scholarly journals Genetic and environmental factors that affect tick infestation in Nelore x Angus crossbreed cattle

2021 ◽  
Vol 51 (9) ◽  
Author(s):  
Giovani Luis Feltes ◽  
Vanessa Tomazetti Michelotti ◽  
Alan Miranda Prestes ◽  
Paulo Roberto Nogara Rorato ◽  
Fernanda Cristina Breda Mello ◽  
...  
Keyword(s):  
Genetic Parameters ◽  
Tick Infestation ◽  
Mean Value ◽  
Suitable Model ◽  
Hair Coat ◽  
Tick Count ◽  
Genetic And Environmental Factors ◽  
Genetic Evaluations ◽  
Criteria For Selection ◽  
Selection Of

ABSTRACT: This study evaluated the effects of seasons and latitude on tick counting and determined the best model to estimate genetic parameters for tick count and hair coat. Records of animals naturally exposed to ticks on farms in several Brazilian states and in Paraguay were used. The ANOVA was used to verify the effects of seasons and latitude on the tick count trait. Spring was the season with the highest average, followed by summer and autumn, which showed no differences between them. The winter presented the lowest average values. Latitude -11° had the highest mean value followed by latitude -18°. The Bayesian approach was used to evaluate tick count and hair coat and to identify a suitable model for estimating genetic parameters for use in genetic evaluations. The data were analyzed using an animal model with four different specifications for “fixed” purposes. The inference was based on a Markov chain Monte Carlo (MCMC). The criteria for selection of the Bayesian model indicated that the M1 model, which considered the breed composition in the contemporary group, was superior to the other models, both for tick count and hair coat. Heritability estimates for tick count and hair coat obtained using the M1 model were 0.14 and 0.22, respectively. The rank correlations between the models for tick count and hair coat were estimated and reordering was verified for tick count. The estimated genetic correlation between tick count and hair coat traits was negative (-0.12). These findings suggest that different genes regulate tick count and hair coat.

scholarly journals Selection of a suitable data set and model for the genetic evaluation of the linear description of conformation and type description in Old Kladruber horses

2012 ◽  
Vol 55 (2) ◽  
pp. 105-112
Author(s):  
L. Vostrý ◽  
K. Mach ◽  
J. Přibyl
Keyword(s):  
Random Effects ◽  
Fixed Effects ◽  
Genetic Parameters ◽  
Suitable Model ◽  
Residual Variance ◽  
Linear Type ◽  
Colour Variant ◽  
Repeated Evaluation ◽  
Estimation Of Genetic Parameters ◽  
Selection Of

Abstract. The objective of this paper was to select a suitable data subset and statistical model for the estimation of genetic parameters for 36 traits of the linear type in 977 Old Kladruber horses. Two subsets were tested to identify a suitable subset for analysis. One subset included repeated evaluation of certain individuals, whereas the other did not. The most suitable subset included repeated evaluation (n=1 390). The selection of a suitable model was made from 4 candidate models. These models comprised a number of random effects (direct individual effect and animal permanent environmental effect of the animal) and a number of fixed effects (colour variant, stud, colour variant × stud interaction, sex, age at description, year of birth, year of description). The model was selected based on the Akaike information criterion (AIC, Akaike 1974), residual variance and heritability coefficient. The model that included colour variant, stud, colour variant × stud interaction, sex, age at description, and year of description as fixed effects and direct individual and animal permanent environment as random effects was the most suitable model for the estimation of genetic parameters and for the subsequent estimation of breeding values.

scholarly journals SIRE-SON CORRELATIONS OF GENETIC EVALUATIONS FOR FAT PERCENTAGE IN HOLSTEIN-FRIESIANS

1987 ◽  
Vol 67 (3) ◽  
pp. 631-635 ◽  
Author(s):  
T. E. ALI ◽  
L. R. SCHAEFFER
Keyword(s):  
Key Words ◽  
Artificial Insemination ◽  
Milk Fat ◽  
Genetic Parameters ◽  
Direct Calculation ◽  
Fat Percentage ◽  
Low Correlation ◽  
Fat Yield ◽  
Genetic Evaluations ◽  
Selection Of

