scholarly journals A Meta-Analysis to Understand the Relationship between Pig Body Weight and Variation from Birth to Market

Animals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 2088
Author(s):  
Andres F. Tolosa ◽  
Joel M. DeRouchey ◽  
Mike D. Tokach ◽  
Robert D. Goodband ◽  
Jason C. Woodworth ◽  
...  

This meta-analysis aims to understand the changes in pig body weight (BW) variation from birth to market and develop prediction equations for coefficient of variation (CV) and standard deviation (SD) as a function of BW. Standard deviation is the measure of dispersion of a set of values from the mean and CV is the SD expressed as a percentage of the mean. Data collected from 16 papers and data sets yielded 117,268 individually weighed pigs with sample size ranging from 120 to 4108 pigs. Polynomial regression analysis was conducted separately for each variation measurement. The resulting prediction equations (CV (%) = 20.04 − 0.135 × (BW) + 0.00043 × (BW)2, R2 = 0.79; SD = 0.41 + 0.150 × (BW) − 0.00041 × (BW)2, R2 = 0.95) suggest that there is a quadratic decreasing relationship between the CV of a population and BW, the slope gets smaller as mean BW increases from birth to market. A quadratic increasing relationship is observed for SD, with slope being smaller as mean BW of pigs increases from birth to market. These prediction equations can be used by swine producers to estimate expected CV and SD of BW among a population of pigs.

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 218-219
Author(s):  
Andres Fernando T Russi ◽  
Mike D Tokach ◽  
Jason C Woodworth ◽  
Joel M DeRouchey ◽  
Robert D Goodband ◽  
...  

Abstract The swine industry has been constantly evolving to select animals with improved performance traits and to minimize variation in body weight (BW) in order to meet packer specifications. Therefore, understanding variation presents an opportunity for producers to find strategies that could help reduce, manage, or deal with variation of pigs in a barn. A systematic review and meta-analysis was conducted by collecting data from multiple studies and available data sets in order to develop prediction equations for coefficient of variation (CV) and standard deviation (SD) as a function of BW. Information regarding BW variation from 16 papers was recorded to provide approximately 204 data points. Together, these data included 117,268 individually weighed pigs with a sample size that ranged from 104 to 4,108 pigs. A random-effects model with study used as a random effect was developed. Observations were weighted using sample size as an estimate for precision on the analysis, where larger data sets accounted for increased accuracy in the model. Regression equations were developed using the nlme package of R to determine the relationship between BW and its variation. Polynomial regression analysis was conducted separately for each variation measurement. When CV was reported in the data set, SD was calculated and vice versa. The resulting prediction equations were: CV (%) = 20.04 – 0.135 × (BW) + 0.00043 × (BW)2, R2=0.79; SD = 0.41 + 0.150 × (BW) - 0.00041 × (BW)2, R2 = 0.95. These equations suggest that there is evidence for a decreasing quadratic relationship between mean CV of a population and BW of pigs whereby the rate of decrease is smaller as mean pig BW increases from birth to market. Conversely, the rate of increase of SD of a population of pigs is smaller as mean pig BW increases from birth to market.


2005 ◽  
Vol 9 (3) ◽  
pp. 214-227 ◽  
Author(s):  
David S. Wallace ◽  
René M. Paulson ◽  
Charles G. Lord ◽  
Charles F. Bond

A meta-analysis of 797 studies and 1,001 effect sizes tested a theoretical hypothesis that situational constraints, such as perceived social pressure and perceived difficulty, weaken the relationship between attitudes and behavior. This hypothesis was confirmed for attitudes toward performing behaviors and for attitudes toward issues and social groups. Meta-analytic estimates of attitude-behavior correlations served to quantify these moderating effects. The present results indicated that the mean attitude-behavior correlation was .41 when people experienced a mean level of social pressure to perform a behavior of mean difficulty. The mean correlation was .30 when people experienced social pressure 1 standard deviation above the mean to perform a behavior that was 1 standard deviation more difficult than the mean. The results suggest a need for increased attention to the “behavior” side of the attitude-behavior equation. Attitudes predict some behaviors better than others.


