scholarly journals Çoklu Doğrusal Bağlantı Durumunda En Küçük Kareler ve Bazı Yanlı Tahmin Edicilerin Karşılaştırılması

Author(s):  
Furkan Yılmaz ◽  
Lütfi Bayyurt ◽  
Samet Hasan Abacı ◽  
Yalçın Tahtalı

The aim of this study is to compare the least squares (LS) method that lost its function in the case of multicollinearity in regression methods with Ridge Regression (RR) and Principal Components Regression (PCR) which are bias estimators. For this aim, the effect of some body measurements on body weight (BW), body length (BL), height at withers (HW), height at rump (HR), chest depth (CD), chest girth (CG) and chest width (CW) obtained from 59 Saanen kids at weaning period raised at Research Farm of Tokat Gaziosmanpaşa University. Determination coefficient (R2) and mean square error (MSE) values were used to evaluate the estimation performance of the methods. The multicollinearity between height at withers (HW) and height at rump (HR) which were used to estimate body weight was eliminated by using RR and PCR. When R2 and HKO values of the examined methods are compared; It has been shown that RR method have better results of live weight of Saanen goats.

Author(s):  
Md. Ahsan Habib ◽  
Ambia Akhtar ◽  
A. K. Fazlul Haque Bhuiyan ◽  
Md. Panir Choudhury ◽  
Most Farhana Afroz

Aims: To develop regression equations for estimation of live weight from the external morphological measurements. Study Design: CRD with non-orthogonal hierarchy. Place and Duration of Study: This study was carried out at 3 rural village communities of Bhaluka Upazila in Mymensingh district of Bangladesh from 2009 to 2013. Methodology: All animals were ear-tagged and maintained under semi-intensive management system with scheduled vaccination and de-worming. Data were collected from a baseline survey along with 3 progressive generations produced from the community foundation stocks. Body length, chest girth, wither height, hip height and body weights were measured in a same day and recorded individually from birth up to 15 month age. Body weights were measured in kilogram by a hanging spring balance and other morphological parameters were measured in centimeter by a measuring tape. The data were analyzed by "SPSS 17.0" statistical program. Results: A total of seven regression models were adopted and analysis of variance showed that all models were fitted significantly (p<0.001). The correlation coefficient was higher when multiple body measurements were included in the model. The study also revealed that when chest girth as a single body measurement was included in the model gave the highest correlation coefficient (R=0.92). For including multiple measurements, body length and chest girth are the best external body measures which exposed same correlation coefficient (R2=0.92) when included more than these two body measures in the model. The differences between actual body weight and body weight predicted from regression equation for different ages were less than 1% (p>0.05) and correlation coefficient between weights was 0.92 (p<0.01). Conclusion: There are strong correlations among morphometric body measurements. Thus, body weight can be estimated from a single or multiple body measurements by regression equation. Chest girth is the best single predictor for estimating live body weight with high accuracy.


2011 ◽  
Vol 51 (No. 8) ◽  
pp. 343-348 ◽  
Author(s):  
Afolayan RA ◽  
Adeyinka IA ◽  
Lakpini CAM

Live body measurements of weight, height, length, girth, stifle- and hip-width and a measure of muscularity (ratio of stifle to hip width) were monitored on 258 Yankasa sheep stratified into age categories of 1 to over 3 years determined mostly from records and partly by dentition. These animals are from purebred Yankasa sheep kept as a part of the open nucleus-breeding scheme of the National Animal Production Research Institute, Shika, Zaria, Nigeria. The effect of sex, type of birth and age group of lambs on live measurements and muscularity were analyzed by least-squares procedures. All variables examined, except sex, had significant (P &lt; 0.001) effects on all body measurements. At birth, male and single-born lambs were significantly heavier than female and twin-born lambs. At early age, most factors significantly (P &lt; 0.01) influenced the body weight, body dimensions and muscularity traits with single-born lambs being 31% heavier, 10% taller and 11% bigger in girth; more highly muscled than the twin-born lambs. This advantage of male over female born lambs (except in hip-width and girth) for growth and developmental traits was maintained reasonably well to the advanced ages. All phenotypic correlations between body measurements were positive and significant (P &lt; 0.001). The highest correlation coefficient was found between chest girth and body weight. The polynomial equation using chest girth as an independent variable predicted body weight more accurately as compared to the linear equation. &nbsp;


2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Oumer Sheriff ◽  
Kefyalew Alemayehu ◽  
Aynalem Haile

Abstract Background An exploratory field research was conducted in northwestern Ethiopia, to characterize the morphological features of Arab and Oromo goat populations as an input to design community-based breeding programs. Ten qualitative and nine quantitative traits were considered from 747 randomly selected goats. All data collected during the study period were analyzed using R statistical software. Results Plain white coat color was predominantly observed in Arab goats (33.72%) while plain brown (deep and light) coat color was the most frequent in Oromo goats (27.81%). The morphometric measurements indicated that Oromo goats have significantly higher body weight and linear body measurements than Arab goats. Positive, strong and highly significant correlations were obtained between body weight and most of the body measurements in both goat populations. The highest correlation coefficients of chest girth with body weight for Arab (r  =  0.95) and Oromo (r  =  0.92) goat populations demonstrated a strong association between these variables. Live body weight could be predicted with regression equations of y  =  − 33.65  +  0.89  ×  for Arab goats (R2  =  90) and y  =  − 37.55  +  0.94  ×  for Oromo goats (R2  =  85), where y and x are body weight and chest girth, respectively, in these goat types. Conclusions The morphological variations obtained in this study could be complemented by performance data and molecular characterization using DNA markers to guide the overall goat conservation and formulation of appropriate breeding and selection strategies.


