scholarly journals Heritability of distichiasis in Havanese dogs in Norway

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Kim K. L. Bellamy ◽  
Frode Lingaas ◽  
Per Madsen
Keyword(s):  
Animal Welfare ◽  
Threshold Model ◽  
Clinical Signs ◽  
Selection Response ◽  
Mass Selection ◽  
Corneal Disease ◽  
Eye Health ◽  
Norwegian Population ◽  
High Heritability ◽  
Simple Mass

Abstract Background Distichiasis is a presumed inherited eyelid disease, characterized by misplaced eyelashes. The effect on eye health and animal welfare varies between individuals; most mild cases show no clinical signs, but some affected animals develop painful corneal disease. In this study, we investigated the prevalence and heritability of distichiasis in the Norwegian population of Havanese dogs. Results A total of 1156 Havanese were included in the study. Out of these, 168 were affected with distichiasis, making the prevalence in our sample 14.5% (95% CI 12.5–16.6%). There was no sex predisposition. Most affected individuals were graded “mildly affected”. The estimates generally showed high heritabilities, which varied between 0.276 (linear model) and 0.720 (Bayesian threshold model). The linear estimates, after conversion to the underlying scale (h2l = 0.664–0.674), corresponds well to the results of the Bayesian models. Conclusions The estimated heritability of distichiasis in Havanese is high and the prevalence is moderate. The high heritability indicate that a significant selection response could be obtained by simple mass selection. To secure good animal welfare, it’s important to control the number of affected individuals and especially the severely affected.

scholarly journals A SIMULATION STUDY OF TRUNCATION SELECTION FOR A QUANTITATIVE TRAIT OPPOSED BY NATURAL SELECTION

Genetics ◽  
1980 ◽  
Vol 94 (4) ◽  
pp. 989-1000
Author(s):  
Francis Minvielle
Keyword(s):  
Natural Selection ◽  
Artificial Selection ◽  
Random Mating ◽  
Selection Response ◽  
Quantitative Character ◽  
Mass Selection ◽  
Frequency Selection ◽  
Selection Experiments ◽  
Selection For ◽  
Selective Process

ABSTRACT A quantitative character controlled at one locus with two alleles was submitted to artificial (mass) selection and to three modes of opposing natural selection (directional selection, overdominance and underdominance) in a large random-mating population. The selection response and the limits of the selective process were studied by deterministic simulation. The lifetime of the process was generally between 20 and 100 generations and did not appear to depend on the mode of natural selection. However, depending on the values of the parameters (initial gene frequency, selection intensity, ratio of the effect of the gene to the environmental standard deviation, fitness values) the following outcomes of selection were observed: fixation of the allele favored by artificial selection, stable nontrivial equilibrium, unstable equilibrium and loss of the allele favored by artificial selection. Finally, the results of the simulation were compared to the results of selection experiments.

The occurrence and severity of grass toxicoses in Australian alpaca (Vicugna pacos) herds

2008 ◽  
Vol 48 (8) ◽  
pp. 1099 ◽  
Author(s):  
Natalia Sampaio ◽  
Mark Gishen ◽  
Kevin Reed ◽  
Mel Brown ◽  
Daphne Gregory ◽  
...  
Keyword(s):  
Nervous System ◽  
Animal Welfare ◽  
Perennial Ryegrass ◽  
Strong Correlation ◽  
Clinical Signs ◽  
South Australia ◽  
Heat Sensitivity ◽  
Head Nodding ◽  
Vicugna Pacos ◽  
Pasture Grasses

A survey of 108 alpaca producers registered with the Australian Alpaca Association examined the occurrence and severity of ‘staggers’ (a colloquial term embracing various diseases of the nervous system in animals, characterised by neck tremors and head nodding in the milder alpaca cases and a lack of coordination in moving, a staggering gait and frequent falling in severe cases) in Australian alpaca and the presence of four pasture grasses, during three production seasons in 2004–2006. There have been few studies on the susceptibility of alpaca to staggers and its effect on productivity and animal welfare. The survey found that 23% of alpaca producers had observed staggering animals, with Victoria and South Australia being the most severely affected states. Clinical signs of staggers were most frequent in January–March, with a mean duration of 3 months. Some animals showed clinical signs lasting up to 12 months. A strong correlation was found between the presence of perennial ryegrass (P < 0.001) and phalaris (P < 0.003) and the occurrence of staggers. Based on grass presence and the timing when staggers was observed, it was concluded that perennial ryegrass toxicosis was the main cause of staggers in alpaca. About 12% and 9% of alpaca grazing pasture containing perennial ryegrass exhibited staggers in the two full seasons for which data were collected. Herds with staggering animals were correlated with those exhibiting possible subclinical effects – heat sensitivity and ill-thrift (P < 0.01) and reduced fertility (P < 0.05) – of perennial ryegrass endophyte toxins. Results indicate that weanlings and cria are more likely to stagger than adults. Thirteen of the 15 mixed farms with staggering alpaca did not observe staggers in other livestock, suggesting that alpaca may be more sensitive to the causal toxins than sheep and cattle.

