Relationship between body weight and body condition score with energy content in the carcass of Pelibuey ewes

The determination of energy content in the carcass and body of domestic animals by direct method involves very intensive work and it is costly. The aim of this study was to evaluate the relationship between body weight (BW) and body condition score (BCS) with the energy content of muscular and adipose tissues of adult Pelibuey ewes. Twenty two adult non-pregnant, nonlactatingewes of 35.63 ± 5.03 kg BW and 2.47±0.55 BCS were used. The correlation coefficients (r) of BCS between muscle energy (ME), fat energy (FE) and total energy (TE) were all significant (P<0.01) with values of 0.64, 0.66 and 0.69, respectively, while for BW between ME, FE and TE they were all significant (P<0.001) with values of 0.90, 0.76 and 0.89, respectively. The regression equations had high determination coefficients (r2) ranging from 0.87 to 0.94 when BCS was used as predictor, while using the BW the r2 ranged from 0.59 to 0.83. The inclusion of both BW and BCS in multiple regressions improved the prediction from 2 to 7%; nonetheless, the inclusion of BCS only was significant in the equation for TE. The use of BCS and BW in Pelibuey ewes provides a good estimate of the ME, TE and FE of the carcass

Relationships between body mass index, ultrasound measurements and, internal body fat depots in pelibuey sheep

The objective of this study was to evaluate the relationship between body mass index (BMI), ultrasound measurements (USM), and internal fat (IF) in hair sheep. The BMI and USM were determined 24 hours before laughter in 35 animals finished in intensive fattening. At slaughter, the IF (inner adipose tissue) was dissected, weighed, and grouped as mesenteric, omental, or perirenal fat; these three depots were summed to obtain their total weight. The relationship of the variables was evaluated through Pearson's correlation coefficient (r) using the CORR procedure and by regression models using the REG procedure of SAS ver. 9.3. The IF and BMI presented r= 0.75 (P 0.05). The regression equation between IF and BMI had a coefficient of determination (r2) of 0.67 (P <.0001). The inclusion of the subcutaneous fat thickness together with the BMI improved the r2 with a range of 0.77. The BMI and the subcutaneous fat thickness could be used to predict the weight of the internal fat in hair sheep

Prediction of carcass energy content of Pelibuey ewes by ultrasound measurements

The aim of this study was to evalúate the relationship between body ultrasound measurements (USM) and carcass energy content (CEC) of Pelibuey ewes. USM were taken 24 h before slaughter in twenty-two ewes. Fat thickness (FT) and Longissimus dorsi area (LDA) were determined in the thoracic (TFT and TLDA) and lumbar región (LFT and LLDA). CEC was considered as the sum of the energy of muscle and adipose tissues in the carcass. The correlation coefficient (r) between body weight (BW) and CEC was 0.89 (p 0.05). The r2 for equation including BW and LFT was 0.87 (RSD= 15.34). The inclusión of LFT improved the prediction by about 8 %. The use of some USM in combination with BW provides good CEC estimates in Pelibuey ewes.El objetivo fue evaluar la relación entre mediciones corporales por ultrasonido (MUS) y el contenido de energía de la canal (CEC) de ovejas Pelibuey. Las MUS se registraron 24 h antes del sacrificio en 22 ovejas. El espesor de grasa (EG) y el área del Longissimus dorsi (ALD) fueron determinados en la región torácica (EGT y ALDT) y lumbar (EGL y ALDL). El CEC se consideró como la suma de la energía del tejido muscular y adiposo en la canal. El coeficiente de correlación (r) entre el peso vivo (PV) y CEC fue de 0.89 (p 0.05). La ecuación que incluyó al PV y EGL, tuvo una r2 de 0.87. La inclusión de EGL mejoró la predicción en un 8 %. El uso de algunas MUS en combinación con el PV en ovejas Pelibuey proporciona buenas estimaciones del CEC

COMPARISON BETWEEN VISUAL ASSESSMENT AND MEASUREMENT OF HEART GIRTH OR HIP-WIDTH TO ESTIMATE LIVE WEIGHT IN CROSSBRED BEEF HEIFERS