2019 ◽  
Vol 1 (2) ◽  
pp. 97-104
Author(s):  
Andualem Walelign

The main aim of this study was to assess the influence of communication on customer satisfaction. Descriptive statistics (mean score and standard deviation) were used to examine the customers’ perceptions and current status of customer satisfaction. The least performance was obtained from the mean score of communication dimension. Correlation and regression analysis were used to see the relationship between dependent and independent variables as well as to investigate cause and effect relationships. The key finding showed that there was a positive and significant effect of communication on customer satisfaction.


1965 ◽  
Vol 45 (1) ◽  
pp. 33-36
Author(s):  
G. W. Rahnefeld

The relationship between thickness of fat measured at the shoulder, last rib, and loin of live pigs and market weight (86.2 to 95.2 kg) was studied in 1596 pigs from the Lacombe and Yorkshire breeds and their reciprocal crosses. No significant breed or sex differences were found in the proportion of fat at the three sites. Breed and sex differences were evident in the average depth of fat. The regression coefficients for the mean of three fat measurements on market weight were.016 ±.003,.019 ±.007, and.017 ±.004 for Lacombe males, barrows, and females respectively;.039 ±.002,.036 ±.005, and.041 ±.001 for Yorkshire males, barrows and females respectively;.027 ±.005 and.029 ±.004 for barrows and females from the Lacombe male × Yorkshire female mating; and.023 ±.007 and.021 ±.009 for barrows and females from the Yorkshire male × Lacombe female mating. Comparisons between animals measured at a relatively constant weight should be made after the fat measurement is adjusted for variations in body weight. The results of this study indicate that separate corrections should be applied for each breed. Separate corrections for sexes within breeds do not appear warranted.


2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Leila Shafie Bafti ◽  
Maryam Alsadat Hashemipour ◽  
Hamidreza Poureslami ◽  
Zeinab Hoseinian

The aim of the present study was to evaluate the relationship between BMI and tooth decay in a population of Iranian children. In this cross-sectional descriptive/analytical study, 1482 children were selected from kindergartens and preschool centers in Kerman, Iran. The children underwent examination of deciduous teeth (using the dmft index) after determination of height and weight for calculation of BMI. The relationship between BMI (after adjustment for age) and dmft was determined using Poisson’s regression model. The mean of dmft in children with normal BMI was 1.5-fold that in subjects with extra body weight. Age had a significant effect on dmft. In addition, dmft was higher in boys compared to girls. The results of the present study showed that caries rate in the deciduous teeth of 3–6-year-old children decreases with an increase in body weight.


1982 ◽  
Vol 16 (3) ◽  
pp. 240-243
Author(s):  
Wayne T. Corbett ◽  
Harry M. Schey ◽  
A. W. Green

The mean and standard deviation over 24 h for 3 groups of animals - active, intermediate and inactive - in physical activity units were 10948 ± 3360, 2611 ± 1973 and 484 ± 316 respectively. The differences were significant ( P = 0·004), demonstrating the ability of the method to distinguish between groups that can be visibly differentiated. The small within-animal physical activity standard deviation (18·85 PAU) obtained in another group, suggests that it also yields reliable physical activity measurements for non-human primates. The monitoring device used can discriminate between individual nonhuman primate physical activity levels in a free-living environment and does not alter daily behaviour. This makes possible the study of the relationship between physical activity and atherosclerosis in nonhuman primates.


1982 ◽  
Vol 62 (1) ◽  
pp. 183-188 ◽  
Author(s):  
R. RIOUX

Barley (Hordeum vulgare L. ’Champlain’) was grown with quackgrass (Agropyron repens (L.) Beauv.) at various densities for 3 yr. According to the regression analysis, a linear relation is appropriate to describe the relationship between yield of barley and biomass or density of quackgrass. A greater proportion of yield variability was explained by density (64%) than by biomass (40%). Density is then a better criterion than biomass to predict yield lost in barley. The linear relationship between barley yield and the shoot density of quackgrass is estimated by the following equation: yield barley = 345.3–0.5682 dens, quackgrass. An increase of 10 shoots/m2 in the mean density of quackgrass resulted in a mean loss of 6 g/m2 in the yield of barley.


