In vivo prediction of body composition from the dilution space of the deuterium oxide in two lactating Spanish dairy breed ewes
1995
Castrillo, C. | Dapoza, C. (Universidad de Zaragoza, Facultad de Veterinaria, Zaragoza (Spain). Dept. de Produccion Animal y Ciencia de los Alimentos) | Baucells, M. (Universitat Autonoma de Barcelona, Facultad de Veterinaria, Bellaterra (Spain). Dept. de Patologia i de Produccio Animal) | Bravo, M.V (Centro de Investigacion y Mejora Agraria, Vitoria (Spain). Granja Modelo Arkaute) | Ovejero, J. (Universidad de Leon, Facultad de Veterinaria, Leon (Spain). Dept. de Produccion Animal I)
Thirteen Churra (5 forty days and 8 seventy days after lambing) and twelve Latxa (6 forty days and 6 a hundred and twenty days after lambing) lactating dairy ewes were used to obtain predicting equations of body fat, protein and energy from the live weight and the dilution space of deuterium oxide (SD2O). Churra ewes presented 2 per cent more water and 1.7 per cent less protein in the fat tree empty body 40 days than 70 days after lambing (P less than 0.01) and fat free empty body water content decreased linearly (R = -0.60) with empty body fat content. There was however a close negative relationship (R2 = 0.97) between fat and water content of fleece free body weight. Neither breed nor stage of lactation significantly affect this relationship. Body water was predicted from SD2O with a residual standard deviation (RSD) of approximately 1 kg when a pool equation was considered, though for a same SD2O, Latxa ewes presented 1.76 kg more water than Churra ewes. Body fat and energy were predicted from live weight and measured body water with a RSD of 0.437 kg and 6.85 Mcal, respectively, when a pool equation was considered. The adjusted means of body energy differed significantly between breeds and when this effect was taken into account the RSD diminished to 3.10 Mcal. When SD2O was substituted for measured body water, resulting RSD were 0.980 kg and 6.85 Mcal, respectively. The intercept of the prediction equation of body fat differed significantly between breeds and when this effect was taken into account RSD decreased to 0,703 kg. The accuracy of body protein prediction from ewes sheared body weight (RSD = 0.569 kg from the pool equation and 0.282 kg for equation taking into account the breed effect) was not improved by the inclusion of SD2O as a second predictive variable. The stage of lactation did not significantly affect any of the equations studied.
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