The accuracy of some body measurements on live beef steers

An investigation was made of the accuracy of measuring some 25 body dimensions of typically commercial beef-type steers. The measurements were chosen on the basis of their likely relationships with quantitative carcass compositional data. One of the objectives of the study was to compare the degree of accuracy obtained with values reported in the literature based on data from dairy cows and calvesThe repeatability was estimated by analysis of variance of duplicate measurements made by a single operator on 15 Hereford steers. F-ratios of the between animal to between repeated measurement mean square variances were significant (P < 0.01) for 21 of the 25 measurements, indicating that these measurements were sufficiently accurate to record differences in the body dimensions of the animals in this experimental sample. Generally, the highest F-ratio values were obtained for those measurements taken with a pair of calipers, and in each case where the length between two points was recorded by means of both flexible tape and caliper the highest F-ratios were obtained from the calipers reading.The standard deviations of the observer errors involved in this study were generally larger (on average 1.4 times larger) than those recorded for the same measurements made on dairy cows and calves.     

Body measurements of west African dwarf sheep as parameters for estimation of live weight

The relationships between live weight and eight body measurements of West African Dwarf (WAD) sheep were studied using 210 animals under on farm condition. Data obtained on height at withers (HW), heart girth (HG), body length (BL), head length (HL), head width (HDW), loin girth (LG), length of hindquarter (LHQ) and width of hindquarter (WHQ) were fitted into linear, allometric and multiple regression models to predict live weight from the body measurements. Results revealed that body measurements of WAD sheep were generally higher in the rams than in the ewes. Coefficient of determination (R(2)) values computed for the body measurements were generally higher (0.87-0.99) using allometric regression model than linear regression model (0.44-0.94). Heart girth (HG) and WHQ depicted the highest relationship to live weight in linear and allometric models compared to other body measurements. Based on stepwise elimination procedure, HG, HL and WHQ were better in predicting live weight in multiple linear regression models. The magnitude of correlation coefficient (r) indicate that WHQ shows the highest correlation with live weight (r = 0.96) compared to HG (r = 0.94).     

Variance components for live weight, body measurements and reproductive traits of pair-mated ostrich females

Estimates of genetic parameters for reproductive traits, live weight and body measurements were obtained using data from a pair-mated ostrich flock at Oudtshoorn in South Africa. Reproductive traits included total egg and chick production, along with hatchability percentage. Live weight, chest circumference and tail circumferences were recorded at the commencement and cessation of breeding. Heritability estimates (h(2)) were 0.23 for egg production, 0.20 for chick production, 0.10 for hatchability, 0.20 to 0.34 for live weight, 0.12 for chest circumference and 0.30 to 0.38 for tail circumference. Female permanent environmental effects (c(2)) amounted to 0.18 for egg production, 0.18 for chick production, 0.21 for hatchability, 0.32 to 0.36 for live weight and 0.23 to 0.32 for chest circumference. Service sire exerted significant effects only on hatchability (0.22) and subsequently chick production (0.09). Genetic correlations of reproductive traits with live weight were low to moderate, variable in sign, and did not differ significantly from zero. Correlations between live weight recorded at the beginning and end of the breeding season were unity for additive genetic and permanent environmental effects. Egg and chick production were highly correlated genetically and phenotypically, with the genetic correlation exceeding the theoretical limit. In unconstrained analyses, hatchability was positively related to chick production, including at the service sire level. Selection gains in the current flock and future generations are likely. No significant adverse relationships were found between live weight, body measurements and reproductive traits.     

Prediction of mature cow carcass composition from live animal measurements

Two trials were conducted with mature cows to develop prediction equations for estimating carcass composition from live animal measurements. Trial 1 involved 82 animals that were used to develop these equations. Subjective criteria (frame and condition scores) also were utilized along with live weight in development of prediction equations. Equations using subjective independent variables predicting energy and carcass tissue weights apparently were slightly more variable in precision (R2 = .69 to .91) than those developed with objective variables (R2 = .74 to .90). Equations predicting percent compositions from subjective variables had lower coefficients of determination (R2 = .49 to .76) than those developed with objective variables (R2 = .63 to .83). Forty-one animals similar to those used in Trial 1 served as a test group in Trial 2. Measured carcass composition was regressed on composition predicted by equations developed in Trial 1. These equations generally had slopes and intercepts with confidence intervals that included 0 and 1, respectively, indicating that most of the prediction equations were unbiased. This work indicates that carcass composition can be predicted from both objective and subjective measurements, with some accuracy and precision.     