scholarly journals SELECTION RESPONSE FOR HIGHER BODY WEIGHT IN NIGERIA'S INDIGENOUS CROSSBRED PIGS

2021 ◽  
Vol 22 (1) ◽  
pp. 21-27
Author(s):  
O. A. ADEBAMBO
Keyword(s):  
Body Weight ◽  
First Generation ◽  
Selection Response ◽  
Average Weight ◽  
White Line ◽  
Black And White ◽  
The Third ◽  
High Heritability ◽  
Foundation Stock ◽  
Crossbred Pigs

Six generations of population selection from 2 lines of improved indigenous pigs *NIGER HUBS" comprising pigs born from the year 1984 - 1990 were evaluated. Continued selection for higher body size resulted in observed increases in 150 day body weight of 26% in the white line A and 41% in the black and white line B from the average weight of the foundation stock and 76 to 84 per cent at 12 month of age for these lines of pius respectively. Moderately high heritability estimates of 0.36 to 0.69 were reported for both lines for the 150 day weight and 0.58 to 0.76 for the yearling weight. Response to selection was highest in the first generation of the Bline and the third generation of the A line. Overall response value of 5.79±1.28kg during the first generation declined to 5.01kg±1.08 during the second generation although this subsequently increased from the third to fifth generations. With the plateau not reached within this 6 generation of selection, further response may still be expected in these lines of pigs

scholarly journals Two-way within-family and mass selection for 8-week body weight in different mouse populations

1984 ◽  
Vol 43 (2) ◽  
pp. 191-200 ◽  
Author(s):  
Ines von Butler ◽  
Henning Willeke ◽  
Franz Pirchner
Keyword(s):  
Body Weight ◽  
Inbred Strains ◽  
Selection Response ◽  
Mass Selection ◽  
Individual Selection ◽  
Family Selection ◽  
Body Weights ◽  
Selection For ◽  
Size At Birth ◽  
Better Than

SUMMARYTwo mouse populations, randombred albino mice and a cross of four inbred strains, were divergently selected for high (H8) and low (L8) 8-week body weight over 18 generations using within-family and individual selection. The crossbreds showed asymmetry of selection response and realized heritabilities (H8 0·29 ± 0·01; L8 0·17 ± 0·01). In the randombred population realized heritabilities were symmetrical (H8 0·23 ± 0·01; L8 0·22 ± 0·02). Over the first nine generations individual selection was nearly 40 per cent better than within-family selection, as was expected from the full sib correlation in both populations. As selection progressed, within-family selection reached 82% and 61% of the responses obtained with individual selection in the crossbreds and randombred respectively. Correlated responses for 3-week (weaning) and 5-week body weights agreed with observations made on direct responses, but selection for L8 did not reduce weaning weight. Selection for L8 decreased and selection for H8 increased first litter size at birth. However, mass-selected L8-pairs had a higher life-reproduction and life-span than H8-pairs.

scholarly journals Severe canine distemper outbreak in unvaccinated dogs in Mozambique

2016 ◽  
Vol 87 (1) ◽  
Author(s):  
Julieta Zacarias ◽  
Alberto Dimande ◽  
Sara Achá ◽  
Paula T. Dias ◽  
Elisa M. Leonel ◽  
...  
Keyword(s):  
Developing Countries ◽  
Animal Welfare ◽  
Low Income ◽  
Immunohistochemical Staining ◽  
Canine Distemper Virus ◽  
Large Scale ◽  
Clinical Signs ◽  
Canine Distemper ◽  
Animal Suffering ◽  
Low Income Families