Background. Estimation of animal body weight (BW) is a fundamental tool in herd management for the development of reproductive, nutritional and health programmes. Objective. To compare the actual BW and its estimation by visual method and measurement of the heart girth (HG) or hip width (HW) for estimating BW in crossbred beef heifers reared under humid tropical conditions in Mexico. Methodology. Data on GH, HW, BW estimated by the visual method (MV) and actual BW were recorded in 105 crossbred replacement heifers (Bos taurus × Bos indicus) Swiss American, Beef Master, Simmental, and Brahman with different degrees of crossbreeding. Heifers ranged in age from three to 20 months and were grazed on star grass (Cynodon nlemfuensis) and humidicola grass (Brachiaria humidicola) pastures without supplementation. BW was recorded using a digital scale, HG was measured using a flexible fibreglass tape and HW was measured using a 65 cm forceps. BW by visual estimation was considered as the average of three observations made by three observers, HG and HW methods using the formula 1) BW (kg): 202.68 - 4.39 × HG + 0.03 × HG2; 2) BW (kg): 0.26 × HW1.90. The Pearson coefficient and the distribution (density) of each variable, were assessed using a correlation matrix graph. Also, a comparison the measures obtained by each of the different estimation methods with the observed weights, by inspecting the paired Bland-Altman plots, prior to logarithmic transformation. Results. Correlations between observed BW and predicted BW for the HG, HW and visual methods showed a positive and significant relationship (P<0.001), with r values of 0.95, 0.89 and 0.92, respectively. The HG method tended to overestimate the real BW, whereas, in the visual and HW methods, the values are evenly and randomly distributed around the line, indicating that these methods neither underestimated nor overestimated the BW. Implications. Although the HG method showed the highest correlation coefficient between observed and predicted BW, the result of the present study showed that visual assessment highlights the ability of observers to visually estimate the BW of growing heifers. Conclusion. Livestock handlers have a very accurate estimation of BW. The use of alternative methods to scales, such as the HG measuring method, can be useful and practical tools to improve the accuracy of the assessment

EQUATIONS FOR BODY WEIGHT ADJUSTMENTS IN BLACK BELLY EWE LAMBS

Background. As body weight (BW) is rarely determined on fasted animals in most production systems, the need to develop accurate mathematical models for adjusting BW has been identified. Objective. To evaluate models for estimating shrunk body weight (SBW) and empty body weight (EBW) in Black Belly growing ewe lambs raised in tropical conditions. Methodology. Data of sixty Black Belly ewe lambs, between four to eight months of age with a mean BW of 26.55± 3.92 kg (± SD) were used. The SBW was estimated based on the BW without fasting (fed) and the EBW based on SBW through three models: 1. Linear; 2.-Linear without intercept and 3.- Exponential. The predictive capacity of the models was evaluated by cross-validation. Results. The correlation coefficients between BW and SBW and SB and EBW were high (r = 0.94; <0.0001). The coefficients of determination (r2) for the equations between BW and SBW were 0.89 (P<0.001); and 0.86 (P<0.001) for the relationship between SBW and EBW. Based on the AIC (26.81) Eq. 2 described the relationship between BW and SBW better than Eq. 1, (AIC = 28.44) and Eq. 3 (AIC =28.35). The final model to estimate SBW as a function of BW was: SBW (kg): 0.96 (±0.001***) × BW. With respect to the SBW and EBW ratio, Equation 5, was better than the linear Eq. 4, (AIC = 33.01) and Eq. 6 (AIC = 33.35). The following model was: EBW (kg): 0.81 (± 0.06***) × SBW. The cross-validation of the equation of the relationship between BW and SBW showed that Eq. 1 had a higher r2 (0.87), and lower RMSEP and MAE than Eq. 2 and Eq. 3. Also, the equation of the relationship between SBW and EBW the cross-validation revealed that Eqs. 4 and 6 had the higher r2 (0.82), and lower RMSEP and MAE and tended to be more accurate than Eq. 5. Implications. The results obtained in present study contributes to the development of mathematical models for more accurate body weight adjustments in tropical sheep. Conclusion. The equations developed and evaluated in the present study revealed that the linear relationship between BW and SBW, and the linear and exponential relationship between SBW and EBW can be used to body weight adjustments in growing Black Belly ewe lambs. It's worth noting that this confirms that the SBW can be calculated using an adjustment factor of 0.96 FBW

Prediction of carcass energy content of Pelibuey ewes by ultrasound measurements/ Predicción del contenido de energético de la canal de ovejas Pelibuey por mediciones de ultrasonido

The aim of this study was to evaluate the relationship between body ultrasound measurements (USM) and carcass energy content (CEC) of Pelibuey ewes. USM were taken 24 h before slaughter in twenty-two ewes. Fat thickness (FT) and Longissimus dorsi area (LDA) were determined in the thoracic (TFT and TLDA) and lumbar region (LFT and LLDA). CEC was considered as the sum of the energy of muscle and adipose tissues in the carcass. The correlation coecient (r) between body weight (BW) and CEC was 0.89 (p < 0.001). Nonetheless, correlations for LDA and CEC were not signicant (p > 0.05). The r2 for equation including BW and LFT was 0.87 (RSD= 15.34). The inclusion of LFT improved the prediction by about 8 %. The use of some USM in combination with BW provides good CEC estimates in Pelibuey ewe