Estimation of body weight in hair ewes using an indirect measurement method

Tropical Animal Health and Production - The aim of the present study was to develop and evaluate an equation to predict body weight (BW) using hip width (HW) in Pelibuey ewe lambs and ewes. Five...     

Prediction of body weight from body measurements in grass cutters

In order to predict the body weight of grass cutters from linear body measurements, the weights and measurements of 50 intensively managed female grass cutters aged 5 months were fitted into linear, quadratic and cubic regression models. Highly significant (p?<?0.01) R ² values ranging from 74 to 98 % were obtained indicating that all body measurements were good predictors of body weight. Although quadratic and cubic models gave slightly higher R ² values than linear models, it is recommended that farmers should use a simple linear equation based on tail length or heart girth to predict the body weight of their grass cutters. The recommended equations are (weight in kg)?=?0.47?+?0.08 (tail length in cm) and (weight in kg)?=?0.32?+?0.07 (heart girth in cm).     

Estimation of genetic parameters for mature weight in Angus cattle

The aim of this study was to estimate genetic parameters for BW of Angus cattle up to 5 yr of age and to discuss options for including mature weight (MW) in their genetic evaluation. Data were obtained from the American Angus Association. Only records from herds with at least 500 animals and with >10% of animals with BW at ≥ 2 yr of age were considered. Traits were weaning weight (WW, n = 81,525), yearling weight (YW, n = 62,721), and BW measured from 2 to 5 yr of age (MW2, n = 15,927; MW3, n = 12,404; MW4, n = 9,805; MW5, n = 7,546). Genetic parameters were estimated using an AIREML algorithm with a multiple-trait animal model. Fixed effects were contemporary group and departure of the actual age from standard age (205, 365, 730, 1,095, 1,460, and 1,825 d of age for WW, YW, MW2, MW3, MW4, and MW5, respectively). Random effects were animal direct additive genetic, maternal additive genetic, maternal permanent environment, and residual. Estimates of direct genetic variances (kg(2)) were 298 ± 71.8, 563 ± 15.1, 925 ± 52.1, 1,221 ± 65.8, 1,406 ± 80.4, and 1,402 ± 66.9; maternal genetic variances were 167 ± 4.8, 153 ± 6.1, 123 ± 9.1, 136 ± 12.25, 167 ± 18.0, and 110 ± 14.0; maternal permanent environment variances were 124 ± 2.9, 120 ± 4.3, 61 ± 7.5, 69 ± 11.9, 103 ± 15.9, and 134 ± 35.2; and residual variances were 258 ± 3.8, 608 ± 8.6, 829 ± 34.2, 1,016 ± 38.8, 1,017 ± 52.1, and 1,202 ± 63.22 for WW, YW, MW2, MW3, MW4, and MW5, respectively. The direct genetic correlation between WW and YW was 0.84 ± 0.14 and between WW and MW ranged from 0.66 ± 0.06 (WW and MW4) to 0.72 ± 0.11 (WW and MW2). Direct genetic correlations ranged from 0.77 ± 0.08 (YW and MW5) to 0.85 ± 0.07 (YW and MW2) between YW and MW, and they were ≥ 0.95 among MW2, MW3, MW4, and MW5. Maternal genetic correlations between WW and YW and MW ranged from 0.52 ± 0.05 (WW and MW4) to 0.95 ± 0.07 (WW and YW), and among MW they ranged from 0.54 ± 0.14 (MW4 and MW5) to 0.94 ± 0.07 (MW2 and MW3). Genetic correlations suggest that a genetic evaluation for MW may be MW2-based and that including BW from older ages could be accomplished by adjusting records to the scale of MW2.     