Although significant animal suffering caused by preventable diseases is frequently seen in developing countries, reports of this are scarce. This report describes avoidable animal suffering owing to a suspected canine distemper (CD) outbreak in unvaccinated dogs owned by low-income families in Mozambique that killed approximately 200 animals. Affected dogs exhibited clinical signs, and gross and microscopic lesions compatible with CD. Immunohistochemical staining confirmed the presence of canine distemper virus (CDV) in the kidney of one dog from the cohort. This brief communication again illustrates that large outbreaks of CDV in unvaccinated dogs occur and that large-scale avoidable suffering and threats to the health of dogs and wild canines continue. Mass vaccination supported by government and non-government organisations is recommended.Keywords: Canine distemper; dogs; outbreak; animal welfare; Mozambique

MASS SELECTION FOR POST-WEANING GROWTH IN SWINE. IV. SELECTION RESPONSE AND CONTROL POPULATION STABILITY

1976 ◽  
Vol 56 (4) ◽  
pp. 783-790
Author(s):  
G. W. RAHNEFELD ◽  
I. GARNETT
Keyword(s):  
Additive Genetic Variance ◽  
Average Daily Gain ◽  
Selection Response ◽  
Relative Magnitude ◽  
Control Population ◽  
Mass Selection ◽  
Gene Effects ◽  
Selection For ◽  
And Control ◽  
Daily Gain

Recurrent mass selection for post-weaning average daily gain was practiced for 11 generations in a population of Lacombe swine. Response to selection was assessed from predicted response, 0.241 ± 0.023 kg; observed response, 0.146 ± 0.018 kg; estimated heritability, 0.327 ± 0.031; and realized heritability, 0.198 ± 0.016. Observed response was estimated to be 0.61 of the predicted. Examination of additive genetic variance, selection differentials, drift variance, inbreeding and regression of post-weaning average daily gain on generation time indicated that the pedigreed Yorkshire control population served as an adequate control. Gene effects were not found to be dependent on the sex of the organism as assessed by the genetic correlation between sexes, covariance between half-sib family means and the relative magnitude of parent–offspring-based estimates of heritability.

scholarly journals Respon Seleksi Indeks Dasar pada Tanaman Jagung (Zea mays L.) di Lahan Kering

2020 ◽  
Vol 6 (2) ◽  
pp. 169
Author(s):  
I Wayan Sudika ◽  
I Nyoman Soemeinaboedhy
Keyword(s):  
Plant Height ◽  
Block Design ◽  
Genetic Parameter ◽  
Genetic Effect ◽  
Selection Response ◽  
Mass Selection ◽  
Initial Population ◽  
Randomized Block Design ◽  
Basic Index ◽  
Number Of Leaves

This research aimed to identificate the selection response, the avarage of yield and fresh stover weight of corn during eight cycles of mass selection with basic index technique and observe the genetic parameter of quantitative characteristics. The randomized block design was used to test the selected with 11 treatment populations. Each treatment was replicated 3 times, in order to obtain 33 experimental units. The experimental data were analyzed with analysis of variance at 5 % levels. The average treatment was tested by the LSD0.05. The selection response was obtained from the simple linear regression coefficient between the observed traits with selection cycles. The result of this research, shows the yield and fresh stover weight has a response mass selection with basic index technique per cycle at 0.230 kgplot-1 (3.39 %) and 10.633 gtan-1 (4.21 %), respectively; both of them moderate catagories. The average of yield of eighth cycle population was higher compare to initial population and Gumarang; but the same with Lamuru variety. The weight of fresh stover was the same between treatments. The yield of initial population, eighth cycle population, Gumarang and Lamuru varieties were 5.653 tha-1; 8.035 tha-1; 5.278 t ha-1 and 7.410 tha-1, respectively. The increased of plant height, total number of leaves per plant, number of fresh leaves at harvest and all yield components, were increased the yield. The increased of fresh stover weight occured when there were increased in plant height, total number of leaves, stem diameter and number of fresh leaves at harvest. The characteristic with the higher genetic effect than the environment effect found in weight of ear harvest, length of ear and yield.

scholarly journals Studies on Genetic Variability of Grain Yield and Quality in F2 and F3 Generations of Aromatic Rice (Oryza sativa L.)

