RESUMO Devido às condições dos sistemas tradicionais de produção de ovinos, a avaliação do crescimento animal a partir do peso vivo (PV) é limitada pelo alto custo da balança pecuária, bem como pela sofisticada manutenção necessária. Assim, nos últimos anos, as medidas biométricas (MB) têm sido avaliadas como um método indireto e preciso para predizer o PV de animais de criação. Portanto, o objetivo desta pesquisa foi avaliar diferentes modelos de predição do PV de cordeiros em crescimento utilizando-se a fórmula do volume corporal (VC). Foram registrados dados de PV, perímetro torácico (PT) e comprimento corporal (CC) de 290 cordeiros entre dois e oito meses de idade. O VC foi calculado com base nos dados PT e CC, sendo usada uma fórmula que calcula o volume de um cilindro. A previsão do PV a partir da fórmula VC foi estimada por meio de equações de regressão, utilizando-se três modelos matemáticos (linear, quadrático e exponencial). Os valores médios do PV, PT, CC e VC dos cordeiros foram 29,12±12,04kg, 70,00±11,69cm, 38,40±6,43cm e 23,93±9,90 (dm3), respectivamente. O coeficiente de correlação entre PV e VC foi r=0,96 (P<0,001). O modelo quadrático apresentou o maior coeficiente de determinação (0,93) e o menor erro de predição (3,29kg) Nas condições do presente estudo, conclui-se que é possível predizer o peso vivo de cordeiros em crescimento por meio da fórmula de volume corporal.

ABSTRACT Due to the conditions in which traditional sheep production systems operate, the evaluation of animal growth from live weight (LW) is limited by the high cost of the livestock scale as well as the sophisticated maintenance required. In this scenario, in recent years, biometric measurements have been investigated as an accurate indirect method to predict the LW of farm animals. Therefore, the present study was undertaken to examine different models for predicting the body weight of growing lambs using the body volume (BV) formula. Body volume, heart girth (HG) and body length (BL) data of 290 lambs aged between two and eight months were recorded. Body volume was calculated from HG and BL data using a formula that calculates the volume of a cylinder. The estimation of LW from the BV formula was achieved through regression equations using three mathematical models (linear, quadratic and exponential). The mean values of LW, HG, BL and BV of the lambs were 29.12±12.04kg, 70.00±11.69cm, 38.40±6.43cm and 23.93±9.90dm3, respectively. The correlation coefficient between LW and BV was r = 0.96 (P<0.001). The quadratic model showed the highest coefficient of determination (0.93) and the lowest prediction error (3.29kg). Under the experimental conditions adopted in this study, it is possible to predict the live weight of growing lambs using the body volume formula.

Abstract The objective of the current study was to relate body mass index (BMI) and body condition score (BCS) in Pelibuey ewes in order to predict BMI based on a well-known method for estimating BCS. Body weight (BW), withers height (WH), body length (BL) and BCS were measured in 402 ewes. The relationships were investigated by regression models. The BMI and BCS had a strong relationship (r = 0.80, p < 0.001). The linear regression for predicting BMI from BCS was as follows: BMI (kg m-2) = 8.38 (± 0.189***) + 1.70 (± 0.064***) xBCS(R 2 = 0.65, MSE: 2.56, RMSE: 1.60, p < 0.0001 and n = 402). In conclusion, BMI can be used as an indicator of the degree of obesity and body fat reserves in non-pregnant and non-lactating Pelibuey ewes under field conditions.

Resumen El objetivo de este estudio fue evaluar la relación entre el índice de masa corporal (IMC) y la condición corporal (CC) en ovejas Pelibuey y predecir el IMC según una estimación conocida de la CC. El peso corporal (PV), la altura de la cruz, (AC), la longitud del cuerpo (LC) y la CC se determinaron en 402 ovejas. Las relaciones se estimaron mediante modelos de regresión. El IMC y la CC mostraron una alta relación (r = 0.80, p < 0.001). La regresión lineal para la predicción del IMC fue la siguiente: IMC (kg m-2) = 8.38 (± 0.189 ***) + 1.70 (± 0.064 ***) xCC(R 2 = 0.65, MSE: 2.56, RMSE: 1.60, p <.0001 y n = 402). El IMC podría usarse como un indicador del grado de obesidad y de las reservas corporales de grasa en ovejas Pelibuey no gestantes y no lactantes en condiciones de campo.

Abstract The present study determined the relationship between body mass index (BMI) and chemical components in Pelibuey ewes. The BMI was determined in 28 ewes. At slaughter, internal organs and blood were weighed, then were mixed and grounded. The half-carcasses were dissected into subcutaneous and intermuscular fat, muscle, and bone. The muscle and fat of each animal were ground together, and one sample of the mixture was taken. The carcass and viscera samples were freeze-dried and further analysed for crude protein (CP), fat (F), and ash (A). The relationship between BMI and body composition were estimated using correlation coefficients (r) and regression models. The r between BMI and carcass crude protein and visceral crude protein were 0.51 and 0.48, respectively (p < 0.001), and between BMI and carcass F and visceral F were 0.82 and 0.71, respectively (p < 0.0001). The r2 of the models relating to BMI and body chemical components ranged from 0.62 to 0.97. There was a quadratic relationship between total body CP, and A. The chemical carcass components (CP, F, and carcass energy [CE]) showed a linear relationship with BMI, with an r2 ranging from 0.67 to 0.96. It was concluded that BMI could be used as predictors of body chemical composition in non-pregnant and non-lactating Pelibuey ewes. The use of empty body weight for calculating BMI yielded more accurate estimates of the chemical components of the body of adult sheep.

Resumen El presente estudio tuvo como objetivo determinar la relación entre el índice de masa corporal (IMC) y los componentes químicos del cuerpo en ovejas Pelibuey. El IMC se determinó en 28 ovejas. Al sacrificio, se pesaron los órganos internos y la sangre de cada oveja y posteriormente se mezclaron y molieron. Las medias canales se diseccionaron en grasa subcutánea e intermuscular, músculo y hueso. El músculo y la grasa de cada animal se mezclaron y molieron, y se tomó una muestra. Las muestras de canal y vísceras se liofilizaron y se analizaron para proteína cruda (PC), grasa (G) y cenizas (C). Las relaciones entre el IMC y la composición corporal se estimaron mediante coeficientes de correlación (r) y modelos de regresión. Los r entre el IMC y la PC de canal y la PC visceral fueron 0.51 y 0.48, respectivamente (p < 0.001), y entre el IMC y la G en canal y la G visceral fueron 0.81 y 0.71, respectivamente (p < 0.0001). El r2 de los modelos que relacionan el IMC y la composición química del cuerpo variaron de 0.62 a 0.97. Se encontró una relación cuadrática entre la PC y la C total del cuerpo. Los componentes químicos de la canal (CP, G y energía de la canal [EC]) mostraron una relación lineal con el IMC, con un r2 entre 0.67 y 0.96. Por lo tanto, el IMC puede usarse como un predictor moderadamente preciso de la composición corporal en ovejas de pelo no gestantes y no lactantes. El uso del peso vivo vacío para calcular el IMC (IMCc) generó estimaciones más precisas de los componentes químicos del cuerpo en ovejas adultas.

ABSTRACT: 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 < 0.001). Nonetheless, correlations for LDA and CEC were not significant (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.

RESUMEN: 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 < 0.001). No obstante, las correlaciones entre ALD y CEC no fueron significativas (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.