scholarly journals Comparing the diversity of the casein genes in the Asian mouflon and domestic sheep

2020 ◽  
Vol 51 (3) ◽  
pp. 470-475 ◽  
Author(s):  
M.G. Luigi‐Sierra ◽  
E. Mármol‐Sánchez ◽  
M. Amills
Keyword(s):  
Domestic Sheep ◽  
Casein Genes

scholarly journals Determinants of Eimeria and Campylobacter infection dynamics in UK domestic sheep: the role of co-infection

Parasitology ◽  
2021 ◽  
Vol 148 (5) ◽  
pp. 623-629
Author(s):  
Raed Taha Al-Neama ◽  
Kevin J. Bown ◽  
Damer P. Blake ◽  
Richard J. Birtles
Keyword(s):  
Domestic Sheep ◽  
Infection Dynamics ◽  
Campylobacter Infection

Abstract

scholarly journals Linkage Disequilibrium in Domestic Sheep

Genetics ◽  
2002 ◽  
Vol 160 (3) ◽  
pp. 1113-1122
Author(s):  
A F McRae ◽  
J C McEwan ◽  
K G Dodds ◽  
T Wilson ◽  
A M Crawford ◽  
...  
Keyword(s):  
Linkage Disequilibrium ◽  
Type I Error ◽  
Statistical Significance ◽  
Domestic Sheep ◽  
Type I ◽  
Single Nucleotide ◽  
Microsatellite Genotype ◽  
Marker Distance ◽  
The Relationship ◽  
Two Populations

Abstract The last decade has seen a dramatic increase in the number of livestock QTL mapping studies. The next challenge awaiting livestock geneticists is to determine the actual genes responsible for variation of economically important traits. With the advent of high density single nucleotide polymorphism (SNP) maps, it may be possible to fine map genes by exploiting linkage disequilibrium between genes of interest and adjacent markers. However, the extent of linkage disequilibrium (LD) is generally unknown for livestock populations. In this article microsatellite genotype data are used to assess the extent of LD in two populations of domestic sheep. High levels of LD were found to extend for tens of centimorgans and declined as a function of marker distance. However, LD was also frequently observed between unlinked markers. The prospects for LD mapping in livestock appear encouraging provided that type I error can be minimized. Properties of the multiallelic LD coefficient D′ were also explored. D′ was found to be significantly related to marker heterozygosity, although the relationship did not appear to unduly influence the overall conclusions. Of potentially greater concern was the observation that D′ may be skewed when rare alleles are present. It is recommended that the statistical significance of LD is used in conjunction with coefficients such as D′ to determine the true extent of LD.

AROMATIZING ACTIVITY OF PLACENTAL MICROSOMAL FRACTIONS FROM EWES IN LATE GESTATION

1975 ◽  
Vol 65 (1) ◽  
pp. 117-125 ◽  
Author(s):  
M. R. MANN ◽  
L. B. CURET ◽  
A. E. COLAS
Keyword(s):  
Sharp Increase ◽  
Enzyme System ◽  
Hydroxysteroid Dehydrogenase ◽  
Relative Increase ◽  
Late Gestation ◽  
Domestic Sheep ◽  
Dramatic Rise ◽  
Oestradiol Production ◽  
Human Placentae

SUMMARY Placental microsomes from eight domestic sheep at 136–146 days of gestation were incubated with radioactive androstenedione, testosterone and dehydroepiandrosterone. Aromatizing activity was examined in the presence and absence of cortisol and the rates of both oestrone and oestradiol synthesis were measured. Oestrone predominated in preference to oestradiol in most of the incubations, a result opposite to that found with human placentae. The sharp increase in the rate of oestradiol production found in the 144- to 146-day-old placentae incubated with testosterone may indicate a more rapid increase of aromatizing than of 17β-hydroxysteroid dehydrogenase activity. The presence of cortisol in the mixtures did not significantly affect the placental aromatizing activity, indicating that there is no direct effect of cortisol on the enzyme system as measured in vitro. The dramatic rise of overall mean aromatizing activity from 4·86 ± 0·22 (s.e.m.) at 138–141 days of gestation to 12·96 ± 0·38 pmol/mg protein/min at 144–146 days (with a greater relative increase in the rate of oestradiol formation), suggests that changes in placental aromatizing activity may play an important role in maternal and foetal plasma oestrogen surges before ovine parturition.