2020 ◽  
pp. 86-91
Author(s):  
L. Krishna ◽  
Y. Chandra Mohan ◽  
C. H. Surender Raju ◽  
D. Bhadru
Keyword(s):  
Grain Yield ◽  
Oryza Sativa L ◽  
Selection Response ◽  
Yield And Quality ◽  
Head Rice ◽  
High Heritability ◽  
High Selection ◽  
Grain Yield And Quality ◽  
F2 Generation ◽  
1000 Grain Weight

The present investigation was carried out for yield and quality related traits in the F2 and F3 populations of twenty eight rice cross combinations developed from five aromatic (Pusa 1121, Improved Pusa Basmati, Basmati 370, Sumathi and RNR 2354) and three non-aromatic (BPT 5204, Akshyadhan and NLR 145) parents. In F2 generation, among the yield characters, the highest values of phenotypic co-efficient of variation (PCV) and genotypic co-efficient of variation (GCV) were recorded for the number of filled grains/panicle followed by grain yield per plant while the lowest values were recorded for days to 50% flowering. However, for the grain quality characters the highest PCV and GCV values were recorded for head rice recovery and lowest for kernel breadth. In F3 population, higher magnitudes of PCV and GCV were recorded for the number of filled grains/panicle and panicle weight, indicating greater scope of obtaining high selection response for these traits. High heritability in narrow sense along with medium to high genetic advance was noticed for the traits like days to 50% flowering, 1000 grain weight and the kernel traits.

A REPEAT MATING DESIGN IN A SELECTION EXPERIMENT

1980 ◽  
Vol 60 (4) ◽  
pp. 833-841
Author(s):  
R. J. PARKER ◽  
T. K. CHEUNG ◽  
K. M. WITTENBERG ◽  
C. G. HICKMAN
Keyword(s):  
Selection Response ◽  
Mass Selection ◽  
Response To Selection ◽  
Genetic Response ◽  
Mating Design ◽  
Litter Weight ◽  
The Third ◽  
Mating Population ◽  
Selection For ◽  
Selection Intensities

The separation of genetic and environmental trends in a repeat mating design and the effectiveness of such a design in producing genetic response to selection were observed during eight cycles of directional selection for high 12-day litter weight in mice. A random-bred control was used to monitor the repeat mating design in estimating environmental trend. Two mass selection populations (M1 and M2) under different selection intensities were used to assess the success of the repeat mating design in achieving selection response. From the third to the eighth cycle, the estimated genetic gain in 12-day litter weight for the repeat mating population was 0.89 ± 0.25 g per cycle. The selection response from the repeat design was lower than from one mass selection population (M2) but higher than from the other (M1). The environmental trend estimate of −0.79 ± 0.78 g per cycle was in fair agreement with the estimate of −0.88 ± 0.55 g per cycle from the random bred control.

scholarly journals Size of population required for artificial selection

1980 ◽  
Vol 35 (1) ◽  
pp. 85-105 ◽  
Author(s):  
F. W. Nicholas
Keyword(s):  
Genetic Drift ◽  
Coefficient Of Variation ◽  
Directional Selection ◽  
Mass Selection ◽  
Selection Line ◽  
Short Term ◽  
Selection Programme ◽  
Standard Normal ◽  
Simple Mass ◽  
Term Response

SUMMARYIt is widely acknowledged that genetic drift is an important source of variation in response to artificial directional selection. How large should a selection line be in order to reduce the effect of genetic drift to an acceptably low level?This paper investigates two criteria that can be used to answer this question in relation to short-term response to selection. The first criterion is coefficient of variation of response, and the second criterion is chance of success, where a successful selection programme is one in which the observed response is greater than a certain proportion, β, of expected response.For a simple mass selection programme with intensity i and heritability h2, the size of population required in order for the coefficient of variation of response to be γ after t generations, is approximately 2/(γih)2t, and the size required for the chance of success to be α after t generations is approximately 2{zα/(β−l)ih}2/t, where zα is the standard normal deviate corresponding to the probability α.As an example, suppose it is required that after t generations the coefficient of variation of response be 10% or that there be a 90% chance of achieving at least 9/10 of expected response. Since ih ≤ 2 in most selection programmes, the size of population required is at least 50/t or 82/t respectively. If ih ≤ 1, the corresponding sizes are 200/t and 328/t.Results are extended to enable the calculation of size of population required for any type of artificial directional selection programme, including those in which generations overlap.

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