[Music] so the second aspect of the net energy measurements is to get estimates or values for fasting reproduction a very popular technique that was used in the past was consisted in measuring reproduction at variable amine intakes and extrapolating the heat production for 0m intake so you get a so-called regression reproduction which corresponds to the fasting reproduction that is illustrated on that figure for cars which will fed different energy levels but for these cars if we also measure their fasting reproduction during the trial you can see that the fasting reproduction that is directly measured on the animal first is much higher than the fasting reproduction obtained by the regression method and is also variable it is as high as the feeding level is high which means that overall the heat increment which we are looking for is dependent on the technology or the metal we use for evaluating fasting and production clearly the best estimate is obtained according to actually measured fasting reproduction and the so-called regression fasting reproduction is producing an estimate of the flooding fasting reproduction which is about almost meaningless and which means that the heat increment obtained according to that methodology is also meaningless so that technology is used with variable amine intakes but i think i'm pretty sure that it shouldn't be used anymore in the future since it provides very strange data meaning less data the second method uh for fasting reproduction is to measure directly the anu the heat production on animals i will not detail all this aspect but that should be done very carefully by taking attack into account the duration of the fast the physical activity of the animals and the different calculation methods and so on but some data are available now and there is no problem for that but one further question when we talk about fasting reproduction is the way of its expression usually in the past fasting reproduction was considered as relatively constant per unit of metabolic body weight the metabolic body weight being historically considered as body weight with a 0.75 exponent which means that the fasting reproduction was proportional to body weight 0.75 but clearly all literature data from over obtained over the last 30 years or 20 years at least uh indicate that the so-called metabolic body weight 0.75 is no more applicable to growing animals it is okay for adults but not for growing and for instance that figure shows that it could it should be something like 0.70 in broilers we have shown as well that it is something equivalent 0.70 for turkeys but it should be something equivalent to 0.60 for pigs and it is even much higher 0.85 for veal calves so fasting reproduction in growing animals is not any more proportional to body weight 0.75 and i think there is some there is a lot of information now providing fasting reproduction values for growing animals and these values could be used in the future you