Age- and sex-dependent regression models for predicting the live weight of West African Dwarf goat from body measurements

The relationships between live weight and eight body measurements of West African Dwarf (WAD) goats were studied using 211 animals under farm condition. The animals were categorized based on age and sex. Data obtained on height at withers (HW), heart girth (HG), body length (BL), head length (HL), and length of hindquarter (LHQ) were fitted into simple linear, allometric, and multiple-regression models to predict live weight from the body measurements according to age group and sex. Results showed that live weight, HG, BL, LHQ, HL, and HW increased with the age of the animals. In multiple-regression model, HG and HL best fit the model for goat kids; HG, HW, and HL for goat aged 13–24 months; while HG, LHQ, HW, and HL best fit the model for goats aged 25–36 months. Coefficients of determination (R ²) values for linear and allometric models for predicting the live weight of WAD goat increased with age in all the body measurements, with HG being the most satisfactory single measurement in predicting the live weight of WAD goat. Sex had significant influence on the model with R ² values consistently higher in females except the models for LHQ and HW.     

Models for genetic evaluation of Nelore cattle mature body weight

Records of 18,770 Nelore animals, born from 1975 to 2002, in 8 herds participating in the Nelore Cattle Breeding Program, were analyzed to estimate genetic parameters for mature BW. The mature BW were analyzed as a single BW taken closest to 4.5 yr of age for each cow in the data file, considering BW starting from 2 (W2Y_S), 3 (W3Y_S), or 4 (W4Y_S) yr of age or as repeated records, including all BW starting from 2 (W2Y_R), 3 (W3Y_R), or 4 (W4Y_R) yr of age. The variance components were estimated by restricted maximum likelihood, fitting univariate and bivariate animal models, including weaning weight. The heritability estimates were 0.29, 0.34, 0.36, 0.41, 0.44, and 0.46 for W2Y_S, W3Y_S, W4Y_S, W2Y_R, W3Y_R, and W4Y_R, respectively. The repeatability estimates for W2Y_R, W3Y_R, and W4Y_R were 0.59, 0.64, and 0.72, respectively. Larger accuracy values associated with the EBV were obtained in the repeated records models. The results indicated the bivariate repeated records model as the most appropriate for analyzing mature BW.     

Bayesian estimates of genetic changes for body weight traits of Moghani sheep using Gibbs sampling

The objective of the present study was to estimate genetic changes of body weight at different ages in Moghani sheep. Traits included were birth weight (BW, n = 4,208), 3-month weight (3MW, n = 4,175), 6-month weight (6MW, n = 3,138), 9-month weight (9MW, n = 2,244), and yearling weight (YW, n = 1,342). Data and pedigree information used in this study were collected at the Breeding Station of Moghani sheep during 1989–2005. The analysis was carried out for five traits, using the MTGSAM program. Breeding values of individual animals were obtained from a multivariate animal model analysis and genetic trends were obtained by regressing the means of predicted breeding values on year of birth for each trait. Direct genetic trends were positive and significant (P < 0.05) for BW, 3MW, 6MW, 9MW, and YW and were 1.63, 69.20, 79.38, 66.83, and 110.22 g/year, respectively. Also, maternal genetic trends for BW, 3MW, 6MW, 9MW, and YW were positive and significant (P < 0.05) and were 2.36, 49.18, 37.33, 17.73, and 9.67 g/year, respectively. The results showed that improvement of body weights of Moghani sheep seems feasible in selection programs.     

Morphometric characterization and estimating body weight of two Algerian camel breeds using morphometric measurements