1987 ◽  
Vol 109 (3) ◽  
pp. 513-518 ◽  
Author(s):  
I. F. M. Marai ◽  
M. S. Nowar ◽  
Layla B. Bahgat ◽  
J. B. Owen

SummaryThirty Ossimi lambs were used in an experiment to compare those whose tail was docked shortly after birth with controls. After weaning at 4 months of age the groups were further subdivided and two of the four groups closely shorn according to a 2 × 2 factorial design.Male lambs at 20 kg were subjected to intensive finishing until the age of 50 weeks and nine were then slaughtered to determine carcass characteristics.There was a trend for increased live-weight gain in the docked lambs in the preweaning stage (up to 16 weeks).This trend was also present, although not statistically significant, in the final phase of intensive feeding from 20 kg weight to 50 weeks. Shearing significantly improved daily gain in this final period (P < 0·05). These increases in gain were also apparently associated with improvements in efficiency, as judged on a group basis.Docking and shearing also tended to cause increases in body measurements: height, chest girth and abdomen girth in the case of docking (P < 0·05) and chest girth, chest depth and abdomen girth in the case of shearing (P < 0–05).Carcass characteristics, measured on a relatively small sample, indicated several effects of docking and shearing on carcass traits although most of these were consistent with the expected differences stemming from the higher carcass weights acheived at 50 weeks of age by docked and sheared lambs.


Author(s):  
Sandeep Kumar ◽  
S. P. Dahiya ◽  
Z. S. Dahiya ◽  
C. S. Patil

Measurements of body conformation in sheep are of value in judging the quantitative characteristics of meat and also helpful in developing suitable selection criterion. Data on 349 Harnali sheep for body length (BL), body height (BH), heart girth (HG), paunch girth (PG), tail length (TL), head circumference (HC), ear length (EL), ear width (EW), face length (FL) and adult body weight (ABW) were analysed to study the relationship between linear body measurements and body weight. The mixed linear model with dam’s weight at lambing as covariate was used to study the effect of non-genetic factors on body measurements and body weight. High estimates of heritability were obtained for BL, BH, HG, TL, HC, EL, EW, FL and ABW while moderate estimate was obtained for PG. The phenotypic correlations of BL, BH, HG, PG, HC and FL with ABW were positive and significant (0.32±0.04 to 0.59±0.08). The genetic correlations of HG, PG, HC and FL with ABW were 0.51±0.13, 0.42±0.19, 0.44±0.13 and 0.43±0.15, respectively. Various combinations of linear type traits to predict ABW were found to have coefficient of determination as high as 0.92. It is concluded that heart girth is the most important trait for estimation of live weight in sheep and the prediction equation is Body weight = -63.72 + 1.23 HG with R2 = 0.87.


Author(s):  
D. Chakraborty ◽  
K. Mehdi Khan ◽  
N. Kumar ◽  
Isfaq Faried ◽  
Rajan Sharma ◽  
...  

Majority of the Kargil sheep populations are indigenous. Very scanty information is available for morphological characterization of Purky sheep population. Therefore, the present study was undertaken with the objectives to study the morpho-metric characteristics and body measurements for phenotypic characterization of the local sheep. A stratified random sample survey was conducted on various parameters (horn size, tail size, chest girth, punch girth, body length, height at wither and body weight) in seven different age groups. Data were collected randomly from 510 sheep of either sex. The local sheep population of Kargil which was selected for the present investigation is named as ‘Purky’ by the name of the community that reared this breed. In Purky sheep white body colour was predominant in both the sexes. The sheep breed was of low to medium body weight. The chest girth, punch girth, height at withers of Purky sheep showed it to be medium sized. Sex had significant effect (P is less than 0.05) on height at wither only. For males the least squares means were higher for all the traits of all age groups baring few exceptions. The phenotypic correlations of age groups with different morpho-metric traits were very high. The phenotypic correlations of body weight with other body measurements like tail size, chest girth, paunch girth, body length and height at wither were very high. Further studies should be carried out to fully exploit their genetic potential and to register the breed and in-situ conservation of this population.


1979 ◽  
Vol 28 (3) ◽  
pp. 353-369 ◽  
Author(s):  
J. M. Bruce ◽  
J. J. Clark

ABSTRACT1. A deterministic model for thermoneutral heat production of growing pigs on barley-based diets has been developed and validated. The model variables are live weight (20 to 100 kg) and metabolizable energy intake (not less than maintenance). The root-mean-square error for 62 data is 049 MJ/day (3·2%).2. A deterministic model for heat production of growing pigs below their critical temperature has been developed and validated. The model variables are: air temperature, air velocity, floor type, live weight (20 to 100 kg), and group size. The root-mean-square error for 78 data is 0·77 MJ/day (5·6%).3. The two heat production models are combined to give a model for the lower critical temperature for growing pigs.4. These models may be used to quantify and compare the effects on energy balance of different combinations of nutrition and environment. They should help to clarify the issues when practical decisions in pig production are made and should also help in the design of nutritional and physiological experiments.


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