The correlation between sire and son genetic evaluations for fat percentage has been shown to be lower than corresponding correlations for milk or fat yield for the population of bulls in artificial insemination. The purpose of this study was to determine the cause of this low correlation. Based on 302 935 first-lactation daughters of 11 396 sires, the heritabilities of milk, fat and fat percentage were 0.28, 0.27 and 0.52, respectively. Indirect versus direct calculation of sire evluations for fat percentage were correlated at 0.997, and resulting sire-son correlations were 0.45 for directly calculated proofs and 0.43 for indirectly calculated proofs. The low sire-son correlations were due to the intense selection of sires of sons, especially for fat percentage, which resulted in a change in genetic parameters among the bulls used as sires of sons compared to the parameters in the overall population. Key words: Fat percentage, pedigree indexing, dairy sires

scholarly journals Selection of a suitable data set and model for the estimation of genetic parameters of the weaning weight in beef cattle

2007 ◽  
Vol 50 (6) ◽  
pp. 562-574
Author(s):  
L. Vostrý ◽  
J. Přibyl ◽  
Z. Veselá ◽  
V. Jakubec
Keyword(s):  
Beef Cattle ◽  
Fixed Effects ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Genetic Effect ◽  
Suitable Model ◽  
Data Set ◽  
Weaning Weight ◽  
Estimation Of Genetic Parameters ◽  
Selection Of

Abstract. The objective of this paper was to select a suitable data subset and statistical model for the estimation of genetic parameters for weaning weight of beef cattle in the Czech Republic. Nine subsets were tested for the selection of a suitable subset. The subsets differed from each other in the limit of sampling criteria. The most suitable subset satisfied these conditions: at least 5 individuals per each sire, 5 individuals per HYS (herd, year, season), 2 sires per HYS, and individuals per dams that have at least one half-sister and two offspring (n = 4 806). The selection of a suitable model was carried out from 10 models. These models comprised some of the random effects: direct genetic effect, maternal genetic effect, permanent maternal environment effect, HYS, sire × herd or sire × year interaction, and some of the fixed effects: dam’s age, sex (young bull, heifer × single, twin born), HYS, year, herd. The direct heritability (h2a) ranged from 0.06 to 0.17, of maternal heritability (h2m) from 0.03 to 0.06. The genetic correlations between the direct and maternal effect (ram) were in the range of –0.15 –0.42.

scholarly journals Assessment of Variability for Floral Characteristics and Out-Crossing Rate in CMS Lines of Hybrid Rice

2019 ◽  
Vol 22 (2) ◽  
pp. 31-39
Author(s):  
MJ Hasan ◽  
MU Kulsum ◽  
AK Paul ◽  
PL Biswas ◽  
MH Rahman ◽  
...  
Keyword(s):  
Seed Yield ◽  
Genetic Parameters ◽  
Mean Value ◽  
Direct Selection ◽  
Path Coefficient ◽  
Filament Length ◽  
Parameters Selection ◽  
Anther Length ◽  
Value Range ◽  
Selection Of

The present investigation was aimed to clarify the interrelationship among various floral traits and out crossing rates. High mean value, range of variability and genotypic variance were observed for all the traits except anther length and breadth, stigma length and breadth. Close differences between genotypic and phenotypic variances and genotypic and phenotypic coefficient of variations were observed for all the traits. Considering all genetic parameters, selection based on panicle exertion rate, angle of florate opening, duration of florate opening, anther length, stigma exertion rate and out crossing rate seemed to be effective for the improvement of CMS lines. Out crossing rate had significant positive correlation with panicle exertion rate, angle of florate opening, duration of florate opening, filament length, stigma length, breadth and exertion rate exhibited interesting results, indicating selection with these traits might be possible without compromising seed yield loss. On the basis of direct selection through panicle exertion rate, angle and duration of florate opening, filament length and stigma exertion rate would significantly improve seed yield of CMS lines. Based on mean, range, genetic parameters, correlation coefficient and path coefficient values, direct selection of eight CMS lines IR79156A, BRRI7A, IR75608A, BRRI13A, BRRI35A, BRRI48A, BRRI50A and BRRI53A might be fruitful as good floral characteristics with high out crossing rate of CMS lines. Bangladesh Rice j. 2018, 22(2): 31-39

scholarly journals Agro-Morphological Characterization and Assessment of Variability in Aromatic Rice Germplasm

