is central to the operation of a dairy herd through initiating lactation and providing replacement animals and offspring for sale. This chapter outlines the steps required to detect reproductive problems and limitations in cows and herds. It then elaborates some strategies to overcome limits to reproductive health and production concentrating on detecting cows requiring attention through record monitoring, analysing herd records to monitor reproduction and identify areas that limit performance and providing strategies to deal with these limits. The main limits addressed are anoestrus and inadequate oestrus detection that are addressed through education of farm workers, aids to oestrus detection and the use of planned breeding programs to induce and control oestrus and breeding. Nutritional causes of limited reproductive performance are also considered as well as strategies to limit abortion.


2019 ◽  
Vol 188 (3) ◽  
pp. 839-847
Author(s):  
Megumu Tsujimoto ◽  
Hiroshi Kagoshima ◽  
Hiroshi Kanda ◽  
Kenichi Watanabe ◽  
Satoshi Imura

Abstract Studies on the long-term survival of animals often focus on the specific instance of survival of animals only, and descriptions of subsequent reproduction are generally not reported. In this study, we recorded the reproductive performance of the first-generation offspring of the resuscitated individual (SB-1) and the hatchling of the resuscitated egg (SB-3) of the Antarctic tardigrade, Acutuncus antarcticus, after being frozen for 30.5 years. By providing further detailed description of the reproduction of SB-1 and SB-3 after revival, and then comparing the reproductive performance with that of their first-generation offspring, the possible indications of the damage accrued during the long-term preservation in SB-1 and SB-3 were more specifically detected. Additionally, the DNA analysis revealed two distinctively different mitochondrial genetic sequences of A. antarcticus between the SB strains and the LSW strain. The observed differences in some of the reproductive parameters between the two genetic types suggested a possible relationship between the life-history traits and genetic type in the species A. antarcticus. Further experiments using the SB-1 and SB-3 strains reared for a long period to exclude the instant effect of preservation are expected to improve our understanding of the mechanisms underlying the long-term survival of animals.


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