This study was carried out in order to identify the body measurements of two different Dromedary camel breeds raised in Algeria. The animal material of the study consisted of a total of 115 animals belong to Steppe (n?=?55) and Sahraoui (n?=?60) camel breeds. Eye and coat colors along with body measurements such as head length, neck length, neck girth, tail length, distance between eyes, distance between ears, body length, withers height, chest girth, and live weight were determined. Least squares means for head length, neck length, neck girth, tail length, distance between eyes, distance between ears, body length, withers height, chest girth, and live weight are found 48.2, 116.9, 65.7, 55.6, 24.1, 22.5, 152.2, 184.5, 141.2 cm, and 217.2 kg for Steppe and 48.1, 101.2, 56.2, 51.2, 23.4, 18.3, 135.6, 167.3, 176.8 cm, and 298.9 kg for Sahraoui camel breeds, respectively. The distribution of brown and black eye colors for the Steppe camel breed is as 58.2% and 41.8%, respectively, while all of the Sahraoui camels studied had a brown eye color. The proportional distribution in terms of body color included are coffee, dark coffee, and red colors for 1.8%, 83.6%, and 14.6% in the Steppe camel and 98.3%, 1.7%, and 0.0% for the Sahraoui camel, respectively. As a result, this study concluded that the withers height and chest girth could estimate the body weight in the two breeds of camels with different ages.

     

Dual-energy X-ray absorptiometry scans accurately predict differing body fat content in live sheep

Background: There is considerable interest in implementing mobile scanning technology for on-farm body composition analysis on live animals.These experiments evaluated the use of dual energy X-ray absorptiometry(DXA) as an accurate method of total body fat measurement in live sheep.Results: In Exp.1,visceral and whole body fat analysis was undertaken in sheep with body condition scores(BCS)in the range 2 to 3.25(scale 1: thin to 5: fat).The relationship of BCS was moderately correlated with visceral fat depot mass(r = 0.59,P 0.01,n = 24) and whole body fat(r = 0.70,P 0.001,n = 24).In Exp.2,sheep with BCS in the range 2.25 to 3.75 were blood sampled to analyse circulating leptin concentrations,and were DXA scanned immediately post mortem for total body fat.Plasma leptin concentrations had low correlations with BCS(r = 0.50,P 0.05,n = 17) and DXA body fat(r = 0.42,P 0.05,n = 17),and no correlation with chemical body fat(r = 0.17,P 0.05,n = 9).There was a moderate correlation between DXA body fat and BCS(r = 0.70,P 0.01,n = 17),and DXA body fat was highly correlated with chemical body fat(r = 0.81,P 0.001,n = 9).In Exp.3,a series of five DXA scans,at 8-week intervals,was performed on growing sheep over a 32-week period.The average BCS ranged from 2.39 ± 0.07(S.E.M.) to 3.05 ± 0.11 and the DXA body fat(%) ranged from 16.8 ± 0.8 to 24.2 ± 1.2.There was a moderate correlation between DXA body fat and BCS over the 32 weeks(r = 0.61,P 0.001,n = 24).Conclusions: Overall,these experiments indicated that there was good agreement between BCS,DXA and chemical analysis for measuring total body fat in sheep,and that DXA scanning is a valid method for longitudinal measurement of total body fat in live sheep.     

Relationship of body measurements and body condition score to body weight in modern Finnish Ayrshire cows

Abstract

The differences in body weight (BW) and measurements between the cows of today and the early 70s was evaluated and the usefulness of heart girth (HG), wither height, body length (BL) and body condition score (BCS) as predictors of the BW of modern Finnish Ayrshire cows was estimated. During the last three decades, the BW, HG and BL has increased indicating change in body conformation. The BW prediction equation based on early 70s data underestimate the BW of modern Ayrshire cows. Based on current data it is recommended to use different models to predict BW for primiparous and multiparous cows. From single measurements, HG predicted BW most accurately. Inclusion of BL in model gave slight improve in BW prediction, especially for primiparous cows. An additional term of age or days in milk (DIM) for primiparous cows and BCS or DIM for multiparous cows along with HG increased slightly the accuracy of BW prediction.     

澳洲白羊体质量与体尺指标的相关及回归分析

[目的]研究澳洲白羊体质量与体尺指标的相关及回归关系,为肉羊新品种选育提供参考.[方法]采用SPSS19.0软件对6月龄澳洲白羊体质量与体尺指标进行相关性分析、通径分析、逐步回归分析,并对其相关系数进行分解,得出了体质量与体尺指标之间的最优回归方程.[结果]体质量(y)与管围(x6)和胸围(x3)相关性极显著(P＜0....