2012 ◽  
Vol 37 (1) ◽  
pp. 1-8 ◽  
Author(s):  
M Parikh ◽  
NK Motiramani ◽  
NK Rastogi ◽  
B Sharma
Keyword(s):  
Genetic Parameters ◽  
Agronomic Traits ◽  
Morphological Characterization ◽  
Aromatic Rice ◽  
Spikelet Sterility ◽  
Plant Parts ◽  
Rice Germplasm ◽  
Spikelets Per Panicle ◽  
Plant Habit ◽  
Selection Of

The present studies were carried out to characterize seventy-one aromatic rice germplasm from IGKV, Raipur. These germplasm were characterized and grouped on the basis of anthocyanin pigmentation, plant habit, and awning character. On the basis of pigmentation distribution in 10 plant parts, a total of twelve groups were formed with group one having no pigmentation and group twelve with pigmentation in 9 plant parts. On the basis of plant habit and awning character, three groups of each were formed. The genetic parameters for the ten agronomic traits indicated that the selection of genotypes may be done for fertile spikelets per panicle, spikelet density, spikelet sterility percentage, and hundred seed weight. Thus, on the basis of above characters, the genotypes Tulsi Mala, Baanspati, Ganga Balu, Samund Chini, Tulsi Amrit, Dudh Dhan, Kari Gilas, Shankar Jeera, and Jata Shankar may be selected for future study. DOI: http://dx.doi.org/10.3329/bjar.v37i1.11168 Bangladesh J. Agril. Res. 37(1): 1-8, March 2012

scholarly journals Selection of cotton lines for high oil content

2017 ◽  
Vol 52 (7) ◽  
pp. 530-538 ◽  
Author(s):  
Luiz Paulo de Carvalho ◽  
Josiane Isabela da Silva Rodrigues ◽  
Francisco José Correia Farias
Keyword(s):  
Oil Content ◽  
Genetic Parameters ◽  
Fiber Quality ◽  
Rio Grande ◽  
Field Trials ◽  
The State ◽  
The Other ◽  
Expected Gain ◽  
High Heritability ◽  
Selection Of

Abstract: The objective of this work was to evaluate the oil content and characters related to fiber quality and yield in cotton lines (Gossypium hirsutum), in order to select genotypes with high oil content and acceptable levels of the other characters. Twenty-two F6 lines and three checks were cultivated in three field trials - two in the municipality of Apodi, in the state of Rio Grande do Norte, and one in the municipality of Barbalha, in the state of Ceará, both in Brazil. The genetic parameters and the genetic gain from selecting 20% of the lines were estimated according to their means in each environment and in the group of environments. Regarding oil content, there is genetic variability, and the selection based on the overall mean is indicated, since this character showed high heritability, with 4.58% expected gain. The lines selected with this criterion have oil contents between 23.52 and 24.51%, which are higher than those of the Brazilian cultivar BRS Aroeira with the highest grain oil content (22.04%).