The Origins of Domestic Sheep and Goats: a Reconsideration in the Light of the Fossil Evidence

1969 ◽  
Vol 34 ◽  
pp. 368-384 ◽  
Author(s):  
Sebastian Payne
Keyword(s):  
Direct Evidence ◽  
Present Situation ◽  
Wild Relatives ◽  
The Other ◽  
Domestic Sheep ◽  
Sheep And Goats ◽  
Animal Domestication ◽  
The Past ◽  
The One ◽  
And Control

In recent discussions of the origins and process of animal domestication (Reed, 1961, Zeuner, 1963), both authors rely on two kinds of evidence: on the one hand, the present distributions and characteristics of the different breeds of whatever animal is being discussed, together with its feral and wild relatives, and, on the other hand, the past record, given by literary and pictorial sources and the bones from archaeological and geological sites. Increased recognition of the limitations of the past record, whether in the accuracy of the information it appears to give (as in the case of pictorial sources), or in the certainty of the deductions we are at present capable of drawing from it (this applies especially to the osteological record), has led these authors to argue mainly from the present situation, using the past record to confirm or amplify the existing picture.Arguing from the present, many hypotheses about the origins and process of domestication are available. The only test we have, when attempting to choose between these, lies in the direct evidence of the past record. The past record, it is freely admitted, is very fragmentary: the information provided by the present situation is more exact, ranges over a much wider field, and is more open to test and control. Nevertheless, the past record, however imperfect it is, is the only direct evidence we have about the process of domestication.

Archaeological Evidence of Domestic Sheep in the Namib Desert During the First millennium AD

2016 ◽  
Vol 14 (1) ◽  
pp. 7-17 ◽  
Author(s):  
John Kinahan
Keyword(s):  
Southern Africa ◽  
Rock Art ◽  
Indirect Evidence ◽  
Domestic Sheep ◽  
Ritual Practice ◽  
Namib Desert ◽  
Broad Agreement ◽  
First Millennium ◽  
Changing Economy ◽  
Fundamental Shift

Bones of domestic sheep dated to the early first millennium AD are described from the Dâures massif in the Namib Desert. The remains confirm earlier investigations which inferred the acquisition of livestock from indirect evidence in the rock art, suggesting a fundamental shift in ritual practice at this time. Dating of the sheep remains is in broad agreement with the dating of other finds in the same area and in southern Africa as a whole. The presence of suspected sheep bone artefacts, possibly used for ritual purposes, draws attention to the importance of livestock as more than a component of diet in the changing economy of hunter-gatherer society.

The importance of survey design in distance sampling: field evaluation using domestic sheep

2011 ◽  
Vol 38 (3) ◽  
pp. 221 ◽  
Author(s):  
Tom A. Porteus ◽  
Suzanne M. Richardson ◽  
Jonathan C. Reynolds
Keyword(s):  
Population Size ◽  
Survey Design ◽  
Distance Sampling ◽  
Field Evaluation ◽  
Stage I ◽  
Stage Ii ◽  
Line Transect ◽  
Domestic Sheep ◽  
Management Decisions ◽  
Mobile Species

Context Sampling methods to estimate animal density require good survey design to ensure assumptions are met and sampling is representative of the survey area. Management decisions are often made based on these estimates. However, without knowledge of true population size it is not possible for wildlife biologists to evaluate how biased the estimates can be if survey design is compromised. Aims Our aims were to use distance sampling to estimate population size for domestic sheep free-ranging within large enclosed areas of hill country and, by comparing estimates against actual numbers, examine how bias and precision are impaired when survey design is compromised. Methods We used both line and point transect sampling to derive estimates of density for sheep on four farms in upland England. In Stage I we used limited effort and different transect types to compromise survey design. In Stage II we increased effort in an attempt to improve on the Stage I estimates. We also examined the influence of a walking observer on sheep behaviour to assess compliance with distance sampling assumptions and to improve the fit of models to the data. Key results Our results show that distance sampling can lead to biased and imprecise density estimates if survey design is poor, particularly when sampling high density and mobile species that respond to observer presence. In Stage I, walked line transects were least biased; point transects were most biased. Increased effort in Stage II reduced the bias in walked line transect estimates. For all estimates, the actual density was within the derived 95% confidence intervals, but some of these spanned a range of over 100 sheep per km2. Conclusions Using a population of known size, we showed that survey design is vitally important in achieving unbiased and precise density estimation using distance sampling. Adequate transect replication reduced the bias considerably within a compromised survey design. Implications Management decisions based on poorly designed surveys must be made with an appropriate understanding of estimate uncertainty. Failure to do this may lead to ineffective management.

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