2020 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Nadia Elyassi ◽  
Ali Malekzadeh Shafaroudi ◽  
Pegah Nasiri ◽  
Mahmood Moosazadeh ◽  
Azam Nahvi

Context: Conflicting results have been reported in the literature concerning the relationship between salivary nitrous oxide concentration and dental caries in children. Metaanalysis studies aim to combine different studies and reduce the difference between the parameters by increasing the number of studies involved in the analysis process. Objectives: Accordingly, this meta-analysis study aimed at determining the relationship between salivary nitrous oxide concentration and dental caries in children. Methods: Databases were searched using the keywords “nitric oxide”, “salivary”, “Caries”, “DMFT Index”, “children”, “early childhood caries” and OR, AND and NOT operators. Quality assessment was then performed based on the Newcastle-Ottawa scale (NOS) checklist. The standardized mean difference (SMD) of DMFT, dmft, and salivary nitric oxide (NO) concentration was estimated. Results: Seven studies made a comparison between the mean salivary NO concentration in children with dental caries and that in the control group. In four studies, the mean salivary NO concentration in children with dental caries was lower, as compared to that in the control group. This difference was significant in all four studies. Also, the mean standardized difference of the salivary NO index was also estimated to be -0.11 (CI 95%: -1.77, 1.55). Conclusions: This meta-analysis study demonstrated that salivary NO concentration was not significantly related to dental caries. Moreover, since salivary NO concentration is affected by various factors, it is not sufficient to determine the likelihood of the incidence of caries.


2015 ◽  
Vol 8 ◽  
pp. CMED.S24111 ◽  
Author(s):  
Juha Saltevo ◽  
Hannu Kautiainen ◽  
Pekka Mäntyselkä ◽  
Antti Jula ◽  
Sirkka Keinänen-Kiukaanniemi ◽  
...  

The association between thyroid function and depression is controversial. Both conditions express many similar symptoms, but the studies done give conflicting results. This study draws on a random, population-based sample of 4500 subjects aged 45–75 years old from Finland. The basic clinical study was done in 2007 for 1396 men and 1500 women (64% participation rate). Thyroid stimulating hormone (TSH), free thyroxine (F-T4), and free triiodothyronine (F-T3) were measured in 2013 from frozen samples. The 21-item Beck Depression Inventory (BDI-21) was applied to assess depressive symptoms (score ≥10 points). The prevalence of depressive symptoms was 17.5% in women and 12.5% in men. In women, the mean levels of TSH, F-T4, and F-T3 without depressive symptoms vs. with the presence of depressive symptoms were 1.92/1.97 mU/L, 13.1/13.1 pmol/L, and 3.91/3.87 pmol/L (NS), respectively. In men, the levels were 1.87/1.94 mU/L, 13.5/13.7 pmol/L, and 4.18/4.12 pmol/L (NS), respectively. In multiple regression analysis, TSH had no relationship to BDI-21 total score. We found no association between depressive symptoms and thyroid values.


2018 ◽  
Vol 46 (4) ◽  
pp. 529-540 ◽  
Author(s):  
Kyung Ryung Kim ◽  
Eun Hee Seo

We conducted a meta-analysis by synthesizing the results of 16 studies involving 4,130 teachers to explore whether or not the relationship between teacher efficacy and students' academic achievement was influenced by the scale used to measure teacher efficacy, and/or by the subfactors of teacher efficacy, length of teaching experience, location of the school, or the students' educational level. The results showed that the mean relationship between teacher efficacy and students' academic achievement was significant but the effect size was small. The results also indicated that the relationship was influenced by some teacher efficacy measures and subfactors, and by length of teaching experience. In studies in which the measure used was Gibson and Dembo's scale, in regard to classroom management, and in the case of teachers with fewer than 11 years of teaching experience, the relationship between teacher efficacy and student academic achievement was nonsignificant.


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