Selection for rate and efficiency of lean gain in Hereford cattle 1. Selection pressure applied and direct responses

1990 ◽  
Vol 51 (1) ◽  
pp. 23-34 ◽  
Author(s):  
R. A. Mrode ◽  
C. Smith ◽  
R. Thompson
Keyword(s):  
Genetic Parameters ◽  
Control Line ◽  
Correlated Responses ◽  
Direct Response ◽  
Lean Growth ◽  
Hereford Cattle ◽  
Frozen Semen ◽  
Phenotypic Standard Deviation ◽  
Selection For ◽  
Selection Of

ABSTRACTSelection of bulls for rate and efficiency of lean gain was studied in a herd of Hereford cattle. There were two selection lines, one selected for lean growth rate (LGR) from birth to 400 days and the other for lean food conversion ratio (LFCR) from 200 to 400 days of age, for a period of 8 years. A control line bred by frozen semen from foundation bulls was also maintained. Generation interval was about 2·4 years and average male selection differentials, per generation were 1·2 and — 1·1 phenotypic standard deviation units for LGR and LFCR respectively.Genetic parameters and responses to selection were estimated from the deviation of the selected lines from a control line and by restricted maximum likelihood (REML) techniques on the same material. Realized heritabilities were 0·40 (s.e. 0·12) for LGR and 0·40 (s.e. 0·13) for LFCR using the control line. Corresponding estimates from REML were 0·42 (s.e. 0·10) and 0·37 (s.e. 0·14). The estimate of the genetic correlation between LGR and LFCR was about — 0·69 (s.e. 0·12) using REML.The estimates of direct annual genetic change using deviations from the control were 3·6 (s.e. 1·3) g/day for LGR and — 0·14 (s.e. 0·07) kg food per kg lean gain for LFCR. Corrsponding estimates from REML were similar but more precisely estimated. The correlated responses for LFCR in the LGR line was higher than the direct response for LFCR.

ADDITIONAL CRITERIA FOR SELECTION OF MALTING QUALITY IN BARLEY BREEDING

1976 ◽  
Vol 56 (4) ◽  
pp. 805-809 ◽  
Author(s):  
V. M. BENDELOW
Keyword(s):  
Specific Gravity ◽  
Filtration Rate ◽  
Sugar Content ◽  
Reducing Sugar ◽  
Malting Quality ◽  
Breeding Programs ◽  
Barley Breeding ◽  
Sample Extraction ◽  
Criteria For Selection ◽  
Selection Of

A procedure that provides information on the suitability of barley for malting and, brewing purposes is described. Three parameters are measured: mash filtration rate, wort viscosity and wort-reducing sugar content, as maltose. Maltose is determined by an auto-analyzer method and this is a satisfactory alternative to the specific gravity procedure for the estimation of percent extract. The addition of these criteria to those already in use enables more discriminatory selection at early generations of barley-breeding programs. The technique requires only one sample extraction and 18 g of laboratory malt.

CRITERIA FOR SELECTION OF PREPARATIONS IN THE DEVELOPMENT OF SORPTION-DETOXIFYING COMPLEXES FOR AGRICULTURAL ANIMALS

2018 ◽  
Vol 1 (2) ◽  
pp. 94-100
Author(s):  
L.L. Zakharova ◽  
◽  
G.A. Zhorov ◽  
V.I. Dorozhkin ◽  
◽  
...  
Keyword(s):  
Chemical Nature ◽  
Negative Impact ◽  
Physiological State ◽  
Animal Husbandry ◽  
Biologically Active ◽  
Combined Pollution ◽  
Wide Range ◽  
Active Substances ◽  
Criteria For Selection ◽  
Selection Of

Negative impact on the environment as a result of economic activity of man increasingly becomes the character of combined pollution of ecotoxicants, including xenobiotics of radiation and chemical nature. In animal husbandry in ecologically unfavorable regions, sorbtion-detoxication technologies based on the complex application of bioprotective substances of different origin are used to reduce the intake and accumulation of xenobiotics, to normalize the physiological state of animals and to obtain safe products. It is necessary to observe certain principles ensuring compatibility of components, a wide range of bioprotective action, efficiency and safety at their use in developing the compositions of such sorption-detoxifying complexes. The article substantiates the criteria that should be followed in creating sorption-detoxifying complexes and presents groups of drugs with different mechanisms of action (sorbents, antioxidants, immunomodulators, adaptogens and other biologically active substances) for inclusion in the formulations of combined compositions.

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